Myocardial bridging: Difference between revisions

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__NOTOC__
__NOTOC__
{{SI}}
{{Coronary angiography2}}
{{CMG}}; {{AOEIC}} {{CZ}}; {{LG}}; '''Assistant Editor-In-Chief:''' Meagan Doherty, B.S.
{{CMG}}; {{AE}} {{Rim}}
 
{{SK}} myocardial bridge, coronary bridge, coronary artery bridge, coronary bridging, coronary artery bridging


==Overview==
==Overview==
A myocardial bridge or MB is defined as a segment of a major [[coronary artery|coronary]] [[epicardial]] [[artery]] that "tunnels" or passes intramurally through the [[myocardium]] beneath the muscle bridge during [[systole]].<ref name="pmid15764618">{{cite journal |author=Alegria JR, Herrmann J, Holmes DR, Lerman A, Rihal CS |title=Myocardial bridging |journal=[[European Heart Journal]] |volume=26 |issue=12 |pages=1159–68 |year=2005 |month=June |pmid=15764618 |doi=10.1093/eurheartj/ehi203 |url=http://eurheartj.oxfordjournals.org/cgi/pmidlookup?view=long&pmid=15764618 |accessdate=2012-07-01}}</ref><ref name="pmid12427660">{{cite journal |author=Möhlenkamp S, Hort W, Ge J, Erbel R |title=Update on myocardial bridging |journal=[[Circulation]] |volume=106 |issue=20 |pages=2616–22 |year=2002 |month=November |pmid=12427660 |doi= |url=http://circ.ahajournals.org/cgi/pmidlookup?view=long&pmid=12427660 |accessdate=2012-07-01}}</ref> Myocardial bridges are generally located in the distribution of the [[left anterior descending artery]] ([[LAD]]) and its [[diagonal branch]]es.
 
A myocardial bridge is defined as a segment of a major [[coronary artery|coronary]] [[epicardial]] [[artery]] that "tunnels" or passes intramurally through the [[myocardium]] beneath the muscle bridge during [[systole]].<ref name="pmid15764618">{{cite journal |author=Alegria JR, Herrmann J, Holmes DR, Lerman A, Rihal CS |title=Myocardial bridging |journal=[[European Heart Journal]] |volume=26 |issue=12 |pages=1159–68 |year=2005 |month=June |pmid=15764618 |doi=10.1093/eurheartj/ehi203 |url=http://eurheartj.oxfordjournals.org/cgi/pmidlookup?view=long&pmid=15764618 |accessdate=2012-07-01}}</ref><ref name="pmid12427660">{{cite journal |author=Möhlenkamp S, Hort W, Ge J, Erbel R |title=Update on myocardial bridging |journal=[[Circulation]] |volume=106 |issue=20 |pages=2616–22 |year=2002 |month=November |pmid=12427660 |doi= |url=http://circ.ahajournals.org/cgi/pmidlookup?view=long&pmid=12427660 |accessdate=2012-07-01}}</ref> Myocardial bridges are generally located in the distribution of the [[left anterior descending artery]] ([[LAD]]) and its [[diagonal branch]]es.
 
Myocardial bridging should be distinguished from ''intramyocardial course'', which is an inborn coronary anomaly defined as a segment of a major epicardial coronary artery running and ending in the myocardium.
 
==Historical Perspective==
==Historical Perspective==
[[Angiographic]]ally, myocardial bridging was first recognized in the 1960's.<ref>Reyman, HC. Disertatis de vasis cordis propiis. Bibl Anat. 1737; 2:366.</ref>
[[Angiographic]]ally, myocardial bridging was first recognized in the 1960's.<ref>Reyman, HC. Disertatis de vasis cordis propiis. Bibl Anat. 1737; 2:366.</ref>
==Pathophysiology==
==Pathophysiology==
====Variants====
====Variants====
There are two basic morphologic variants:
There are two basic morphologic variants:
*Deep variant
*Deep variant
*[[Superficial]] variant
*[[Superficial]] variant
====Extent====
====Extent====
Majority of the cases, [[systolic]] bridging is usually not severe or extensive and completely reverses during [[diastole]]; except in patients with [[HOCM]], wherein severe [[systolic]] bridging of the [[septal]] perforators may be a predisposing factor to the development of [[myocardial ischemia]].<ref name="pmid307341">{{cite journal |author=Faruqui AM, Maloy WC, Felner JM, Schlant RC, Logan WD, Symbas P |title=Symptomatic myocardial bridging of coronary artery |journal=[[The American Journal of Cardiology]] |volume=41 |issue=7 |pages=1305–10 |year=1978 |month=June |pmid=307341 |doi= |url= |accessdate=2012-07-01}}</ref><ref name="pmid7397963">{{cite journal |author=Morales AR, Romanelli R, Boucek RJ |title=The mural left anterior descending coronary artery, strenuous exercise and sudden death |journal=[[Circulation]] |volume=62 |issue=2 |pages=230–7 |year=1980 |month=August |pmid=7397963 |doi= |url=http://circ.ahajournals.org/cgi/pmidlookup?view=long&pmid=7397963 |accessdate=2012-07-01}}</ref><ref name="pmid19620504">{{cite journal |author=Ishikawa Y, Akasaka Y, Suzuki K, Fujiwara M, Ogawa T, Yamazaki K, Niino H, Tanaka M, Ogata K, Morinaga S, Ebihara Y, Kawahara Y, Sugiura H, Takimoto T, Komatsu A, Shinagawa T, Taki K, Satoh H, Yamada K, Yanagida-Iida M, Shimokawa R, Shimada K, Nishimura C, Ito K, Ishii T |title=Anatomic properties of myocardial bridge predisposing to myocardial infarction |journal=[[Circulation]] |volume=120 |issue=5 |pages=376–83 |year=2009 |month=August |pmid=19620504 |doi=10.1161/CIRCULATIONAHA.108.820720 |url=http://circ.ahajournals.org/cgi/pmidlookup?view=long&pmid=19620504 |accessdate=2012-07-01}}</ref><ref name="pmid19914131">{{cite journal |author=Utuk O, Bilge A, Bayturan O, Tikiz H, Tavli T, Tezcan U |title=Thrombosis of a coronary artery related to the myocardial bridging |journal=[[Heart, Lung & Circulation]] |volume=19 |issue=8 |pages=481–2 |year=2010 |month=August |pmid=19914131 |doi=10.1016/j.hlc.2009.08.006 |url=http://linkinghub.elsevier.com/retrieve/pii/S1443-9506(09)01052-X |accessdate=2012-07-01}}</ref><ref name="pmid21448858">{{cite journal |author=Hostiuc S, Curca GC, Dermengiu D, Dermengiu S, Hostiuc M, Rusu MC |title=Morphological changes associated with hemodynamically significant myocardial bridges in sudden cardiac death |journal=[[The Thoracic and Cardiovascular Surgeon]] |volume=59 |issue=7 |pages=393–8 |year=2011 |month=October |pmid=21448858 |doi=10.1055/s-0030-1270703 |url=http://www.thieme-connect.com/DOI/DOI?10.1055/s-0030-1270703 |accessdate=2012-07-01}}</ref><ref name="pmid21123275">{{cite journal |author=Husmann L, Nkoulou R, Wolfrum M, Kaufmann PA |title=Myocardial bridging causing infarction and ischaemia |journal=[[European Heart Journal]] |volume=32 |issue=7 |pages=790 |year=2011 |month=April |pmid=21123275 |doi=10.1093/eurheartj/ehq423 |url=http://eurheartj.oxfordjournals.org/cgi/pmidlookup?view=long&pmid=21123275 |accessdate=2012-07-01}}</ref>
Majority of the cases, [[systolic]] bridging is usually not severe or extensive and completely reverses during [[diastole]]; except in patients with [[HOCM]], wherein severe [[systolic]] bridging of the [[septal]] perforators may be a predisposing factor to the development of [[myocardial ischemia]].<ref name="pmid307341">{{cite journal |author=Faruqui AM, Maloy WC, Felner JM, Schlant RC, Logan WD, Symbas P |title=Symptomatic myocardial bridging of coronary artery |journal=[[The American Journal of Cardiology]] |volume=41 |issue=7 |pages=1305–10 |year=1978 |month=June |pmid=307341 |doi= |url= |accessdate=2012-07-01}}</ref><ref name="pmid7397963">{{cite journal |author=Morales AR, Romanelli R, Boucek RJ |title=The mural left anterior descending coronary artery, strenuous exercise and sudden death |journal=[[Circulation]] |volume=62 |issue=2 |pages=230–7 |year=1980 |month=August |pmid=7397963 |doi= |url=http://circ.ahajournals.org/cgi/pmidlookup?view=long&pmid=7397963 |accessdate=2012-07-01}}</ref><ref name="pmid19620504">{{cite journal |author=Ishikawa Y, Akasaka Y, Suzuki K, Fujiwara M, Ogawa T, Yamazaki K, Niino H, Tanaka M, Ogata K, Morinaga S, Ebihara Y, Kawahara Y, Sugiura H, Takimoto T, Komatsu A, Shinagawa T, Taki K, Satoh H, Yamada K, Yanagida-Iida M, Shimokawa R, Shimada K, Nishimura C, Ito K, Ishii T |title=Anatomic properties of myocardial bridge predisposing to myocardial infarction |journal=[[Circulation]] |volume=120 |issue=5 |pages=376–83 |year=2009 |month=August |pmid=19620504 |doi=10.1161/CIRCULATIONAHA.108.820720 |url=http://circ.ahajournals.org/cgi/pmidlookup?view=long&pmid=19620504 |accessdate=2012-07-01}}</ref><ref name="pmid19914131">{{cite journal |author=Utuk O, Bilge A, Bayturan O, Tikiz H, Tavli T, Tezcan U |title=Thrombosis of a coronary artery related to the myocardial bridging |journal=[[Heart, Lung & Circulation]] |volume=19 |issue=8 |pages=481–2 |year=2010 |month=August |pmid=19914131 |doi=10.1016/j.hlc.2009.08.006 |url=http://linkinghub.elsevier.com/retrieve/pii/S1443-9506(09)01052-X |accessdate=2012-07-01}}</ref><ref name="pmid21448858">{{cite journal |author=Hostiuc S, Curca GC, Dermengiu D, Dermengiu S, Hostiuc M, Rusu MC |title=Morphological changes associated with hemodynamically significant myocardial bridges in sudden cardiac death |journal=[[The Thoracic and Cardiovascular Surgeon]] |volume=59 |issue=7 |pages=393–8 |year=2011 |month=October |pmid=21448858 |doi=10.1055/s-0030-1270703 |url=http://www.thieme-connect.com/DOI/DOI?10.1055/s-0030-1270703 |accessdate=2012-07-01}}</ref><ref name="pmid21123275">{{cite journal |author=Husmann L, Nkoulou R, Wolfrum M, Kaufmann PA |title=Myocardial bridging causing infarction and ischaemia |journal=[[European Heart Journal]] |volume=32 |issue=7 |pages=790 |year=2011 |month=April |pmid=21123275 |doi=10.1093/eurheartj/ehq423 |url=http://eurheartj.oxfordjournals.org/cgi/pmidlookup?view=long&pmid=21123275 |accessdate=2012-07-01}}</ref>


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==Natural History, Complications and Prognosis==  
==Natural History, Complications and Prognosis==  
===Complications===
===Complications===
[[Complication]]s of [[myocardial]] bridging include the following:
[[Complication]]s of [[myocardial]] bridging include the following:
*[[Ischemia]] and [[acute coronary syndromes]],
 
*[[Coronary artery spasm]],
* [[Angina]] and [[ischemia]]
*[[Ventricular septal rupture]],
* [[Acute coronary syndromes]] if there is plaque rupture in or adjacent to the myocardial bridge
*[[Arrythmias]],
* [[Coronary artery spasm]]
*Exercise-induced [[AV block|atrioventricular conduction block]],
* [[Ventricular septal rupture]]
*[[Myocardial stunning]],
* [[Arrythmias]]
*Transient [[ventricular dysfunction]],
* Exercise-induced [[AV block|atrioventricular conduction block]]
*Early death after [[cardiac transplantation]] and
* [[Myocardial stunning]]
*[[Sudden cardiac death]].
* Transient [[ventricular dysfunction]]
* Early death after [[cardiac transplantation]]
* [[Sudden cardiac death]]


===Prognosis===
===Prognosis===
The combined presence of [[hypertrophic cardiomyopathy]] and [[myocardial]] bridging is associated with a worse [[prognosis]] as compared to [[hypertrophic cardiomyopathy]] alone<ref name="pmid9780340">{{cite journal |author=Yetman AT, McCrindle BW, MacDonald C, Freedom RM, Gow R |title=Myocardial bridging in children with hypertrophic cardiomyopathy--a risk factor for sudden death |journal=[[The New England Journal of Medicine]] |volume=339 |issue=17 |pages=1201–9 |year=1998 |month=October |pmid=9780340 |doi=10.1056/NEJM199810223391704 |url=http://dx.doi.org/10.1056/NEJM199810223391704 |accessdate=2012-07-01}}</ref>.
The combined presence of [[hypertrophic cardiomyopathy]] and [[myocardial]] bridging is associated with a worse [[prognosis]] as compared to [[hypertrophic cardiomyopathy]] alone<ref name="pmid9780340">{{cite journal |author=Yetman AT, McCrindle BW, MacDonald C, Freedom RM, Gow R |title=Myocardial bridging in children with hypertrophic cardiomyopathy--a risk factor for sudden death |journal=[[The New England Journal of Medicine]] |volume=339 |issue=17 |pages=1201–9 |year=1998 |month=October |pmid=9780340 |doi=10.1056/NEJM199810223391704 |url=http://dx.doi.org/10.1056/NEJM199810223391704 |accessdate=2012-07-01}}</ref>.


==Diagnosis==
==Diagnosis==
===Coronary Angiography===
===Coronary Angiography===
*[[Systolic]] narrowing of the [[epicardial]] [[artery]] with complete reversal during [[diasole]].<ref name="pmid15764618">{{cite journal |author=Alegria JR, Herrmann J, Holmes DR, Lerman A, Rihal CS |title=Myocardial bridging |journal=[[European Heart Journal]] |volume=26 |issue=12 |pages=1159–68 |year=2005 |month=June |pmid=15764618 |doi=10.1093/eurheartj/ehi203 |url=http://eurheartj.oxfordjournals.org/cgi/pmidlookup?view=long&pmid=15764618 |accessdate=2012-07-01}}</ref>
*[[Angiographic]] manifestation depends on:<ref name="pmid15764618">{{cite journal |author=Alegria JR, Herrmann J, Holmes DR, Lerman A, Rihal CS |title=Myocardial bridging |journal=[[European Heart Journal]] |volume=26 |issue=12 |pages=1159–68 |year=2005 |month=June |pmid=15764618 |doi=10.1093/eurheartj/ehi203 |url=http://eurheartj.oxfordjournals.org/cgi/pmidlookup?view=long&pmid=15764618 |accessdate=2012-07-01}}</ref>
**Thickness and length of [[myocardial]] bridge,
**Reciprocal orientation of the [[coronary artery]] and [[myocardial]] fibers,
**Presence of loose [[connective tissue]] or [[adipose tissue]] around the bridged segment,
**Presence of an [[left ventricular outflow tract obstruction|aortic outflow tract obstruction]],
**Intrinsic tone of the wall of the [[coronary artery]],
**Presence of a [[proximal]] [[coronary artery|coronary]] fixed obstruction and
**State of [[myocardial]] [[contractility]].
*[[Nitroglycerine]] provocation to demonstrate [[systolic]] bridging may be employed in patients with [[exertional angina]]. 


=====Examples of Myocardial Bridging=====
* [[Systolic]] narrowing of the [[epicardial]] [[artery]] with complete reversal during [[diastole]].<ref name="pmid15764618">{{cite journal |author=Alegria JR, Herrmann J, Holmes DR, Lerman A, Rihal CS |title=Myocardial bridging |journal=[[European Heart Journal]] |volume=26 |issue=12 |pages=1159–68 |year=2005 |month=June |pmid=15764618 |doi=10.1093/eurheartj/ehi203 |url=http://eurheartj.oxfordjournals.org/cgi/pmidlookup?view=long&pmid=15764618 |accessdate=2012-07-01}}</ref>
Shown below is an image depicting myocardial bridge.  Note the narrowing of the coronary artery diameter during systole compared to its diameter in diastole.
* [[Angiographic]] manifestation depends on:<ref name="pmid15764618">{{cite journal |author=Alegria JR, Herrmann J, Holmes DR, Lerman A, Rihal CS |title=Myocardial bridging |journal=[[European Heart Journal]] |volume=26 |issue=12 |pages=1159–68 |year=2005 |month=June |pmid=15764618 |doi=10.1093/eurheartj/ehi203 |url=http://eurheartj.oxfordjournals.org/cgi/pmidlookup?view=long&pmid=15764618 |accessdate=2012-07-01}}</ref>
[[Image:Myocardial bridge.gif]]
** Thickness and length of [[myocardial]] bridge
<br clear="left"/>
** Reciprocal orientation of the [[coronary artery]] and [[myocardial]] fibers
[[C. Michael Gibson|Copyleft Image courtesy of C. Michael Gibson MS. MD.]]
** Presence of loose [[connective tissue]] or [[adipose tissue]] around the bridged segment
<br clear="left"/>
** Presence of an [[left ventricular outflow tract obstruction|aortic outflow tract obstruction]]
** Intrinsic tone of the wall of the [[coronary artery]]
** Presence of a [[proximal]] [[coronary artery|coronary]] fixed obstruction
** State of [[myocardial]] [[contractility]]
* [[Nitroglycerine]] provocation to demonstrate [[systolic]] bridging may be employed in patients with exertional [[angina]]
 
=====Case 1=====


Click '''[[Coronary angiography myocardial bridge|here]]''' to view more angiography examples of myocardial bridge.
Shown below is an animated image depicting myocardial bridge.
 
[[Image:Myocardial-Bridging.gif|300px| Myocardial bridging]]
 
----
 
Shown below are two static images of the same case depicting myocardial bridge.  Outlined with yellow in the image on the left is the part of the coronary artery during diastole.  This same part of the coronary artery is outlined in yellow in the image on the right during systole; note that this outlined part is narrowed compared to its shape during diastole.
 
[[Image:Myocardial bridging static 1.gif|300px| Shape of the coronary artery during diastole]]
[[Image:Myocardial-Bridging-Static-2.gif|300px| The coronary artery is narrowed during systole which is consistent myocardial bridging.]]
 
----
 
=====Case 2=====
 
Shown below are an animated image and a static image depicting myocardial bridge.
 
[[Image:Myocardial-bridge-case-01.gif|300px| Myocardial bridging]]
[[Image:Myocardial-bridge-case-01-static.gif|300px| Myocardial bridging]]


===Intracoronary ultrasound===
===Intracoronary ultrasound===
*Half moon phenomenon: caused by [[adipose tissue]] that is surrounding the bridged segment of the [[artery]] <ref>Möhlenkamp S, Hort W, Ge J, Erbel R. Update on myocardial bridging.Circulation. 2002;106:2616 –2622. </ref>
 
*[[Ultrasound]] images have shown that in patients with [[myocardial]] bridging there is delayed relaxation of the [[artery]] in early [[diastole]].<ref> Erbel R, Rupprecht HJ, Ge J, Gerber T, Görge G, Meyer J. Coronary artery shape and flow changes induced by myocardial bridging. Echocardiography. 1993;1:71–77.]</ref>. This may reduce [[coronary artery|coronary]] [[vasodilator]] reserve.<ref>Rouleau JL, Chuck LH, Hollosi G, Kidd P, Sievers RE, Wikman Coffelt J, Parmley WW. Verapamil preserves myocardial contractility in the hereditary cardiomyopathy of the Syrian hamster. Circ Res. 1982;50:405–412. </ref>
* Half moon phenomenon: caused by [[adipose tissue]] that is surrounding the bridged segment of the [[artery]] <ref>Möhlenkamp S, Hort W, Ge J, Erbel R. Update on myocardial bridging.Circulation. 2002;106:2616 –2622. </ref>
*An impaired [[coronary flow reserve]] has also been noted in patients with [[myocardial]] bridging. This can be corrected with [[Intracoronary Stenting|intracoronary stent implantation]].<ref> Klues HG, Schwarz ER, vom Dahl J, Reffelmann T, Reul H, Potthast K, Schmitz C, Minartz J, Krebs W, Hanrath P. Disturbed intracoronary hemodynamics in myocardial bridging: early normalization by intracoronary stent placement. Circulation. 1997;96:2905–2913.</ref><ref> Jeremias A, Haude M, Ge J, Görge G, Liu F, Konorza T, Erbel R. Emergency stent implantation in the area of extensive muscle bridging of the anterior interventricular ramus after post-interventional dissection [in German]. Z Kardiol. 1997;86:367–372. </ref>
* [[Ultrasound]] images have shown that in patients with [[myocardial]] bridging there is delayed relaxation of the [[artery]] in early [[diastole]].<ref> Erbel R, Rupprecht HJ, Ge J, Gerber T, Görge G, Meyer J. Coronary artery shape and flow changes induced by myocardial bridging. Echocardiography. 1993;1:71–77.]</ref>. This may reduce [[coronary artery|coronary]] [[vasodilator]] reserve.<ref>Rouleau JL, Chuck LH, Hollosi G, Kidd P, Sievers RE, Wikman Coffelt J, Parmley WW. Verapamil preserves myocardial contractility in the hereditary cardiomyopathy of the Syrian hamster. Circ Res. 1982;50:405–412. </ref>
*[[Intracoronary ultrasound]] demonstrates that although many times the bridged section of the [[artery]] was free of disease, [[plaque]]s were found next to the bridged fragment of the [[artery]].<ref> Ge J, Erbel R, Görge G, Haude M, Meyer J. High wall shear stress proximal to myocardial bridging and atherosclerosis: intracoronary ultrasound and pressure measurements. Br Heart J. 1995;73:462– 465.] </ref>
* An impaired [[coronary flow reserve]] has also been noted in patients with [[myocardial]] bridging. This can be corrected with [[Intracoronary Stenting|intracoronary stent implantation]].<ref> Klues HG, Schwarz ER, vom Dahl J, Reffelmann T, Reul H, Potthast K, Schmitz C, Minartz J, Krebs W, Hanrath P. Disturbed intracoronary hemodynamics in myocardial bridging: early normalization by intracoronary stent placement. Circulation. 1997;96:2905–2913.</ref><ref> Jeremias A, Haude M, Ge J, Görge G, Liu F, Konorza T, Erbel R. Emergency stent implantation in the area of extensive muscle bridging of the anterior interventricular ramus after post-interventional dissection [in German]. Z Kardiol. 1997;86:367–372. </ref>
*Echolucent half moon phenomenon over the bridge segment.
* [[Intracoronary ultrasound]] demonstrates that although many times the bridged section of the [[artery]] was free of disease, [[plaque]]s were found next to the bridged fragment of the [[artery]].<ref> Ge J, Erbel R, Görge G, Haude M, Meyer J. High wall shear stress proximal to myocardial bridging and atherosclerosis: intracoronary ultrasound and pressure measurements. Br Heart J. 1995;73:462– 465.] </ref>
*[[Systolic]] compression of the bridge segment of the [[coronary artery]].
* Echolucent half moon phenomenon over the bridge segment.
*Retrograde flow in the [[proximal]] segment ([[systolic]] flow reversal).
* [[Systolic]] compression of the bridge segment of the [[coronary artery]].
*Accelerated flow velocity at early [[diastole]] (Finger-tip phenomenon).
* Retrograde flow in the [[proximal]] segment ([[systolic]] flow reversal).
*No or reduced [[systolic]] antegrade flow.
* Accelerated flow velocity at early [[diastole]] (Finger-tip phenomenon).
*Decreased [[diastolic]]/[[systolic]] velocity ratio.
* No or reduced [[systolic]] antegrade flow.
* Decreased [[diastolic]]/[[systolic]] velocity ratio.


==Treatment==
==Treatment==
===Medical Treatment===
===Medical Treatment===
* [[Beta Blocker]]s.
 
* [[Calcium channel blocker]]s (preferably non-[[dihydropyridine]]s).
* [[Calcium channel blocker]]s (preferably non-[[dihydropyridine]]s)
* [[Nitrates]] are contra-indicated because reduction in [[preload]] causes reflex [[sympathetic]] stimulation.<ref name="pmid15764618">{{cite journal |author=Alegria JR, Herrmann J, Holmes DR, Lerman A, Rihal CS |title=Myocardial bridging |journal=[[European Heart Journal]] |volume=26 |issue=12 |pages=1159–68 |year=2005 |month=June |pmid=15764618 |doi=10.1093/eurheartj/ehi203 |url=http://eurheartj.oxfordjournals.org/cgi/pmidlookup?view=long&pmid=15764618 |accessdate=2012-07-01}}</ref>
* [[Beta Blocker]]s may reduce contractility, but they may also increase [[coronary spasm]] by blocking beta mediated vascular relaxation
* [[Nitrates]] are contra-indicated because reduction in [[preload]] may cause reflex [[sympathetic]] stimulation and tachcardia.<ref name="pmid15764618">{{cite journal |author=Alegria JR, Herrmann J, Holmes DR, Lerman A, Rihal CS |title=Myocardial bridging |journal=[[European Heart Journal]] |volume=26 |issue=12 |pages=1159–68 |year=2005 |month=June |pmid=15764618 |doi=10.1093/eurheartj/ehi203 |url=http://eurheartj.oxfordjournals.org/cgi/pmidlookup?view=long&pmid=15764618 |accessdate=2012-07-01}}</ref>
 
===PCI/Stenting===
===PCI/Stenting===
*[[Stenting]] can abolish [[hemodynamic]] abnormalities associated with [[myocardial]] bridging and may improve clinical [[symptom]]s in patients with [[myocardial]] bridges.<ref name="pmid9386156">{{cite journal |author=Klues HG, Schwarz ER, vom Dahl J, Reffelmann T, Reul H, Potthast K, Schmitz C, Minartz J, Krebs W, Hanrath P |title=Disturbed intracoronary hemodynamics in myocardial bridging: early normalization by intracoronary stent placement |journal=[[Circulation]] |volume=96 |issue=9 |pages=2905–13 |year=1997 |month=November |pmid=9386156 |doi= |url=http://circ.ahajournals.org/cgi/pmidlookup?view=long&pmid=9386156 |accessdate=2012-07-01}}</ref><ref name="pmid10814636">{{cite journal |author=Prendergast BD, Kerr F, Starkey IR |title=Normalisation of abnormal coronary fractional flow reserve associated with myocardial bridging using an intracoronary stent |journal=[[Heart (British Cardiac Society)]] |volume=83 |issue=6 |pages=705–7 |year=2000 |month=June |pmid=10814636 |pmc=1760858 |doi= |url=http://heart.bmj.com/cgi/pmidlookup?view=long&pmid=10814636 |accessdate=2012-07-01}}</ref>
 
*Care must be exercised in [[stent]] placement to assure that the bridge is not just moved upstream or downstream of the [[stent]].
* [[Stenting]] can abolish [[hemodynamic]] abnormalities associated with [[myocardial]] bridging and may improve clinical [[symptom]]s in patients with [[myocardial]] bridges.<ref name="pmid9386156">{{cite journal |author=Klues HG, Schwarz ER, vom Dahl J, Reffelmann T, Reul H, Potthast K, Schmitz C, Minartz J, Krebs W, Hanrath P |title=Disturbed intracoronary hemodynamics in myocardial bridging: early normalization by intracoronary stent placement |journal=[[Circulation]] |volume=96 |issue=9 |pages=2905–13 |year=1997 |month=November |pmid=9386156 |doi= |url=http://circ.ahajournals.org/cgi/pmidlookup?view=long&pmid=9386156 |accessdate=2012-07-01}}</ref><ref name="pmid10814636">{{cite journal |author=Prendergast BD, Kerr F, Starkey IR |title=Normalisation of abnormal coronary fractional flow reserve associated with myocardial bridging using an intracoronary stent |journal=[[Heart (British Cardiac Society)]] |volume=83 |issue=6 |pages=705–7 |year=2000 |month=June |pmid=10814636 |pmc=1760858 |doi= |url=http://heart.bmj.com/cgi/pmidlookup?view=long&pmid=10814636 |accessdate=2012-07-01}}</ref>
*Of note, there have been reports of [[coronary artery perforation]]<ref name="pmid9417754">{{cite journal |author=Hering D, Horstkotte D, Schwimmbeck P, Piper C, Bilger J, Schultheiss HP |title=[Acute myocardial infarct caused by a muscle bridge of the anterior interventricular ramus: complicated course with vascular perforation after stent implantation] |language=German |journal=[[Zeitschrift Für Kardiologie]] |volume=86 |issue=8 |pages=630–8 |year=1997 |month=August |pmid=9417754 |doi= |url= |accessdate=2012-07-01}}</ref><ref name="pmid20339502">{{cite journal |author=Zhang M, Kang WC, Moon CI, Han SH, Ahn TH, Shin EK |title=Coronary artery perforation following implantation of a drug-eluting stent rescued by deployment of a covered stent in symptomatic myocardial bridging |journal=[[Korean Circulation Journal]] |volume=40 |issue=3 |pages=148–51 |year=2010 |month=March |pmid=20339502 |pmc=2844983 |doi=10.4070/kcj.2010.40.3.148 |url=http://www.koreancircj.kr/DOIx.php?id=10.4070/kcj.2010.40.3.148 |accessdate=2012-07-01}}</ref> and target vessel revascularization<ref name="pmid19427426">{{cite journal |author=Tsujita K, Maehara A, Mintz GS, Doi H, Kubo T, Castellanos C, Liu J, Yang J, Oviedo C, Franklin-Bond T, Sugirtharaj DD, Dangas GD, Lansky AJ, Stone GW, Moses JW, Leon MB, Mehran R |title=Impact of myocardial bridge on clinical outcome after coronary stent placement |journal=[[The American Journal of Cardiology]] |volume=103 |issue=10 |pages=1344–8 |year=2009 |month=May |pmid=19427426 |doi=10.1016/j.amjcard.2009.01.340 |url=http://linkinghub.elsevier.com/retrieve/pii/S0002-9149(09)00457-3 |accessdate=2012-07-01}}</ref><ref name="pmid10995410">{{cite journal |author=Haager PK, Schwarz ER, vom Dahl J, Klues HG, Reffelmann T, Hanrath P |title=Long term angiographic and clinical follow up in patients with stent implantation for symptomatic myocardial bridging |journal=[[Heart (British Cardiac Society)]] |volume=84 |issue=4 |pages=403–8 |year=2000 |month=October |pmid=10995410 |pmc=1729426 |doi= |url=http://heart.bmj.com/cgi/pmidlookup?view=long&pmid=10995410 |accessdate=2012-07-01}}</ref> in patients with [[myocardial]] bridging during/following [[stent]] placement, respectively.
* Care must be exercised in [[stent]] placement to assure that the bridge is not just moved upstream or downstream of the [[stent]].
* Of note, there have been reports of [[coronary artery perforation]]<ref name="pmid9417754">{{cite journal |author=Hering D, Horstkotte D, Schwimmbeck P, Piper C, Bilger J, Schultheiss HP |title=[Acute myocardial infarct caused by a muscle bridge of the anterior interventricular ramus: complicated course with vascular perforation after stent implantation] |language=German |journal=[[Zeitschrift Für Kardiologie]] |volume=86 |issue=8 |pages=630–8 |year=1997 |month=August |pmid=9417754 |doi= |url= |accessdate=2012-07-01}}</ref><ref name="pmid20339502">{{cite journal |author=Zhang M, Kang WC, Moon CI, Han SH, Ahn TH, Shin EK |title=Coronary artery perforation following implantation of a drug-eluting stent rescued by deployment of a covered stent in symptomatic myocardial bridging |journal=[[Korean Circulation Journal]] |volume=40 |issue=3 |pages=148–51 |year=2010 |month=March |pmid=20339502 |pmc=2844983 |doi=10.4070/kcj.2010.40.3.148 |url=http://www.koreancircj.kr/DOIx.php?id=10.4070/kcj.2010.40.3.148 |accessdate=2012-07-01}}</ref> and target vessel revascularization<ref name="pmid19427426">{{cite journal |author=Tsujita K, Maehara A, Mintz GS, Doi H, Kubo T, Castellanos C, Liu J, Yang J, Oviedo C, Franklin-Bond T, Sugirtharaj DD, Dangas GD, Lansky AJ, Stone GW, Moses JW, Leon MB, Mehran R |title=Impact of myocardial bridge on clinical outcome after coronary stent placement |journal=[[The American Journal of Cardiology]] |volume=103 |issue=10 |pages=1344–8 |year=2009 |month=May |pmid=19427426 |doi=10.1016/j.amjcard.2009.01.340 |url=http://linkinghub.elsevier.com/retrieve/pii/S0002-9149(09)00457-3 |accessdate=2012-07-01}}</ref><ref name="pmid10995410">{{cite journal |author=Haager PK, Schwarz ER, vom Dahl J, Klues HG, Reffelmann T, Hanrath P |title=Long term angiographic and clinical follow up in patients with stent implantation for symptomatic myocardial bridging |journal=[[Heart (British Cardiac Society)]] |volume=84 |issue=4 |pages=403–8 |year=2000 |month=October |pmid=10995410 |pmc=1729426 |doi= |url=http://heart.bmj.com/cgi/pmidlookup?view=long&pmid=10995410 |accessdate=2012-07-01}}</ref> in patients with [[myocardial]] bridging during/following [[stent]] placement, respectively.
* Stents placed in this position may be placed under torsional strain, extrinsic compression, and repeated flexion which may theoretically increase the risk of stent strut fracture.
 
===Surgery===
===Surgery===
[[Surgery]] is limited to patients with [[symptom]]s that persist despite medical treatment.
[[Surgery]] is limited to patients with [[symptom]]s that persist despite medical treatment.
=====1. CABG=====
=====1. CABG=====
Minimally invasive [[CABG]] with placement of a [[left internal mammary artery]] to the distal [[left anterior descending artery]] is one option.
Minimally invasive [[CABG]] with placement of a [[left internal mammary artery]] to the distal [[left anterior descending artery]] is one option.
=====2. Myectomy=====
=====2. Myectomy=====
Myectomy can be performed on the [[myocardium]] surrounding the [[coronary artery]]. The procedure involves [[surgery|surgical]] division (unroofing) of the [[coronary artery]]. [[surgery|Surgical]] unroofing of the [[myocardial]] bridge often results in clinical improvement.<ref name="pmid9780340">{{cite journal |author=Yetman AT, McCrindle BW, MacDonald C, Freedom RM, Gow R |title=Myocardial bridging in children with hypertrophic cardiomyopathy--a risk factor for sudden death |journal=[[The New England Journal of Medicine]] |volume=339 |issue=17 |pages=1201–9 |year=1998 |month=October |pmid=9780340 |doi=10.1056/NEJM199810223391704 |url=http://dx.doi.org/10.1056/NEJM199810223391704 |accessdate=2012-07-01}}</ref><ref name="pmid8935519">{{cite journal |author=Katznelson Y, Petchenko P, Knobel B, Cohen AJ, Kishon Y, Schachner A |title=Myocardial bridging: surgical technique and operative results |journal=[[Military Medicine]] |volume=161 |issue=4 |pages=248–50 |year=1996 |month=April |pmid=8935519 |doi= |url= |accessdate=2012-07-01}}</ref><ref name="pmid7458489">{{cite journal |author=Hill RC, Chitwood WR, Bashore TM, Sink JD, Cox JL, Wechsler AS |title=Coronary flow and regional function before and after supraarterial myotomy for myocardial bridging |journal=[[The Annals of Thoracic Surgery]] |volume=31 |issue=2 |pages=176–81 |year=1981 |month=February |pmid=7458489 |doi= |url= |accessdate=2012-07-01}}</ref><ref name="pmid1439639">{{cite journal |author=Iversen S, Hake U, Mayer E, Erbel R, Diefenbach C, Oelert H |title=Surgical treatment of myocardial bridging causing coronary artery obstruction |journal=[[Scandinavian Journal of Thoracic and Cardiovascular Surgery]] |volume=26 |issue=2 |pages=107–11 |year=1992 |pmid=1439639 |doi= |url= |accessdate=2012-07-01}}</ref><ref name="pmid6385889">{{cite journal |author=Ochsner JL, Mills NL |title=Surgical management of diseased intracavitary coronary arteries |journal=[[The Annals of Thoracic Surgery]] |volume=38 |issue=4 |pages=356–62 |year=1984 |month=October |pmid=6385889 |doi= |url= |accessdate=2012-07-01}}</ref> Potential [[complication]]s include [[right ventricular perforation]] and left [[ventricular aneurysm]] which can be avoided with the use of [[echocardiography]] to follow the course of the [[vessel]].<ref>Hiratzka LF, McPherson DD, Brandt B 3d, Lamberth WC Jr, Marcus ML, Kerber RE. Intraoperative high-frequency epicardial echocardiography in coronary revascularization: locating deeply embedded coronary arteries. Ann Thorac Surg 1986 Dec;42(6 Suppl):S9-11</ref>


=====Surgery Contra-Indication=====
Myectomy can be performed on the [[myocardium]] surrounding the [[coronary artery]]. The procedure involves [[surgery|surgical]] division (unroofing) of the [[coronary artery]]. [[surgery|Surgical]] unroofing of the [[myocardial]] bridge often results in clinical improvement.<ref name="pmid9780340">{{cite journal |author=Yetman AT, McCrindle BW, MacDonald C, Freedom RM, Gow R |title=Myocardial bridging in children with hypertrophic cardiomyopathy--a risk factor for sudden death |journal=[[The New England Journal of Medicine]] |volume=339 |issue=17 |pages=1201–9 |year=1998 |month=October |pmid=9780340 |doi=10.1056/NEJM199810223391704 |url=http://dx.doi.org/10.1056/NEJM199810223391704 |accessdate=2012-07-01}}</ref><ref name="pmid8935519">{{cite journal |author=Katznelson Y, Petchenko P, Knobel B, Cohen AJ, Kishon Y, Schachner A |title=Myocardial bridging: surgical technique and operative results |journal=[[Military Medicine]] |volume=161 |issue=4 |pages=248–50 |year=1996 |month=April |pmid=8935519 |doi= |url= |accessdate=2012-07-01}}</ref><ref name="pmid7458489">{{cite journal |author=Hill RC, Chitwood WR, Bashore TM, Sink JD, Cox JL, Wechsler AS |title=Coronary flow and regional function before and after supraarterial myotomy for myocardial bridging |journal=[[The Annals of Thoracic Surgery]] |volume=31 |issue=2 |pages=176–81 |year=1981 |month=February |pmid=7458489 |doi= |url= |accessdate=2012-07-01}}</ref><ref name="pmid1439639">{{cite journal |author=Iversen S, Hake U, Mayer E, Erbel R, Diefenbach C, Oelert H |title=Surgical treatment of myocardial bridging causing coronary artery obstruction |journal=[[Scandinavian Journal of Thoracic and Cardiovascular Surgery]] |volume=26 |issue=2 |pages=107–11 |year=1992 |pmid=1439639 |doi= |url= |accessdate=2012-07-01}}</ref><ref name="pmid6385889">{{cite journal |author=Ochsner JL, Mills NL |title=Surgical management of diseased intracavitary coronary arteries |journal=[[The Annals of Thoracic Surgery]] |volume=38 |issue=4 |pages=356–62 |year=1984 |month=October |pmid=6385889 |doi= |url= |accessdate=2012-07-01}}</ref> Potential [[complication]]s include right ventricular perforation and left [[ventricular aneurysm]] which can be avoided with the use of [[echocardiography]] to follow the course of the [[vessel]].<ref>Hiratzka LF, McPherson DD, Brandt B 3d, Lamberth WC Jr, Marcus ML, Kerber RE. Intraoperative high-frequency epicardial echocardiography in coronary revascularization: locating deeply embedded coronary arteries. Ann Thorac Surg 1986 Dec;42(6 Suppl):S9-11</ref>
 
=====Surgery Contraindications=====
 
[[Cardiac surgery]] is not indicated for [[hypertrophic cardiomyopathy]] associated [[myocardial]] bridging, and medical [[therapy]] may provide adequate anti-[[ischemic]] [[therapy]].<ref name="pmid11127472">{{cite journal |author=Mohiddin SA, Begley D, Shih J, Fananapazir L |title=Myocardial bridging does not predict sudden death in children with hypertrophic cardiomyopathy but is associated with more severe cardiac disease |journal=[[Journal of the American College of Cardiology]] |volume=36 |issue=7 |pages=2270–8 |year=2000 |month=December |pmid=11127472 |doi= |url=http://linkinghub.elsevier.com/retrieve/pii/S0735-1097(00)00987-6 |accessdate=2012-07-01}}</ref>
[[Cardiac surgery]] is not indicated for [[hypertrophic cardiomyopathy]] associated [[myocardial]] bridging, and medical [[therapy]] may provide adequate anti-[[ischemic]] [[therapy]].<ref name="pmid11127472">{{cite journal |author=Mohiddin SA, Begley D, Shih J, Fananapazir L |title=Myocardial bridging does not predict sudden death in children with hypertrophic cardiomyopathy but is associated with more severe cardiac disease |journal=[[Journal of the American College of Cardiology]] |volume=36 |issue=7 |pages=2270–8 |year=2000 |month=December |pmid=11127472 |doi= |url=http://linkinghub.elsevier.com/retrieve/pii/S0735-1097(00)00987-6 |accessdate=2012-07-01}}</ref>


==References==  
==References==
{{Reflist|2}}
 
{{reflist|2}}
 
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Latest revision as of 17:13, 5 August 2014

Coronary Angiography

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Preprocedural Lesion Morphology

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Lesion Morphology

Quantitative Coronary Angiography
Definitions of Preprocedural Lesion Morphology
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Rim Halaby, M.D. [2]

Synonyms and keywords: myocardial bridge, coronary bridge, coronary artery bridge, coronary bridging, coronary artery bridging

Overview

A myocardial bridge is defined as a segment of a major coronary epicardial artery that "tunnels" or passes intramurally through the myocardium beneath the muscle bridge during systole.[1][2] Myocardial bridges are generally located in the distribution of the left anterior descending artery (LAD) and its diagonal branches.

Myocardial bridging should be distinguished from intramyocardial course, which is an inborn coronary anomaly defined as a segment of a major epicardial coronary artery running and ending in the myocardium.

Historical Perspective

Angiographically, myocardial bridging was first recognized in the 1960's.[3]

Pathophysiology

Variants

There are two basic morphologic variants:

Extent

Majority of the cases, systolic bridging is usually not severe or extensive and completely reverses during diastole; except in patients with HOCM, wherein severe systolic bridging of the septal perforators may be a predisposing factor to the development of myocardial ischemia.[4][5][6][7][8][9]

Epidemiology and Demographics

The reported frequency varies with different modalities used to identify myocardial bridges. Generally, with coronary angiography, the reported frequent ranges from 0.5-16% [2][1][10][4][11][12][13][14] and with pathological or coronary CT, the frequency is between 5-86%.[2][1][15][16][17][18]

Irrespective of the modality used, the left anterior descending coronary artery is most commonly involved and a higher incidence is observed in patients with hypertrophic coronary artery and cardiac transplants.[2][14] Among the pediatric age group, the occurrence of myocardial bridging is rare but an increased incidence may be observed in association with hypertrophic cardiomyopathy.

Natural History, Complications and Prognosis

Complications

Complications of myocardial bridging include the following:

Prognosis

The combined presence of hypertrophic cardiomyopathy and myocardial bridging is associated with a worse prognosis as compared to hypertrophic cardiomyopathy alone[19].

Diagnosis

Coronary Angiography

Case 1

Shown below is an animated image depicting myocardial bridge.

Myocardial bridging

Shown below are two static images of the same case depicting myocardial bridge. Outlined with yellow in the image on the left is the part of the coronary artery during diastole. This same part of the coronary artery is outlined in yellow in the image on the right during systole; note that this outlined part is narrowed compared to its shape during diastole.

Shape of the coronary artery during diastole The coronary artery is narrowed during systole which is consistent myocardial bridging.

Case 2

Shown below are an animated image and a static image depicting myocardial bridge.

Myocardial bridging Myocardial bridging

Intracoronary ultrasound

Treatment

Medical Treatment

PCI/Stenting

  • Stenting can abolish hemodynamic abnormalities associated with myocardial bridging and may improve clinical symptoms in patients with myocardial bridges.[26][27]
  • Care must be exercised in stent placement to assure that the bridge is not just moved upstream or downstream of the stent.
  • Of note, there have been reports of coronary artery perforation[28][29] and target vessel revascularization[30][31] in patients with myocardial bridging during/following stent placement, respectively.
  • Stents placed in this position may be placed under torsional strain, extrinsic compression, and repeated flexion which may theoretically increase the risk of stent strut fracture.

Surgery

Surgery is limited to patients with symptoms that persist despite medical treatment.

1. CABG

Minimally invasive CABG with placement of a left internal mammary artery to the distal left anterior descending artery is one option.

2. Myectomy

Myectomy can be performed on the myocardium surrounding the coronary artery. The procedure involves surgical division (unroofing) of the coronary artery. Surgical unroofing of the myocardial bridge often results in clinical improvement.[19][32][33][34][35] Potential complications include right ventricular perforation and left ventricular aneurysm which can be avoided with the use of echocardiography to follow the course of the vessel.[36]

Surgery Contraindications

Cardiac surgery is not indicated for hypertrophic cardiomyopathy associated myocardial bridging, and medical therapy may provide adequate anti-ischemic therapy.[37]

References

  1. ↑ 1.0 1.1 1.2 1.3 1.4 1.5 Alegria JR, Herrmann J, Holmes DR, Lerman A, Rihal CS (2005). "Myocardial bridging". European Heart Journal. 26 (12): 1159–68. doi:10.1093/eurheartj/ehi203. PMID 15764618. Retrieved 2012-07-01. Unknown parameter |month= ignored (help)
  2. ↑ 2.0 2.1 2.2 2.3 Möhlenkamp S, Hort W, Ge J, Erbel R (2002). "Update on myocardial bridging". Circulation. 106 (20): 2616–22. PMID 12427660. Retrieved 2012-07-01. Unknown parameter |month= ignored (help)
  3. ↑ Reyman, HC. Disertatis de vasis cordis propiis. Bibl Anat. 1737; 2:366.
  4. ↑ 4.0 4.1 Faruqui AM, Maloy WC, Felner JM, Schlant RC, Logan WD, Symbas P (1978). "Symptomatic myocardial bridging of coronary artery". The American Journal of Cardiology. 41 (7): 1305–10. PMID 307341. Unknown parameter |month= ignored (help); |access-date= requires |url= (help)
  5. ↑ Morales AR, Romanelli R, Boucek RJ (1980). "The mural left anterior descending coronary artery, strenuous exercise and sudden death". Circulation. 62 (2): 230–7. PMID 7397963. Retrieved 2012-07-01. Unknown parameter |month= ignored (help)
  6. ↑ Ishikawa Y, Akasaka Y, Suzuki K, Fujiwara M, Ogawa T, Yamazaki K, Niino H, Tanaka M, Ogata K, Morinaga S, Ebihara Y, Kawahara Y, Sugiura H, Takimoto T, Komatsu A, Shinagawa T, Taki K, Satoh H, Yamada K, Yanagida-Iida M, Shimokawa R, Shimada K, Nishimura C, Ito K, Ishii T (2009). "Anatomic properties of myocardial bridge predisposing to myocardial infarction". Circulation. 120 (5): 376–83. doi:10.1161/CIRCULATIONAHA.108.820720. PMID 19620504. Retrieved 2012-07-01. Unknown parameter |month= ignored (help)
  7. ↑ Utuk O, Bilge A, Bayturan O, Tikiz H, Tavli T, Tezcan U (2010). "Thrombosis of a coronary artery related to the myocardial bridging". Heart, Lung & Circulation. 19 (8): 481–2. doi:10.1016/j.hlc.2009.08.006. PMID 19914131. Retrieved 2012-07-01. Unknown parameter |month= ignored (help)
  8. ↑ Hostiuc S, Curca GC, Dermengiu D, Dermengiu S, Hostiuc M, Rusu MC (2011). "Morphological changes associated with hemodynamically significant myocardial bridges in sudden cardiac death". The Thoracic and Cardiovascular Surgeon. 59 (7): 393–8. doi:10.1055/s-0030-1270703. PMID 21448858. Retrieved 2012-07-01. Unknown parameter |month= ignored (help)
  9. ↑ Husmann L, Nkoulou R, Wolfrum M, Kaufmann PA (2011). "Myocardial bridging causing infarction and ischaemia". European Heart Journal. 32 (7): 790. doi:10.1093/eurheartj/ehq423. PMID 21123275. Retrieved 2012-07-01. Unknown parameter |month= ignored (help)
  10. ↑ Ge J, Jeremias A, Rupp A, Abels M, Baumgart D, Liu F, Haude M, Görge G, von Birgelen C, Sack S, Erbel R (1999). "New signs characteristic of myocardial bridging demonstrated by intracoronary ultrasound and Doppler". European Heart Journal. 20 (23): 1707–16. doi:10.1053/euhj.1999.1661. PMID 10562478. Retrieved 2012-07-01. Unknown parameter |month= ignored (help)
  11. ↑ Ge J, Erbel R, Rupprecht HJ, Koch L, Kearney P, Görge G, Haude M, Meyer J (1994). "Comparison of intravascular ultrasound and angiography in the assessment of myocardial bridging". Circulation. 89 (4): 1725–32. PMID 8149538. Retrieved 2012-07-01. Unknown parameter |month= ignored (help)
  12. ↑ Angelini P, Velasco JA, Flamm S (2002). "Coronary anomalies: incidence, pathophysiology, and clinical relevance". Circulation. 105 (20): 2449–54. PMID 12021235. Retrieved 2012-07-01. Unknown parameter |month= ignored (help)
  13. ↑ Kramer JR, Kitazume H, Proudfit WL, Sones FM (1982). "Clinical significance of isolated coronary bridges: benign and frequent condition involving the left anterior descending artery". American Heart Journal. 103 (2): 283–8. PMID 7055058. Retrieved 2012-07-01. Unknown parameter |month= ignored (help)
  14. ↑ 14.0 14.1 Sorajja P, Ommen SR, Nishimura RA, Gersh BJ, Tajik AJ, Holmes DR (2003). "Myocardial bridging in adult patients with hypertrophic cardiomyopathy". Journal of the American College of Cardiology. 42 (5): 889–94. PMID 12957438. Retrieved 2012-07-01. Unknown parameter |month= ignored (help)
  15. ↑ Hongo Y, Tada H, Ito K, Yasumura Y, Miyatake K, Yamagishi M (1999). "Augmentation of vessel squeezing at coronary-myocardial bridge by nitroglycerin: study by quantitative coronary angiography and intravascular ultrasound". American Heart Journal. 138 (2 Pt 1): 345–50. PMID 10426850. Unknown parameter |month= ignored (help); |access-date= requires |url= (help)
  16. ↑ Iskandrian AE, Nallamothu N, Heo J (1996). "Nonatherosclerotic causes of myocardial ischemia". Journal of Nuclear Cardiology : Official Publication of the American Society of Nuclear Cardiology. 3 (5): 428–35. PMID 8902676. |access-date= requires |url= (help)
  17. ↑ La Grutta L, Runza G, Lo Re G, Galia M, Alaimo V, Grassedonio E, Bartolotta TV, Malagò R, Tedeschi C, Cademartiri F, De Maria M, Cardinale AE, Lagalla R, Midiri M (2009). "Prevalence of myocardial bridging and correlation with coronary atherosclerosis studied with 64-slice CT coronary angiography". La Radiologia Medica. 114 (7): 1024–36. doi:10.1007/s11547-009-0446-y. PMID 19697102. Retrieved 2012-07-01. Unknown parameter |month= ignored (help)
  18. ↑ Hwang JH, Ko SM, Roh HG, Song MG, Shin JK, Chee HK, Kim JS (2010). "Myocardial bridging of the left anterior descending coronary artery: depiction rate and morphologic features by dual-source CT coronary angiography". Korean Journal of Radiology : Official Journal of the Korean Radiological Society. 11 (5): 514–21. doi:10.3348/kjr.2010.11.5.514. PMC 2930159. PMID 20808694. Retrieved 2012-07-01.
  19. ↑ 19.0 19.1 Yetman AT, McCrindle BW, MacDonald C, Freedom RM, Gow R (1998). "Myocardial bridging in children with hypertrophic cardiomyopathy--a risk factor for sudden death". The New England Journal of Medicine. 339 (17): 1201–9. doi:10.1056/NEJM199810223391704. PMID 9780340. Retrieved 2012-07-01. Unknown parameter |month= ignored (help)
  20. ↑ Möhlenkamp S, Hort W, Ge J, Erbel R. Update on myocardial bridging.Circulation. 2002;106:2616 –2622.
  21. ↑ Erbel R, Rupprecht HJ, Ge J, Gerber T, Görge G, Meyer J. Coronary artery shape and flow changes induced by myocardial bridging. Echocardiography. 1993;1:71–77.]
  22. ↑ Rouleau JL, Chuck LH, Hollosi G, Kidd P, Sievers RE, Wikman Coffelt J, Parmley WW. Verapamil preserves myocardial contractility in the hereditary cardiomyopathy of the Syrian hamster. Circ Res. 1982;50:405–412.
  23. ↑ Klues HG, Schwarz ER, vom Dahl J, Reffelmann T, Reul H, Potthast K, Schmitz C, Minartz J, Krebs W, Hanrath P. Disturbed intracoronary hemodynamics in myocardial bridging: early normalization by intracoronary stent placement. Circulation. 1997;96:2905–2913.
  24. ↑ Jeremias A, Haude M, Ge J, Görge G, Liu F, Konorza T, Erbel R. Emergency stent implantation in the area of extensive muscle bridging of the anterior interventricular ramus after post-interventional dissection [in German]. Z Kardiol. 1997;86:367–372.
  25. ↑ Ge J, Erbel R, Görge G, Haude M, Meyer J. High wall shear stress proximal to myocardial bridging and atherosclerosis: intracoronary ultrasound and pressure measurements. Br Heart J. 1995;73:462– 465.]
  26. ↑ Klues HG, Schwarz ER, vom Dahl J, Reffelmann T, Reul H, Potthast K, Schmitz C, Minartz J, Krebs W, Hanrath P (1997). "Disturbed intracoronary hemodynamics in myocardial bridging: early normalization by intracoronary stent placement". Circulation. 96 (9): 2905–13. PMID 9386156. Retrieved 2012-07-01. Unknown parameter |month= ignored (help)
  27. ↑ Prendergast BD, Kerr F, Starkey IR (2000). "Normalisation of abnormal coronary fractional flow reserve associated with myocardial bridging using an intracoronary stent". Heart (British Cardiac Society). 83 (6): 705–7. PMC 1760858. PMID 10814636. Retrieved 2012-07-01. Unknown parameter |month= ignored (help)
  28. ↑ Hering D, Horstkotte D, Schwimmbeck P, Piper C, Bilger J, Schultheiss HP (1997). "[Acute myocardial infarct caused by a muscle bridge of the anterior interventricular ramus: complicated course with vascular perforation after stent implantation]". Zeitschrift Für Kardiologie (in German). 86 (8): 630–8. PMID 9417754. Unknown parameter |month= ignored (help); |access-date= requires |url= (help)
  29. ↑ Zhang M, Kang WC, Moon CI, Han SH, Ahn TH, Shin EK (2010). "Coronary artery perforation following implantation of a drug-eluting stent rescued by deployment of a covered stent in symptomatic myocardial bridging". Korean Circulation Journal. 40 (3): 148–51. doi:10.4070/kcj.2010.40.3.148. PMC 2844983. PMID 20339502. Retrieved 2012-07-01. Unknown parameter |month= ignored (help)
  30. ↑ Tsujita K, Maehara A, Mintz GS, Doi H, Kubo T, Castellanos C, Liu J, Yang J, Oviedo C, Franklin-Bond T, Sugirtharaj DD, Dangas GD, Lansky AJ, Stone GW, Moses JW, Leon MB, Mehran R (2009). "Impact of myocardial bridge on clinical outcome after coronary stent placement". The American Journal of Cardiology. 103 (10): 1344–8. doi:10.1016/j.amjcard.2009.01.340. PMID 19427426. Retrieved 2012-07-01. Unknown parameter |month= ignored (help)
  31. ↑ Haager PK, Schwarz ER, vom Dahl J, Klues HG, Reffelmann T, Hanrath P (2000). "Long term angiographic and clinical follow up in patients with stent implantation for symptomatic myocardial bridging". Heart (British Cardiac Society). 84 (4): 403–8. PMC 1729426. PMID 10995410. Retrieved 2012-07-01. Unknown parameter |month= ignored (help)
  32. ↑ Katznelson Y, Petchenko P, Knobel B, Cohen AJ, Kishon Y, Schachner A (1996). "Myocardial bridging: surgical technique and operative results". Military Medicine. 161 (4): 248–50. PMID 8935519. Unknown parameter |month= ignored (help); |access-date= requires |url= (help)
  33. ↑ Hill RC, Chitwood WR, Bashore TM, Sink JD, Cox JL, Wechsler AS (1981). "Coronary flow and regional function before and after supraarterial myotomy for myocardial bridging". The Annals of Thoracic Surgery. 31 (2): 176–81. PMID 7458489. Unknown parameter |month= ignored (help); |access-date= requires |url= (help)
  34. ↑ Iversen S, Hake U, Mayer E, Erbel R, Diefenbach C, Oelert H (1992). "Surgical treatment of myocardial bridging causing coronary artery obstruction". Scandinavian Journal of Thoracic and Cardiovascular Surgery. 26 (2): 107–11. PMID 1439639. |access-date= requires |url= (help)
  35. ↑ Ochsner JL, Mills NL (1984). "Surgical management of diseased intracavitary coronary arteries". The Annals of Thoracic Surgery. 38 (4): 356–62. PMID 6385889. Unknown parameter |month= ignored (help); |access-date= requires |url= (help)
  36. ↑ Hiratzka LF, McPherson DD, Brandt B 3d, Lamberth WC Jr, Marcus ML, Kerber RE. Intraoperative high-frequency epicardial echocardiography in coronary revascularization: locating deeply embedded coronary arteries. Ann Thorac Surg 1986 Dec;42(6 Suppl):S9-11
  37. ↑ Mohiddin SA, Begley D, Shih J, Fananapazir L (2000). "Myocardial bridging does not predict sudden death in children with hypertrophic cardiomyopathy but is associated with more severe cardiac disease". Journal of the American College of Cardiology. 36 (7): 2270–8. PMID 11127472. Retrieved 2012-07-01. Unknown parameter |month= ignored (help)


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