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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Hilda Mahmoudi M.D., M.P.H.[2]; Twinkle Singh, M.B.B.S. [3]; Rim Halaby, M.D. [4]

Narrow Complex Tachycardia Resident Survival Guide Microchapters
Overview
Causes
Diagnosis
Treatment
Do's
Don'ts

Overview

Narrow complex tachycardia (NCT) is characterized by heart rate > 100 beats per minute and QRS complex of duration < 120 milliseconds. The NCT may originate in the sinus node, the atria, the AV node, the His bundle, or combination of these tissues causing rapid activation of the ventricles. Diagnosis of NCT is established by surface ECG in correlation with history and physical examination. Hemodynamically unstable patients should receive urgent cardioversion.

Causes

Life Threatening Causes

Life-threatening causes include conditions which may result in death or permanent disability within 24 hours if left untreated.

Common Causes

Diagnosis

Shown below is an algorithm summarizing the approach for diagnosing narrow complex tachycardia according to the 2003 ACC/AHA/ESC guidelines for the management of patients with supraventricular arrhythmias.[1] ECG: electrocardiogram; SVT: supraventricular tachycardia; ms: Milliseconds; bpm: beats per minute; NCT: Narrow complex tachycardia

 
 
 
 
 
 
 
Characterize the symptoms:

❑ Asymptomatic (most common presentation)
Palpitations
Dyspnea
Fatigue
Chest discomfort
Lightheadedness
Syncope
Polyuria <br

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

Differential Diagnosis of NCT
AV nodal reentrant tachycardia (AVNRT)
Atrioventricular reentrant tachycardia (AVRT)
❑ Junctional tachycardia
Sinus tachycardia
❑ Inappropriate sinus tachycardia
Sinus node re-entry tachycardia
❑ Intraatrial reentrant tachycardia (IART)
❑ Atrial tachycardia
Multifocal atrial tachycardia
Atrial fibrillation
Atrial flutter

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

Examine the patient:


General appearance
❑ Well appearing


Vitals
Pulse

❑ Rate
Tachycardia
❑ Rhythm
❑ Regular
❑ Regular irregular
❑ Irregularly irregular
❑ Strength
❑ Weak
❑ Alternating in strength

Respiration

Tachypnea

Blood pressure

Hypotension (in hemodynamically unstable patients)

Neck

❑ Absent a wave in jugular venous pressure (in atrial fibrillation)

Cardiovascular examination
❑ Auscultation

Heart sounds
❑ Rapid regular or irregular rhythm (depending on the type of arrhythmia)
❑ Murmurs (depending on the underlying cardiac disease such as aortic stenosis)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

❑ Assess hemodynamic stability

❑ Monitor the blood pressure
❑ Monitor the heart rate

❑ Order and monitor the ECG

Perform urgent cardioversion in unstable patients in which the rhythm is not sinus tachycardia

❑ Give oxygen if needed

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Narrow QRS tachycardia
❑ Heart rate > 100 beats/min
❑ QRS duration < 120 ms
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
❑ Determine the regularity of rhythm
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Regular rhythm
 
 
 
 
 
 
 
Irregular rhythm
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Consider the following causes:

AVRT
AVNRT
Atypical AVNRT
Atrial tachycardia

Atrial flutter
 
 
 
 
 
 
 
Consider the following causes:

Atrial fibrillation
❑ Atrial tachycardia/flutter with variable AV conduction

MAT
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Determine P wave morphology
 
 
 
 
 
 
 
Determine P wave morphology
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
❑ P waves are not visible
 
❑ P waves are visible
 
❑ > 3 P wave morphologies
 
❑ Absent P waves
 
❑ Sawtooth appearance of P waves
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
❑ Consider AVNRT
 
Determine if atrial rate is greater than ventricular rate
 
MAT
 
Atrial fibrillation
 
Atrial flutter
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Atrial rate > ventricular rate
 
Atrial rate ≤ ventricular rate
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Consider the following causes:
Atrial flutter
Atrial tachycardia
 
❑ Determine if RP interval > PR interval
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
RP < PR
 
 
 
RP > PR
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Determine the duration of RP interval
 
 
 
Consider the following causes:

Atrial tachycardia
❑ PJRT

Atypical AVNRT
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
< 70 ms
 
> 70 ms
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Consider the following cause:
AVNRT
 
Consider the following causes:
AVRT
AVNRT
Atrial tachycardia
 
 
 
 
 
 
 
 
 


Identification of the Rhythm on ECG

Shown below is an algorithm summarizing the approach to differentiate various types of narrow complex tachycardia according to the 2003 guidelines issued by ACC/AHA/ESC for the management of patients with supraventricular arrhythmias.[1]
Abbreviations: AV: atrioventricular; AVNRT: atrioventricular nodal reciprocating tachycardia; MAT: multifocal atrial tachycardia; ms: milliseconds; PJRT: permanent form of junctional reciprocating tachycardia

Note: Patients with focal junctional tachycardia may mimic the pattern of slow-fast AVNRT and may show AV dissociation and/or marked irregularity in the junctional rate.

Treatment

Initial Approach

Shown below is an algorithm summarizing the initial approach for narrow complex tachycardia according to the 2003 ACC/AHA/ESC guidelines for the management of patients with supraventricular arrhythmias.[1]

 
 
 
 
 
 
Assess the hemodynamic stability of the patient
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Unstable patient
 
 
 
 
 
Stable patient
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
If the rythm isn't sinus tachycardia:
Urgent cardioversion
 
If the rythm is sinus tachycardia:

❑ Control the rate:

❑ IV metoprolol (2.5 to 5 mg over 2 minutes up to a maximum of 15 mg).
❑ Treat the underlying cause
 
Documented arrhythmia
 
 
 
Undocumented arrhythmia
(ECG is normal)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
❑ Identify the specific type of NCT based on the ECG findings
❑ Treat accordingly
 
History suggestive of extra premature beats

❑ Sensation of a pause followed by a strong heart beat OR

❑ Irregularities in heart rhythm
 
History suggestive of paroxysmal arrhythmia

❑ Regular palpitations with sudden onset and termination

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Rule out the following:
Caffeine
Alcohol
Nicotine
Recreational drugs
Hyperthyroidism
 
❑ Refer for an invasive electrophysiological study AND/OR
Catheter ablation
❑ Educate about vagal maneuvers
❑ Consider beta blocker
 


Short Term Treatment of SVT in a Hemodynamically Stable Patient

Shown below is an algorithm summarizing the management of narrow complex tachycardia according to the 2003 ACC/AHA/ESC guidelines for the management of patients with supraventricular arrhythmias.[1]
Abbreviations: AF: atrial fibrillation; AV: atrioventricular; AVNRT: atrioventricular nodal reciprocating tachycardia; AVRT: atrioventricular reciprocating tachycardia; BBB: bundle-branch block; ECG: electrocardiography; IV: intravenous; LV: left ventricle; SVT: supraventricular tachycardia; VT: ventricular tachycardia

 
 
Acute management:

❑ Perform vagal maneuvers (Class I, level of evidence B)

Valsalva maneuver
❑ Carotid massage
❑ Monitor ECG continuously
 
 
 
 
 
 
 
 
 
 
 
 
If vagal maneuvers fail:

❑ Administer IV adenosine† (Class I, level of evidence A)

❑ First dose: 6 mg rapid IV push, followed by 20 mL of normal saline bolus
❑ Second dose: 12 mg (if no response in 1-2 min)[2]
❑ Monitor ECG continuously
 
 
 
 
 
 
 
 
 
 
 
 
❑ Assess changes on ECG following adenosine administration
Changes on ECG Possible causes
No change❑ Inadequate delivery of the medication
❑ Inadequate dose
VT
Gradual slowing then re-acceleration of rateSinus tachycardia

❑ Focal AT

❑ Nonparoxysmal junctional tachycardia
Abrupt terminationAVNRT
AVRT
❑ Sinus node re-entry
❑ Focal AT
Persisting atrial tachycardia with transient high-grade AV blockAtrial flutter
Atrial tachycardia
 
 
 
 
 
 
 
 
 
If adenosine fails, administer ONE of the following:

❑ IV verapamil 5 mg IV every 3-5 min, maximum 15 mg (Class I, level of evidence A)[2]
❑ IV diltiazem (Class I, level of evidence A)

❑ 0.25 mg/kg over 2 minutes
❑ Additional 0.35 mg/kg over 2 minutes
❑ Maintenance infusion of 5-15 mg/hour[2]

❑ IV beta blocker (Class IIb, level of evidence C)

Metoprolol
❑ 5 mg over 2 minutes
❑ Up to 3 doses within 15 minutes
Esmolol
❑ 250-500 μg/kg over 1 minute
❑ Maintenance with 50-200 μg/kg over 4 minutes (if needed)
Propranolol
❑ 0.15 mg/kg over 2 minutes[2]

❑ Monitor ECG continuously
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Terminated arrhythmia
 
Persistent arrhythmia
 
 
 
 
 
 
 
 
 
 
 
 
 
No further therapy is required if:
❑ Patient is stable
LV function is normal
❑ Normal sinus rhythm on ECG
 
❑ Administer AV-nodal-blocking agent AND one of the following
❑ IV ibutilide
❑ 1 mg over 10 minutes (if ≥ 60 kg)
❑ 0.01 mg/kg over 10 minutes (if <60 kg)
❑ Repeat once after 10 minutes if needed
❑ IV procainamide
❑ 30 mg/min infusion, maximum 17 mg/kg
❑ Maintenance 2-4 mg/min
❑ IV flecainide 2mg/kg over 10 min[2]

OR

❑ DC cardioversion
 

Adenosine should be used cautiously in patients with severe coronary artery disease and may produce AF.
Ibutilide is especially indicated for patients with atrial flutter but should not be used in patients with ejection fraction less than 30% as it increases risk of polymorphic VT.

Type of Arrhythmia EKG (lead II)† Clues
Supraventricular tachycardia Any tachyarrhythmia that is initiated and maintained in atrial tissue or atrioventricular junctional tissue.[1]
Sinus tachycardia Rhythm with heart rate > 100 bpm, originating in SA node due to its increased automaticity.
Sinus node re-entry tachycardia Rare paroxysmal tachycardia arising due to re-entry circuits with in SA node.[3]
Atrial fibrillation Supraventricular tachycardia with irregularly irregular rhythm and absent P waves on EKG.
Atrial flutter Cardiac rhythm characterized by an atrial rate ranging from 240 to 400 beats per minute and regular continuous wave-form.[4]
AVNRT Most common form of PSVT with a heart rate of 140-250 bpm, re-entrant circuit involves two separate anatomical pathways (slow and fast) loacted in perinodal tissue.
AVRT Re-entrant tachycardia occurring due to an accessory pathway in addition to AV node, accessory pathway is essential for the initiation and the maintenance of tachycardia.
Focal atrial tachycardia Focal atria tachycardia refers to a rhythm originating from a single site either in the left or right atrium with an atrial rate of 100-250 bpm.
Nonparoxysmal junctional tachycardia Benign tachycardia occurring due to increased automaticity arising from a high junctional focus.
Multifocal atrial tachycardia Irregular tachycardia characterized by 3 different P wave morphologies on EKG.

EKG strips are a courtesy from ECGpedia.



Do's

  • Refer patients with narrow complex tachycardia with any of the following to a cardiac arrhythmia specialist:
  • Consider trying different types of anti-arrhythmic agents in case the SVT is refractory; however, closely monitor the blood pressure and heart rate.[2]
  • Consider invasive electrophysiological investigation in presence of pre-excitation and severe disabling symptoms.
  • Consider esophageal pill electrodes in cases of invisible P waves.
  • Administer higher doses of adenosine in patients taking theophylline.
  • Perform the following tests when indicated:
  • Echocardiography in case of sustained SVT to rule out structural heart disease
  • 24 hour holter monitor in case of frequent but transient tachycardia
  • Loop recorder in patients with less frequent arrhythmias
  • Trans-esophageal atrial recordings if other investigations have failed to document an arrhythmia

Don'ts

  • Do not perform esophageal stimulation if an invasive electrophysiological investigation is planned.
  • Do not initiate treatment with anti-arrhythmic agents in a patient with undocumented arrhythmia.
  • Do not administer adenosine in patients with severe bronchial asthma or heart transplant recipients.[2]

References

  1. 1.0 1.1 1.2 1.3 1.4 "ACC/AHA/ESC Guidelines for the Management of Patients With Supraventricular Arrhythmias—Executive Summary". Retrieved 15 August 2013.
  2. 2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 Delacrétaz E (2006). "Clinical practice. Supraventricular tachycardia". N Engl J Med. 354 (10): 1039–51. doi:10.1056/NEJMcp051145. PMID 16525141.
  3. Cossú, SF.; Steinberg, JS. "Supraventricular tachyarrhythmias involving the sinus node: clinical and electrophysiologic characteristics". Prog Cardiovasc Dis. 41 (1): 51–63. PMID 9717859.
  4. Dhar S, Lidhoo P, Koul D, Dhar S, Bakhshi M, Deger FT (2009). "Current concepts and management strategies in atrial flutter". South. Med. J. 102 (9): 917–22. doi:10.1097/SMJ.0b013e3181b0f4b8. PMID 19668035. Unknown parameter |month= ignored (help)


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