Sandbox:Sahar

Pathophysiology of Syncope

Cerebral hypoperfusion

Low cardiac output

Low peripheral resistance

Regular

Irregular

Regular

Irregular

• Sinus bradycardia • Junctional bradycardia • Complete AV block (junctional escape) • Atrial flutter with high degree block

• Sinus arrhythmia, pause or arrest • Sinoatrial exit block (second degree) • AF with slow ventricular response • Atrial flutter with variable block • Second degree AV block, type I • Second degree AV block, type II

• Idioventricular rhythm • Complete AV block (ventricular escape) • Sinoventricular rhythm • Regular bradycardias with aberrancy or bundle branch block

• Second degree AV block, type I • Second degree AV block, type II • Sinoatrial exit block (second degree) with bundle branch block • Irregular bradycardias with bundle branch block

Common Causes of Sick sinus syndrome
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Images

Contrast enhanced CT: Aortic intramural hematoma, Courtesy of radiopaedia

Contrast enhanced CT: Aortic intramural hematoma, Courtesy of radiopaedia

Contrast enhanced CT: Aortic intramural hematoma, Courtesy of radiopaedia

Contrast enhanced CT: Aortic intramural hematoma, Courtesy of radiopaedia

Contrast enhanced CT: Aortic intramural hematoma, Courtesy of radiopaedia

Contrast enhanced CT: Aortic intramural hematoma, Courtesy of radiopaedia

Disease Name	Age of Onset	Gender Preponderance	Signs/Symptoms	Imaging Feature(s)	Macroscopic Feature(s)	Microscopic Feature(s)	Laboratory Findings(s)	Other Feature(s)	ECG view