1. -Prof .Dr.Gowrishankar’s Unit -Dr.A.Ishwarya

9. Bradyarrhythmia-Type Incidence Sinus Bradycardia 25% Junctional Escape Rhythm 20% Idioventricular escape rhythm 15% I Degree AV Block 15% II Degree AV Block –Type 1 12% II Degree AV Block –Type 2 4% Complete Heart block 15% RBBB 7% LBBB 5% LAFB 8% LPFB 0.5%

13. Site of block Intranodal Infranodal Site of infarction Inferoposterior Anteroseptal Compromised arterial supply RCA (90%), LCX (10%) Septal perforators of LAD Pathogenesis Ischemia, excess parasympathetic activity Ischemia, necrosis, hydropic cell swelling Predominant type of AV nodal block First-degree (PR > 200 msec) Mobitz type I second-degree Mobitz type II second-degree Third-degree Location Proximal conduction system (His bundle) Distal conduction system (bundle branches) QRS width <0.12/sec [*] >0.12/sec Rate 45-60/min but may be as low as 30/min Often <30/min

14. Stability of escape rhythm Rate usually stable; asystole uncommon Rate often unstable with moderate to high risk of ventricular asystole Duration of high-grade AV block Usually transient (2-3 days) Usually transient but some form of AV conduction disturbance and/or intraventricular defect may persist Associated mortality rate Low unless associated with hypotension and/or congestive heart failure High because of extensive infarction associated with power failure or ventricular arrhythmias