HEART FAILURE

Second degree AV heart block - Mobitz Type 2

ECG characteristics

· Atrial rhythm : regular

· Ventricular rhythm : regular or irregular , pause corresponds to non-

conducted beat

· PR interval : remains constant until QRS complex is absent

· QRS complex : duration and configuration usually normal ,

Complex is periodically absent

Possible causes

· Organic heart disease i.e. Anterior wall myocardial infarction

Severe coronary artery disease

Acute myocarditis

NOTE: Type II AV block is more dangerous than type I due to the higher

incidence of associated symptoms and progression to third degree heart block

Treatment

· If symptomatic - atropine or isuprel may be administered

Consider CPR

Consider pacing therapy

Third degree AV block - (Complete heart block)

ECG characteristics

· Atrial rhythm : regular , no relationship between atrial

and ventricular rhythm.

· Ventricular rhythm : regular

· Atrial rate : usually exceeds ventricular rate

· Ventricular rate : usually less than 40 beats per minute

· PR interval : varies , no relationship with P wave and

QRS complex exists

· QRS complex : configuration varies

Possible causes

· Mitral valve replacement surgery (chronic block)

· Severe digoxin toxicity

· Anterior or inferior wall myocardial infarction (acute block)

· Cardiac catheterisation , angioplasty (transient block)

· Bilateral bundle branch block

· Congenital abnormality

· Rheumatic fever

· Hypoxia

Treatment

· If asymptomatic - monitor patient, consider permanent pacemaker

· If symptomatic - Transthoracic (Zoll) pacing until transvenous / permanent pacing can be instituted.

· If transthoracic pacing not effective: - perform CPR until transvenous or pacing swan is inserted.