Management of Type 2 Second-Degree AV Block (Mobitz Type II)

Diagnostic Evaluation

The American College of Cardiology recommends an echocardiogram as the initial evaluation for Mobitz Type II second-degree AV block to assess for structural heart disease, ventricular function, and underlying cardiac pathology 1, 2
An ambulatory ECG monitor (Holter) is recommended to assess the burden of block and detect progression 1
An exercise ECG test is recommended to evaluate the response to increased heart rate demands 1
The echocardiogram identifies structural heart disease that may be causing the conduction abnormality, assesses ventricular function, and guides pacing decisions 1, 3

Referral to an electrophysiologist is essential once the initial workup is complete, as Mobitz Type II block requires permanent pacemaker implantation regardless of symptoms 1, 2, 4
Infranodal blocks require pacing regardless of form or symptoms because they represent disease in the His-Purkinje system with a risk of progression to complete heart block 4
Permanent pacing is indicated for persistent second-degree AV block in the His-Purkinje system with bilateral bundle branch block, or transient advanced second-degree infranodal AV block with associated bundle branch block 4