Category Archives: Atrioventricular Block

Exercise-Related Atrioventricular Block (4)

Given the large area of distribution of the right coronary artery in the patient presented herein, which included blood supply to the AV node and a significant portion of the interventricular septum, conduction block could have resulted from transient AV nodal ischemia or secondary to ischemia of the infranodal system. The fact the exercise-related conduction block was not seen following angioplasty of the right coronary artery further supports this hypothesis.

Exercise-Related Atrioventricular Block (3)

Exercise-Related Atrioventricular Block (3)Further support is derived from a case report by Bharati et al that demonstrated transient conduction block proximal to the His bundle occurring during an episode of presumed coronary artery spasm in a patient with 90 percent obstruction of the right coronary artery.
Exercise-induced ST elevations in the anterior precordial leads suggests severe disease in the left anterior artery, often occurring in association with marked left ventricular wall motion abnormality, but cardiac catheterization did not reveal evidence of either problem in this patient. One explanation for ST elevations in the absence of significant obstructive disease is coronary artery spasm, which may also lead to nonsustained ventricular arrhythmia and heart block. However, while coronary artery spasm has been reported to occur during exercise,,(M3 none of these reports includes mention of exercise-related conduction block. In addition, the fact that the exercise-related ST elevation and arrhythmia occurred with the patient receiving a calcium channel blocker goes somewhat against attributing the findings to coronary artery spasm.

Exercise-Related Atrioventricular Block (2)

Cardiac catheterization revealed a right dominant circulation, with a 90 percent proximal obstruction of the right coronary artery (Fig 3). The left anterior descending and circumflex arteries had no obstructions, and the ventricular conduction pattern was normal.
The patient subsequendy underwent successful angioplasty using a perfusion balloon dilatation catheter to allow continuous blood flow during inflations; no arrhythmia occurred during die procedure. Follow-up thallium exercise testing three weeks later (while receiving diltiazem) revealed no arrhythmia or evidence of inducible myocardial ischemia.

Exercise-Related Atrioventricular Block (1)

Exercise-Related Atrioventricular Block (1)Exercise-related atrioventricular (AV) block is an uncommon arrhythmia that has recently been attributed to intrinsic conduction system disease. The following case report shows the importance of considering ischemia as a possible cause for exercise-related AV block.