Sinoatrial Block: CVA

Report:

Sinus rhythm

Sinus pauses - probable Wenckebach exit block

Junctional escape beats and rhythm

Atrial fusion beats

SVEB.

Comment:

The sinus cycles tend to shorten before the pause, a characteristic of Möbitz 1 (Wenckebach) exit block. There is no concomitant prolongation of the PR intervals; the entire P-QRS-T sequence accelerates before the block. The pauses created cannot be determined due to the intervention of the subsidiary, junctional pacemaker. They appear longer than two (shortest) sinus cycles, perhaps through an associated sinus arrhythmia.

Some junctional escape beats are followed by P waves smaller than the sinus P waves, possibly atrial fusion between the tall sinus P waves and the inverted junctional ones. A simpler explanation would be atrial escape beats.

Prominent P waves have been described in a variety of cerebral diseases28.

The best clue that a trace may be affected by brain injury is prolongation of the QT interval. It is not striking in this example, but it is there: the interval is obviously longer than ½ R-R interval at faster rates and it does not shorten.

Despite the occasional call in the literature29 for monitoring the patients with CVAs electrocardiographically, I have yet to see one who benefited from this. Many are monitored simply because they are in the ICU anyway. Those that do not require ICU on other grounds do not appear to need it for monitoring of arrhythmias. No therapy was even contemplated for this patient.