Congenital Complete Heart Block: Ventriculophasic Sinus Arrhythmia

Report:

Sinus rhythm 67 – 70/min

Third degree AV block

Junctional escape rhythm 42/min

Ventriculophasic sinus arrhythmia

Right atrial abnormality (RAA)

Comment:

The ventricular rate is regular and slow, the faster P waves completely dissociated: complete AV block.

The P waves are themselves regularly irregular. This is a good example of ventriculophasic effect in complete AV block; it is usually more discernible in second degree blocks. The P waves surrounding the QRS are much closer together than those with “empty” cycles.

The patient received a permanent pacemaker (Fig 80a). Note the atrial pacing spikes trying, unsuccessfully, to contribute their share of pacing. They are too late for that and merely distort the native P waves (pseudofusion beats, a term more commonly applied to spikes in native QRS complexes).

The patient has normal “septal” q wave in V6, excluding corrected transposition as the cause of her block.

Fig 80a. Sensed sinus rhythm with ventricular pacing. The atrial electrode, however, fails to always sense the P wave and fires into it nevertheless.

Fig 81. 73 year old man with bradycardia and fatigue.