Intraventricular Conduction Delay

Report:

Atrial fibrillation with rapid ventricular response 159/min

Intraventricular conduction delay (IVCD), QRS 0.26”

Comment:

The tracing has some elements of RBBB with marked LAD due to QS in lead 2 and Qr in 3 and aVF. In lead 1, however, the initial QRS is delayed as much as the terminal QRS: this is not a simple fascicular conduction defect. The designation of IVCD does not necessarily negate a fascicular (BBB or a hemiblock) contribution to the overall QRS prolongation, but the latter has to remain speculative.

The speculation in this case naturally led to Chagasic cardiomyopathy, often expressed as RBBB + LAHB. Indeed, the autopsy showed massively enlarged (1 Kg) heart and a recent basal infarction; most of the enlargement, however, was due to fibrosis consistent with chronic Chagas disease.

The irregularity of the uniform complexes practically excludes VT (diagnosed by the computer); anomalous (WPW) conduction of AF would be expected to be faster and not completely uniform. Below is another trace, less obviously AF. Before measuring the cycles I thought it might be atrial flutter. The terminal negative notches resembling retrograde P waves are still present in the inferior leads: they are part of the QRS complex.

Fig 58a.

Fig 59. 23 year old man with cirrhosis and portal and pulmonary hypertension since infancy.