Alternating LBBB with Right Axis Deviation

Report:

Sinus rhythm 93/min

Alternating complete & incomplete left bundle branch block

Axis +95o with complete LBBB

Indeterminate axis with incomplete LBBB

Comment:

The basic LBBB morphology is, as always, best seen in lead V1. In the limb leads, both complete and incomplete LBBB are widely notched and atypical. The incomplete LBBB is, roughly, equiphasic in all 6 frontal plane leads – the indeterminate axis. The complete LBBB is slightly more negative than positive – or, at least, also equiphasic – in lead 1, producing the RAD.

This is the only patient with normal ventricle and LBBB/RAD combination I have seen so far. He presented with distal dissection only, when a normal transœsophageal echo was obtained. Taken to OR to repair the intima, he dissected proximally and the aortic root had to be replaced, with resuspension of the valve. On few occasions he was profoundly hypotensive: this may well be the mechanism of myocardial damage to account for transient LBBB. One usually suspects the surgeon’s fingers in cases like this, but this is unfair.

Subsequently, LV function and the ECG (Fig 33a) normalised.

An example of permanent LBBB and RAD in a patient with congestive cardiomyopathy is shown in Fig 33b.

Fig 33a. Two days later the ECG normalised.

Fig 33b. Different patient, a 73 year old lady with chronic AF, cardiomegaly and LV failure, but no angina. LBBB with RAD is rare, but typical of congestive cardiomyopathy. Lead V6 is probably misplaced.

Fig 33c. Same patient 6 months earlier, with normal axis.

Fig 34. 18 year old girl following ingestion of (potentially) fatal amount of hydroxychloroquine.