Intermittent LBBB and P Mitrale or Tricuspidale?

Intermittent LBBB and P Mitrale or Tricuspidale? Intermittent LBBB and P Mitrale or Tricuspidale Intermittent left bundle branch block pattern is seen as wide notched QRS complexes with cycle length of 570 ms. Narrower QRS complexes at cycle length of 600 ms are seen towards the end of the tracing. This can be considered as phasic aberrancy which is rate dependent. Classically rate dependent left bundle branch block is deceleration dependent rather than acceleration dependent. Acceleration dependent block is usually right bundle branch block. P waves are wide and notched, suggesting left atrial overload. But close scrutiny shows that the initial peak is taller than the second peak. In P mitrale we expect the second peak to be taller as left atrial component of P waves is the second part. Here comes the discussion on P tricuspidale, which has a taller first peak in lead II [1,2]. The original description of ‘P tricuspidale’ was by Zuckermann R et al in 1952 [3]. The pattern is a mirror image of the ‘P mitrale‘ in which the second peak is taller. P tricuspidale was noted by Gamboa R and associates in 81% of their 37 patients with tricuspid atresia, while it was seen in only 2 of their 20 patients with pulmonary atresia [1]. In P tricuspidale, the taller initial peak is the right atrial component and the second wider peak is the left atrial component. That is how it indicates biatrial enlargement with preponderance of right atrium. It may be noted that i...
Source: Cardiophile MD - Category: Cardiology Authors: Tags: ECG / Electrophysiology ECG Library Source Type: blogs