Left ventricular function-conduction impairment as reflected by the ECG in chronic aortic regurgitation.

The study was conducted to ascertain that the ECG assists in the assessment of systolic dysfunction in chronic aortic regurgitation. Five variables were reviewed in 146 adults without bundle branch block who underwent angiocardiography: total 12-lead QRS amplitude, QRS duration, maximum R peak time in I, V5 or V6, maximum R peak time relative to S peak time of the maximum S in V1, V2 or V3, and maximum T wave amplitude and polarity in I, V6 or aVF. In order to define which of them could differentiate left ventricular ejection fraction (EF) ≥50% (n = 101) from EF <50% (n = 45) they were subjected to stepwise linear discriminant analysis.

[Cardiac memory of the ECG following ventricular pacing].

During abnormal pacemaker depolarization, abnormal repolarization occurs and persists in normal QRS beats often seen in alternation with paced beats. The T-wave direction of normal beats is typically similar to the direction of the QRS complex during pacing, hence the term cardiac memory. The normal nonpaced beats have shown a sensitivity of 92% and a specificity of 100% for cardiac memory in the presence of T-wave inversions (TWI) in the precordial and inferior (II, III and aVF) leads with a positive T wave in aVL, a positive or isoelectric T wave in lead I, and the maximal precordial TWI being greater than the TWI of lead III, discriminating it from ischemic precordial TWI.