MASHHAD , IRAN
Background- Electrocardiography is one of the oldest, easiest, simplest and most important inexpensive paraclinical tools in cardiology. Being able to use this easy method with enough sensitivity would be a great aid to the cardiologist in evaluating a common problem like congestive heart failure (CHF).
Method- Two hundred cases with left bundle branch block (LBBB) were chosen and divided into two groups: QRS duration less than 120msec in the first group, and more than 120msec in the second group. Left ventricular ejection fraction (LVEF) was studied by 2D, M-mode and Doppler echocardiography as an index of LV systolic function. Results- In cases with QRS duration less than 120msec, LVEF averaged between 40-50%. In the other group with QRS duration more than or equal 120mseconds, LVEF was between 30-40%. Finally, when QRS duration exceeded 160msec, almost all of the patients had LVEF less than 30%.
Conclusion- LV systolic function could be estimated with an acceptable sensitivity by observing surface ECG in LBBB cases. This observation may lead to conceptual support for attempts at normalizing QRS duration by biventricular or multi-site ventricular pacing in patients with severe LV systolic dysfunction (Iranian Heart Journal 2003; 4 (4):31-34).