SURFACE ECG: AN ACCEPTABLE METHOD FOR EVALUATING LV FUNCTION IN LBBB CASES

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).