Selection of patients for cardiac resynchronisation therapy (CRT) in an unselected heart failure population

In patients with chronic heart failure (CHF), the presence of conduction delay across the myocardium is a well-known feature. During recent years an increasing number of CHF patients have been treated with cardiac resynchronisation therapy (CRT). So far in many protocols patients have been selected using the criteria of left ventricular ejection fraction (LVEF) ≤35% concomitant with signs of widening of the QRS on the surface electrocardiogram, either with or without left bundle branch block (LBBB) morphology.

In this article we discuss which of the patients admitted with CHF to a regular cardiology practice could be candidates for this therapy. Data were obtained from January 2000 to December 2004 on a total of 861 CHF patients, of whom 309 had an LVEF ≤35%. Of these patients, 123 patients showed a QRS width >120 msec, while 81 patient had a QRS width >140 msec. In total, 89 patients had an LBBB morphology on the electrocardiogram, while 21 patients had univentricular pacing devices in situ. In those patients with an LVEF >35%, QRS width was 108±27msec.

A substantial number of patients presenting with CHF in a regular cardiology practice are suitable candidates for CRT therapy according to currently used criteria of QRS width and LVEF. This number could be increased even more if recent information concerning intraventricular conduction delay in CHF patients with less widening of the QRS complex were to be applied, as judged by echocardiographic techniques.