SEARCH FOR AN ALTERNATIVE TREATMENT: The concept of stimulating the ventricle to improve heart function in patients with severe heart failure is an old one, but the first published series was reported about 10 years ago and provided encouraging results that lead to numerous other studies. A PROMISING TECHNIQUE: Excepting a few patients with a long PR, stimulation of the right ventricle is ineffective or even deleterious. Stimulation of the lateral region of the left ventricle has produced some undeniably favorable and sometimes even spectacular improvement in hemodynamic performances. Permanent stimulation of both ventricles or the left ventricle produces an overall clinical improvement in patients with severe heart failure (NYHA III or IV) and major left intraventricular conduction disorders (QRS > 140 ms). These results have been recently confirmed in a prospective randomized trial. CAREFUL OPEN QUESTIONS: There is no fully satisfactory explanation for the improvement which, it is important to note, does not occur in all patients. A more homogeneous contraction of the left ventricle certainly plays a fundamental role. Resynchronization of the two ventricles with dual stimulation is more complex and costly and remains to be evaluated. One crucial question is currently being examined: what is the effect of stimulation on the high mortality in these patients?