Introduction: The therapeutical limits of drug and surgical therapy for severe chronic heart failure make the research for adjunctive treatment options necessary. After the positive effects of AV-synchronous pacemaker stimulation in patients with dilatative cardiomyopathy and 1st degree AV-block, this study was to evaluate the benefit of transient pacemaker stimulation in patients with dilated cardiomyopathy and left bundle branch block.
Methods and patients: 19 patients (14 male, 5 female, age 60 +/- 8 yrs) were included in the study. Inclusion criteria were congestive heart failure, stage NYHA III or greater and left bundle branch block. Transient stimulation of the myocardium was applied via two electrodes (right atrium and right ventricle) in VDD mode, whereby a series of AV-delay-times between 80 and 180 ms was tested. Thermodilution was used to determine cardiac output, pulmonary capillary pressure and pulmonary arterial pressure.
Results: In 16 patients, pacemaker stimulation led to a significant increase of cardiac output (3.8 +/- 0.5 l/min to 4.6 +/- 0.5 l/min; p < 0.002), cardiac index (1.90 +/- 0.20 l/min/m2 to 2.3 +/- 0.2 l/min/m2; p < 0.002) and of stroke volume (51 +/- 8 ml to 62 +/- 6 ml; p < 0.002) as well as a significant reduction of mean pulmonary capillary pressure (19 +/- 1 mmHg to 15 +/- 1 mmHg; p < 0.01). The mean pulmonary arterial pressure remained unchanged. Three patients did not benefit from the treatment.
Conclusion: AV-sequential pacemaker-stimulation (right ventricular electrode placement) can be a valuable adjunctive therapy in selected patients with late stage congestive heart failure and left bundle branch block.