Ventricular endocardial right bifocal stimulation in the treatment of severe dilated cardiomyopathy heart failure with wide QRS

The QRS widening by ventricular conventional pacing impairs the systolic an d diastolic functions and increases mitral regurgitation. The aim of this s tudy was to compare conventional pacing to an alternative stimulation mode with a narrower QRS using two leads in the RV. Thirty-nine (25 men, 14 wome n; mean age 60,1 +/- 15.1 years) dilated cardiomyopathy patients (Chagas' d isease fn = 17], coronariopathy [n = 9], AV ablation for tachycardiomyopath y [n = 3], and other [n = 10]) with cardiac failure (NYHA 3,1 +/- 0.8), pac emaker indication, and chronic AV block (22 AF) had endocardial pacemaker i mplantations (27 Biotronik, 12 Guidant). Two RV leads (one septa], one conv entional [RV apex] were connected, respectively, to the atria] and ventricu lar pacemaker plugs. After clinical stabilization they were studied under t hree stimulation modes in the same session: AAI (septal), VVI (conventional ), and ventricular endocardial right bifocal stimulation (VERBS) (DDT/DVI/D DD = AV interval = 15/10 ms). In comparison to conventional pacing, VERBS i ncreased ejection fraction (0,124), cardiac output (19,5%), and peak fillin g rate (31.0%), and decreased QRS duration (24.7%), left atrium area (11.9% ), mitral regurgitation area (32.3%), the diastolic transmitral flow (EIA r elation) (19.3%), and the propagation flow time (18.0%) from the mitral val ve to the left ventricular apex (tE_col), (P < 0.05). The quality-of-life s howed an impressive score reduction of 50.4%. The septa] stimulation alone showed a less expressive benefit. In severe dilated cardiomyopathy with cla ssic pacemaker indication, VERBS showed significantly better performance th an the septal or the conventional stimulation alone. There was a good systo lic and a remarkable diastolic improvement causing an important reduction i n the quality-of-life score.