[Hemodynamic indications for DDD mode pacing therapy]

Because there are limits to the drug treatment or surgical intervention of advanced heart failure, alternative methods are being explored. It was the aim of this study to investigate the extent to which optimal atrioventricular (AV) sequence of dual pacemaker stimulation in patients with advanced dilated cardiomyopathy (DCM) of different aetiology increases their usually much reduced cardiac output.

The study group consisted of 22 patients (five women, 17 men; aged 54-84 years) with heart failure in class I-IV (New York Heart Association classification). Temporary dual electrode stimulations (in the right atrium and ventricle) in the VDD or DDD mode were performed with programmed AV intervals between 80 and 180 ms. Cardiac output (CO), pulmonary capillary and pulmonary arterial pressures were measured via an indwelling catheter.

In 17 patients with a 1 degree AV block and/or left bundle branch block in the surface ECG pacing produced a significant increase in CO (from 3.7 +/- 0.75 to 4.6 +/- 0.65 l/min; P < 0.005) and cardiac index (from 2.05 +/- 0.43 to 2.47 +/- 0.37 l/min/m2; P < 0.005). There was no increase in patients with normal PR interval and QRS duration. Mean pulmonary capillary and pulmonary arterial pressures remained unchanged.

Alteration of AV sequence by pacemaker in selected patients in the late stage of heart failure, particularly if there is also abnormal atrioventricular and/or intraventricular conduction delay, may be an effective complementary method of treatment.