The effect of heart rate on the working capacity of patients with complete heart block and physiological pacemaker
Lukl, J.; Heinc, P.
Cor et Vasa 33(6): 506-513
1991
ISSN/ISBN: 0010-8650 PMID: 1842943 Document Number: 386027
The effect of heart rate (HR) on maximum working capacity was studied in 18 patients (mean age 55 years) with a physiological pacemaker implanted for chronic complete heart block of different aetiology. Exercise testing was performed by bicycle ergometry in 3 pacing protocols in randomized sequence, and without the patients knowing the preprogrammed pacing mode: 1) VVI pacing at a rate of 30 beats/min--exercise on heart block; 2) VVI pacing at a rate of 70 beats/min; 3) physiological DDD or QT pacing. While patients with heart block had a mean HR of 54 +/- 16 beats/min and working capacity of 81 +/- 31 W, on VVI 70 pacing the values were 73 +/- 9 beats/min (+35%, p < 0.002) and 100 +/- 45 W (+24%, p < 0.008), respectively. Exercise during physiological pacing led to an increase in HR to 140 +/- 15 beats/min (+169%, p < 0.002) and in working capacity to 130 +/- 52 W (+61%, p < 0.002). Thus, the increment in working capacity was 2.5 times higher on physiological than standard ventricular pacing (p < 0.005) if compared with the working capacity of patients with heart block.