Plasma natriuretic peptide levels and daily physical activity in patients with pacemaker implantation

To determine whether plasma ANP and,,or BNP levels can be used to detect li mitations in daily physical activity after pacemaker implantation, we measu red plasma ANP and BNP levels at a pacemaker follow-up clinic in 56 patient s (62 +/- 15 yrs. 2AAI 9VVI, 34DDD. 7VDD and 4 rate-responsive modes). dail y physical activity evaluated by a specific activity scale questionnaire (M ETs) and VO2 max obtained by expired gas analysis during ergometer exercise . A very clouse correlation (n=6, r=0.89, p <0.05) was obseved between. ANP in patients with daily physical activity class III (2-4 METS, n=21) was si gnificantly higher than class II (5-6 METs, n=23, p <0.01) and class I (>7 METs, n=8, p <0.01), while BNP in class III patients was significantly high er than in class II (p <0.0001) and class I (p <0.0001) patients. Significa nt correlations between daily physical activity and BNP (r=-0.64, p <0.0001 ) and ANP (r=0.43, p <0.001) were observed. Physiological pacing mode did n ot necessarily offer a better profile for BNP levels compared with non-phys iological pacing modes. Patients with ventricular pacing (wide QRS: VDD. RR -VVI and VVI) showed significantly high ANP (p <0.01) and BNP (p <0.01) lev els compared with those in patients with atrial pacing (narrow QRS: AAI and RR-AAI). During exercise, plasma catecholamines and ANP levels were signif icantly elevated, however, BNP levels. which were already elevated at rest, did not change significantly, and reflected a limitation of daily physical activity. The present study revealed that 37.5% of the patients displayed an elevation in BNP and this was judged to be a limitation of physical acti vity class III being equivalent to NYHA II or more. Elevated resting BNP le vels reflected a [imitation in daily physical activity in these patients. T hese findings suggested a third condition for physiological pacing-synchron ization of ventricular contraction (narrow QRS pacing)-in addition to the t wo conventional conditions of atrioventricular synchrony and rate-responsiv eness.