Treadmill exercise increased alpha-hANP levels in complete heart block patients with coordinated atrial contraction (to 238.4 pg/mL, P=0.002) but not in those with chronic atrial fibrillation.
Observational (n=12)
Does the presence of coordinated atrial contraction affect the release of plasma atrial natriuretic peptide during exercise in patients with complete heart block?
Coordinated atrial contraction is required for the release of atrial natriuretic peptide during exercise in patients with complete heart block, independent of ventricular rate.
p-value: p=0.002
It is generally accepted that plasma atrial natriuretic peptide release occurs secondary to atrial stretch. The influence of coordinated atrial contraction (AC) upon this process is not fully appreciated. The aim of the study was to determine the importance of coordinated AC upon peripheral atrial natriuretic peptide levels (alpha-hANP) during exercise. Peripheral alpha-hANP levels were measured at rest and during exercise in 12 patients with complete heart block (CHB) and permanent rate responsive pacemakers. Seven patients had coordinated AC and five had chronic atrial fibrillation (AF). Each patient performed three treadmill exercise tests. Maximal inspired oxygen volume (VO2 max) was determined during test 1. Tests 2 and 3 were performed to 70% VO2 max, the pacemaker being programmed to either VVI or VVIR mode. Plasma alpha-hANP was measured using a two-site immunoradiometric assay. At rest there was a small but significant difference between the two patient groups: AF 60.2 pg/mL versus AC97.6 pg/mL; P = 0.03. During exercise in the AC patients, there was a significant increase in alpha-hANP levels, in VVIR mode, to 238.4 pg/mL, and in VVI mode, to 207.9 pg/mL, P = 0.002 and 0.003, respectively. In those patients with chronic AF, there was no significant rise or fall in alpha-hANP levels in either pacing mode, VVIR 65.2 pg/mL, VVI 46.6 pg/mL. Previous workers have suggested that alpha-hANP release by nonfunctioning atria is normal. We have shown that the presence of coordinated AC is required for the release of alpha-hANP during exercise in patients with CHB, and that this appears to be independent of ventricular rate.
Kelly et al. (Wed,) conducted a observational in Complete heart block (n=12). Treadmill exercise vs. Chronic atrial fibrillation was evaluated on Peripheral alpha-hANP levels (p=0.002). Treadmill exercise increased alpha-hANP levels in complete heart block patients with coordinated atrial contraction (to 238.4 pg/mL, P=0.002) but not in those with chronic atrial fibrillation.