N-terminal pro-atrial natriuretic peptide and exercise prescription in patients with myocardial infarction.

BACKGROUND

Left ventricular end-diastolic pressure (LVEDP) during exercise workload is an important parameter to guide an exercise prescription for patients with cardiovascular disease. Plasma levels of neuro-hormonal factors can be used as a reflection of real-time LVEDP, but its utility is limited by its short half-life. By contrast, the N-terminal fragment of pro-ANP (NT-ANP) has a longer half-life of 1 h.

OBJECTIVE

To determine whether plasma NT-ANP levels at 30 min after exercise can be used as a marker of LVEDP during peak exercise workload in patients with previous myocardial infarction.

PATIENTS

Twenty patients with a previous history of myocardial infarction.

INTERVENTIONS

Cardiopulmonary exercise test was performed to determine peak VO(2) and anaerobic threshold. Plasma levels of ANP, BNP, NT-ANP, vasopressin and plasma catecholamine were measured at rest, maximum exercise, and 30 min after exercise (recovery).

RESULTS

With the exception of NT-ANP, the levels of each of neuro-hormonal factors peaked at maximum exercise and returned to baseline at recovery. By contrast, NT-ANP levels also increased at peak exercise but remained elevated at 30 min after exercise. Furthermore, NT-ANP levels at recovery correlated with ANP levels at maximum exercise (p<0.01, R=0.75), left ventricular ejection fraction (p<0.02, R=-0.54) and left ventricular systolic dimension (p<0.015, R=0.50).

CONCLUSION

Plasma NT-ANP levels at 30 min after exercise reflect ANP levels at maximum exercise and left ventricular overload during exercise. These data indicate that plasma NT-ANP after exercise may be a useful parameter to guide prescription of cardiac rehabilitation.