OBJECTIVE: Abnormal left ventricular diastolic function, and NT-proBNP levels have been demonstrated in patients with hypertrophic cardiomyopathy (HCM), but there is lack of information about exercise hemodynamics. In this prospective study, we aimed to examine the prognostic value of diastolic function, and NT-proBNP levels response to exercise in HCM patients.MATERIAL AND METHODS: Twenty patients (age: 52.6±11.3 years; n=12 (60%) men) with diagnosis of nonobstructive HCM and 11 volunteers (age: 46.4±13.0 years; n=8 (72.7%) men) serving as controls performed incremental cycle ergometry (25 –W, 2 minutes). Mitral inflow (E/A ratio), septal mitral annulus velocities (E/E’ ratio), and NT-proBNP levels were measured at rest and at submaximal exercise. Furthermore, patients were followed for four years.RESULTS: Higher E/E’ ratio and NT-proBNP levels were detected at rest in HCM patients (E/E’ratio : 15.36 ±4.90 vs 7.97± 1, 44; p< 0.001, NT-proBNP: 348,25±215.71 pg/ml vs 37.27±11.93 pg/ml; p< 0.001). With exercise there was no significant elevation in controls, however E/E’ ratio and, NT-proBNP levels incresed significantly in patients with HCM ( E/E’ ratio: 23.83±10.85 vs 8.01±2.22; p< 0.001, NT-proBNP: 591.25±276.28 pg/ml vs 40.0± 12.03 pg/ml; p<0.001 ). Also, four-year follow-up, none of the patients had died.CONCLUSIONS: Nonobstructive HCM patients have diastolic dysfunction, elevated filling pressures and NT-proBNP levels and these abnormalities worsen during maximal exercise. but our findings did not predict mortality.