Impact of diastolic Doppler indices on exercise capacity in hypertensive patients with electrocardiographic left ventricular hypertrophy (a LIFE substudy).
Academic Article
Overview
abstract
OBJECTIVE: To assess whether Doppler evidence of impaired early diastolic relaxation during exercise is associated with lesser exercise capacity in hypertensive patients. DESIGN: Single center addition to the echocardiographic substudy in the Losartan Intervention For Endpoint (LIFE) reduction in hypertension study. SETTING: University hospital out-patient clinic. METHODS: A total of 60 patients (29 women and 31 men) with essential hypertension and electrocardiographic LV hypertrophy. INTERVENTIONS: Assessment of Doppler echocardiography and ergospirometry during semi-upright bicycling. MAIN OUTCOME MEASURE: Exercise capacity and its relation to diastolic Doppler indices at rest and during exercise. RESULTS: Average resting blood pressure was 181/97 +/- 18/9 mmHg, LV mass/body surface area 127 +/- 26 g/m2, midwall shortening 16 +/- 2%, and isovolumic relaxation time (IVRT) and transmitral early to atrial filling velocity (E/A) ratio 121 ms and 0.80, respectively. Exercise capacity, assessed as peak oxygen uptake and exercise load at exhaustion in all patients, were 20 and 25% higher, respectively, in men than women (both P < 0.01). In multivariate analysis, higher peak exercise load was related to male gender, higher E/A ratio at rest, greater reduction in IVRT during exercise and higher peak exercise heart rate (multiple R2 = 0.59, P < 0.01). Younger age, greater reduction in IVRT during exercise, higher midwall shortening and peak exercise heart rate were associated with higher peak oxygen uptake (multiple R2 = 0.47, P < 0.01). CONCLUSION: Diastolic LV performance significantly influences exercise capacity in hypertensive patients with LV hypertrophy. Impaired exercise capacity is more strongly associated with blunted reduction in IVRT during exercise than with lower E/A ratio at rest.
