Abstract 4432: Reduced Longitudinal Functional Reserve on Exercise in Hypertensive Patients with Exertional Dyspnoea and Normal Echocardiography at Rest
Background: Many patients with hypertension complain of breathlessness for which there often appears to be no obvious cardiac or pulmonary cause. Despite normal ventricular function at rest, reserve may be impaired on exercise which may account for the symptoms. Therefore, we have conducted exercise-echocardiography studies in a group of hypertensive patients with normal pulmonary function and normal ejection fraction.
Methods: Hypertensive patients with exertional dyspnoea and normal LV and LA chamber size, LV mass and LVEF>50%, and age-matched controls were recruited. Supine exercise echocardiography was performed to comparable heart rates and images were analysed off-line (EchoPac). LV systolic and diastolic longitudinal reserve indices (LFRI) were determined from the peak annular velocities by TDI (PW-Doppler) at rest and on exercise (Difference=Δ); longitudinal functional reserve index =Δ Sm(or Em)*(1–1/Sm(or Em) at rest). All echocardiograms were read by 2 observers and results averaged.
Results: 28 pts (age 69±7 yrs, 17 females, LVEF 60±7%) with dyspnoea on exercise and 13 age matched normal controls (age 66±5 yrs, 10 females, LVEF 62±9%) with adequate images and heart rate responses on exercise were analysed. The LV mass index (LVMI) and the inter-ventricular septum thickness were similar in both groups (79±17g/m 2 vs. 80±20g/m2 and 1.01±0.30cm vs. 0.99±0.25cm). The patients had significantly lower LFRI (systolic LFRI 0.9± 1.4 vs. 2.2±1.4 (p=0.008); diastolic LFRI 2.2±1.5 vs. 3.9 ±2.9 (p= 0.023)).
Conclusions: Exercise echocardiography can reveal abnormal LV function which is not apparent at rest. This may account for the symptoms of exertional dysnoea in hypertensive patients even in the absence of LV hypertrophy.