Background: Left ventricular diastolic dysfunction (DD) is common after myocardial infarction (MI) despite preservation of left ventricular ejection fraction, yet it remains unclear how or whether DD affects cardiac hemodynamics with stress.
Methods and results: Invasive hemodynamic exercise testing was performed in 46 patients with a recent MI and left ventricular ejection fraction >45% and in 10 healthy volunteers. MI patients were enrolled prospectively and divided into those with DD (MI+DD; left atrial volume index >34 mL/m(2) and diastolic E/e' ratio>8; n=35) and those without DD (MI-DD; left atrial volume index <34 mL/m(2) and E/e' ratio<8; n=11). All underwent a supine cycle ergometer test with simultaneous right heart catheterization and echocardiography. At rest, 10 patients in MI+DD (29%) had pulmonary capillary wedge pressure >15 (14±4 mm Hg), whereas none of the MI-DD (10±2 mm Hg) or controls (9±2 mm Hg) displayed pulmonary capillary wedge pressure elevation (P=0.03). During exercise, an abnormal rise in pulmonary capillary wedge pressure (>25 mm Hg) was observed in 94% of MI+DD (36±6 mm Hg) compared with 36% of MI-DD (24±6 mm Hg) and none of the controls (16±6 mm Hg; P<0.0001). Exercise right atrial pressure was the highest in MI+DD followed by MI-DD and control (15±5 versus 9±4 versus 7±5 mm Hg; P<0.001), whereas no difference in cardiac index was found between groups.
Conclusions: In post-MI patients with preserved ejection fraction and left ventricular DD, cardiac output with exercise is maintained at the expense of substantially increased filling pressure. DD and loss of diastolic reserve may promote progression from stage B to stage C heart failure after MI.