Pathophysiological characterization of isolated diastolic heart failure in comparison to systolic heart failure

Context Many older patients with symptoms of congestive heart failure have a preserved left ventricular ejection fraction (LVEF). However, the pathophysiology of this disorder, presumptively termed diastolic heart failure (DHF), is not well characterized and it is unknown whether it represents true heart failure. Objective To assess the 4 key pathophysiological domains that characterize classic heart failure by systematically performing measurements in older patients with presumed DHF and comparing these results with those from age-matched healthy volunteers and patients with classic systolic heart failure (SHF). Design and Setting Observational clinical investigation conducted in 1998 in a general community and teaching hospital in Winston-Salem, NC. Participants A total of 147 subjects aged at least 60 years. Fifty-nine had isolated DHF defined as clinically presumed heart failure, LVEF of at least 50%, and no evidence of significant coronary, valvular, or pulmonary disease. Sixty had typical SHF (LVEF :less than or equal to35%). Twenty-eight were age-matched healthy volunteer controls. Main Outcome Measures Left ventricular structure and function, exercise capacity, neuroendocrine function, and quality of life. Results By echocardiography, mean (SE) LVEF was 60% (2%) inpatients with DHF vs 31% (2%) in those with SHF and 54% (2%) in controls. Mean (SE) LV mass-volume ratio was markedly increased in patients with DHF (2.12 [0.14] g/mL) vs those with SHF (1.22 [0.14] g/mL) (P<.001) and vs controls (1.49 [0.17] g/mL) (P=.002). Peak oxygen consumption by expired gas analysis during cycle ergometry was similar in the DHF and SHF groups (14.2 [0.5] and 13.1 [0.5] mL/kg per minute, respectively; P=.40) and in both was markedly reduced compared with healthy controls (19.9 [0.7] mL/kg per minute) (P=.001 for both). Ventilatory anaerobic threshold was similar in the DHF and SHF groups (9.1 [0.3] and 8.7 [0.3] mL/kg per minute, respectively; P<.001) and in both was reduced compared with healthy controls (11.5 [0.4] mL/kg per minute) (P<.001). Norepinephrine levels were similar in the DHF (306 [64] pg/mL) and SHF (287 [62] pg/mL) groups (P=.56) and in both were markedly increased vs healthy controls (169 [80] pg/mL) (P=.007 and .03, respectively). Brain natriuretic peptide was substantially increased in both the DHF (56 [30] pg/mL) and the SHF (154 [28] pg/mL) groups compared with healthy controls (3 [38] pg/mL) (P=.02 and .001, respectively). Quality-of-life decrement score as assessed by the Minnesota Living with Heart Failure Questionnaire was substantially increased from the benchmark score of 10 in both groups (SHF: 43.8 [3.9]; DHF: 24.8 [4.4]). Conclusion Patients with isolated DHF have similar though not as severe pathophysiologic characteristics compared with patients with typical SHF, including severely reduced exercise capacity, neuroendocrine activation, and impaired quality of life.