Force- and relaxation-frequency relations in patients with diastolic heart failure.
BACKGROUND
Chronotropic effects on myocardial contractility (the positive force-frequency relation) and relaxation (the positive relaxation-frequency relation) are impaired in patients with congestive heart failure and depressed left ventricular (LV) ejection fraction (systolic heart failure [SHF]). However, the force- and relaxation-frequency relation and LV-arterial coupling in patients with diastolic heart failure (DHF) has not been fully investigated.


RESULTS
To examine inotropic and lusitropic responsiveness to atrial pacing, LV pressure-volume relations were measured using a conductance catheter and microtip manometer in patients with DHF (n = 18) and SHF (n = 11). In patients with SHF, an increase in heart rate by 40 beat/min did not affect LV end-systolic elastance (Ees), which reflects LV contractility, or the time constant of LV relaxation. By contrast, in patients with DHF, an increase in heart rate by 40 beat/min significantly enhanced Ees (2.1 vs 2.9 mm Hg/mL, P < .05) but not the time constant. Furthermore, LV-arterial coupling, quantified as Ees/arterial elastance, was impaired during pacing in patients with DHF (1.1 vs 0.8, P < .05) as well as SHF.


CONCLUSIONS
In patients with DHF, the force-frequency relation was preserved, but the relaxation-frequency relation was impaired. Furthermore, LV-arterial coupling was impaired as heart rate increased, which may be related to the impaired LV function. These results suggest that the impaired relaxation-frequency relation and exacerbated LV-arterial coupling during tachycardia may be an important therapeutic target in patients with DHF.
Yamanaka
Takashi
T
The First Department of Internal Medicine, Mie University School of Medicine, Tsu, Japan.
Onishi
Katsuya
K
Tanabe
Masaki
M
Dohi
Kaoru
K
Funabiki-Yamanaka
Kaoru
K
Fujimoto
Naoki
N
Kurita
Tairo
T
Tanigawa
Takashi
T
Kitamura
Tetsuya
T
Ito
Masaaki
M
Nobori
Tsutomu
T
Nakano
Takeshi
T
D000328:Adult; D000368:Aged; D002304:Cardiac Pacing, Artificial; D003971:Diastole / Q000502:physiology; D005260:Female; D006333:Heart Failure / Q000503:physiopathology*; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009200:Myocardial Contraction / Q000502:physiology*; D013610:Tachycardia / Q000503:physiopathology; D018487:Ventricular Dysfunction, Left / Q000503:physiopathology*