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. METHODS AND 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.
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. METHODS AND 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.
Authors: Margaret Infeld; Kramer Wahlberg; Jillian Cicero; Sean Meagher; Nicole Habel; Anand Muthu Krishnan; Daniel N Silverman; Daniel L Lustgarten; Markus Meyer Journal: Heart Rhythm O2 Date: 2021-12-07