Influence of the force—frequency relationship on haemodynamics and left ventricular function in patients with non-failing hearts and in patients with dilated cardiomyopathy

Abstract

In isolated human myocardium it was shown that a positive force-frequency relationship occurs in non-failing myocardium; however, the force-frequency relationship was found to be inverse in myocardium from failing human hearts. In order to investigate the clinical relevance of these experimental findings, the influence of heart rate changes on haemodynamics and left ventricular function was studied in eight patients without heart failure and in nine with failing dilated cardiomyopathy (NYHA II-III). Right ventricular pacing was performed at a rate slightly above sinus rate and at 100, 120 and 140 beats.min-1. Haemodynamic parameters were obtained by right heart catheterization and by high-fidelity left ventricular pressure measurements. Left ventricular angiography was performed at basal pacing rate and at 100 and 140 beats.min-1. With increasing heart rate, cardiac index increased in patients with normal left ventricular function from 2.9 +/- 0.2 to 3.5 +/- 0.21.min-1.m-2 (P < 0.01) and decreased continuously in patients with dilated cardiomyopathy from 2.6 +/- 0.1 to 2.2 +/- 0.1 l.min-1. m-2 (P < 0.05). With increasing heart rate, the maximum rate of left ventricular pressure rise increased in non-failing hearts from 1388 +/- 86 to 1671 +/- 88 mmHg.s-1 (P < 0.01) and did not change in failing hearts. Ejection fraction decreased from 27 +/- 3% to 19 +/- 2% in patients with dilated cardiomyopathy (P < 0.05) when the pacing rate was changed from 84 +/- 2 beats.min-1 to 140 beats.min-1, which was associated with a significant increase in end-systolic volume without significant changes in end-diastolic volume.(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiac Hypertrophy and Impaired Relaxation in Transgenic Mice Overexpressing Triadin 1

“…Cardiomyocyte Shortening-frequency Relationship-A correlation between an impaired SR-Ca 2ϩ handling and an altered force-frequency relationship in myocardium has been described previously (35,36). Therefore, we compared the shorteningfrequency relationship in isolated cardiomyocytes from wildtype and triadin 1-overexpressing mice.…”

Determinants of frequency-dependent contraction and relaxation of mammalian myocardium

“…The accelerated relaxation that occurs with an increase in stimulation frequency remains less well understood, but recent studies suggest that not only the faster intracellular calcium decline, but also the myofilament responsiveness plays a critical role. Given the fact that the altered frequency-dependent response is a critical modulator of cardiac function, and this modulating function is severely impaired in various cardiomyopathies [57,58], a better understanding of the mechanisms underlying frequency-dependent modulation of contractility and relaxation, including post-rest potentiation and extra-systolic beat behavior, may be paramount in development of treatment of these cardiomyopathies. Comparison of the force frequency relationships in various species.…”

Canadian Cardiovascular Society consensus conference recommendations on heart failure 2006: Diagnosis and management

“…The presence of atrial fibrillation can potentially cause an adverse effect in several different ways (54)(55)(56)(57). Loss of atrial enhancement of ventricular filling may compromise cardiac output.…”