Force-frequency relationship as a predictor of long-term prognosis in patients with heart diseases

Adequate evaluation of the nature of the residual failing myocardium, as well as the severity of myocardial injury, is important for managing patients with heart failure. The aim of this study was to investigate the myocardial function and the prognosis of patients with heart diseases using the force-frequency relationship (FFR). We enrolled 76 patients with sinus rhythm who had miscellaneous heart diseases and performed incremental right atrial pacing at the time of diagnostic cardiac catheterization. The first derivatives of left ventricular pressure (d P /d t ) were recorded using a micro manometer-tipped catheter during the study. To represent properties of FFR, two parameters—the peak force rate (PFR) and force gain (FG)—were estimated. PFR was defined as the heart rate at which d P /d t became maximum. FG was defined as the difference between d P /d t at PFR and d P /d t at the basal heart rate. FG decreased as the severity of left ventricular (LV) dysfunction increased (372.0 ± 110.7, 209.5 ± 29.1 and 116.3 ± 13.1 mmHg/s for normal LV function, mild LV dysfunction and severe LV dysfunction groups, P