Synchronous force and Ca²⁺ measurements for repeated characterization of excitation-contraction coupling in human...

Dysfunctional Ca²⁺ signaling affects the myocardial systole and diastole, may trigger arrhythmia and cause transcriptomic and proteomic modifications in heart failure. Thus, synchronous real-time measurement of Ca²⁺ and force is essential to investigate the relationship between contractility and Ca²⁺ signaling and the alteration of excitation-contraction coupling (ECC) in human failing myocardium. Here, we present a method for synchronized acquisition of intracellular Ca²⁺ and contraction force in long-term cultivated slices of human failing myocardium. Synchronous time series of contraction force and intracellular Ca²⁺ were used to calculate force-calcium loops and to analyze the dynamic alterations of ECC in response to various pacing frequencies, post-pause potentiation, high mechanical preload and pharmacological interventions in human failing myocardium. We provide an approach to simultaneously and repeatedly investigate alterations of contractility and Ca²⁺ signals in long-term cultured myocardium, which will allow detecting the effects of electrophysiological or pharmacological interventions on human myocardial ECC.