Heart failure commonly results in a progressive decline of electrical and hemodynamic cardiac function. Furthermore, activation of compensatory mechanisms affecting the surviving myocardium and cardiomyocytes significantly contributes to cardiac dysfunction. To address pathophysiological mechanisms in heart failure, we investigate multiple levels from cellular biophysics to in vivo physiology with a focus on early, potentially causal alterations. The following (i) disease models and (ii) strategies are considered. (i) Rapidly progressing disease models including myocardial infarction; monogenetic, late-onset disease models; monogenetic models requiring modifier mechanisms for disease expression. (ii) The following techniques are considered in the context of heart failure and cardiomyopathy: diagnostic in vivo phenotyping techniques; noninvasive imaging and quantitative electrophysiological evaluation of the multicellular substrate; isolated cell imaging and electrophysiology; and subcellular super-resolution imaging. Examples of a combination of strategies to elucidate multifactorial disease mechanisms of defective ion transport and abnormal membrane excitability are discussed. In conclusion, progressive tissue remodeling and arrhythmogenic substrate expression represent complex disease biology, improved understanding of which depends critically on reproducible pathophysiological models and integrative translational approaches.