High resolution

Module 7: Figure heart summary

Summary of major physiological and pathophysiological processes in the heart.

The sinoatrial node cell, which has a typical membrane oscillator, is responsible for pacemaking by generating an action potential that spreads to the atrial and ventricular cells to initiate excitation–contraction coupling that occurs on a millisecond time scale. Phenotypic remodelling through phosphorylation/dephosphorylation processes can change the force of contraction (positive and negative inotropy) over a time scale of seconds. Phenotypic remodelling operating over minutes/hours or longer can enhance the size of the heart (hypertrophy) and can also lead to pathophysiological changes resulting in arrhythmias and congestive heart failure (CHF).