What is depolarization of the heart?

Depolarization of the heart refers to the electrical activation of the heart muscle cells during each heartbeat. The depolarization wave starts from the sinoatrial (SA) node, spreads through both atria causing them to contract, and then moves to the atrioventricular (AV) node before continuing through the bundle of His, Purkinje fibers and ventricular muscle, causing the ventricles to contract.

The depolarization is caused by the movement of positively charged ions, primarily sodium (Na+) and calcium (Ca2+), across the cell membrane, allowing for the rapid electrical activation of the cells. Once the depolarization wave passes, the cells recover and go through a period of repolarization before being ready for the next contraction.

The depolarization and repolarization of the heart can be measured through an electrocardiogram (ECG), which records the electrical activity of the heart and can help diagnose various cardiac conditions. Any abnormalities in the depolarization of the heart can lead to arrhythmias, tachycardia or other cardiac issues.