10.2 : 심부정맥의 기전

The cardiac function relies on synchronized electrical activity to maintain a regular rate and rhythm, ensuring effective hemodynamics.

Any deviation leads to cardiac arrhythmias  or dysrhythmias.

These deviations manifest as bradyarrhythmia, characterized by a slow heart rate, or tachyarrhythmia, a rapid heart rate. Their clinical symptoms include palpitations, dizziness, and unconsciousness.

Arrhythmias occur due to various interrelated mechanisms causing abnormal impulse formation or defective heart conductions.

For instance, electrical impulses may originate from structures other than the heart's natural pacemakers —the SA node. This phenomenon is termed ectopic pacemaker activity or enhanced automaticity.

Further, unusually high intracellular Ca²⁺ levels disrupt the action potential, causing delayed afterdepolarizations.

Sometimes, myocardial damage can alter the normal conduction pathway, resulting in the reentry and looping of electrical impulses, causing continuous cardiac stimulation.

Diseases of conducting structures, like AV node fibrosis, lead to different heart block degrees.

Arrhythmia diagnosis involves an ECG analysis to detect anomalies.