Bundle Branch and Fascicular Blocks Right Bundle-Branch Block 1. Septal Depolarization In the presence of a right bundle-branch block (RBBB), septal depolarization occurs in a normal left-to-right pattern (orange arrow)…
Sinus Dysfunction Sinus Arrhythmia Sinus arrhythmia occurs in young and healthy individuals and is not a form of sinus node dysfunction. Sinus arrhythmia is characterized by variation in cardiac cycle…
Concept Review Action Potential—Myocardial Cell The different phases of the action potential relate directly to the waveforms, intervals, and segments that constitute a cardiac cycle on the ECG. Each phase…
