An S wave is the first wave after the R wave that dips below the baseline (isoelectric line). The end of the S wave occurs

The SA node, usually the dominant pacemaker, is located in the right atrium at the opening of the superior vena cava. The SA (sinoatrial) node

A sudden group of 3 or more ectopic beats or complexes (also called a burst or a run). 1. Six Second ECG Guidebook (2012), T

A hybrid form of second degree AV block is a block with 2:1 conduction where every second ‘P’ wave is a lonely ‘P’ wave. The

A cardiac rhythm characterized by occasional P waves without a QRS (lonely Ps) and an observable pattern of progressive lengthening of the PR interval followed

A cardiac rhythm characterized by occasional P waves without a QRS (lonely Ps) and a fixed PR interval; 1 lonely P wave may be present

A line between waves. Segments measure time between waves (waves are not included in a segment). While waves are fairly self-explanatory, intervals measure time from

Valves located at the exit route of the ventricles; for the right ventricle, connects with the pulmonary artery; for the left ventricle, connects with the

A function of an artificial pacemaker to sense intrinsic electrical activity of the heart. 1. Six Second ECG Guidebook (2012), T Barill, p. 205

Normal ventricular depolarization begins with the septal fascicle of the left bundle branch (causing a Q wave) followed by a simultaneous depolarization of the remaining

Signs and symptoms of shock include shortness of breath, chest pain, hypotension, and an altered level of consciousness (due to hemodynamic compromise). As a general

A PR interval shorter than normal (less than 0.12 seconds) occurs commonly with junctional rhythms (the impulse begins somewhere in the AV junction) because part