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 Read More
Archives
Salvo
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 Read More
Second Degree Atrioventricular Block 2:1
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 Read More
Second Degree Atrioventricular Block Type I
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 Read More
Second Degree Atrioventricular Block Type II
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 Read More
Segment
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 Read More
Semilunar Valves
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 Read More
Sensitivity
A function of an artificial pacemaker to sense intrinsic electrical activity of the heart. 1. Six Second ECG Guidebook (2012), T Barill, p. 205 Read More
Septal Fascicle
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 Read More
Shock
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 Read More