2:1 ATRIOVENTRICULA (AV) BLOCK:     A disorder of the atrioventricular (AV) node, characterized by two (2) P waves for every QRS complex (E.g. P wave, QRS, P wave, dropped QRS (repeating)). This is a subset of second degree atrioventricular (AV) block and could be either Mobitz type 1 (Wenckebach), or Mobitz type 2.   […]

ABERRANCY (VENTRICULAR):     Intermittent abnormal conduction of a supraventricular impulse into the ventricle through the bundles. Because of this abnormal conduction, the QRS complex does not appear normal.

ACCELERATED IDIOVENTRICULAR RHYTHM (AIVR):     A rhythm originating from the ventricle at a rate between 40 and 100 beats per minute.

ACCELERATED JUNCTIONAL RHYTHM:     A rhythm originating from the atrioventricular (AV) node (junction) at a rate between 60 and 100 beats per minute.

AIVR:     See:  Accelerated idioventricular rhythm

ANTERIOR LEADS:     Leads V3 and V4

ANTIARRHYTHMIC AGENTS:     Antiarrhythmic agents are medication used to control abnormal heartbeats and abnormal cardiac rhythms. There are a multitude of agents, all with specific effects and side effects. Here is a generalization of the effects of each class on the ECG. Specific agents should be looked up elsewhere.   CLASS 1a: Wide QRS; […]

ARRHYTHMIA:     Abnormality of cardiac impulse formation and/or conduction.

ASHMAN’S PHENOMENON:     Aberrancy of a supraventricular impulse into the ventricle, through the bundles, because of a change in the QRS cycle length. Typically, there is a normal QRS complex, a relatively long RR interval, another normal QRS complex, a relatively short RR interval and then aberrant QRS complex. (QRS…….QRS…….QRS……..QRS………………………QRS……Aber…….QRS…….QRS…….QRS) Long RR      […]