ECG Atlas

A ventricular rhythm that runs faster than a ventricular escape rhythm but slower than ventricular tachycardia.

A rhythm in which many electrical impulses arise throughout the atria instead of from the SA node.

The heart's normal rhythm, with each beat initiated by the sinoatrial (SA) node and conducted through the AV node and His-Purkinje system in the usual sequence.

A physiologic, cyclic variation in sinus rate driven by respiration and vagal tone - the rate speeds up on inspiration and slows on expiration.

A sinus rhythm slower than normal for the patient, with the SA node still setting the pace.

A sinus rhythm faster than normal for the patient, still originating from the SA node.

A fast rhythm that starts somewhere above the ventricles, either in the atria or around the AV node, and then travels down the normal conduction system, so the QRS stays narrow.

Three or more consecutive ventricular ectopic beats - a run of wide, bizarre QRS complexes faster than, and dissociated from, the underlying sinus rhythm.

Early beats that start somewhere in the atria other than the SA node and then reach the ventricles by the usual route.

Early beats that start in the ventricular muscle itself rather than arriving from above, so they miss the fast conduction system and have to spread the slow way.

A delay or block of conduction down one bundle branch, so the ventricles depolarize one after the other rather than together and the QRS widens.

A consistent prolongation of the PR interval in which every atrial impulse still reaches the ventricles.

An intermittent failure of AV conduction in which some P waves are not followed by a QRS.

The Wenckebach form of second-degree AV block: the AV node fatigues progressively with each beat until one impulse fails to get through, then recovers and the cycle repeats.

A second-degree AV block in which conduction fails abruptly, without the progressive AV-nodal fatigue of Mobitz I.

A complete failure of AV conduction: no atrial impulses reach the ventricles at all.

The atria have stopped producing electrical activity altogether.

A protective backup rhythm from the AV junction that emerges when the sinus node fails to pace the heart quickly enough.

A disorder of the sinoatrial node that fails to pace the heart reliably.

A transient failure of the sinoatrial node to generate an impulse.

A protective backup rhythm arising from a focus in the ventricular myocardium when every faster pacemaker has failed.

A Q wave that is abnormally deep and broad, rather than the small initial downward deflection that normally comes from the septum depolarizing.

Displacement of the ST segment above or below the isoelectric baseline, so the stretch between the end of the QRS and the start of the T wave no longer sits level with the rest of the trace.

A T wave that is tall, narrow and sharply pointed, taking up more of the complex than usual, instead of the broader and more rounded shape normally seen.

A QT interval that is long for the heart rate at which it was measured.