Syncope can be caused by a cardiac arrhythmia. The presence of certain ECG changes can help identify a patient with arrhythmic syncope.
Some patients will have a history of palpitations preceding the syncopal episode.
ECG changes
Association
(1) presence of Q waves
acute myocardial infarction
(2) negative T waves in the right precordial leads, epsilon waves, and ventricular late potentials
arrhythmogenic right ventricular dysplasia
(3) right bundle range block with ST-elevation in V1, V2 and V3
Brugada syndrome
(4) bifascicular block
(5) pre-excited QRS complexes
(6) prolonged QT interval
may be drug-induced
(7) biventricular block
(8) QRS duration >= 0.12 seconds
other intraventricular conduction abnormalities
(9) Mobitz type I second degree atrioventricular (AV) block
(10) sinoatrial block
(11) asymptomatic sinus bradycardia with heart rate < 50 beats per minute
where:
• Biventricular block is defined as (either left bundle branch block or right bundle branch block) AND (either left anterior OR left posterior fascicular block).
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