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Patient
79-year-old man with treated arterial hypertension; consultation for palpitations occurring since a few days;
Trace
Characteristic pattern of atrial fibrillation; rapid, disorganized atrial activity with baseline tremor; broad, irregular QRS complexes with typical complete right bundle branch block pattern (QRS > 120 ms, rsR' pattern in V1 with major delay of the intrinsicoid deflection, wide S wave in V6 and lead I);
Trace
ECG recorded after performing a programmed electric shock; left atrial enlargement with prolonged P wave (> 120 ms), bifid in leads I, II and aVL; right bundle branch block identical to that for tachycardia;
Exergue
The sinus ECG in patients with episodes of atrial arrhythmia can reveal different elements:
1) premature atrial extrasystoles (P-on-T phenomenon) as a trigger for arrhythmia induction,
2) a left atrial "enlargement" indicative of a favorable atrial substrate,
3) a QRS pattern suggestive of the presence of heart disease (infarction sequela, left ventricular hypertrophy, etc.).
We have previously seen that initiation of an atrial fibrillation requires a trigger (usually an early atrial extrasystole from the pulmonary veins). This tracing also shows that the risk is increased in patients with favorable substrate.