Atrial fibrillation wave (intermittent) This is the most common type of cardiac arrhythmias. Flicker occurs as a result of disconnection of atrioventricular conduction. Ventricular contractions are interrupted by atrial contractions - endocardial or systolic fibrillation, AV conduction is disrupted, and atrial extrasystole is detected. An ECG can reveal the smallest changes in the shape of the P wave and the duration of the P-P interval if the flickering is moderate, and with a full series of extrasystoles it is necessary to use special ECG analysis techniques.