A 77-year-old female patient presented to the hospital’s emergency department with palpitations. The electrocardiogram shows a supraventricular bigeminy where the premature beats are due to aberrant conduction (wider and deeper S waves from lead V1 to V5 and ‘RSR’ morphology in lead V6) but the rhythm is not sinus (Fig. 1). What is the mechanism?

Fig. 1
figure 1

A particular bigeminy with aberrant conduction during atrial tachycardia

Answer

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