Focal Atrial Tachycardia From the Right Superior Pulmonary Vein with Irregular Cycle and P Wave Morphology: the Missing Link in the Chain Connecting Organized and Disorganized Atrial Arrhythmias?

Abstract

This 38-year-old female patient had mild hypertension with a 2-year history of poorly tolerated irregular palpitations. During symptoms, the surface electrocardiogram showed short runs of atrial arrhythmia (Fig.1), with irregular cycle length (between 275 and 340 ms) and beat-to-beat variations of the P wave morphology although its polarity was constantly negative in aVL and aVR and positive in the other leads. The variations of the P wave morphology were more evident in leads V₁-V₂. During prolonged electro cardiographic monitoring, longer salvos of atrial tachycardia were observed. These were characterised by a more constant P wave morphology and shorter cycle-length variations, between 270 and 310 ms, with 2:1 atrioventricular conduction (Fig. 2). Degeneration into atrial fibrillation was never observed, even at prolonged monitoring. The findings suggested the presence of a multifocal automatic atrial tachycardia, likely originating from the left atrium. Symptoms worsened over the six months before the procedure, and at the time of the procedure the patient complained of iterative palpitation with dizziness, especially during daily activities. Therapy with IC antiarrhythmic drugs and beta-blockers, even in combination, was only minimally effective. Blood pressure values were constantly within the normal range with the administration of ACE inhibitors. Transthoracic and transesophageal echocardiograms showed normal findings. Thyroid function was also normal.