Propafenone‐Induced Syncope and Atrial Pacemaker

Abstract

A 77-year-old female patient was admitted to our emergency department with syncope and suspected pacemaker dysfunction. An AAI pacemaker implantation () is mentioned in her medical history due to tachycardiabradycardia syndrome 3 years earlier with the prescription of 300-mg propafenone orally to be taken twice a day. The patient was free of complaints for over 2 years and had no documented or long-lasting arrhythmias since then. The pacemaker interrogation 1 week before recent admission showed good device function; with battery voltage at 2.77 V, battery impedance at 0.7 kOhm, lead impedance at 593 Ohm, as well as pacing thresholds at 0.8 V/0.75 ms and 1.2 V/0.40 ms. The atrial sensing was measured to be between 1.7 mV and 2.2 mV at a spontaneous sinus rate of 47 beats/min. The initial programmed parameters were atrial pulse amplitude at 2.4 V, pulse width 0.40 ms, and sensitivity at 0.8 mV. On the morning of the admission our patient felt palpitations again and therefore took another 300-mg propafenone as advised by the "pill in the pocket" concept (900-mg propafenone within 13 hours). Four hours later, she first felt dizziness with nausea, then lost consciousness for a few moments shortly afterwards. The emergency electrocardiogram performed on-site revealed normal regular, but ineffective, atrial pacemaker stimuli with 800 ms as well as a narrow QRS ventricular escape rhythm with cycle lengths of 1,920 ms (Fig. 1). The emergency therapy given from the medical staff at her home was 3-mg atropine given intravenously as well as 500-mL saline infusion. On admission to our Coronary Care Unit, the cycle length of the escape rhythm was already shorter at 550 ms Address for reprints: János Tomcsányi, M.D., Budai Irgalmasrendi Kórház Kardiológia,Árpád fejedelem u.7,