He responded within a few minutes, remaining with his eyes closed and being unable to make any verbal response, despite painful stimuli.

At 30min post-procedure, the patient reported an extremely dry mouth and at 1h presented dyspnea and psychomotor agitation that intensified and required 1.5mg IV midazolam. The patient remained asymptomatic after adequate pacemaker rhythm had been achieved, with normal cardiorespiratory status. This was repeated twice with 1mg IV each time, at 3min intervals. During the procedure, the patient developed extreme bradycardia with 80/35 mmHg blood pressure and Stokes-Adams syndrome, which was treated with 1mg IV atropine, producing a partial response.

Intravenous perfusion of isoprenaline was initiated and the patient presented rhythmic narrow QRS tachycardia at 150 bpm, which was poorly tolerated. In emergency room, an electrocardiogram (ECG) recorded complete atrioventricular block, 24 bpm escape rhythm and 120ms QRS. He reported no adverse reactions to medicines but in previous weeks had presented presyncopes attributed to a vasovagal reaction, rather than transitory ischemic accidents, and which had been scheduled for study. A 75-year-old man came to our emergency room for syncope.

Atropine antidote