A 48-year-old man presented with a several-year history of multiple syncopal events occurring in circumstances of enhanced vagal activity, such as after meals, or in church. The episodes were associated with prodromes, including perspiration and a sensation of warmth. He presented after 2 recent episodes of sudden loss of consciousness without prodrome, the latter complicated by a fall and facial trauma. The surface ECG revealed the presence of right bundle branch block and a tilt-table test elicited a mixed response, with bradycardia to 30 bpm and a precipitous fall in arterial pressure, followed by loss of consciousness. The prodromes were reminiscent of those associated with syncope occurring in the most distant past. Electrophysiologic studies revealed the presence of a borderline HV interval at 68 ms. Because of the changes in the severity of symptoms and the borderline HV interval, a Reveal DX Holter was implanted. This patient is currently being remotely followed.
The remotely transmitted episode corresponded to the spontaneous symptoms reported by the patient. The recording was triggered by syncope preceded by postprandial prodromes. The graph provides an overall illustration of the episode, while the ECG recording allows a more precise diagnosis:
This and the previous recording have similarities. While the quality of this tracing is lower, complicating the distinction between atrioventricular block and sinus node dysfunction, the sinus rate accelerates before what appears to be a sinus pause considerably shorter than in the previous example. Thus, this tracing belongs to the IA classification of ISSUE. The clinical circumstances and the recording strongly suggest a vagally-mediated episode. However, whereas in the previous patient the length of the pause and frequent occurrence of the episodes seemed to support the implantation of a pacemaker, in this patient this recommendation was less clear. Some elements, in this case, were against the implantation of a pacemaker:
1) the patient was young and the risk of long-term complications was high;
2) while the mechanism of syncope and bradycardia was clearly vagal, the pause was not particularly long;
3) in these cases, the efficacy of permanent pacing has not been confirmed, although, on the short term, the ISSUE 3 study suggested a benefit. The point highlighted by this and the following cases, is the importance of a decision to implant a pacemaker based on the clinical context and individual characteristics of each patient, including when a pause is recorded at the time of a symptomatic event
