Persistent Fainting after Implantation of a “Curative” Pacemaker

To the Editor:

Syncope is a common and disabling problem, and its cause may be difficult to elucidate. A 64-year-old right-handed male taxi driver was referred to us for the investigation of syncope in April 2007. Four weeks previously, at dinner, he had suddenly felt strange and dizzy before losing consciousness for 2 minutes. On recovery, he was fully oriented. Several days before admission, he described feelings of “impending doom” that lasted for 2 minutes during breakfast.

He was previously well. He was a nondrinker and nonsmoker, and he was taking aspirin for secondary prevention of a transient ischemic attack. Results of physical examination, blood tests, electrocardiography (ECG), echocardiography, 48-hour Holter monitoring, and magnetic resonance imaging of the brain and electroencephalography (EEG) after he had undergone sleep deprivation were normal; an implantable loop recorder was inserted.

Three weeks later, while watching television, he had a dizzy spell lasting several minutes, followed by syncope. The reading from the loop recorder showed that the syncopal event preceded a sinus-node arrest lasting 25 seconds (Figure 1Figure 1Reading from a Loop Recorder Showing a Prolonged Pause of 25 Seconds after a Sinus Bradycardia.). A dual-chamber pacemaker was implanted.

Despite normal pacemaker function, he had numerous confusional episodes during the subsequent days. These episodes were unrelated to activity and mostly occurred while he was sitting down. He collapsed again several weeks later, while sitting for a meal at a wedding. Repeat EEG with simultaneous ECG revealed a localized, epileptogenic disturbance in the left anterior temporal region. Temporal-lobe epilepsy was diagnosed, and he was treated with oxcarbazepine. He remains asymptomatic at 1 year of follow-up.

Ictal bradycardia is a rare manifestation of epileptic seizures. Autonomic modifications may result because of ictal discharges in the region of the structures of the central autonomic network. There is limited evidence of a preferential left temporal-lobe onset.1 Most patients are male and 60 years of age or older.2 This pattern of epilepsy may induce central or obstructive apneas as well as malignant arrhythmias and is linked to sudden unexpected death in patients with epilepsy.3 Temporal-lobe epilepsy may present with feelings of panic and impending doom, palpitations, diaphoresis, dyspnea, and paresthesias. Hence, it is easily misdiagnosed as an anxiety attack.4 The discovery of a major arrhythmia without EEG monitoring may lead to an incorrect diagnosis of primary cardiac disease and treatment with cardiac pacing.

Cardiac pacemakers may be indicated in symptomatic ictal bradycardia or asymptomatic bradycardia lasting more than 5 seconds. However, cardiac pacemakers have not been proved to reduce the incidence of sudden unexpected death among patients with epilepsy.3 Physician awareness, patient education, and effective seizure control are of prime importance in preventing ictal asystole and potential sudden unexpected death among patients with epilepsy.

Sazzli Kasim, M.R.C.P.I.
Michael Hennessy, M.D.
James Crowley, M.D.
University College Hospital, Galway, Ireland
sazzlikasim@gmail.com

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