Research Day

Malignant Vasovagal Syncope Presenting With Seizure-Like Activity

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CASE: The patient is a 34 year old woman with a 20 year history of suspected seizures. Episodes included loss of consciousness with incontinence, preceded by nausea, headache, staring spells, and abnormal vocalization. Episodes were followed by confusion and fatigue. No epileptic activity seen on previous EEGs. She was placed on outpatient cardiac monitoring to evaluate for alternative causes.

Cardiac monitoring showed prolonged periods of asystole, lasting up to 21 seconds. These cardiac events correlated with her seizure-like episodes. Due to the severity of her asystolic periods, a single-chamber cardiac pacer was placed. Patient was diagnosed with malignant vasovagal syncope.

DISCUSSION: Malignant vasovagal syncope is defined as recurrent and severe syncope in which a neural reflex causes severe bradycardia, with eventual asystole. There are very few cases reported of syncope with prolonged asystole.

It is important to rule out cardiac arrhythmia, structural disease, and non-cardiac causes when working up syncopal episodes. A head-up tilt-table test can be done while patient is on a cardiac monitor to induce the neuro-reflex. For infrequent syncopal episodes, long term cardiac monitoring can be used.

It is a Class 1, Level C recommendation to place a permanent pacemaker if there is syncope with periods of asystole greater than 3 seconds. Most randomized, placebo-controlled clinical studies to date show no difference between medical management for vasovagal syncope and placebo groups.

CONCLUSION: Although potentially fatal causes of syncope are rare, prompt diagnosis and treatment is critical to prevent serious complication.

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