What is the medical term for seizures caused by ventricular arrhythmias?

Medical Term for Seizures Induced by Ventricular Arrhythmia

The medical term for seizures caused by ventricular arrhythmias is "convulsive syncope." 1

Definition and Pathophysiology

Convulsive syncope refers to seizure-like motor activity (convulsive movements) that occurs secondary to cerebral hypoperfusion caused by cardiac arrhythmias, including ventricular tachycardia and ventricular fibrillation. 1, 2 This is fundamentally different from epileptic seizures, which arise from primary epileptogenic neural activity rather than cardiac-induced cerebral hypoperfusion. 3

• The mechanism involves ventricular arrhythmias causing sudden circulatory arrest, leading to inadequate cerebral perfusion and subsequent convulsive movements that mimic epileptic seizures. 1, 2

• This condition represents a critical diagnostic challenge because convulsive syncope and epileptic seizures share many overlapping clinical features, yet require completely different management approaches. 1, 3

Critical Diagnostic Distinctions

Features Suggesting Cardiac-Induced Convulsive Syncope (NOT Epilepsy)

• Syncope during exertion or while supine strongly suggests a cardiac arrhythmic cause rather than epilepsy. 4

• Absence of prodromal symptoms (no aura, no nausea/diaphoresis beforehand) points toward arrhythmic syncope. 4

• Palpitations occurring seconds before loss of consciousness indicate an arrhythmic trigger. 4

• Brief duration of unconsciousness (<30 seconds) favors syncope over epileptic seizure (which typically lasts 74-90 seconds). 5, 6

• History of structural heart disease or heart failure is the strongest predictor of cardiac syncope, with 95% sensitivity. 4

Features Suggesting True Epileptic Seizures (NOT Cardiac)

• Symmetrical, synchronous bilateral movements characterize epileptic seizures, whereas convulsive syncope shows asynchronous, side-to-side thrashing. 5, 6

• Eyes open during unconsciousness suggests epileptic seizure; eyes closed suggests psychogenic non-epileptic seizures (but this distinction is less reliable for convulsive syncope). 5, 6

• Lateral tongue biting is highly specific for epileptic seizures and uncommon in syncope. 5, 6

• Chewing, smacking, and blinking suggest epileptic rather than cardiac events. 5, 6

Essential Diagnostic Workup

When a patient presents with seizure-like episodes and suspected cardiac etiology:

1. Obtain detailed history focusing on:

   • Exact circumstances (supine vs. upright, at rest vs. exertion) 4
   • Presence or absence of palpitations immediately before the event 4
   • Duration of unconsciousness 5, 6
   • History of structural heart disease or heart failure 4
   • Family history of sudden cardiac death in relatives <30 years old 4

2. Perform 12-lead ECG immediately to identify:

   • Brugada syndrome patterns (which can cause ventricular arrhythmias presenting as convulsive syncope) 2
   • Long QT syndrome 4
   • Evidence of prior myocardial infarction or structural disease 7
   • Conduction abnormalities 8

3. Cardiac device interrogation if the patient has an implantable cardioverter-defibrillator (AICD) or pacemaker, as this can definitively document ventricular tachycardia/fibrillation during the event. 1

4. Combined EEG/ECG telemetry is helpful when the diagnosis remains unclear, as it can capture both cardiac arrhythmias and epileptiform activity simultaneously. 3

Critical Clinical Pitfalls

• Do NOT rely on serum biomarkers (neuron-specific enolase, prolactin, creatine kinase) to differentiate convulsive syncope from epileptic seizures—these are unreliable. 5, 6

• Beware of diagnostic anchoring: Patients with known epilepsy can still develop cardiac arrhythmias causing convulsive syncope, and vice versa—the two conditions may coexist. 3, 8

• Recognize that seizures can cause arrhythmias: In rare cases, epileptic seizures can trigger cardiac arrhythmias (ictal bradycardia syndrome), further blurring the distinction. 8

• Brugada syndrome has variable ECG findings: The classic ECG pattern may be transient, so a single normal ECG does not exclude this diagnosis in patients presenting with convulsive syncope. 2

Management Implications

• Convulsive syncope from ventricular arrhythmias requires cardiac intervention (antiarrhythmic drugs, AICD implantation, or ablation), NOT antiepileptic drugs. 1, 2

• Early accurate diagnosis is critical to prevent sudden cardiac death in patients misdiagnosed as having epilepsy. 1, 2

• Patients with structural heart disease and seizure-like episodes should be presumed to have cardiac-induced convulsive syncope until proven otherwise, given the 18-33% annual mortality rate of cardiac syncope versus 0-12% for non-cardiac causes. 4