How are cardiac causes of seizures managed?

Management of Cardiac Causes of Seizures

When seizure-like episodes are suspected to have a cardiac origin, immediate cardiovascular assessment with 12-lead ECG takes priority over neurologic workup, and urgent specialist referral is required for any suspicion of inherited cardiac conditions, arrhythmias, or structural heart disease that could lead to sudden death. 1

Initial Assessment and Risk Stratification

The critical first step is distinguishing true cardiac syncope from epileptic seizures, as brief seizure-like activity can occur during cardiac syncope without requiring neurologic investigation. 1

Key features suggesting cardiac (not epileptic) origin:

• Loss of consciousness during exercise or exertion 1
• Family history of sudden cardiac death or inherited cardiac conditions 1
• Absence of typical epilepsy features (no prolonged post-ictal confusion, no lateral tongue biting, no characteristic auras) 2
• ECG abnormalities suggesting arrhythmia or conduction disease 1

Urgent Cardiovascular Management

Immediate specialist cardiovascular assessment is mandatory for: 1

• Severe bradycardia or atrioventricular block requiring urgent cardiac pacing 1
• Suspected long QT syndrome or other inherited arrhythmia syndromes 1
• History or physical signs of heart failure 1
• Structural heart disease on examination or ECG 1

Diagnostic Workup Algorithm

Step 1: 12-lead ECG (essential and integral) 1

• Obtain automated report with subsequent expert review if abnormalities detected 1
• Patient should receive copy of ECG and report 1

Step 2: If structural heart disease suspected 1

• Cardiac imaging via echocardiography first 1
• Recognize that patients with structural disease may also have vasovagal syncope, orthostatic hypotension, or arrhythmias 1

Step 3: If cardiac arrhythmia suspected or cause unclear 1

• Ambulatory ECG recording as next investigation 1
• Device choice dictated by frequency of events and baseline ECG findings 1
• If ECG shows conduction abnormality: 24-48 hour Holter to detect asymptomatic severe AV block 1
• If no conduction abnormality: aim to capture ECG during another event 1

Specific Cardiac Arrhythmia Management

Ictal asystole (most common clinically relevant seizure-related arrhythmia): 3, 4

• Typically self-limiting and occurs during focal dyscognitive seizures 4
• Prevalence of 0.318% in refractory epilepsy patients 4
• May require cardiac pacemaker implantation 3
• Predominantly temporal lobe onset (91% of cases) 4

Postictal arrhythmias (more concerning for sudden death): 4

• Associated with convulsive seizures and near-SUDEP events 4
• Include postictal ventricular fibrillation, AV-conduction block, and atrial fibrillation 4
• Require different management approach than ictal arrhythmias due to distinct pathomechanisms 4

Critical Pitfall to Avoid

Do not order EEG when history clearly indicates cardiac syncope. 1 Brief seizure activity during syncope (including vasovagal syncope) does not require neurologic investigation or referral. 1 Inappropriate EEG use in these patients leads to misdiagnosis. 1

Treatment of Underlying Cardiac Conditions

For severe bradycardia/AV block: 1

• Urgent cardiac pacing required 1
• No further assessment for loss of consciousness needed once treated 1

For inherited cardiac conditions (long QT syndrome, etc.): 1

• Prompt specialist cardiovascular assessment to prevent sudden death 1
• Risk stratification for severe adverse events including sudden cardiac death 1

For orthostatic hypotension: 1

• Identify and address contributing medications 1
• Appropriate clinical assessment as part of cardiovascular workup 1

For carotid sinus syndrome: 1

• Include in further cardiovascular assessment protocol 1

Long-term Monitoring Considerations

Recurrent seizures may have remote impact on cardiac properties, termed "epileptic heart syndrome," requiring ongoing cardiovascular surveillance in patients with epilepsy. 3, 5 Full control of tonic-clonic seizures through antiseizure medication, neuromodulatory devices, or epilepsy surgery should be pursued to prevent potentially serious cardiovascular complications. 5