Epileptic Heart

# Overview
Chronic epileptic episodes and the subsequent catecholamine surges and hypoxic events may affect the heart and coronary vessels and result in the dysfunction of the heart.  This condition is known as the "epileptic heart." This concept was first described by Dr. Richard L. Verrier and his colleagues in 2020.

# Historical Perspective
- Absence of cardiac activity during epileptic seizure was first described by Dr. A.E. Russell, an English physician, in 1906.
- The epileptic heart was first described by Drs. Verrier, Pang, Nearing, and Schachter, in 2020.

# Classification
- There is no established system for the classification of the epileptic heart.

# Pathophysiology
- The exact mechanisms involved in the development of the epileptic heart are still being elucidated. However, the conceptual framework below provides helpful information on the development of heart disease in patients with epilepsy.

## Epilepsy and Cardiac Arrhythmia
Cardiac arrhythmias have long been observed in patients with epilepsy. Three different mechanisms explain this association:
- Direct (causal) pathway
- Co-existence of epilepsy and cardiac arrhythmia in the context of genetic disorders:
Genes involved in epilepsy: SCN1A, KCNA1, and SCN8A
Genes involved in inherited arrhythmogenic heart diseases: KCNQ1, KCNH2, SCN5A, RYR2
- Genes involved in epilepsy: SCN1A, KCNA1, and SCN8A
- Genes involved in inherited arrhythmogenic heart diseases: KCNQ1, KCNH2, SCN5A, RYR2
- Resultant association:
Certain anti-epileptic medications with sodium channel blocking properties have been known to cause arrhythmia.
Seizure may also cause arrhythmia.
Ictal phase may be associated with tachycardia, asystole, bradycardia, and AV block.
Postictal phase may be associated with asystole, AV block, atrial flutter or fibrillation, and ventricular fibrillation.
- Certain anti-epileptic medications with sodium channel blocking properties have been known to cause arrhythmia.
- Seizure may also cause arrhythmia.
Ictal phase may be associated with tachycardia, asystole, bradycardia, and AV block.
Postictal phase may be associated with asystole, AV block, atrial flutter or fibrillation, and ventricular fibrillation.
- Ictal phase may be associated with tachycardia, asystole, bradycardia, and AV block.
- Postictal phase may be associated with asystole, AV block, atrial flutter or fibrillation, and ventricular fibrillation.

## Epilepsy and Structural Heart Disease
Three mechanisms have been suggested to explain the association between epilepsy and structural heart disease:
- Direct (causal) pathway in which structural heart disease may result in  embolic stroke and subsequent epilepsy.
- Common risk factors contribute to the development of both epilepsy and structural heart disease.
- Resultant pathway:
Epilepsy may stimulate myocardial ischemia and a Takotsubo-like syndrome.
Certain anti-epileptic medications contribute to the development of arteriosclerosis, weight gain, non-alcoholic fatty liver disease and metabolic syndrome and result in a poorer cardiovascular risk profile.
- Epilepsy may stimulate myocardial ischemia and a Takotsubo-like syndrome.
- Certain anti-epileptic medications contribute to the development of arteriosclerosis, weight gain, non-alcoholic fatty liver disease and metabolic syndrome and result in a poorer cardiovascular risk profile.
- On microscopic histopathological analysis of patients with epilepsy a range of pathologies has been reported. These changes include fibrosis, myofibrillar degeneration, ventricular hypertrophy, focal myocardial fibrosis, perivascular and interstitial myocardial fibrosis, and mild to moderate coronary atherosclerosis.

# Causes
Epileptic heart may be caused by the following:
- Accelerated atherosclerotic process due to side effect of longstanding antiepileptic therapy such as carbamazepine, gabapentin on lipid profile 
- Increased occurrence of arrhythmia due to hyperadrenergic state in seizure episodes 
- Cardiac autonomic dysfunction due to repeated siezue episodes, a predisposing factor of arrhythmia 
- Arrhythmogenic effect of antiepileptic drugs due to blockage of sodium channels  on heart 
- Susceptibility  to ventricular fibrillation before or after seizure episodes 
- Structural myocardium damage due to repeated seizures, such as myocardial calcified lesions, myocardial stiffness, cardiomegaly, ventricular hypertrophy, left artial dilation 
- Neurogenic stunned myocardium similar to tukotsubo, a reversible cardiomyopathy after a seizure episode 
- Increased occurrence of atrial fibrillation  after seizure episode 

# Differentiating epileptic heart from other Diseases
- Epileptic heart  must be differentiated from other diseases that cause  loss of consciousness or sudden death  such as:
- Sudden unexpected death in epilepsy( SUDEP)
- Convulsion syncope
- Epileptic seizure

# Epidemiology and Demographics
- The incidence of heart disease such as coronary artery disease, heart attack in patients with epilepsy is approximately 25600 per 100,000 individuals between 45-64 years old. This amount in patients without epilepsy is 11500 per 100,000 individuals between 45-64 years old. 
- In 2018, the incidence of sudden cardiac death  in epileptic patients was estimated to be 4400 cases per 100,000 individuals in the united states which was 4.5 fold of SUDEP cases. 
- The incidence of heart disease in patients with epilepsy was 9% higher than patients without epilepsy. 

## Age
- Sudden cardiac death associated with chronic epilepsy  is more commonly observed among patients older than 40 years old. 
- Cardiac diseases associated to the chronic epilepsy is more commonly observed among patients between 45-64 years old. 

## Gender
- Males are more commonly affected with the epileptic heart than females.

## Race
- There is no racial predilection for epileptic heart.

# Risk Factors
- Common risk factors in the development of epileptic heart may include:
- Low socioeconomic status 
- Long-standing antiepileptic therapy
- Hypertension
- Hyperlipidemia
- Diabetes mellitus
- Male sex
- Smoking
- Aging
- Progression of underlying cardiac disease

# Screening
Currently, there is no guideline statement that recommended routine cardiac evaluation of patients with epilepsy. However, a resting 12-lead EKG and/or ambulatory EKG patch recording may be useful in identifying the patients at risk of cardiac pathology and further follow the progression of their cardiac pathology. 

# Natural History, Complications and Prognosis
- Patients with epileptic heart suffer from chronic epilepsy and antiepileptic drug resistance for many years.
- Early clinical features include manifestation related to cardiac involvement such as syncope, chest discomfort, exertional dyspnea, and palpitation.
- Patients with chronic epilepsy may progress to develop complications of arrhythmia and myocardial ischemia.
- Common complications of the epileptic heart include coronary artery disease, heart failure, sudden cardiac arrest, sudden cardiac death.
- Prognosis is generally poor, and the 1-year mortality of patients with chronic epilepsy due to sudden cardiac death is approximately 4.4%. 

# Diagnosis

## Diagnostic Criteria
- The diagnosis of the epileptic heart is made when the following  diagnostic criteria are met:
- Resistant epilepsy
- Longstanding use of antiepileptic drugs
- Presence of  arrhythmia syncope and high level of T waves alternance  as a marker of repolarization abnormality and ventricular fibrillation on ECG
- Presence of ischemic heart disease earlier than the common age
- Evidence of myocardial injury such as  high level of troponin I 

## Hisory and Symptoms
- Symptoms of the epileptic heart may include the following:
- Abrupt palpitation
- Shortness of breath
- Angina pectori
- lightheadness
- Dizziness
- Falling
- Near falling

## Physical Examination
- Physical examination associated with epilepsy include:
- Automatic behaviors
- Upward eye-rolling
- Unconsciousness
- Drolling
- Cyanosis
- Tachycardia
- Hypertension
- Postictal drowsiness
- Fever
- Mydriasis
- Nystagmus
- Urine and fecal incontinence
- Disorientation to person, place, time
- Altered mental status
- Physical examination associated with heart involvement in chronic epilepsy may include:
- Syncope
- Leg edema
- Elevated JVP
- S3,S4
- Tachypnea
- Hypotension
- Pulsus alternans
- Systolic murmur in heart apex
- Irregular pulses

## Laboratory Findings
Common laboratory findings related to epileptic heart may include:
- An elevated concentration of serum troponin I as the  marker of myocardial injury in patients with generalized tonic-clonic seizure 
- Increased CRP, lipid profile due to induction of cytochrome P450  by antiepileptic drugs such as carbamazepine, gabapentin 

## Electrocardiogram
An ECG may be helpful in the diagnosis of epileptic heart. Findings on an ECG suggestive of effects of seizure on the heart include: 
- Bundle-branch block
- ST-segment changes indicating  myocardial ischemia in 40% of seizures 
- T-wave inversion
- Bradycardia, asystole due to hypoxia or respiratory disturbance in postictal phase
- Sinus tachycardia in ictal phase due to sympathetic activity or reduction in vagal tone in 82% of cases
- QT interval  prolongation
- QT interval dispersion
- Increased T wave alternance in preictal and post ictal phases of generalized tonic-clonic seizure indicating repolarization abnormality
- Decreased heart rate variability indicating  decreased vagus nerve activity   during seizure
- Sinus tachycardia, heart rate >150/min indicating sympathetic discharge
- Common ECG markers associated sudden cardiac death include:
- Peri ictal QT prolongation
- Increased T waves alternance
- Decreased heart rate variability 
- Arrhythmia associated seizure include: 
- Ictal bradycardia
- Ictal AV conduction block
- Ictal asystole
- Post ictal asystole
- Post ictal AV conduction block
- Post ictal atrial flutter
- Post ictal ventricular fibrillation 
- Ictal asystole, bradycardia, AV block were self limiting.
- Post ictal arrhythmia such as asystole, AV block, atrial fibrillation, ventricular fibrillation were associated with near SUDEP or convulsion syncope.

## X-ray
A Chest-x-ray may be helpful in the diagnosis of atherosclerosis associated with chronic epilepsy. Findings on an CXR suggestive of heart involvement in epilepsy include:
- Aortic arch calcification 
- Cardiomegaly
- Pulmonary congestion
- Left atrial enlargement
- Left ventricle enlargement

## Echocardiography or Ultrasound
Echocardiography  may be helpful in the diagnosis of epilectic heart. Findings on an echocardiography diagnostic of epileptic heart include: 
- Increased left ventricular filling pressures
- Increased left atrial volume
- Increase left ventricular end systolic diameter
- Increased left ventricular end systolic volume 64,65,66

## CT scan
Coronary CT angiography may be helpful in the diagnosis of ischemic heart disease in chronic epilepsy. Findings on coronary CTangiography suggestive of ischemic hear disease include:
- Coronary artery calcification
- Narrowing of the coronary arteries
- Plaque morphology
- Plaque burden

## MRI
Cardiac magnetic resonance angiograpgy (MRA) may be helpful in the diagnosis of ischemic heart disease in chronic epilepsy. Findings on MRA suggestive of high-risk patients include: 
- Severe coronary artery stenosis(>70%)
- Plaque with thick lipid-rich core and a thin fibrous cap and intraplaque inflammation

## Other Imaging Findings
There are no other imaging findings associated with epileptic heart.

## Other Diagnostic Studies
Holter ECG 24-48 hours may be helpful in the diagnosis of the arrhythmia-related epileptic heart. Findings suggestive the probability of the occurrence of ventricular fibrillation  include: 
- Higher level of T waves alternance
- Decrease heart rate variability
- QT prolongation
- Other diagnostic studies for epileptic include ECG patches which are worn for 14 days with a higher chance for detection of tachyarrhythmia compared with Holter ECG.

# Treatment

## Medical Therapy
- The mainstay of therapy for epileptic heart is autonomic modulation by increased parasympathetic activity, decreased sympathetic activity which is effective for reducing the seizure episodes and increased cardiac electrical stability by the following: 
- Changing the arrhythmogenic antiepileptic drugs to other types
- vagus nerve stimulation therapy for reducing sympathetic activity which is a major risk factor for ventricular fibrillation 

## Surgery
- Vagus Nerve Stimulation (VNS) can be used in resistance epilepsy by inserting a pacemaker under the skin in the chest and sending regular, mild pulses to the brain via the vagus nerve.

## Prevention
- Primary prevention measures in epileptic heart include:
- Screening risk factors of coronary artery disease in every patients diagnosed with epilepsy consisting obesity,hypertension, hyperlipidemia,diabetes mellitus,smoking
- The role of ICD implantation for primary prevention of ventricular tachyarrhythmia in patients with chronic epilepsy is unclear. 
- The strategy for secondary prevention in chronic epileptic patients who are at risk of arrhythmia include:
- Changing  arrhythmogenic drugs  that block sodium channel such as carbamazepine, phenytoin to other types
- Vagus Nerve Stimulation therapy (VNS) for a reduction in T wave alternans 
- Chronic epileptic patients should be followed up for detection of T waves alternans and finding the risk of ventricular fibrillation by: 
- 12 lead ECG
- Holter ECG 24-48 hours
- Wireless ECG patches(patient-friendly tool, worn for 14 days, increased chance for detection of arrhythmia compared  with Holter ECG)