Sudden Unexpected Death in Epilepsy (SUDEP) and Cardiovascular Dysfunction – Unraveling the Link: A Narrative Review

Abstract

Sudden unexpected death in epilepsy (SUDEP) represents a major cause of mortality in individuals with epilepsy, accounting for 8–17% of epilepsy-related deaths. Its multifactorial pathogenesis implicates autonomic dysfunction, impaired heart rate variability, seizure-related arrhythmias, genetic channelopathies, and the potential influence of antiepileptic drugs. Epidemiological studies demonstrate increased SUDEP risk in patients with refractory epilepsy, poor seizure control, and polytherapy, with additional contributions from genetic predisposition and sleep-related seizures. Cardiac abnormalities, including ictal tachyarrhythmias, bradyarrhythmias, and altered QT dynamics, may provide the electrophysiological substrate for lethal events. This review synthesizes current understanding of epidemiology, neuro-cardio-respiratory mechanisms, and cardiovascular contributions to SUDEP, highlighting the role of autonomic and genetic factors, as well as peri-ictal cardiac disturbances. The Mortality in Epilepsy Monitoring Unit Study has provided central insights into the cardiorespiratory cascade leading to SUDEP, while emerging risk-stratification tools such as the SUDEP-7 and SUDEP-3 inventories offer promise for clinical risk assessment. Molecular autopsy approaches identifying channelopathies in DEPDC5, SCN1A, and cardiac ion channel genes may inform family screening and personalized prevention strategies. Preventive strategies remain limited, although closer collaboration between neurology and cardiology, improved seizure control, adherence to antiepileptic regimens, and consideration of cardiac monitoring or device therapy may help reduce risk. Future research should focus on large-scale prospective studies incorporating implantable monitoring and systematic molecular autopsies to clarify mechanisms and guide individualized preventive strategies tailored to resource settings.

Introduction

Sudden unexpected death in epilepsy (SUDEP) is defined as a sudden, unexpected, witnessed or unwitnessed, non-traumatic death in an individual with epilepsy, with or without evidence of a seizure, excluding documented status epilepticus, and in which postmortem examination does not reveal a structural or toxicological cause of death.[1] SUDEP remains one of the most devastating complications of epilepsy, representing a significant burden on patients, families, and healthcare systems worldwide. Epilepsy affects approximately 3% of the global population, making it among the most common serious neurological disorders.[2] Compared with the general population, individuals with epilepsy face substantially elevated mortality risk, with standardized mortality ratios ranging from 1.6 to 9.3.[3]

Multiple physiological mechanisms are thought to contribute to SUDEP, including central apnea, impaired autonomic regulation of cerebral and cardiac perfusion, reduced heart rate variability (HRV), and neurogenic pulmonary edema.[4] Cardiac disturbances such as tachyarrhythmia, bradyarrhythmia, asystole, atrial fibrillation, supraventricular tachycardia, and conduction block have been documented during peri-ictal, interictal, and postictal periods. The precise role these disturbances play in SUDEP pathogenesis remains incompletely understood. Longstanding epilepsy appears capable of producing both acute and chronic autonomic alterations that predispose to arrhythmogenic events.[5]

This review synthesizes current evidence on the epidemiology, clinical risk factors, neuro-cardio-respiratory mechanisms, genetic contributions, and cardiovascular aspects of SUDEP. We focus on lesser-studied areas, including the Mortality in Epilepsy Monitoring Unit Study (MORTEMUS) findings, risk-stratification tools, the emerging role of molecular autopsy, and practical implications for clinicians, particularly in resource-limited settings. Understanding the complex interplay between epileptic activity and cardiovascular dysfunction is essential for developing effective prevention strategies and reducing SUDEP-related mortality.

Epidemiology of SUDEP

Incidence and burden

SUDEP is estimated to account for approximately 8–17% of all deaths in people with epilepsy.[6] Population-based studies report variable incidence rates depending on the cohort studied, with community-based estimates generally ranging from 0.1 to 2.4 per 1,000 person-years. Sveinsson and colleagues conducted a nationwide population-based cohort study in Sweden examining over 43,000 patients with epilepsy, reporting an incidence of definite or probable SUDEP of 1.2 per 1,000 person-years.[7] Similar community-based incidence rates have been documented in other European and North American cohorts.[8] Recent Indian data from the Sree Chitra Tirunal Institute SUDEP-monitored cohort similarly indicate elevated long-term mortality risk in people with epilepsy.[9]

Incidence varies dramatically based on epilepsy severity and clinical setting. Patients with refractory epilepsy demonstrate substantially higher risk, with estimates ranging from 1.1 to 5.9 per 1,000 person-years.[10] The highest incidence has been observed among individuals evaluated for epilepsy surgery or those with persistent seizures following resection, where rates may reach 6.3 to 9.3 per 1,000 person-years.[11] These figures underscore the strong association between poor seizure control and SUDEP risk.

Demographics and high-risk groups

Several demographic patterns have emerged from epidemiological studies. Males appear to face higher SUDEP risk than females, with incidence rates in population-based cohorts showing male predominance (approximately 1.4 vs 1.0 per 1,000 person-years in the Swedish study).[7] SUDEP cases span a wide age spectrum, from infancy to late adulthood, although most deaths occur in young to middle-aged adults.[11]

Certain epilepsy syndromes carry a particularly elevated risk. Dravet syndrome, caused by SCN1A mutations, demonstrates one of the highest SUDEP rates among pediatric epilepsies, with cumulative risk approaching 10–20% by early adulthood.[12] Similarly, individuals with focal epilepsies associated with DEPDC5 mutations and mTOR pathway dysregulation may face increased SUDEP risk, although precise incidence data remain limited.[13]

Clinical risk factors and risk scores

Established clinical risk factors

Multiple clinical features have been consistently associated with elevated SUDEP risk across epidemiological studies. The most robust predictors include the following:

Seizure-related factors: Frequent generalized tonic-clonic seizures (GTCS) represent the single strongest predictor of SUDEP, with risk increasing proportionally to seizure frequency.[14,15] Nocturnal seizures, particularly those occurring during sleep without witnessed supervision, confer additional vulnerability.[16]

Epilepsy severity and duration: Refractory epilepsy uncontrolled by antiepileptic drugs substantially increases risk compared to well-controlled disease. Chronic epilepsy duration (typically >10–15 years) has been associated with higher mortality, potentially reflecting cumulative autonomic dysfunction.[14]

Medication factors: Polytherapy with three or more antiepileptic drugs (AEDs) has been linked to higher SUDEP likelihood compared to monotherapy in some case-control studies, likely serving as a marker of severe, treatment-resistant epilepsy rather than direct drug toxicity.[15] Conversely, lack of AED treatment or nonadherence to prescribed regimens dramatically increases risk, with one large retrospective cohort demonstrating more than three-fold elevation in mortality among nonadherent patients [hazard ratio (HR) 3.32; 95% confidence interval (CI), 3.11–3.54].[17]

Developmental and syndromic factors: Intellectual disability, developmental delay, and specific genetic epilepsy syndromes (particularly Dravet syndrome, Lennox–Gastaut syndrome, and focal epilepsies with DEPDC5 mutations) confer elevated risk.[11]

Lifestyle factors: Living alone, prone sleeping position, and alcohol consumption have been identified as modifiable risk factors in some studies.[18]

Recent efforts to develop practical risk-stratification tools have yielded promising instruments. The SUDEP-7 risk inventory is a composite score incorporating seven clinical variables: GTCS frequency (past year), total GTCS number (lifetime), seizure duration, epilepsy duration, presence of ≥3 AEDs, developmental disability, and age at epilepsy onset.[19] Scores range from 0 to 10, with higher scores correlating with increased SUDEP risk. Elevated SUDEP-7 scores have been associated with objective markers of autonomic dysfunction, including reduced high-frequency HRV, specifically lower root mean square of successive differences (RMSSD) values, suggesting biological plausibility for the risk stratification.[20]

The SUDEP-3 inventory represents a simplified three-item assessment derived from key risk factors, designed for rapid clinical screening. While specifics vary by validation cohort, most versions incorporate GTCS frequency, AED number, and epilepsy duration or control status. These tools remain primarily research instruments requiring prospective validation before routine clinical implementation, but offer promise for identifying high-risk patients who may benefit from intensified monitoring, counseling, and preventive interventions. A comparison of currently described risk-stratification tools is provided in Table 1.

Table 1.

Comparison of currently described SUDEP risk-stratification tools

Tool		Items included		Score range		Validation status		Setting
SUDEP-7 Inventory		GTCS frequency (past year); lifetime GTCS number; epilepsy duration; ≥3 AEDs; developmental disability; age at epilepsy onset; seizure duration		0–10 (higher=greater risk)		Cross-sectional validation; correlated with reduced HRV		Tertiary epilepsy centers; research
SUDEP-3 Inventory (revised)		GTCS frequency; AED number; epilepsy duration or seizure-control status (variable across versions)		0–3 (simplified)		Limited prospective validation		Rapid bedside screening
Modified clinical risk scores (Devinsky/ILAE-derived)		Composite of GTCS frequency, polytherapy, intellectual disability, nocturnal seizures, supervision status		Variable		Used in epidemiologic case-control work; not formally validated as a clinical tool		Counseling; epidemiologic studies

AED: Antiepileptic drug, GTCS: Generalized tonic-clonic seizure, HRV: Heart rate variability, SUDEP: Sudden unexpected death in epilepsy, ILAE: International League Against Epilepsy

Neuro-cardio-respiratory mechanisms

The MORTEMUS study: Defining the terminal cascade

The MORTEMUS provided landmark insights into the pathophysiological sequence leading to SUDEP through analysis of monitored deaths occurring in epilepsy monitoring units.[21] This multicenter study documented cardiorespiratory patterns during terminal events, revealing a consistent sequence: GTCS → postictal generalized electroencephalogram (EEG) suppression (PGES) → central apnea with progressive hypoxemia → terminal bradycardia and asystole. Most monitored SUDEP cases occurred during sleep or rest periods, with seizure onset typically nocturnal.

The MORTEMUS findings established that respiratory failure appears primary in most cases, with cardiac arrest developing secondary to severe hypoxemia and brainstem dysfunction. PGES duration correlated with poor outcome, suggesting that prolonged postictal cortical suppression may reflect concurrent brainstem suppression affecting respiratory drive and autonomic cardiovascular control. This pattern contrasts with primary cardiac arrhythmia as the initiating event, although the study demonstrated that both tachyarrhythmias and bradyarrhythmias can occur during the terminal cascade. These observations explain why interventions targeting respiratory support during the postictal period may prove beneficial, and why nocturnal supervision, avoidance of prone position, and rapid response to prolonged seizures represent practical preventive measures.

Autonomic dysfunction and HRV

The cardiovascular autonomic network is regulated by an integrated neuronal system spanning cortical, limbic, and brainstem structures. Key cortical regions involved in autonomic control include the insula, anterior cingulate cortex, and ventromedial prefrontal cortex, which together comprise the central autonomic network.[22] Notably, these regions frequently serve as epileptogenic foci in temporal and frontal lobe epilepsies, explaining the high frequency of autonomic phenomena during seizures. Seizure activity originating in the temporal or frontal cortices propagates to the insular cortex and hippocampus, then to limbic regions and ultimately to medullary autonomic nuclei, producing increased sympathetic output and reduced parasympathetic tone.

Interictal autonomic dysfunction has been documented in chronic epilepsy. Cardiac metaiodobenzylguanidine (MIBG) scintigraphy studies have demonstrated impaired cardiac uptake in individuals with chronic temporal lobe epilepsy compared to controls, suggesting disturbances in postganglionic cardiac sympathetic innervation.[23] Reduced MIBG uptake has been particularly observed in patients with ictal asystole, pointing to cardiac sympathetic dysfunction as a potential substrate for life-threatening bradyarrhythmias.[24]

Heart rate variability as a SUDEP biomarker: HRV reflects beat-to-beat fluctuations in heart rate primarily governed by vagal modulation. Reduced HRV is a well-established predictor of mortality in cardiac disease and sudden cardiac death. Patients with poorly controlled epilepsy exhibit markedly lower high-frequency HRV values compared to those with well-controlled seizures,[25,26] suggesting that impaired autonomic control may increase SUDEP vulnerability. However, results remain inconsistent across studies,[27] likely reflecting small sample sizes, heterogeneous patient populations, and variable methodology. The observation that SUDEP-7 scores correlate inversely with HRV parameters provides biological validation for the risk inventory and suggests autonomic dysfunction represents a mechanistic link between clinical risk factors and sudden death.

Cortical-cardiac network and the lock-step phenomenon

Electrical stimulation studies have revealed direct cortical influences on cardiovascular function. Stimulation of the limbic system and insular cortex can provoke dramatic heart rate changes, including bradycardia, tachycardia, and asystole. Anatomical localization matters: left posterior insular stimulation tends to trigger bradycardia and hypotension, whereas right anterior insular stimulation more commonly produces tachycardia and hypertension.[22] Animal experiments have demonstrated the lock-step phenomenon, in which epileptiform cortical activity directly correlates with postganglionic sympathetic cardiac discharges, allowing seizure activity to entrain cardiac rhythm and potentially precipitate severe bradyarrhythmia or asystole.[28]

This mechanism may be particularly pronounced during non-rapid eye movement sleep, characterized by periodic fluctuations in cortical and autonomic arousal, as well as frequent interictal and subclinical epileptiform discharges. Seizures arising from sleep may provoke abrupt transitions from vagal dominance to excessive sympathetic activation, potentially triggering fatal arrhythmias.[29] This sleep-related vulnerability aligns with MORTEMUS observations indicating that most monitored SUDEP events occurred during nocturnal sleep periods.

Genetics and molecular autopsy

Cardiac and neuronal channelopathies

Because several ion channels are expressed in both brain and heart tissue, genetic defects affecting these channels represent plausible SUDEP contributors capable of producing both epilepsy and fatal cardiac arrhythmias. The potassium channel gene KCNQ1 was the first ion channel definitively linked to SUDEP. Mouse models carrying human KCNQ1 mutations associated with long QT syndrome developed spontaneous seizures that could trigger lethal cardiac arrhythmias,[30] demonstrating proof-of-concept for dual brain–heart channelopathies.

The SCN1A gene encoding the voltage-gated sodium channel Nav1.1 may influence cardiac function directly or via autonomic pathways. Two SUDEP cases were reported in a family with generalized epilepsy with febrile seizures plus (GEFS+) harboring an SCN1A mutation,[31] and Dravet syndrome patients face markedly elevated SUDEP risk. RYR2 mutations, encoding the cardiac ryanodine receptor and calcium release channel, have been associated with both seizure-like activity and sudden death.[32] Tu and colleagues examined postmortem genetic testing in 68 SUDEP patients and identified six nonsynonymous variants in KCNH2 and SCN5A, all previously described in long QT syndrome.[33] The principal genes implicated in SUDEP are summarized in Table 2.

Table 2.

Genetic channelopathies and epilepsy genes implicated in SUDEP

Gene		Inheritance		Primary phenotype		SUDEP-relevant mechanism		Brain–heart expression
SCN1A		AD; mostly de novo		Dravet syndrome; GEFS +		Loss of GABAergic interneuron Nav1.1 function; possible direct cardiac effect		Brain (predominant); cardiac (experimental)
KCNQ1		AD		Long QT syndrome type 1; epilepsy phenotypes in mouse models		Reduced IKs; QT prolongation; seizure-triggered fatal arrhythmia		Both
KCNH2		AD		Long QT syndrome type 2		Reduced IKr; QT prolongation; torsades de pointes; identified in postmortem SUDEP cohorts		Both
SCN5A		AD		Long QT syndrome type 3; Brugada syndrome		Altered cardiac Nav1.5; ventricular arrhythmia; identified in postmortem SUDEP cohorts		Cardiac (predominant)
RYR2		AD		Catecholaminergic polymorphic ventricular tachycardia (CPVT); seizure-like activity		Diastolic Ca²⁺ leak; adrenergically triggered ventricular arrhythmia		Both
DEPDC5		AD		Familial focal epilepsy with variable foci; FCD-associated epilepsy		mTOR hyperactivation; elevated SUDEP risk; possible autonomic/cardiac contribution		Brain (predominant)
CACNA1A/CACNA1H		AD		Generalized/absence epilepsies; ataxia syndromes		Voltage-gated calcium channel dysfunction, reported in molecular autopsy panels		Both

AD: Autosomal dominant, FCD: Focal cortical dysplasia, GEFS +: Generalized epilepsy with febrile seizures plus, SUDEP: Sudden unexpected death in epilepsy

DEPDC5, mTOR pathway, and Dravet syndrome

Emerging evidence implicates DEPDC5 and the GATOR1 complex in SUDEP pathogenesis.[34] DEPDC5 encodes a component of the GATOR1 complex that negatively regulates mTOR signaling. Loss-of-function mutations result in mTOR hyperactivation, abnormal neuronal excitability, and focal epilepsies. DEPDC5-related epilepsies may carry elevated SUDEP risk and potentially increased susceptibility to cardiac abnormalities, although mechanisms remain under investigation.[35]

Dravet syndrome deserves particular emphasis given its exceptionally high SUDEP rate. This severe developmental and epileptic encephalopathy, typically caused by de novo SCN1A mutations, manifests with early-onset seizures, developmental delay, and treatment-resistant epilepsy. Dravet patients demonstrate frequent nocturnal seizures, prolonged seizures, and autonomic instability—all established SUDEP risk factors. Recognition of Dravet syndrome should prompt intensive SUDEP counseling, optimized seizure control efforts, and consideration for heightened monitoring.[12]

Molecular autopsy: Definition and clinical implications

Molecular autopsy refers to postmortem genetic testing of sudden death victims to identify pathogenic variants in genes associated with epilepsy, cardiac arrhythmias, and sudden death syndromes.[36] In the SUDEP context, molecular autopsy typically involves sequencing panels encompassing epilepsy genes (SCN1A, DEPDC5, GATOR1 complex), long QT syndrome genes (KCNQ1, KCNH2, SCN5A, KCNE1, KCNE2), Brugada syndrome and other cardiac channelopathy genes, and catecholaminergic polymorphic ventricular tachycardia genes (RYR2, CASQ2).

The goals of molecular autopsy include establishing a genetic diagnosis that may explain the death mechanism, enabling cascade genetic screening of at-risk family members, informing reproductive counseling, and improving understanding of SUDEP pathophysiology through systematic genotype–phenotype correlations. When pathogenic or likely pathogenic variants are identified in surviving relatives, targeted preventive interventions may be implemented, including optimized AED therapy, cardiac monitoring, beta-blocker therapy for long QT syndrome, and potentially implantable cardioverter–defibrillator (ICD) placement in select high-risk cases. Molecular autopsy should be considered a standard component of SUDEP investigation, although implementation faces barriers including cost, availability of genetic testing facilities, consent requirements, and variable medicolegal practices.

Antiepileptic drug effects and polytherapy

An important clinical question is whether specific AEDs or their combinations directly contribute to SUDEP risk. Available evidence remains limited and somewhat conflicting. In older SUDEP case series, phenytoin, phenobarbital, and valproic acid were commonly identified, but these likely reflected prescribing patterns of the era rather than specific drug toxicity. Carbamazepine influences autonomic nervous system function in epilepsy patients; treatment initiation may slow atrioventricular conduction and shift autonomic balance toward sympathetic dominance, while abrupt discontinuation can reduce HRV and create sympathetic predominance during sleep.[37] Lamotrigine inhibits delayed rectifier potassium channels, a mechanism linked to QT prolongation in other contexts; one small case series reported four individuals with idiopathic generalized epilepsy who experienced SUDEP while taking lamotrigine, although causality could not be established.[38]

Polytherapy with multiple simultaneous AEDs has been identified as a SUDEP risk factor in several studies. Polytherapy almost certainly serves as a marker of epilepsy severity rather than representing direct drug toxicity, because patients requiring multiple medications have refractory seizures—itself the strongest SUDEP predictor. Critically, the lack of AED treatment poses a substantially greater risk than potential drug adverse effects. A large case-control study of 154 autopsy-confirmed SUDEP cases found that the absence of AED therapy carried an odds ratio of 21.7 (95% CI 4.4–106).[39] Similarly, nonadherence to prescribed AED regimens increased death risk more than three-fold (HR 3.32, 95% CI 3.11–3.54) in a large retrospective cohort.[17] These findings underscore that optimal seizure control through appropriate medication use, with emphasis on adherence, represents the most evidence-based SUDEP prevention strategy currently available.

QT interval and repolarization abnormalities

Electrocardiographic evidence of abnormal cardiac repolarization, including QT interval prolongation or shortening and increased QT dispersion, represents a recognized marker for life-threatening ventricular arrhythmias and sudden cardiac death. Seizures themselves have been linked to dynamic QT abnormalities, with both prolongation and shortening documented during ictal and postictal periods. Prolonged QT intervals increase ventricular repolarization time, creating substrate for polymorphic ventricular tachycardia (torsades de pointes) and ventricular fibrillation. The association between prolonged QTc and SUDEP remains controversial, with case-control studies reporting conflicting findings. Potential mechanisms underlying peri-ictal QTc changes include cerebral dysregulation of cardiac autonomic control, cardiorespiratory interactions, hypoxemia, and acidosis.

Current evidence does not support routine QT interval screening in all epilepsy patients, given inconsistent findings and lack of demonstrated clinical utility for SUDEP risk stratification. However, a baseline electrocardiogram (ECG) should be considered in patients with personal or family history suggesting cardiac arrhythmia risk (syncope, palpitations, family history of sudden death), those prescribed medications known to prolong QT, and patients with epilepsy syndromes associated with cardiac channelopathies.

Acute cardiac effects of seizures and device-based management

Ictal and postictal ECG abnormalities

Systematic ECG monitoring during seizures has revealed a wide spectrum of cardiac abnormalities. PGES following GTCS has been associated with concurrent autonomic disturbance and is regarded as a potential SUDEP biomarker.[40] Studies using prolonged video-EEG with concurrent ECG monitoring have demonstrated that 39–44% of epilepsy patients exhibit at least one peri-ictal ECG abnormality, with higher frequency associated with longer seizure duration and GTCS events. Zijlmans and colleagues retrospectively reviewed 281 seizures across 81 patients and noted abnormalities in 26% of seizures and 44% of patients, predominantly during ictal and postictal periods, including sinus arrhythmia, atrial premature beats, sinus pauses, ST-segment deviations, and T-wave inversions.[41] ST-segment depression during seizures raises concern for myocardial ischemia; Tigaran et al. reported ST depression in 40% of individuals with refractory focal epilepsy,[42] although troponin assays performed following complex partial and GTCS show no consistent elevation, suggesting that clinically significant myocardial injury is rare in uncomplicated seizures absent preexisting coronary disease.[43] Nei et al. similarly documented a range of ECG abnormalities during partial seizures in refractory epilepsy.[44]

Tachyarrhythmias

Ictal tachycardia represents the most common cardiac manifestation, occurring in up to 87% of seizures. Heart rate elevation can precede, coincide with, or follow EEG seizure onset, and is most frequently documented in temporal lobe seizures. Episodes of peri-ictal ventricular tachycardia and ventricular fibrillation have been documented even in patients without structural heart disease, suggesting that seizure-induced repolarization abnormalities can create arrhythmic substrate.

Bradyarrhythmias and ictal asystole

Seizure-related bradyarrhythmias and asystole occur far less frequently than tachycardia, complicating fewer than 2% of seizures. These events likely result from heightened parasympathetic output or disruption of sympathetic tone due to seizure propagation through autonomic cortical and subcortical networks. Schuele and colleagues reported ictal asystole in only 0.27% of nearly 7,000 patients undergoing video-EEG monitoring.[45] The ictal bradycardia syndrome, characterized by recurrent symptomatic seizure-related bradycardia, has been described in selected case series.[46] While brief pauses (2–3 seconds) are likely clinically insignificant, prolonged bradycardia or asystole exceeding 6–10 seconds combined with hypoxemia can produce critical cerebral hypoperfusion. Long-term outcome data from cohorts with ictal asystole/bradycardia suggest that pacemaker therapy reduces syncope and falls but does not necessarily eliminate SUDEP risk.[47]

Syncope, falls, and diagnostic challenges

Syncope can be difficult to distinguish from seizure-related collapse. Cardiovascular syncope may be accompanied by brief myoclonic jerks that mimic epileptic seizures, creating diagnostic confusion. Ideally, simultaneous EEG and ECG monitoring with video telemetry is required for definitive distinction, although in practice diagnosis often relies on clinical history. Accurate differentiation is crucial because appropriate patients may benefit from pacemaker implantation, which can prevent injurious falls.

Cardiac monitoring and device therapy

In high-risk epilepsy patients, cardiac monitoring is recommended to identify rhythm disturbances and guide management aimed at reducing sudden death and preventing syncopal falls. Diagnostic options include standard 12-lead ECG, 24-hour Holter monitoring, extended ambulatory event monitoring, and implantable loop recorders for prolonged rhythm surveillance. Rugg-Gunn and colleagues prospectively followed 20 patients with medically intractable focal epilepsy fitted with implantable loop recorders; over two years and more than 220,000 patient-hours of monitoring, more than one-third exhibited ictal bradycardia with asystole, and over half ultimately required pacemaker placement.[48] This finding suggested the potential benefit of surveillance and prophylactic pacing in selected high-risk subgroups. Limited case data describe pacemaker implantation in patients with documented prolonged ictal asystole, with reduction in syncope and falls but uncertain SUDEP prevention benefit.[49] Pacemakers cannot eliminate SUDEP risk entirely, since tachyarrhythmias and respiratory failure may represent the primary terminal mechanism in many cases. Selection of patients for device therapy should follow joint neurology-cardiology evaluation.

Clinical practice implications for neurologists

Translation of SUDEP research into clinical practice, particularly in resource-limited settings common throughout India and Asia, requires pragmatic approaches. The following represent evidence-based recommendations adaptable to varying resource availability.

Patient identification and counseling: Systematically assess SUDEP risk factors in all epilepsy patients, with particular attention to those with frequent GTCS, nocturnal seizures, refractory epilepsy, intellectual disability, or genetic syndromes. Consider using the SUDEP-7 inventory for structured risk assessment in tertiary epilepsy centers; scores ≥5 warrant heightened vigilance and counseling. Provide individualized SUDEP counseling, balancing appropriate awareness with avoidance of excessive anxiety. For Dravet syndrome and other high-risk syndromes, intensive counseling and monitoring protocols should be the standard of care.

Cardiac workup in resource-limited settings: Baseline 12-lead ECG in patients with personal or family history of syncope, palpitations, or sudden death; Dravet or suspected genetic epilepsy; or polytherapy with QT-prolonging medications. Consider 24-hour Holter monitoring in patients with suspected seizure-related cardiac arrhythmias, recurrent unexplained falls, or a history of witnessed ictal asystole. For patients with documented concerning arrhythmias, a cardiology referral for consideration of extended monitoring or an implantable loop recorder is appropriate.

Seizure control and medication optimization: Prioritize optimal seizure control as the most evidence-based SUDEP prevention strategy. Emphasize medication adherence through patient education, family involvement, and addressing barriers (cost, side effects, stigma). Regularly assess for polypharmacy interactions, particularly those related to QT prolongation, although maintaining seizure control takes precedence.

Supervision and safety strategies: Encourage nocturnal supervision or monitoring for high-risk patients. Avoid prone sleeping position when possible; consider specialized monitoring devices (seizure alarms, nocturnal surveillance systems) where available. Emphasize general safety measures: avoid isolated swimming, bathing supervision, and tub bathing in favor of showers for high-risk patients.

Cardiology collaboration: Establish clear referral pathways between neurology and cardiology for epilepsy patients with cardiac symptoms or documented arrhythmias. For patients with documented ictal asystole >6 seconds with symptoms or falls, discuss pacemaker consideration with cardiology. For patients with a history of aborted sudden cardiac death or documented malignant ventricular arrhythmias, consider ICD evaluation in conjunction with cardiology.

Family screening when indicated: When genetic epilepsy with cardiac channelopathy is suspected (Dravet, long QT-associated epilepsies, positive family history), offer genetic counseling and consider cascade screening of first-degree relatives. Encourage molecular autopsy in SUDEP deaths to enable family screening and advance understanding.

These recommendations must be adapted to local resources, cultural contexts, and healthcare infrastructure. Even in settings with limited access to advanced monitoring, emphasis on seizure control, medication adherence, patient education, and practical safety measures can meaningfully reduce SUDEP risk.

Future directions and research priorities

Despite progress in understanding SUDEP mechanisms, critical gaps remain. Five priority research areas would advance prevention efforts: (1) prospective cohort studies using implantable loop recorders in high-risk epilepsy populations to characterize arrhythmia burden and identify patients likely to benefit from device therapy; (2) systematic molecular autopsy protocols across all SUDEP cases to enable robust genotype–phenotype correlations and family screening; (3) prospective validation of SUDEP-7, SUDEP-3, and emerging biomarker-based risk models in diverse populations, with integration of genetic data, autonomic testing, and imaging biomarkers; (4) mechanistic studies of postictal central apnea, brainstem serotonergic systems, and respiratory chemoreceptor function using animal models with conditional channelopathy expression; and (5) randomized prevention trials evaluating supervised sleeping arrangements, wearable monitoring devices, prophylactic nocturnal oxygen therapy, and medication optimization strategies. Until more definitive evidence emerges, a multidisciplinary team-based approach involving neurology, cardiology, genetics, and primary care, tailored to individual patient risk profiles and resource availability, represents the most rational strategy for SUDEP prevention.

Conclusions

SUDEP remains a partially preventable cause of death in epilepsy, with multifactorial pathogenesis involving autonomic dysfunction, neuro-cardio-respiratory interactions, genetic predisposition, and seizure-related cardiac arrhythmias. The MORTEMUS study has clarified the typical terminal cascade, emphasizing respiratory failure followed by secondary cardiac arrest, while risk-stratification tools such as SUDEP-7 offer promise for clinical assessment. Cardiac channelopathies and epilepsy genes contribute to dual brain–heart vulnerability, particularly in Dravet syndrome and DEPDC5-related epilepsies. Molecular autopsy enables postmortem investigation, family screening, and mechanistic insight.

Current evidence supports optimal seizure control, medication adherence, and nocturnal supervision as the most evidence-based prevention strategies. Cardiac monitoring and device therapy may benefit selected high-risk patients with documented arrhythmias, although their role in broad SUDEP prevention remains undefined. Practical implementation in resource-limited settings requires prioritizing seizure control, patient education, and pragmatic safety measures adaptable to local infrastructure. Multidisciplinary collaboration between neurology, cardiology, genetics, and primary care, with emphasis on individualized risk assessment and shared decision-making, offers the best current approach to reducing SUDEP mortality and supporting affected families.

Author contributions

MPK: conceptualization; study design; literature review; data interpretation; writing—original draft; manuscript revision; project administration; and correspondence with the journal. SK: literature review; data curation; writing—review and editing. NB: literature review; data collection; writing—review and editing. AAM: literature review; data interpretation; writing—review and editing. AS: literature review; critical revision of the manuscript; writing—review and editing. UT: literature review; writing—review and editing. FD: critical revision of the manuscript; supervision; and writing—review and editing. SH: literature review; writing—review and editing. JDS: data interpretation; critical revision of the manuscript; and writing—review and editing. NP: supervision; conceptual guidance; critical revision of the manuscript; and final approval of the manuscript.

Conflicts of interest

There are no conflicts of interest.

Funding Statement

Nil.