8 Apr 2022

Scientists expose the lethal link between irregular heartbeats and epilepsy

How it works: an implanted cardiac monitor records continuous ECG data, which is transmitted during follow-up visits at the cardiology clinic. The data are reviewed together with patient-reported seizures, giving a detailed clinical picture for tailoring preventive treatment. Schematic image: Dr Shobi Sivathamboo

A trial led by researchers at Monash University and Alfred Health, in collaboration with the Royal Melbourne Hospital has detected a high incidence of irregular heartbeats that can lead to cardiac arrest in people with chronic drug-resistant epilepsy, providing a new pathway for preventive treatment. 

The breakthrough finding suggests there is a link between irregular cardiac arrhythmia and the incidence of premature mortality including Sudden Unexpected Death in Epilepsy (SUDEP), previously thought to be irrelevant. 

As a result of the trial, three participants received potentially life-saving treatment, including Sheeba Solomon. Ms Solomon has a condition called ictal asystole where the heart stops beating for long pauses, because of a seizure. 

“My seizures would cause me to have frequent blackouts and falls, without any warning. I have had many injuries to my head, neck and back because of my falls. I trained as a lawyer, but due to my epilepsy, I had to stop working. I even collapsed in court several times and I was really
embarrassed by this,” she said. 

“The study found that my heart stopped beating during my seizures, so I was treated with a pacemaker and since this time, I haven’t had any falls.” 

The researchers used implantable cardiac monitors with 31 patients over a 12 month period to assess the link between epilepsy and the heart. The researchers detected a high incidence of a repeating pattern of cardiac arrhythmia called ventricular tachycardia, which can lead to ventricular fibrillation – a life-threatening arrhythmia – and cardiac arrest. 

The findings are now published in Neurology.

Patients with epilepsy are at an increased risk of premature death from cardiovascular disease (CVD), including from SUDEP. 

Led by Dr Shobi Sivathamboo, from the Monash Central Clinical School’s Department of Neuroscience and Alfred Health’s Department of Neurology, together with collaborators from The Royal Melbourne Hospital, the researchers say the link between epilepsy and CVD was not clear and the novel finding may be a contributing factor associated with the incidence of premature mortality including SUDEP.

“We’d selected patients who were otherwise asymptomatic – there was no clinical indication to monitor them other than the fact that they had severe or poorly controlled epilepsy,” Dr Sivathamboo said. 

“We found that 10 per cent (3 out of 31) of patients we monitored had serious cardiac arrhythmia that required further cardiology management which is highly interesting as it was previously thought that ventricular tachycardia was irrelevant to SUDEP, but our findings suggest that this may not be the case,” Dr Sivathamboo said. 

The findings follow a previous study with collaborators from New York University and published in Neurology late last year that revealed Heart Rate Variability, specifically when there is little variation between heartbeats, acted as a marker for SUDEP in epilepsy patients. The findings of the international, multi-centre retrospective study may provide a low-cost, non-invasive biomarker to stratify SUDEP risk in epilepsy patients. 

SUDEP, diagnosed when no other cause of death is found during an autopsy, is the leading cause of mortality in people with uncontrolled seizures. 

Dr Sivathamboo said SUDEP may also have other underlying causes. “SUDEP is really complicated to study. I think multiple mechanisms may be involved but it highlights that cardiovascular management should be a key treatment strategy for epilepsy patients, managed by cardiologists with medications or surgical interventions,” she said. 

Dr Sivathamboo is now leading a change in standard clinical practice so that all patients admitted for epilepsy monitoring at The Alfred hospital long-term, now have their respiration and blood oxygen levels monitored as well as ECG data. 

“That’s going to pick up patients who stop breathing as a result of their seizures – sometimes they can stop breathing and that relates to cardiac arrhythmias,” she said. 

Instrumental to the study were co-investigators, Head of the Department of Neuroscience Professor Terence O’Brien and Patrick Kwan, Professor of Neurology, and Royal Melbourne Hospital cardiologist Dr Paul Sparks

Read the full paper in Neurology:

Shobi Sivathamboo, Zining Liu, Fiona Sutherland, Erica Minato, Pablo M. Casillas-Espinosa, Nigel C. Jones, Marian Todaro, Udaya Seneviratne, Varduhi Cahill, Raju Yerra, Christopher French, John-Paul Nicolo, Piero Perucca, Patrick Kwan, Paul B. Sparks, and Terence J. O’Brien. Serious cardiac arrhythmias detected by subcutaneous long-term cardiac monitors in patients with drug-resistant epilepsy. Neurology 6 April 2022 DOI https://doi.org/10.1212/WNL.0000000000200173

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