By Marilynn Larkin
NEW YORK—A "considerable subset" of patients with recent-onset schizophrenia spectrum disorders (SSD) have ECGs suggesting Brugada syndrome (BrS), researchers say.
"It is well known that patients with schizophrenia have a much higher risk of dying by sudden cardiac death (SCD) than the average population. This has always been attributed to the increased risk of cardiovascular diseases these patients have due to their generally more unhealthy lifestyle and to medication side effects," Dr. Arjen Sutterland of the University of Amsterdam told Reuters Health by email.
"But there are doubts whether these factors fully explain the 2-4 times increased risk of SCD," he said. "From large genetic studies we know that several genes that influence ion channel functioning - which, in turn, can influence neurotransmission - are affected in schizophrenia. Some of these genes are also implicated in BrS."
Dr. Sutterland and colleagues analyzed ECGs of 388 patients with recent-onset SSD and 844 medical students who served as controls. Those with SSD had a mean age of 22 and 82% were men; the median age for controls was 20 and 35% were men.
Patients' diagnoses included schizophrenia (71%), schizoaffective disorder (14%), schizophreniform disorder (6%) and psychosis (8.5%). Nearly 8% of patients used cannabis; 90% were taking antipsychotics; 81%, QT-prolonging drugs; and 7%, antidepressants.
Anyone with a suspect BrS-ECG was offered an ajmaline provocation. Clinical and ECG variables were compared for patients with and without suspect BrS-ECG.
As reported online June 24 in Schizophrenia Research, 33 patients (8.5%) and 13 controls (1.5%) had a suspect BrS-ECG (odds ratio, 3.5). The finding was not explained by potential confounders such as gender, age, ethnicity, cannabis use, cardiovascular risk factors, medication use or serum electrolytes, according to the authors. BrS was confirmed in three patients and one control.
The authors state, "A considerable subset of patients with recent-onset SSD have suspect BrS-ECG, extending earlier findings in patients with chronic schizophrenia. Screening for BrS in schizophrenia could be relevant both to prevent sudden cardiac death and to identify a subgroup of patients with possible ion-channel dysfunctioning."
Nonetheless, Dr. Sutterland said, "It is still too early to routinely screen for this disease, since an ECG pattern suggestive of BrS alone is not enough (to make a) diagnosis and the diagnosis was only confirmed in a few patients."
"At this stage, we would advise clinicians whose patients with schizophrenia have symptoms suggestive of cardiac arrhythmias to not only screen for QTc prolongation, but to also consider BrS, especially since preventive measures can be taken, including not prescribing certain psychotropic drugs."
"Screening for BrS should be done by cardiologist, preferably one who specializes in cardiac arrhythmias," he added.
Dr. Scott Krakower, assistant unit chief, psychiatry, at Zucker Hillside Hospital in Glen Oaks, New York, said in an email to Reuters Health, "It is plausible that there may be a link between disruption in ion channels and schizophrenia. Whether or not patients have BrS specifically, it is important for providers to routinely screen for underlying cardiac conditions in this population."
Schizophr Res 2019.
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