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ECG risk score may predict sudden cardiac arrest in certain patients
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A novel cumulative ECG risk score predicted sudden cardiac arrest in patients with left ventricular ejection fraction greater than 35%, according to a study published in the European Heart Journal.
“In the patients with low ejection fraction, the ejection fraction by itself is not good enough and for those who have ejection fraction over 35%, we [don’t have] good predictors,” Sumeet S. Chugh, MD, medical director of the Heart Rhythm Center at the Cedars-Sinai Heart Institute, said in an interview with Cardiology Today. “What my group and I have been doing for almost 20 years is working on novel predictors we can find for sudden cardiac arrest.”
ECG risk score
Aapo L. Aro, MD, PhD, a visiting postdoctoral fellow at Cedars-Sinai, and colleagues analyzed data from more than 1 million participants from the Oregon Sudden Unexpected Death Study, and compared 522 participants (mean age, 65 years; 66% men) with sudden cardiac arrest who had 12-lead ECG data available vs. 736 geographical controls. Participants in the control group had risk factors for sudden cardiac arrest, but did not have a history of ventricular arrhythmias or cardiac arrest.
Data points including LV hypertrophy, heart rate, QRS-T angle, Tpeak-to-Tend, QTc and QRS transition zone were reviewed in the ECG.
A high ECG risk score of four or more abnormal markers was seen in 16% of the sudden cardiac arrest group vs. 3% of the control group (P < .001). Low scores — one or no abnormal markers — were more commonly seen in the control group (74%) compared with the sudden cardiac arrest group (37%).
Increased risk with higher score
Participants with an ECG risk score of 4 or greater had an increased risk for sudden cardiac arrest (OR = 21.2; 95% CI, 9.4-47.7). The risk score was highly predictive in participants with LVEF greater than 35% with four or more ECG abnormalities (OR = 26.1; 95% CI, 9.9-68.5); a similar pattern was not seen in those with LVEF of 35% or less, but the sample size of that subgroup was small, the researchers wrote.
The C statistic increased from 0.625 to 0.753 (P < .001) with an overall net reclassification improvement of 0.319 (P < .001) when the ECG risk score was added to a model including LVEF and demographic and clinical factors, according to the researchers.
The researchers validated the findings using participants from the ARIC study. Participants with an ECG risk score of 4 or higher had an increased risk for sudden cardiac arrest (HR = 4.84; 95% CI, 2.34-9.99). The C statistic for the risk score plus clinical factors including hypertension, age, sex and diabetes was higher (0.774) vs. that for the clinical parameters alone (0.759; P = .019).
“The reason that we’re excited about this work is that we found this in the Northwest U.S., and then we took this simple electrical risk score to this other separate population and it seemed to work there as well,” Chugh told Cardiology Today.
“We think that the next step is to take these findings and prospectively validate them,” Chugh said. “That could be done, for example, in patients who have defibrillators already, to see if the ones that have the higher electrical risk score are actually the ones that receive shocks."– by Darlene Dobkowski
Disclosures: The authors report no relevant financial disclosures.
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