Abstract Body (Do not enter title and authors here): Introduction
Specific markers on the sinus rhythm ECG are independently associated with increased risk of sudden cardiac death (SCD) with several published ECG risk scores. However due to distinctive activation of the heart, ventricular-paced (VP) ECGs are typically excluded from these studies, especially in the general population.
Hypothesis
Markers on the VP ECG can predict risk of SCD in the general population.
Methods
We conducted a case-control analysis in an ongoing community-based study of SCD in the Northwestern US (catchment population ~ 1 million; 2002-2020). SCD cases were included if they were aged ≥18 years, had archived ECGs performed prior to and unrelated to SCD that demonstrated continuous ventricular pacing. Control participants with identical ECG selection criteria and no history of ventricular arrhythmias or cardiac arrest were recruited from the same geographical area. Individuals with biventricular pacing and fusion rhythm were excluded. The ECG markers analyzed included QRS duration, QT, QTc, JTc, Tpeak-end, and heart rate.
Results
Among 104 cases and 36 controls meeting criteria, VP SCD cases exhibited significantly longer QRS duration (median 172 ms, interquartile range [IQR] 157-192 vs. 161 ms, IQR 144-172, p=0.02), QTc (median 521 ms, IQR 495-560 vs. 511 ms, IQR 483-529 ms, p=0.001), and Tpeak-end interval (median 113 ms, IQR 97-124 vs. 99 ms, IQR 84-111, p=0.02) than VP controls. The highest quartile of QRS duration, QTc, and Tpeak-end were associated with 3.9, 7.6, and 5.2-fold higher odds of SCA, respectively, compared to the lowest quartiles. After performing multivariable regression analysis with demographic factors and comorbidities, QRS duration and Tpeak-end remained independent predictors of SCA (Figure).
Conclusion
Our findings suggest that specific markers from ventricular paced ECGs are also associated with SCD. Further investigation is warranted to validate these results in other populations and to explore the implications for SCD risk stratification in the previously neglected sub-group of individuals with ventricular-paced rhythms.