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ECG-derived spatial QRS-T angle is associated with ICD implantation, mortality and heart failure admissions in
Sarah Gleeson1, Yi-Wen Liao1, Clementina Dugo1,2
1Department of Cardiology, North Shore Hospital, Waitemata District Health Board, Auckland, New Zealand.
Insights
A large spatial QRS-T angle, greater than 110 degrees, strongly predicts mortality and implantable cardioverter defibrillator (ICD) events in patients with reduced ejection fraction. Advanced ECG and echocardiographic analysis reveals key risk markers for improved clinical decision-making.
Area of Science:
- Cardiology
- Medical Imaging
- Biomedical Engineering
Background:
- Increased spatial QRS-T angle is a known predictor of implantable cardioverter defibrillator (ICD) therapy in patients with left ventricular systolic dysfunction (LVSD).
- This study focuses on patients with a left ventricular ejection fraction (LVEF) between 31-40% to further investigate predictive markers.
Purpose of the Study:
- To assess the relationship between spatial QRS-T angle and other advanced ECG (A-ECG) and echocardiographic parameters.
- To identify predictors of all-cause mortality or ICD implantation for secondary prevention in patients with moderate LVSD.
Main Methods:
- Retrospective cohort study of 534 patients (≤75 years) with LVEF 31-40%.
- Digital 12-lead ECGs and echocardiographic data were analyzed for 295 patients.
- Data mining and machine learning were employed to identify novel risk markers and develop predictive models.
Main Results:
- 49 patients (17%) experienced events (mortality or ICD implantation).
- 24 A-ECG and 3 echocardiographic parameters were significantly associated with events after multiplicity adjustment.
- A spatial QRS-T angle >110° was strongly associated with secondary ICD implantation/all-cause death (adjusted HR 3.4) and heart failure admission (adjusted HR 4.1).
Conclusions:
- Spatial QRS-T angle >110° is a significant predictor of adverse outcomes, including arrhythmic events and all-cause mortality.
- Comprehensive analysis of ECG and echocardiographic data reveals complex relationships important for clinical decision-making.
- Large-scale application of these advanced analytical techniques holds promise for future patient management.
Background:
Increased spatial QRS-T angle has been shown to predict appropriate implantable cardioverter defibrilIator (ICD) therapy in patients with left ventricular systolic dysfunction (LVSD). We performed a retrospective cohort study in patients with left ventricular ejection fraction (LVEF) 31-40% to assess the relationship between the spatial QRS-T angle and other advanced ECG (A-ECG) as well as echocardiographic metadata, with all-cause mortality or ICD implantation for secondary prevention.
Methods:
534 patients ≤75 years of age with LVEF 31-40% were identified through an echocardiography reporting database. Digital 12-lead ECGs were retrospectively matched to 295 of these patients, for whom echocardiographic and A-ECG metadata were then generated. Data mining was applied to discover novel ECG and echocardiographic markers of risk. Machine learning was used to develop a model to predict possible outcomes.
Results:
49 patients (17%) had events, defined as either mortality (n = 16) or ICD implantation for secondary prevention (n = 33). 72 parameters (58 A-ECG, 14 echocardiographic) were univariately different (p<0.05) in those with vs. without events. After adjustment for multiplicity, 24 A-ECG parameters and 3 echocardiographic parameters remained different (p<2x10-3). These included the posterior-to-leftward QRS loop ratio from the derived vectorcardiographic horizontal plane (previously associated with pulmonary artery pressure, p = 2x10-6); spatial mean QRS-T angle (134 vs. 112°, p = 1.6x10-4); various repolarisation vectors; and a previously described 5-parameter A-ECG score for LVSD (p = 4x10-6) that also correlated with echocardiographic global longitudinal strain (R2 = - 0.51, P < 0.0001). A spatial QRS-T angle >110° had an adjusted HR of 3.4 (95% CI 1.6 to 7.4) for secondary ICD implantation or all-cause death and adjusted HR of 4.1 (95% CI 1.2 to 13.9) for future heart failure admission. There was a loss of complexity between A-ECG and echocardiographic variables with an increasing degree of disease.
Conclusion:
Spatial QRS-T angle >110° was strongly associated with arrhythmic events and all-cause death. Deep analysis of global ECG and echocardiographic metadata revealed underlying relationships, which otherwise would not have been appreciated. Delivered at scale such techniques may prove useful in clinical decision making in the future.