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Cardiac structural and functional profile of patients with delayed QRS transition zone and sudden cardiac death
Aapo L Aro1,2, Derek Phan1, Carmen Teodorescu1
1Heart Institute, Cedars-Sinai Medical Center, Advanced Health Sciences Pavilion, Suite A3100, 127 S. San Vicente Boulevard, Los Angeles, CA 90048, USA.
Insights
Delayed QRS transition zone on ECG is linked to higher sudden cardiac death (SCD) risk. This electrical remodeling marker is associated with structural heart changes and predicts SCD independently of ejection fraction.
Area of Science:
- Cardiology
- Electrophysiology
- Cardiac Imaging
Background:
- Delayed QRS transition zone on ECG is a potential risk marker for sudden cardiac death (SCD).
- Underlying mechanisms linking ECG findings to SCD risk are not fully understood.
- Investigating cardiac structural and functional alterations associated with delayed QRS transition is crucial.
Purpose of the Study:
- To correlate echocardiographic findings with ECG and clinical characteristics.
- To investigate how cardiac structure and function alterations contribute to delayed QRS transition zone risk.
- To explore delayed QRS transition zone as a potential predictor of SCD.
Main Methods:
- Comparative analysis of SCD cases (n=627) and controls (n=801) from the Oregon Sudden Unexpected Death Study.
- Identification of subjects with delayed QRS transition (V5 or later).
- Correlation of delayed transition with clinical data and echocardiographic parameters (LV mass, LV diameter, LVEF).
Main Results:
- Delayed transition was observed in 31% of SCD cases vs. 17% of controls.
- Delayed transition associated with older age, cardiovascular risk factors, and myocardial infarction history.
- Significant associations found between delayed transition and increased LV mass, larger LV diameter, and reduced LVEF.
- Multivariate analysis confirmed independent association of delayed transition with myocardial infarction, reduced LVEF, and LV hypertrophy.
- The link between delayed transition and SCD remained significant even after adjusting for LVEF (OR 1.57).
Conclusions:
- Delayed QRS transition zone reflects underlying cardiac remodeling beyond prior myocardial infarction and reduced LVEF.
- This ECG finding is an independent predictor of SCD.
- Delayed QRS transition zone should be further investigated as a novel risk stratification tool for SCD.
Aims:
Delayed QRS transition zone in the precordial leads of the 12-lead electrocardiogram (ECG) has been recently associated with increased risk of sudden cardiac death (SCD), but the underlying mechanisms are unknown. We correlated echocardiographic findings with ECG and clinical characteristics to investigate how alterations in cardiac structure and function contribute to this risk marker.
Methods And Results:
From the ongoing population-based Oregon Sudden Unexpected Death Study (catchment population ∼1 million), SCD cases with prior ECG available (n = 627) were compared with controls (n = 801). Subjects with delayed transition at V5 or later were identified, and clinical and echocardiographic patterns associated with delayed transition were analysed. Delayed transition was present in 31% of the SCD cases and 17% of the controls. These subjects were older and more likely to have cardiovascular risk factors and history of myocardial infarction. Delayed transition was associated with increased left ventricular (LV) mass (122.7 ± 40.2 vs. 102.9 ± 33.7 g/m2; P < 0.001), larger LV diameter (53.3 ± 10.4 vs. 49.2 ± 8.0 mm; P < 0.001), and lower LV ejection fraction (LVEF) (46.4 ± 15.7 vs. 55.6 ± 12.5%; P < 0.001). In multivariate analysis, delayed transition was independently associated with myocardial infarction, reduced LVEF, and LV hypertrophy. The association between delayed transition and SCD was independent of the LVEF (OR 1.57; 95% CI 1.04-2.38; P = 0.032).
Conclusion:
The underpinnings of delayed QRS transition zone extend beyond previous myocardial infarction and reduced LVEF. Since the association with sudden death is independent of these factors, this novel marker of myocardial electrical remodelling should be explored as a potential risk predictor of SCD.
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