Impact of electrocardiographic interpretability on outcome in patients referred for stress testing
Alberto Bouzas-Mosquera1, Jesús Peteiro, Francisco J Broullón
1Department of Cardiology, Hospital Universitario A Coruña, A Coruña, Spain. alberto.bouzas.mosquera@sergas.es
Insights
Uninterpretable electrocardiograms (ECGs) in patients undergoing stress testing are linked to significantly worse outcomes. This includes higher rates of death and cardiac events, highlighting the prognostic importance of ECG interpretability.
Area of Science:
- Cardiology
- Medical Diagnostics
Background:
- Limited understanding exists regarding the prognostic value of electrocardiogram (ECG) interpretability in patients referred for stress testing.
- Assessing ECG interpretability is crucial for risk stratification in cardiovascular disease management.
Purpose of the Study:
- To investigate the association between electrocardiogram interpretability and patient outcomes following stress testing.
- To determine if uninterpretable ECGs predict adverse cardiovascular events and mortality.
Main Methods:
- Exercise echocardiography was performed in 8226 patients with known or suspected coronary artery disease.
- Electrocardiograms were classified as uninterpretable based on specific criteria including left bundle-branch block (LBBB), left ventricular hypertrophy (LVH) with strain, and digitalis therapy.
- Outcomes assessed included all-cause mortality, cardiac death, and hard cardiac events (cardiac death or nonfatal myocardial infarction).
Main Results:
- A significant proportion of patients (2450/8226) had uninterpretable ECGs.
- Patients with uninterpretable ECGs exhibited substantially higher 5-year rates of death (18.7% vs. 9.5%), cardiac death (10.9% vs. 4.1%), and hard cardiac events (18.8% vs. 10.9%) compared to those with interpretable ECGs (P < 0.001).
- Lack of ECG interpretability independently predicted all-cause mortality (HR 1.25), cardiac death (HR 1.63), and hard cardiac events (HR 1.28) after covariate adjustment. Specific abnormalities like LBBB and LVH were significant predictors of adverse outcomes.
Conclusions:
- Uninterpretable electrocardiograms are associated with a significantly worse prognosis in patients undergoing stress testing.
- The findings underscore the importance of ECG interpretability as a prognostic marker in cardiovascular risk assessment.
- Specific ECG abnormalities contributing to uninterpretability, such as LBBB and LVH, are independent predictors of adverse cardiac events.
Background:
There is limited insight into the association of electrocardiographic interpretability with outcome in patients referred for stress testing.
Methods:
Exercise echocardiography was performed in 8226 patients with known or suspected coronary artery disease. Electrocardiograms were considered uninterpretable in the presence of left bundle-branch block (LBBB), left ventricular hypertrophy (LVH) with strain, repolarization abnormalities because of digitalis therapy, ventricular paced rhythm, preexcitation or ST depression ≥ 0.1 mV because of other causes. End points were all-cause mortality, cardiac death and hard cardiac events (i.e. cardiac death or nonfatal myocardial infarction).
Results:
A total of 2450 patients had uninterpretable electrocardiograms. During a follow-up period of 4.1 ± 3.5 years, there were 1011 deaths (of which 478 were cardiac deaths) and 1069 patients experienced a hard cardiac event. The 5-year rates of death, cardiac death and hard cardiac events were, respectively, 18.7%, 10.9% and 18.8% in patients with uninterpretable ECGs, compared with 9.5%, 4.1% and 10.9% in those with interpretable ECGs (P < 0.001). After covariate adjustment, lack of ECG interpretability remained an independent predictor of all-cause mortality (hazard ratio [HR] 1.25, 95% confidence interval [CI] 1.08-1.44, P = 0.002), cardiac death (HR 1.63, 95% CI 1.32-2.01, P < 0.001) and hard cardiac events (HR 1.28, 95% CI 1.11-1.47, P < 0.001). When the specific ECG abnormalities were included as covariates, LBBB, LVH and digitalis therapy remained predictors of cardiac death; LBBB and LVH were predictors of hard cardiac events, and LVH remained predictive of all-cause mortality.
Conclusion:
Uninterpretable ECGs portend a worse prognosis in patients referred for stress testing.
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