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Intraventricular conduction delay: a prognostic marker in chronic heart failure
W Shamim1, D P Francis, M Yousufuddin
1Royal Brompton Hospital and National Heart and Lung Institute, Cardiac Medicine Department, London, UK. w.shamim@excite.com
Insights
Intraventricular conduction delay (IVCD) on ECG is a strong predictor of mortality in chronic heart failure (CHF) patients. This ECG marker, combined with exercise capacity, offers superior prognostic value compared to other indicators.
Area of Science:
- Cardiology
- Clinical Electrophysiology
Background:
- Chronic heart failure (CHF) presents a significant mortality risk.
- Established clinical and laboratory markers predict CHF prognosis.
- Novel ECG parameters require evaluation for prognostic utility.
Purpose of the Study:
- Identify the optimal electrocardiogram (ECG) parameter for predicting mortality in CHF.
- Compare the prognostic value of ECG markers against established indicators.
- Determine the best combination of predictors for CHF mortality.
Main Methods:
- Retrospective analysis of data from 241 CHF patients.
- Utilized Cox proportional Hazard models for univariate and bivariate analyses.
- Developed a multivariate model incorporating ECG, exercise testing, and clinical data.
Main Results:
- Intraventricular conduction delay (IVCD) and QTc interval were significant univariate predictors of mortality.
- A combination of IVCD and MVO2 (maximal oxygen uptake) demonstrated superior predictive power.
- Multivariate analysis identified IVCD, MVO2, and left ventricular ejection fraction (LVEF) as the best predictors, with no added benefit from plasma sodium, age, or NYHA class.
- IVCD showed a graded increase in mortality risk with increasing values and outperformed QTc.
Conclusions:
- Intraventricular conduction delay (IVCD) is a powerful and independent ECG predictor of prognosis in CHF patients.
- Combining IVCD with measures of exercise capacity enhances mortality prediction in CHF.
- ECG parameters, particularly IVCD, offer valuable prognostic information in CHF management.
Abstract:
Chronic heart failure (CHF) is associated with high mortality, and there are several established clinical and laboratory parameters that predict mortality in CHF. The purpose of this study was (a) to identify the best ECG parameter that predicts mortality, (b) to evaluate the prognostic marker of ECG against well-established indicators of prognosis. Relevant data from 241 CHF patients were analysed retrospectively. Cardiopulmonary exercise testing and radionuclide ventriculogram were also performed where possible. The mean follow-up period was 31 months. On univariate analysis by the Cox proportional Hazard method, intraventricular conduction delay (IVCD) [P<0.0001, hazard ratio 1.017 (1.011-1.024)] and QTc [P<0.0001, hazard ratio 1.012 (1.006-1.017)] were identified as predictors of mortality. On bivariate analysis, IVCD and MVO2 were better predictors when combined together. A model based on multivariate analysis showed that IVCD, MVO2 and left ventricular ejection fraction (LVEF) were the best predictors of mortality. The addition of plasma sodium, age and NYHA class had no added benefit on the predictive power of the model. Further analysis of IVCD and QTc showed that, for different cut-off values, IVCD is better than QTc, and that there is a graded increase in mortality with increasing value of IVCD. We have found that IVCD is an important ECG predictor of prognosis in patients with CHF.