Heart failure is a very common condition in the UK with a significant proportion of newly diagnosed patients dying within a year. The prognostic implications of surface electrocardiogram (ECG) markers in chronic heart failure (CHF) patients are not well characterised. This study aims to determine whether the presence of surface ECG markers such as prolonged PR interval or QRS duration or both act as predictors of clinical outcome in chronic heart failure.Methods
735 patients with chronic heart failure who were also in sinus rhythm were analysed based on the presence of electrical dyssynchrony (ED) markers such as first-degree atrioventricular block (ED_PR, PR >200ms, n = 163) and QRS duration (ED_QRS, QRS ≥ 120ms, n = 252), both PR and QRS prolongation (ED_both, n = 81) and neither (ED_neither, n = 340). PR intervals and QRS duration was calculated from 12-lead ECGs obtained at the time of recruitment. The primary end point investigated in this study was all-cause mortality.Results
After a median follow up period of 15.85 months (IQR 7.6–23 months), the mortality rate for ED_PR, ED_QRS and ED_both increased (16%, 17%, 17% respectively) compared to the control group (8%). A Kaplan-Meier survival analysis showed that survival distribution of ED_PR, ED_QRS and ED_both was lower compared to ED_neither (log-rank p < 0.0001). In addition, our results showed that prolonged PR interval (HR 1.95, 95% CI 1.02–3.73, p < 0.05) and combined PR and QRS prolongation (HR 2.36, 95% CI 1.26–4.42, p < 0.01) had a contributory effect on all-cause mortality after adjusting for New York Heart Association (NYHA) classification.Conclusion and Implications
In conclusion, we found out that prolonged PR interval and a combination of both prolonged PR and QRS interval is associated with higher all-cause mortality in chronic heart failure patients, after adjusting for NYHA classification. Surface ECG markers such as PR and QRS intervals can therefore aid clinicians in risk stratification and improved pharmacological management of chronic heart failure patients.