PURPOSE: Chronic obstructive pulmonary disease (COPD) can induce typical electrocardiographic (ECG) features like p-pulmonale, right heart axis, right ventricular hypertrophy and right bundle branch block, which have been associated with poor prognosis. There are other ECG parameters that are associated with prognosis (atrial fibrillation - AF, prolonged QTc interval - <440ms, wide QRS complex - >120ms), that have not been evaluated comprehensively in previous studies. We aimed to determine the prevalence of COPD typical and other ECG changes and to evaluate association with survival.
METHODS: This retrospective cohort study screened all consecutive discharges between 2002-2007 and identified 1185 potentially eligible patients with confirmed COPD. ECGs were unavailable/poor quality in 184 patients and remaining 1001 ECGs were evaluated by three independent investigators. The survival was ascertained with Central population registry and the database was censored on November 1st, 2008.
RESULTS: We included 1001 patients (70±9 years, 72% men, 63% GOLD III/IV). At least one COPD typical ECG feature was present in 33% of patients (p-pulmonale 9%, right heart axis 11%, right ventricular hypertrophy 17%, right bundle branch block 8%) and correlated with GOLD stage (p<0.05). AF, prolonged QTc interval, and wide QRS complex were present in 13%, 37%, and 11%, respectively. During the median follow-up 481 (48%) of patients died. In Kaplan-Meier analysis, none of COPD typical but all other (p<0.01 for all) ECG changes predicted poor survival. In an adjusted (age, gender, GOLD, body mass index, smoking) Cox model of proportional hazards, AF (hazard ration 10.68, 95% confidence interval 2.40-47.52) and prolonged QTc interval (hazard ratio 1.28, 95% confidence interval 1.01-1.64) remained predictive of poor survival.
CONCLUSIONS: ECG changes in COPD patients are common and correlate with the severity of disease. AF and prolonged QTc interval but not COPD typical ECG changes were predictive of poor survival.
CLINICAL IMPLICATIONS: Electrocardiogram could be useful for risk stratification of patients with COPD and should guide disease specific management.
DISCLOSURE: The following authors have nothing to disclose: Ursa Bones, Miha Zabret, Irena Sarc, Mitja Kosnik, Stanislav Suskovic, Mitja Lainscak
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