Screening asymptomatic adults with resting or exercise electrocardiography: a review of the evidence for the U.S. Preventive Services Task Force.

BACKGROUND: Coronary heart disease is the leading cause of death in adults. Screening for abnormalities by using resting or exercise electrocardiography (ECG) might help identify persons who would benefit from interventions to reduce cardiovascular risk.
PURPOSE: To update the 2004 U.S. Preventive Services Task Force evidence review on screening for resting or exercise ECG abnormalities in asymptomatic adults. DATA SOURCES: MEDLINE (2002 through January 2011), the Cochrane Library database (through the fourth quarter of 2010), and reference lists. STUDY SELECTION: Randomized, controlled trials and prospective cohort studies. DATA EXTRACTION: Investigators abstracted details about the study population, study design, data analysis, follow-up, and results and assessed quality by using predefined criteria. DATA SYNTHESIS: No study evaluated clinical outcomes or use of risk-reducing therapies after screening versus no screening. No study estimated how accurately resting or exercise electrocardiography classified participants into high-, intermediate-, or low-risk groups, compared with traditional risk factor assessment alone. Sixty-three prospective cohort studies evaluated abnormalities on resting or exercise ECG as predictors of cardiovascular events after adjustment for traditional risk factors. Abnormalities on resting ECG (ST-segment or T-wave abnormalities, left ventricular hypertrophy, bundle branch block, or left-axis deviation) or exercise ECG (ST-segment depression with exercise, chronotropic incompetence, abnormal heart rate recovery, or decreased exercise capacity) were associated with increased risk (pooled hazard ratio estimates, 1.4 to 2.1). Evidence on harms was limited, but direct harms seemed minimal (for resting ECG) or small (for exercise ECG). No study estimated harms from subsequent testing or interventions, although rates of angiography after exercise ECG ranged from 0.6% to 2.9%. LIMITATIONS: Only English-language studies were included. Statistical heterogeneity was present in several of the pooled analyses.
CONCLUSION: Abnormalities on resting or exercise ECG are associated with an increased risk for subsequent cardiovascular events after adjustment for traditional risk factors, but the clinical implications of these findings are unclear.