Risk assessment of left ventricular systolic dysfunction in primary care: cross sectional study evaluating a range of diagnostic tests

OBJECTIVES: To assess the probability of left ventricular systolic dysfunction without echocardiography in patients from general practice. DESIGN: Cross sectional study using multivariate regression models to examine the relation between clinical variables and left ventricular systolic dysfunction as determined by echocardiography. SETTING: Three general practices in Copenhagen. SUBJECTS: 2158 patients aged >40 years were screened by questionnaires and case record reviews; 357 patients with past or present signs or symptoms of heart disease were identified, of whom 126 were eligible for and consented to examination. MAIN OUTCOME MEASURES: Clinical variables that were significantly (P<0.05) related to ejection fraction ⩽0.45 and their predictive value for left ventricular systolic dysfunction. RESULTS: 15 patients (12%) had left ventricular systolic dysfunction. The prevalence was significantly related to three questions: does the electrocardiogram have Q waves, left bundle branch block, or ST-T segment changes? (P=0.012); is resting supine heart rate greater than the simultaneous diastolic blood pressure? (P=0.002); and is plasma N-terminal atrial natriuretic peptide>0.8 nmol/l? (P=0.040)? Only one of 60 patients with a normal electrocardiogram had systolic dysfunction (2%, 95% confidence interval 0% to 9%) regardless of response to the other two questions. The risk of dysfunction was appreciable in patients with a yes answer to two or three questions (50%, 27% to 73%). CONCLUSIONS: A normal electrocardiogram implies a low risk of left ventricular systolic dysfunction. Patients can be identified for echocardiography on the basis of an abnormal electrocardiogram combined with increased natriuretic peptide concentration or a heart rate greater than diastolic blood pressure, or both.