Large Q and S waves in lead III on the electrocardiogram distinguish patients with hypertrophic cardiomyopathy from athletes. Issue 22 (21st April 2018)

• Record Type: Journal Article
• Authors: Chen, Alvin S; Bent, Rachel E; Wheeler, Matthew; Knowles, Joshua W; Haddad, Francois; Froelicher, Victor; Ashley, Euan; Perez, Marco V
• Is Part Of: Heart. Volume 104:Issue 22(2018)
• Page Start: 1871
• Page End: 1877
• Publication Date: 2018-04-21
• Subjects: athlete -- hypertrophic cardiomyopathy -- screening electrocardiogram -- international criteria -- septal hypertrophy; Heart -- Diseases -- Treatment -- Periodicals; Cardiology -- Periodicals; 616.12
• DOI: 10.1136/heartjnl-2017-312647
• Languages: English
• ISSNs: 1355-6037

Abstract

Abstract : Objective: To identify electrocardiographic findings, especially deep Q and S waves in lead III, that differentiate athletes from patients with hypertrophic cardiomyopathy (HCM). Methods: Digital ECGs of athletes and patients with HCM followed at the Stanford Center for Inherited Cardiovascular Disease were studied retrospectively. All patients with HCM had an echocardiogram performed. A multivariable logistic regression model was used to calculate ORs for various demographic and ECG characteristics. Linear regression was used to correlate ECG characteristics with echocardiogram findings. Results: We studied 1124 athletes and 240 patients with HCM. The average Q+S wave amplitude in lead III (IIIQ+S ) was significantly higher in patients with HCM compared with athletes (0.71±0.69 mV vs 0.21±0.17 mV, p<0.001). In patients with HCM, IIIQ+S directly correlated with interventricular septal (IVS) thickness on echocardiography (ρ=0.45, p<0.001). In a multivariable analysis adjusted for demographic and ECG characteristics, higher IIIQ+S values remained independently associated with HCM compared with athletes (OR=4.2 per 0.5 mV, p<0.001). In subgroup analyses of young patients, African–American subjects and subjects without left axis deviation (LAD), IIIQ+S remained associated with HCM. The addition of IIIQ+S >1.0 mV as an abnormal finding to the International Criteria for athletic ECG interpretation improved sensitivity from 64.2% to 70.4%, with a minimal decrease in specificity. Conclusion: Large Q and S waves in lead III distinguished athletes from patients with HCM, independent of axis and well-known ECG markers associated with HCM. The correlation between IVS thickness in patients with HCM and IIIQ+S suggests a partial explanation for this association.