Objective To test the hypothesis that 12-lead ECG QRS scoring quantifies myocardial scar and correlates with disease severity in Chagas' heart disease.
Design Patients underwent 12-lead ECG for QRS scoring and cardiac magnetic resonance with late gadolinium enhancement (CMR-LGE) to assess myocardial scar.
Setting University of São Paulo Medical School, São Paulo, Brazil.
Patients 44 Seropositive patients with Chagas' disease without a history of myocardial infarction and at low risk for coronary artery disease.
Main outcome measures Correlation between QRS score, CMR-LGE scar size and left ventricular ejection fraction. Relation between QRS score, heart failure (HF) class and history of ventricular tachycardia (VT).
Results QRS score correlated directly with CMR-LGE scar size (R=0.69, p<0.0001) and inversely with left ventricular ejection fraction (R=−0.54, p=0.0002), which remained significant in the subgroup with conduction defects. Patients with class II or III HF had significantly higher QRS scores than those with class I HF (5.1±3.4 vs 2.1±3.1 QRS points (p=0.002)) and patients with a history of VT had significantly higher QRS scores than those without a history of VT (5.3±3.2% vs 2.6±3.4 QRS points (p=0.02)). A QRS score ≥2 points had particularly good sensitivity and specificity (95% and 83%, respectively) for prediction of large CMR-LGE, and a QRS score ≥7 points had particularly high specificity (92% and 89%, respectively) for predicting significant left ventricular dysfunction and history of VT.
Conclusions The wide availability of 12-lead ECG makes it an attractive screening tool and may enhance clinical risk stratification of patients at risk for more severe, symptomatic Chagas' heart disease.
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Funding DGS was supported by the Sarnoff Cardiovascular Research Foundation (Great Falls, Virginia, USA), and has subsequently moved to the US Food and Drug Administration. CER was supported by FAPESP (Fundação de Amparo ã Pesquisa do Estado de São Paulo, Brazil) grant 01/04358–0 and the Zerbini Foundation. KCW was supported by the Donald W. Reynolds Cardiovascular Research Center at Johns Hopkins University (Baltimore, Maryland, USA).
Competing interests None.
Ethics approval This study was conducted with the approval of the Heart Institute (InCor), University of São Paulo Medical School.
Provenance and peer review Not commissioned; externally peer reviewed.
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