Abstract 15548: Screening Entire Health System ECG Databases to Identify Patients with Arrhythmogenic Myocardial Substrate at Increased Risk of Death
Background: Current methods to identify candidates for implantable defibrillators, primarily reduced ejection fraction (EF), miss ∼80% of patients who suffer sudden cardiac death. We propose a novel strategy to screen hospital ECG databases with QRS scoring (to detect myocardial scar) and QRS-T angle analysis (to detect abnormal repolarization) to identify patients with arrhythmogenic substrate. We assessed the feasibility of screening 3 hospital ECG databases and tested the hypothesis that patients with abnormal QRS scores and QRS-T angles have high 1-year mortality.
Methods: Patients with ECGs obtained in hospital areas with known high mortality (e.g. oncology, intensive care, transplant) were excluded. Only the most recent ECG per patient was analyzed from a 6-month interval at 3 large hospitals (n=19,750, 16,789 and 11,223 ECGs, respectively). Clinical data were abstracted from electronic medical records for patients with QRS-T angle ≥105º and QRS score ≥5 points (hospital 1 only), and mortality was assessed at 1 year.
Results: QRS scores and QRS-T angles were similarly distributed at the 3 hospitals (Figure). At hospital 1, 8.0% of patients had QRS-T angle ≥105º and QRS score ≥5 (clinically-screened patients). The 1-year mortality rate of the clinically-screened patients was 6.1%. Only 17% of these patients had a known EF ≤35%. The subgroup with QRS score ≥6 and QRS-T angle ≥135º had significantly higher mortality of 8.4% (p=0.005). Multivariable logistic regression of 14 clinical variables demonstrated that QRS score (p<0.001), chronic renal insufficiency (p<0.001) and EF (p=0.037) predicted mortality.
Conclusions: Screening hospital ECG databases with QRS scoring and QRS-T angle analysis is feasible and identifies a population with high 1-year mortality but predominantly preserved EF. This approach may represent a widely-applicable method to identify patients at increased risk of mortality who are missed by standard clinical assessment.
- © 2011 by American Heart Association, Inc.