Unipolar Voltage Mapping to Predict Recovery of Left Ventricular Ejection Fraction in Patients With Recent-Onset Nonischemic Cardiomyopathy

BACKGROUND: The ability to predict recovery of left ventricular ejection fraction (LVEF) in response to guideline-directed therapy among patients with nonischemic cardiomyopathy is desired. We sought to determine whether left ventricular endocardial unipolar voltage measured during invasive electroanatomic mapping could be used to predict LVEF recovery among those with recent-onset nonischemic cardiomyopathy. METHODS: We analyzed the left ventricular voltage maps of patients included in the eMAP trial (Electrogram-Guided Myocardial Advanced Phenotyping; NCT03293381), a prospective, nonrandomized, interventional trial conducted at 2 institutions between 2017 and 2020. Patients had recent-onset nonischemic cardiomyopathy defined by LVEF ≤45% and development of symptoms or signs of heart failure within the past 6 months. Detailed voltage maps of the left ventricular endocardium were generated using the CARTO electroanatomic mapping system. Abnormal unipolar amplitude was defined as <8.27 mV. The primary end point was recovery of LVEF (Recovery) defined by a 1-year LVEF ≥50% or ≥45% with ≥10% increase from baseline. RESULTS: Of the 29 enrolled patients (median age, 49 years [25th percentile, 39; 75th percentile, 59], 8 females [27.6%]), LVEF recovered in 13 (44.8%) by 1-year follow-up. The percentage of total endocardial surface area with unipolar voltage abnormality (AUA) was significantly lower among Recovery patients than No Recovery patients (18.2% [6.4, 22.4] versus 80.0% [29.5, 90.9]; P =0.004). Percent AUA was associated with lower likelihood of Recovery (odds ratio, 0.64 per 10% increase in AUA; 95% CI, 0.47–0.88; P =0.006). A 28% cutoff value for percent AUA was 92% sensitive and 75% specific with an area under the receiver operating characteristic curve of 0.81 (95% CI, 0.63–0.99; P =0.001) for predicting recovery versus no recovery. The majority of patients (12 of 13; 92.3%) with a percent AUA >28% did not recover. CONCLUSIONS: Left ventricular unipolar voltage abnormality is a potent predictor of LVEF recovery among patients recently diagnosed with nonischemic cardiomyopathy. Detailed left ventricular unipolar voltage mapping could therefore be used as a valuable prognostic tool in guiding treatment decisions.