Endocardial unipolar voltage mapping (cut-off 6.78 mV, AUC 0.78) and bipolar mapping (cut-off 1.55 mV, AUC 0.69) effectively detected MRI-defined intramural scar in structural heart disease.
Observational (n=15)
Effect estimate: AUC 0.78
p-value: p=<0.0001
BACKGROUND: Ventricular arrhythmias have been described to originate from intramural locations. Intramural scar can be assessed by delayed-enhanced MRI, but MRIs cannot be performed on every patient. The objective of this study was to assess the value of voltage mapping to detect MRI-defined intramural scar and to correlate the scar with ventricular arrhythmias. METHODS AND RESULTS: In 15 consecutive patients (3 women; age 55±16 years; ejection fraction, 49±13%) with structural heart disease, intramural scar was detected by delayed-enhanced MRI. All patients underwent endocardial unipolar and bipolar voltage mapping guided by the registered intramural scar. Scar volume by MRI was 11.7±8 cm3 with a scar thickness of 4.6±0.7 mm and a preserved endocardial/epicardial rim of 3.3±1.6 and 4.8±2.6 mm, respectively. Endocardial bipolar voltage was 1.6±1.73 mV at the scar, 2.12±2.15 mV in a 1 cm perimeter around the scar, and 2.83±3.39 mV in remote myocardium without scar. The corresponding unipolar voltage was 4.94±3.25, 6.59±3.81, and 8.32±3.39 mV, respectively (P<0.0001). Using receiver-operator characteristic curves, a unipolar cut-off value of 6.78 mV (area under the curve, 0.78) and a bipolar cut-off value of 1.55 mV (area under the curve, 0.69) best separated endocardial measurements overlying scar as compared with areas not overlying a scar. At least 1 intramural ventricular arrhythmia was eliminated in all but 2 patients in this series. CONCLUSIONS: Intramural scar can be detected by unipolar and bipolar voltage, unipolar voltage being more useful. Mapping and ablation of intramural arrhythmias originating from an intramural focus can be accomplished.
Desjardins et al. (Thu,) conducted a observational in Nonischemic Cardiomyopathy with structural heart disease (n=15). Endocardial unipolar and bipolar voltage mapping vs. Remote myocardium without scar was evaluated on Detection of MRI-defined intramural scar using unipolar voltage mapping (AUC 0.78, p=<0.0001). Endocardial unipolar voltage mapping (cut-off 6.78 mV, AUC 0.78) and bipolar mapping (cut-off 1.55 mV, AUC 0.69) effectively detected MRI-defined intramural scar in structural heart disease.