What is the clinical evidence from this study?

Study design: Observational. Population: Right ventricular outflow tract ventricular tachycardia (n=15). Intervention: Mean absolute deviation (MAD) and correlation coefficient (CORR) of 12-lead ECG waveforms vs. Successful vs unsuccessful ablation sites. Primary outcome: MAD score for successful vs unsuccessful ablation sites (p=0.01).

What question did this study set out to answer?

This study aims to quantify similarity between 12-lead ECG waveforms of ventricular tachycardia and pace-maps using quantitative metrics.

April 22, 2026

Quantitative comparison of spontaneous and paced 12-lead electrocardiogram during right ventricular outflow tract ventricular tachycardia

Key Result

A mean absolute deviation (MAD) score ≤12% between RVOT VT and a pace-map was 93% sensitive and 75% specific for identifying a successful ablation site (9.5% vs 13.3%; p=0.01).

Key Points

This study aims to quantify similarity between 12-lead ECG waveforms of ventricular tachycardia and pace-maps using quantitative metrics.
Acquired 12-lead ECG pace-maps during ablation of right ventricular outflow tract VT in 15 patients.
Compared ECG waveforms using mean absolute deviation (MAD) and correlation coefficient (CORR) metrics.
Evaluated pace-maps from three superior septal and three superior free wall sites.
MAD scores were lower at septal sites (15.9 +/- 5.3%) than at free wall sites (25.3 +/- 10.2%; p < 0.001).
Successful ablation sites had a lower MAD score (9.5 +/- 2.8%) compared to unsuccessful sites (13.3 +/- 5.6%; p = 0.01).
A MAD score ≤12% showed 93% sensitivity and 75% specificity for identifying successful ablation sites.

Study Design

Type

Observational (n=15)

Structured PICO

Does quantitative comparison of 12-lead ECG waveforms using mean absolute deviation (MAD) identify successful ablation sites in patients with right ventricular outflow tract ventricular tachycardia?

Population

15 patients undergoing ablation of right ventricular outflow tract (RVOT) ventricular tachycardia (VT)

Intervention

Quantitative comparison of 12-lead ECG waveforms of clinical tachycardia and pace-maps using mean absolute deviation (MAD) and correlation coefficient (CORR)

Outcome

Similarity of 12-lead ECG waveforms (MAD and CORR scores) between clinical tachycardia and pace-maps at successful versus unsuccessful ablation sitessurrogate

A mean absolute deviation (MAD) score <=12% between RVOT VT and a pace-map provides an objective, highly sensitive metric for identifying successful ablation sites.

Main Result

Absolute Event Rate: 9.5% vs 13.3%

p-value: p=0.01

Abstract

OBJECTIVES: The purpose of this study was to objectively quantify the similarity of 12-lead electrocardiogram (ECG) waveforms using two quantitative metrics, the correlation coefficient (CORR) and the mean absolute deviation (MAD). BACKGROUND: Comparison of the 12-lead ECG morphology between ventricular tachycardia (VT) and a pace-map is frequently performed; however, there are no objective criteria for quantifying the similarity between two waveform morphologies. METHODS: During ablation of right ventricular outflow tract (RVOT) VT, 12-lead ECG pace-maps were acquired from three superior septal sites, three superior free wall sites, and before each ablation attempt in 15 patients. The 12-lead ECG waveforms of the clinical tachycardia and pace-maps were compared using both MAD and CORR at each site. RESULTS: The MAD scores were lower (i.e., more closely matched) for septal compared with free wall sites (15.9 +/- 5.3% vs. 25.3 +/- 10.2%; p 12% between RVOT VT and a pace-map at any site suggests sufficient dissimilarity to dissuade ablation at that site. The MAD score can be used to standardize 12-lead ECG waveform morphology comparisons among different laboratories, and may be useful for guiding ablation of VT.