July 26, 2019Open Access
Monophasic action potential amplitude for substrate mapping
Key Result
Bipolar voltage amplitude mapping performed most accurately in quantifying infarct size, successfully distinguishing healthy from border tissue (P=0.0015) and border from scar tissue (P=0.0094).
Structured PICO
Does MAPA mapping improve the accuracy of infarct size quantification compared to other mapping modalities in a rat model of ischemic heart failure?
P
Population
21 Sprague-Dawley rats in a left coronary artery ligation model of ischemic heart failure.
I
Intervention
Monophasic action potential amplitude (MAPA) mapping
C
Comparator
MAP duration to 90% repolarization (MAPD90), unipolar voltage amplitude (UVA), and bipolar voltage amplitude (BVA) mapping
O
Outcome
Accuracy of in vivo ventricular epicardial maps compared with gold standard histopathological measurement of infarct sizesurrogate
Contrary to the hypothesis, bipolar voltage amplitude mapping was more accurate than monophasic action potential amplitude mapping for quantifying infarct size in a rat model of ischemic heart failure.
Abstract
Although radiofrequency ablation has revolutionized the management of tachyarrhythmias, the rate of arrhythmia recurrence is a large drawback. Successful substrate identification is paramount to abolishing arrhythmia, and bipolar voltage electrogram’s narrow field of view can be further reduced for increased sensitivity. In this report, we perform cardiac mapping with monophasic action potential (MAP) amplitude. We hypothesize that MAP amplitude (MAPA) will provide more accurate infarct sizes than other mapping modalities via increased sensitivity to distinguish healthy myocardium from scar tissue. Using the left coronary artery ligation Sprague-Dawley rat model of ischemic heart failure, we investigate the accuracy of in vivo ventricular epicardial maps derived from MAPA, MAP duration to 90% repolarization (MAPD 90 ), unipolar voltage amplitude (UVA), and bipolar voltage amplitude (BVA) compared with gold standard histopathological measurement of infarct size. Numerical analysis reveals discrimination of healthy myocardium versus scar tissue using MAPD 90 ( P = 0.0158) and UVA ( P < 0.001, n = 21). MAPA and BVA decreased between healthy and border tissue ( P = 0.0218 and 0.0015, respectively) and border and scar tissue ( P = 0.0037 and 0.0094, respectively). Contrary to our hypothesis, BVA mapping performed most accurately regarding quantifying infarct size. MAPA mapping may have high spatial resolution for myocardial tissue characterization but was quantitatively less accurate than other mapping methods at determining infarct size. BVA mapping’s superior utility has been reinforced, supporting its use in translational research and clinical electrophysiology laboratories. MAPA may hold potential value for precisely distinguishing healthy myocardium, border zone, and scar tissue in diseases of disseminated fibrosis such as atrial fibrillation. NEW & NOTEWORTHY Monophasic action potential mapping in a clinically relevant model of heart failure with potential implications for atrial fibrillation management.