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 (MAPD90), 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 MAPD90 (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.