Monophasic action potential amplitude for substrate mapping

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 (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.

Sinus rhythm voltage fingerprinting in patients with mitral valve disease using a high-density epicardial mapping approach

“… 14 It is for these reasons that U-EGMs are more and more used in newly developed mapping systems. 6 , 15 …”

Guidelines for assessment of cardiac electrophysiology and arrhythmias in small animals

“…1 . In terms of species used, the majority of these studies (∼67%) used rodents, with approximately equal distribution between mice ( 23 – 33 ) and rats ( 34 – 42 ). Guinea pig ( 43 – 45 ) and porcine hearts ( 46 – 48 ) were each used in ∼10% of studies, followed by a small number of reports in rabbit ( 49 ), zebrafish ( 50 ), quail ( 51 ), and canine ( 52 ) hearts.…”

“…In terms of disease models, genetically modified mice ( 23 , 26 , 28 – 33 ) or specific rat strains (e.g., spontaneously hypertensive rat) ( 34 , 35 , 40 ) were most commonly assessed (∼37% of studies), and myocardial infarction, ischemia, or hypoxia were evaluated in ∼27% of studies ( 25 , 31 , 35 , 38 , 42 , 44 , 45 , 47 ). Around 16% of investigations used pharmacological modulation ( 24 , 43 , 49 , 50 , 52 ).…”

“…A small number of studies investigated environmental effects [including herbicide ( 36 ), vaping ( 27 ), and alcohol ( 51 )], aging and development ( 25 , 28 , 41 ), nonischemic heart failure ( 39 ), and the remaining studies performed electrophysiological assessments in nondiseased hearts ( 37 , 46 , 48 ). The most commonly used techniques to evaluate electrophysiological parameters and arrhythmia susceptibility were in vivo electrocardiogram (ECG) or electrode recordings in conscious or anesthetized animals (∼56% of studies) ( 23 – 28 , 30 , 32 , 36 , 38 , 40 – 42 , 46 – 48 , 52 ) or optical mapping in excised hearts or tissues (∼47% of studies) ( 27 , 30 , 31 , 33 – 35 , 39 , 41 , 43 – 45 , 49 – 51 ). The remaining studies used electrode-based or ECG recordings in excised hearts and tissues ( 24 , 25 , 29 , 31 , 32 , 35 , 40 , 41 , 50 ) or in vivo ECG telemetry ( 27 , 29 , 33 , 37 ), and often, a combination of multiple approaches were used to rigorously evaluate electrophysiological properties (including experiments in isolated cardiomyocytes, which are not covered in detail in these guidelines).…”

Prolonged duration of repolarization and decreased conduction velocity in the atrial myocardium after hypothermic ischemia-reperfusion may be related to expressions of inward rectifier potassium channel 2.1 protein and connexin 40

“…After 30 minutes of continuous perfusion, a self-made composite electrode was slowly placed on the anterior wall of the right atrium. 10,11 The electrode wire was connected with the signal input line of the BL-420 F Biological Function Experimental System (Chengdu Tai League Software Co., Ltd., Chengdu, China). Right atrial monophasic action potential (MAPs) at 30 minutes of continuous perfusion in group C and group IR (T 0 ), at 105 minutes of continuous perfusion in group C, or 15 minutes of reperfusion in group IR (T 1 ) and 120 minutes of continuous perfusion in group C or 30 minutes of reperfusion in group IR (T 2 ), were recorded, and MAPDs at 50% and 90% of repolarization (MAPD 50 and MAPD 90 ) were measured.…”