Recording of Monophasic Action Potentials in Human Using a Modified-tip Platinum Ablation Catheter(摘要 )

Recording of Monophasic Action Potentials in Human Using a Modified-tip Platinum Ablation Catheter

Objective:In this study, a comparison of MAP qualities recorded by ordinary or modified Navi-Star ablation catheters (Navi-Star, Biosense Webster) was performed prospectively in patients who underwent electrophysiologic study. Methods: Twenty-six arrhythmia patients referred for electrophysiologic study and/or catheter ablation were included. Sixteen of the patients were men and 8 women, with a mean age of 53±15 (range from 17 to 78) years. The arrhythmias were atrioventricular reciprocating tachycardia mediated by accessory pathway in 4, ventricular arrhythmias in 3, atrioventricular nodal reentrant tachycardia in 8, paroxysmal atrial fibrillation in 8, atrial flutter in 2 and unexplained palpitation in 1 patient(s). The MAP recordings were obtained in 12 patients using an ordinary 7 French platinum ablation catheter. A modified small tip ablation catheter, the end surface of tip electrode was 0.81 mm2 and 1 mm in diameter, was used for MAP recording in 14 patients. All MAP recordings were performed during sinus rhythm using electroanatomical mapping system.Results: Two hundred and ninety-five MAP recordings were obtained using ordinary catheter in 12 patients, 95 from right atrium in 8 patients and 200 from right ventricle in 4 patients. One hundred and sixty-seven MAP recordings were obtained using modified catheter in 14 patients, 111 from right atrium in 13 patients and 56 from right ventricle 1 patients. Significantly more MAP recordings using modified catheters had a high MAPamp (≥ 3 mV in atrium and ≥ 10 mV in ventricle) than those using ordinary catheters both in right atrium and ventricle (p<0.0001). The mean MAP amplitude recorded using modified catheters was significant higher than using ordinary catheters both in right atrium and ventricle (p<0.0001). Fewer right atrial MAP recordings had a high amplitude (≥ 3 mV) (49%) compared with right ventricular MAP electrograms (≥ 10 mV) (79%). The global activation and repolarization sequence and MAP duration distribution were constructed using modified catheters both in atrium and in ventricle. The activation sequence both in atrium and ventricle could be determined three-dimensionally.Conclusion: MAP electrograms recorded using the modified platinum catheter were associated with a higher amplitude. The construction of the global myocardial activation and repolarization sequence is feasible using the electroanatomical mapping system and MAP recording technique via the modified catheter. The ability to combine MAP recording and spatial information provides a unique tool for both research and clinical electrophysiology.

Objectives: It is a big challenge to manage noninducible ventricular tachycardia (VT) during attempted radiofrequency ablation procedure. In this report we describe successful elimination of noninducible VT by identifying the arrhythmia substrate using electroanatomic mapping system. Methods and Results: A 38-year-old man was admitted for arrhythmia management due to 7 years' recurrent paroxysmal palpitations that were not related to exercise or emotional stress. A 200 beat per minute VT was documented clinically during the spell of palpitation and it could be terminated by intravenous infusion of verapamil. The QRS morphology of VT indicating a left anterior fascicle origin, rS in leads I and aVL, qR in II, III and aVF, rsR in V1 and rS in V6 with a right axis in the frontal plane (140). Structural heart disease was not established by physical examination, transthoracic echocardiography, chest X ray and magnetic resonance imaging. During the attempted ablation procedure, however, VT could not be induced both from atrium and ventricle, even with the challenge of isoproterenol. The left anterior and posterior fascicles were localized during sinus rhythm using the electroanatomic mapping system (CARTO). A linear line was created with 5 sequential radiofrequency lesions across the medial part of left anterior fascicle guided by the electroanatomic mapping system. After ablation, the depth of the S wave in leads I and aVF was significantly decreased, so was the amplitude of the R wave in lead III. Eight months later, the patient is free from recurrences of VT despite difficult arrhythmia control preprocedure. Conclusions: Idiopathic left VT has been shown to be due to reentry anchored in left posterior or anterior fascicles and the Purkinje system. The most prevalent form verapamil-sensitive intrafascicular tachycardia characterized by right bundle branch block and left axis morphology originates in the region of left posterior fascicle of the left bundle. Idiopathic VT characterized by right bundle branch block and right axis deviation originating in the left anterior fascicle is rare. Earlier studies have shown that successful ablation of idiopathic left ventricular tachycardia could be achieved at sites proximal to the tachycardia exit site. The findings of this case report demonstrated that noninducible idiopathic VT could be successfully suppressed by identifying the reentry circuit using electroanatomic mapping system.