Naoki Sugi

What variables were associated with the inducibility of ventricular fibrillation during electrophysiologic stimulation test in patients without apparent organic heart disease

OBJECTIVE The purpose of our study was to determine what variables were associated with ventricular fibrillation (VF) induced during electrophysiological stimulation test in patients without apparent organic heart disease. METHODS Our study evaluated 77 patients (51+/-15 years) who underwent electrophysiological stimulation test, signal averaging, and Na+ channel-blocker challenge test (pilsicainide test). The subjects were divided into two groups, the Brugada group and non-Brugada group. Further, the patients were divided into three subgroups on the base of symptoms (8, 7 symptomatic; 9, 13 syncope; 28, 12 asymptomatic group; in the Brugada and non-Brugada groups, respectively). Multivariate analyses evaluated the association between baseline clinical factors and the induction of VF. RESULTS The inducibility of VF was significantly (p<0.0001) higher in the Brugada group (n=33, 73%) than the non-Brugada group (n=4, 13%). The multivariate analysis demonstrated that symptoms (odds ratio (OR) 31.6; 95% confidence interval (CI): 2.3-430.6; p<0.01), type 1 electrocardiogram after pilsicainide test (OR 21.3; CI: 1.7-272.2; p<0.02), and syncope (OR 13.5; CI: 1.2-158.8; p<0.05) were strongly associated with the inducibility of VF, but not with family history, type 1 electrocardiogram in control, positive in late potential, maxDeltaST elevation (>==200microV) after pilsicainide test. CONCLUSIONS The symptoms, syncope, and type 1 electrocardiogram after pilsicainide test were independently associated with the electrophysiological substrate of VF in patients without apparent heart disease.

Conduction Velocity around the Tricuspid Valve Annulus during Typical Atrial Flutter by Electro-anatomic Mapping System

Objective: Conduction velocity around the tricuspid valve annulus (TA. during typical atrial flutter (AFL. has been shown to be slowest in the inferior vena cava‐tricuspid valve (IVC‐TV. isthmus when compared to the septal or free wall segments of the TA. We investigated the conduction velocity in IVC‐TV isthmus, dividing into three areas. Methods: We evaluated conduction velocity around the TA during typical AFL in 10 patients, using an electro‐anatomic mapping system (CARTO™). Conduction velocity was calculated at six areas around the TA including the septal wall, upper wall, lateral wall, and isthmus wall, which was further divided into three areas, lateral isthmus, mid isthmus, and septal isthmus. Results: Conduction velocity around the TA during typical AFL was slowest in the IVC‐TV isthmus. Further, conduction velocities (m/sec. in the mid isthmus (0.44±0.17. and septal isthmus (0.45±0.22. were significantly slower (p < 0.05. than that in the upper wall (0.67±0.26). Conclusions: The relatively slower conduction in IVC‐TV isthmus resulted from the relatively slower conduction in the area from mid to septal isthmus.

Catheter Ablation for Electrical Storm as Polymorphic Ventricular Tachycardia in a Case with Ischemic Cardiomyopathy after Coronary Artery Bypass Graft

We report a case involving a patient with ischemic cardiomyopathy who developed polymorphic ventricular tachycardia (PVT) and ventricular fibrillation storm after coronary artery bypass graft. Because PVT was initiated by various right bundle branch type premature ventricular contractions (PVCs), we assessed the relatively monomorphic ventricular tachycardia (MVT) during PVT. Electroanatomical mapping revealed that the earliest ventricular activation of the MVT was located in the scar border zone at the posterior septum of the left ventricle. Stable potentials which preceded the MVT were observed. Catheter ablation for the preceding potential suppressed the maintenance of the PVT, although triggered PVCs appeared frequently. Catheter ablation was effective as a bailout therapy in a patient with PVT‐induced cardiomyopathy after cardiac operation.