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Masahiro Mizobuchi

Publications and source records attributed to Masahiro Mizobuchi.

6 recordsLinked to original sources
PubMed2006

Case report: Focal ablation for atrial fibrillation originating from the inferior vena cava and the posterior left atrium.

We identified a case of paroxysmal atrial fibrillation (AF) originating from inferior vena cava (IVC) and the low-posterior left atrium (LA). Both foci, the IVC and the low-posterior LA, simultaneously served not only as trigger but also as driver for maintenance of AF. During AF, the IVC and the low-posterior LA continuously demonstrated the rapid and fractionated potentials that exit into both atria with conduction block. Focal ablation for ectopic beats within the IVC and the low-posterior LA completely eliminated the storm of AF.

Aged, 80 and over↗
PubMed2006

Two atrial reentrant tachycardias originating from the superior vena cava: electrophysiological characteristics and radiofrequency ablation.

A case with two different types of atrial reentrant tachycardia of superior vena cava (SVC) origin is presented. Recent clinical studies have shown that the origin of focal atrial tachycardia typically lies in the venous structures connecting to both atria--the coronary sinus, the superior and inferior vena cava, and the pulmonary vein. These foci have atrial muscle fiber extensions which have electrophysiological characteristics essential to generation of focal ectopic firing. However, little is known about reentrant mechanism of these venous structures. In this report, we present a case of two atrial tachycardias (SVT1 and SVT2) independently originating from the SVC. SVT1 had 430 ms of tachycardia cycle length, and SVT2 had 390 ms of tachycardia cycle length. Both of them showed the character of reentry, and their earliest activations were recorded in the SVC. They were successfully eliminated by focal radiofrequency ablation in the SVC.

Body Surface Potential Mapping↗
PubMed2006

Catheter ablation for an incessant form of antiarrhythmic drug-resistant ventricular fibrillation after acute coronary syndrome.

A 77-year-old man was admitted with an acute coronary syndrome (ACS), severe heart failure (HF), and repeated ventricular fibrillation (VF) episodes. A single premature ventricular complex (PVC) induced ventricular tachycardia (VT), which degenerated to VF reproducibly. This PVC was eliminated by catheter ablation at the left ventricular posteroseptal region where double Purkinje potentials preceding the ventricular wave had been recorded. The electrical storm disappeared, and programmable stimulation failed to induce any tachyarrhythmias after the ablation. A Purkinje fiber network-related PVC served as a trigger and as a substrate for VT and VF in a case of ACS with HF.

Aged↗
PubMed2006

Bundle brunch reentrant ventricular tachycardia with two distinct conduction patterns in a patient with complete right bundle branch block.

We report a rare case of bundle branch reentrant ventricular tachycardia [BBRVT]. A 67-year-old female was admitted for management of wide QRS tachycardia (right bundle branch block [RBBB] and a southwest axis). The mapping procedure revealed the tachycardia circuit consisted of the left anterior fascicle (LAF) as an antegrade, and the right bundle as a retrograde pathway. She presented RBBB during sinus rhythm. LAF ablation changed the tachycardia configuration to a northwest axis and prolonged the cycle length. Left posterior fascicle ablation terminated the tachycardia, and complete atrioventricular block occurred, which showed the unidirectional conduction over the right bundle.

Aged↗
PubMed2004

Dystonic posturing associated with putaminal hyperperfusion depicted on subtraction SPECT.

PURPOSE: Dystonic posturing (DP) is one of the most reliable lateralizing indicators for temporal lobe epilepsy (TLE). We evaluated the ictal hyperperfusional areas in patients with DP by using ictal-interictal subtraction single-photon emission computed tomography (SPECT). METHODS: Ninety-seven patients were treated surgically for intractable TLE, and 39 patients underwent ictal and interictal SPECT studies with the same isotope. These patients were divided into three groups: group I with DP of the contralateral side extended to the epileptogenic focus, group II with elevated muscle tonus but without DP, and group III without DP or alteration of muscle tonus. Ictal, interictal SPECT and thin-slice magnetic resonance imaging (MRI) were overlaid by using the automatic multimodality registration program to construct ictal-interictal subtracted images of SPECT on MRI. RESULTS: Thirteen patients belonged to group I; 14, to group II; and 12, to group III. A statistically significant difference in hyperperfusion rate was observed in the putamen (10 patients in group I, three in group II and two in group III; p < 0.01) and mesial temporal lobe (10 patients in group I, seven in group II, and two in group III; p < 0.05) on the ipsilateral side of the epileptogenic focus. No statistically significant difference was observed for other ictal symptoms except ipsilateral upper-limb automatism (eight patients in group I, three in group II, and none in group III; p < 0.01). CONCLUSIONS: A strong correlation between DP and hyperperfusion in the putamen and mesial temporal lobe was demonstrated. Some patients showed a wide hyperperfusion area extending from the mesial temporal lobe to putamen, which may correspond to the propagation of epileptic discharges. Our results suggest a correlation between hyperperfusion of putamen and contralateral dystonic posturing.

Adolescent↗