Biomedical subjects

Masahiko Goya

Publications and source records attributed to Masahiko Goya.

10 recordsLinked to original sources

PubMed2006

Substrate mapping vs. tachycardia mapping using CARTO in patients with coronary artery disease and ventricular tachycardia: impact on outcome of catheter ablation.

AIMS: For ablation of ventricular tachycardia (VT) in patients after myocardial infarction, a three-dimensional mapping system is often used. We report on our overall success rate of VT ablation using CARTO in 47 patients, with a subgroup analysis comparing VT mapping with the results of mapping that had to be performed during sinus rhythm or pacing (substrate mapping). METHODS AND RESULTS: A CARTO map was performed and VT ablation attempted using two strategies: Patients in the VT-mapping group had incessant VT (four patients) or inducible stable VT (18 patients) such that the circuit of the clinical VT could be reconstructed using CARTO. During VT, the critical area of slow conduction was identified using diastolic potentials and conventional concealed entrainment pacing. In contrast, patients in the substrate-mapping group had initially inducible VT. However, a complete VT map was not possible because of catheter-induced mechanical block (six patients) or because haemodynamics deteriorated during the ongoing VT (19 patients). Therefore, pathological myocardium was identified by fragmented, late- and/or low-amplitude (<1.5 mV) bipolar potentials during sinus rhythm or pacing, and the ablation site was primarily determined by pace mapping inside or at the border of this pathological myocardium. Acute ablation success in all patients with regard to non-inducibility of the clinical VT or any slower VT was 79% after a single ablation procedure, but increased to 95% after a mean of 1.2 ablation procedures. However, chronic success was 75%, when it was defined as freedom from any ventricular tachyarrhythmia (VT or VF) during a follow-up of 25+/-13 months. In the subgroup analysis, patients in the VT-mapping group were not significantly different from patients in the substrate-mapping group with regard to age (65+/-7 vs. 65+/-9 years), ejection fraction (30+/-7 vs. 30+/-8%), VT cycle length (448+/-81 vs. 429+/-82 ms), number of radiofrequency applications (17+/-9 vs. 14+/-6 applications), use of an irrigated tip catheter (23 vs. 32%), and ablation results. CONCLUSION: When using a CARTO-guided approach for VT ablation in patients with coronary artery disease, the freedom from any ventricular arrhythmia is high (75%), but leaves the patient at a 23% risk of developing fast VT/VF during follow-up. Mapping during sinus rhythm or pacing is as successful as mapping during VT.

Aged↗

PubMed2003

A model for in vivo validation of linear lesions in the right atrium.

UNLABELLED: Linear lesions have been proposed for treatment of complex atrial arrhythmias including atrial macroreentry tachycardia and compartmentalization in atrial fibrillation. AIM: To judge the effectiveness of a given lesion design, definite endpoints are necessary to ascertain the completeness of the line of block produced. METHODS AND RESULTS: We report validation criteria for long linear lesions in the right atrium in 42 pts, that combine both conventional and 3D mapping information (CARTO). Transferring from the validation of bi-directional block of the cavotricuspid isthmus line for atrial flutter, we validated 2 additional long linear lesions in the right atrium (anterior line and intercaval line). In addition to a complete isthmus line in all 42 pts, in 28 pts a complete anterior line was achieved and validated by both conventional and CARTO criteria. A complete intercaval line was deployed in 11 pts with complete anterior and isthmus lines (with a characteristic shift for the intercaval line) and in 5 pts without a complete anterior line (without characteristic shift). CONCLUSIONS: Conventional catheters placed at strategic locations on opposite sides of the intended ablation line, can depict a sudden characteristic change in the activation sequence. Using a combination of both techniques, deployment and validation of long linear lesion can be facilitated.

Action Potentials↗

PubMed2003

Ostial PV isolation: is there a role for three-dimensional mapping?

Pulmonary vein (PV) isolation by elimination of spike potentials has been reported to cure drug refractory atrial fibrillation. Because of the heterogenous morphology of the PVs, sequential electroanatomic reconstruction of the PVs was performed in 39 patients (group A), who underwent subsequent PV isolation by interruption of all conductive myocardial fibers by distinct RF current applications using a "lasso" approach. In group B (157 patients), only biplane two-dimensional fluoroscopy was performed to guide the diagnostic and the ablation catheters. After reprocedures (in 7% of patients in group A and 22% of group B), which depicted a recurrence of a spike potential inside or at the ostium of >1 previously isolated PV in all restudied patients, stable sinus rhythm was documented in 69% of patients in group A and 60% of patients in group B. Reasons for the relapse of the previously eliminated spike potentials include a temporary ablation effect and a too distal interruption of the conducting myocardial fiber. Detailed knowledge of the individual three-dimensional morphology enhanced the clinical success rate of PV isolation but is time-consuming using CARTO (8.0 +/- 1.7 vs 5.0 +/- 1.6, P < 0.001). Further technical improvement to fuse the individual three-dimensional anatomy and the electrophysiological markers to a composed "electroanatomic" map may overcome this limitation in the future.

Action Potentials↗

PubMed2003

Total pulmonary vein occlusion as a consequence of catheter ablation for atrial fibrillation mimicking primary lung disease.

INTRODUCTION: Catheter ablation has recently been used for curative treatment of atrial fibrillation. METHODS AND RESULTS: Three of 239 patients who underwent ablation close to the pulmonary vein (PV) ostia at our institute developed severe hemoptysis, dyspnea, and pneumonia as early as 1 week and as late as 6 months after the ablation. Because the patients were arrhythmia-free, the treating physician initially attributed the symptoms to new-onset pulmonary disease (e.g., bronchopulmonary neoplasm). After absent PV flow was confirmed by transesophageal echocardiography, transseptal contrast injection depicted a totally occluded PV in all three patients. Successful recanalization, even in chronically occluded Pvs, was performed in all patients. During follow-up, Doppler flow measurements by transesophageal echocardiography demonstrated restenosis in all primarily dilated PV, which led to stent implantation. CONCLUSION: PV stenosis/occlusion after catheter ablation of atrial fibrillation occurs in a subset of patients. However, because in-stent restenosis occurred in two patients after 6 to 10 weeks, final interventional strategy for PV stenosis or occlusion remains unclear. To prevent future PV stenosis or occlusion, a decrease in target temperature and energy of radiofrequency current or the use of new energy sources (ultrasound, cryothermia, microwave) seems necessary.

Angiography↗

PubMed2003

Reentrant tachycardia in pulmonary veins of patients with paroxysmal atrial fibrillation.

INTRODUCTION: Although slow automatic pulmonary vein (PV) activity dissociated from the atrium after achievement of PV isolation in patients with atrial fibrillation (AF) has been reported, little is known about dissociated PV tachycardia. The aim of this study was to investigate the inducibility and the mechanism of sustained PV tachycardia (SPVT). METHODS AND RESULTS: One hundred thirty-two patients with drug-refractory paroxysmal AF underwent PV isolation by radiofrequency catheter ablation. Programmed stimulation was performed in 269 PVs of 110 of these patients after achievement of PV isolation. In 7 PVs (2.6%; left superior PV: n = 2, right superior PV: n = 4, right inferior PV: n = 1) of 7 (6.4%) of 110 patients, 18 SPVTs were induced. Fifteen regular SPVTs (mean cycle length 152 +/- 34 msec) were induced in 6 of 7 PVs, and 3 irregular SPVTs (cycle length range: 94-276 msec) were induced in 3 of 7 PVs. In 2 PVs, both regular and irregular SPVTs were induced. SPVT was terminated by burst pacing in 4 PVs, and entrainment was observed during regular SPVT in 5 PVs. Slow PV automatic activity dissociated from the atrium and decremental conduction properties were shown in all 7 PVs. The shortest pacing cycle length with 1:1 capture was < or =150 msec in 6 of 7 PVs. CONCLUSION: Reentrant tachycardia can occur in some isolated PVs with both decremental conduction properties and short refractory periods, which suggests that reentry may be one of the mechanisms of PV arrhythmogenicity.

Adult↗

PubMed2002

Electroanatomic mapping and catheter ablation of breakthroughs from the right atrium to the superior vena cava in patients with atrial fibrillation.

BACKGROUND: The superior vena cava (SVC) is one of the sources of ectopies that can initiate atrial fibrillation (AF). We investigated by radiofrequency ablation the electrophysiological characteristics of the junction of the right atrium (RA) and the SVC and the feasibility of electrical disconnection of the SVC from the RA. METHODS AND RESULTS: Sixteen patients with paroxysmal AF after pulmonary vein isolation underwent electroanatomic mapping at the RA-SVC junction during sinus rhythm. Mapping showed sharp potentials (SVC potentials) inside the SVC. Activation spread from the earliest SVC potential (breakthrough) to the rest of the SVC. SVC potentials were found over a large amount of the circumference, suggesting widespread muscle coverage of the SVC. Breakthroughs from the RA to SVC were located anteriorly, laterally, posteriorly, and septally in 3, 4, 10, and 6 patients, respectively. The number of breakthroughs was 1.4+/-0.5 per patient. Radiofrequency energy was applied with the end point of electrical disconnection. All breakthroughs were eliminated with 3.1+/-1.7 applications per breakthrough without complications. CONCLUSIONS: SVC potentials can be recorded inside the SVC. There are specific breakthroughs from the RA to the SVC that can be identified by electroanatomic mapping. The electrical disconnection of the SVC from the RA is feasible.

Atrial Fibrillation↗

PubMed2002

Characterization of reentrant circuits in left atrial macroreentrant tachycardia: critical isthmus block can prevent atrial tachycardia recurrence.

BACKGROUND: Left atrial macroreentrant tachycardia (LAMRT) has not been characterized in detail. METHODS AND RESULTS: Twenty-eight patients with LAMRT, including 4 patients with ablated typical atrial flutter (AFL), underwent electroanatomic mapping of the left atrium (LA) between February 1999 and October 2001. LA maps were performed during LAMRT in 26 patients and during sinus rhythm in 2 patients. Electrically silent areas or continuous lines of double potentials were identified as acquired anatomic barriers in all patients. In 23 of 26 patients with LAMRT mapping, 42 reentry circuits with a protected isthmus were identified. The isthmus was 11.8+/-5.9 mm wide, with the maximal amplitude of 0.07 to 3.61 mV. Radiofrequency pulses terminated all LAMRTs in 23 patients and resulted in conduction block across the isthmus in 20 patients. In 2 patients with sinus mapping, all identified isthmuses were ablated. Additionally, AFL was induced and ablated in 6 patients. Atrial tachycardia recurred in 4 patients: 3 patients without validated block across the isthmus presented with recurrence of the same LAMRT, and 1 patient without ablated cavotricuspid isthmus presented with AFL. All tachycardias were abolished during a second procedure. Of 25 patients with identified isthmuses, 20 patients were without atrial arrhythmia and 5 had only atrial fibrillation during a median follow-up of 14 months. CONCLUSION: The reentry circuit with a protected isthmus can be identified in 89% patients with LAMRT by electroanatomic mapping. The isthmuses were amenable to radiofrequency applications in most patients. No atrial tachycardia recurred in any patients with isthmus block.

Adolescent↗

PubMed2002

Repetitive monomorphic ventricular tachycardia originating from the aortic sinus cusp: electrocardiographic characterization for guiding catheter ablation.

OBJECTIVES: We sought to investigate the electrocardiographic (ECG) characteristics for guiding catheter ablation in patients with repetitive monomorphic ventricular tachycardia (RMVT) originating from the aortic sinus cusp (ASC). BACKGROUND: Repetitive monomorphic ventricular tachycardia can originate from the right ventricular outflow tract (RVOT) and ASC in patients with a left bundle branch block (LBBB) morphology and an inferior axis. METHODS: Activation mapping and ECG analysis was performed in 15 patients with RMVT or ventricular premature contractions. The left main coronary artery (LMCA) was cannulated as a marker and for protection during radiofrequency delivery if RMVT originated from the left coronary ASC. RESULTS: During arrhythmia, the earliest ventricular activation was recorded from the superior septal RVOT in eight patients (group 1) and from the ASC in the remaining seven patients (group 2). The indexes of R-wave duration and R/S-wave amplitude were significantly lower in group 1 than in group 2 (31.8+/-13.5% vs. 58.3+/-12.1% and 14.9+/-9.9% vs. 56.7+/-29.5%, respectively; p < 0.01), despite similar QRS morphology. In five patients from group 2, RMVT originated from the left ASC, with a mean distance of 12.2+/-3.2 mm (range 7.3 to 16.1) below the ostium of the LMCA. In the remaining two patients, the RMVT origin was in the right ASC. All arrhythmias were successfully abolished. None of the patients had recurrence or complications during 9+/-3 months of follow-up. CONCLUSIONS: On the surface ECG, RMVT from the ASC has a QRS morphology similar to that of RVOT arrhythmias. The indexes of R-wave duration and R/S-wave amplitude can be used to differentiate between the two origins. Radiofrequency ablation can be safely performed within the left ASC with a catheter cannulating the LMCA.

Adolescent↗

PubMed2002

Electroanatomic substrate of idiopathic left ventricular tachycardia: unidirectional block and macroreentry within the purkinje network.

BACKGROUND: An abnormal potential (retroPP) from the left posterior Purkinje network has been demonstrated during sinus rhythm (SR) in some patients with idiopathic left ventricular tachycardia (ILVT). We hypothesized that this potential can specifically be identified and be a critical substrate for ILVT. METHODS AND RESULTS: In 9 patients with ILVT and 6 control patients who underwent mapping of the left ventricle during SR using 3-dimensional electroanatomic mapping, an area with retroPP was found within the posterior Purkinje fiber network only in patients with ILVT. The earliest and latest retroPP was 185.4+/-57.4 and 465.2+/-37.3 ms after Purkinje potential; in the other patient with ILVT, an entire left ventricle mapping demonstrated a slow conduction area and passive retrograde activation along the posterior fascicle during ILVT. ILVT was noninducible in 3 patients after SR mapping. Diastolic potentials critical for ILVT during ILVT coincided with the earliest retroPP during SR in 7 patients. Mechanical termination of ILVT occurred in 5 patients. A single radiofrequency pulse was applied at the site with mechanical translation in 5 patients and the site with diastolic potential in 2 patients, and 3 radiofrequency pulses were delivered to the site with the earliest retroPP in the other 3 patients without inducible ILVT after SR mapping. No ILVT was inducible during control stimulation, and none recurred during follow-up of 9.1+/-5.1 months. CONCLUSION: In patients with ILVT, abnormal retroPP within the posterior Purkinje fiber network is a common finding. The earliest retroPP critical for ILVT substrate can be used for guiding successful ablation.

Adolescent↗

PubMed2002

[Primary catheter ablation in atrial fibrillation].

BACKGROUND: Primary catheter ablation of atrial fibrillation is a new and curative option for the treatment of patients with drug-refractory atrial fibrillation. It is aiming at a long-term restoration of sinus rhythm and thereby causing a coordinated atrial contraction. ABLATION METHODS: Two different ablation strategies have been established: The "trigger elimination" tries to identify triggering atrial extrasystoles (mostly within the pulmonary veins), followed by focal ablation or isolation within the pulmonary veins. The "substrate modification" changes by long linear radiofrequency-induced lesions the ability of the atrial myocardium to sustain atrial fibrillation. VALUATION: Both treatment options still have to prove their effectiveness in carefully monitored follow-up, before they can be offered to the general patient population with atrial fibrillation.

Atrial Fibrillation↗