Takahiro Saeki

Optimal Force-Time Integral for Pulmonary Vein Isolation According to Anatomical Wall Thickness Under the Ablation Line.

Background Low contact force and force–time integral (FTI) during catheter ablation are associated with ineffective lesion formation, whereas excessively high contact force and FTI may increase the risk of complications. We sought to evaluate the optimal FTI for pulmonary vein (PV) isolation based on atrial wall thickness under the ablation line. Methods and Results Contact force parameters and FTI during anatomical ipsilateral PV isolation for atrial fibrillation and atrial wall thickness were assessed retrospectively in 59 consecutive patients for their first PV isolation procedure. The PV antrum was divided into 8 segments, and the wall thickness of each segment under the ablation line was determined using multidetector computed tomography. The FTI for each ablation point was divided by the wall thickness of the PV antrum segment where each point was located to obtain FTI/wall thickness. In total, 5335 radiofrequency applications were delivered, and 85 gaps in PV isolation ablation lines and 15 dormant conductions induced by adenosine were detected. The gaps or dormant conductions were significantly associated with low contact force, radiofrequency duration, FTI, and FTI/wall thickness. Among them, FTI/wall thickness had the best prediction value for gaps or dormant conductions by receiver operating characteristic curve analysis. FTI/wall thickness of <76.4 gram‐seconds per millimeter (gs/mm) predicted gaps or dormant conductions with sensitivity (88.0%) and specificity (83.6%), and FTI/wall thickness of <101.1 gs/mm was highly predictive (sensitivity 97.0%; specificity 69.6%). Conclusions FTI/wall thickness is a strong predictor of gap and dormant conduction formation in PV isolation. An FTI/wall thickness ≈100 gs/mm could be a suitable target for effective ablation.

Chronic Ischemia Induced by Woven Coronary Artery Anomaly with Typical Atrial Flutter: Insights from Multiple Imaging Devices

A 75-year-old man with a 120-bpm tachycardia and typical atrial flutter was admitted. Echocardiography showed a dilated left ventricle with anterior and apical wall akinesia. Tachycardia was terminated with cavotricuspid isthmus ablation. Multiple imaging findings revealed a woven coronary artery anomaly (WCAA) in the left anterior descending artery. Stress myocardial perfusion imaging was performed after ablation in the sinus rhythm and revealed stress-induced ischemia and a fixed low uptake in the WCAA territory. WCAA is generally regarded as a benign condition; however, compromised blood flow within the anomaly, caused by tachycardia-related diastolic shortening, may induce ischemia.

Relation between hemodynamic changes after endoscopic transthoracic sympathicotomy and the number of sympathetic segments operated.

Abstract.We examined the relation between hemodynamic changes after endoscopic transthoracic sympathicotomy (ETS) and the number of sympathetic segment operated. Cardiac functional indices using echocardiography and plasma noradrenaline concentration (NOR) were measured before and after ETS in 25 patients with palmar hyperhidrosis. Patients were divided into 2 groups. Group Th2–3 consisted of 16 patients (mean age 28 ± 8 years),who underwent Th2–3 ETS. Group Th2–4 consisted of 6 patients (mean age 29 ± 9 years), who underwent Th2–4 ETS. Before ETS, all hemodynamic parameters and NOR were similar between the 2 groups. After ETS, heart rate, systolic, diastolic, and mean blood pressures, rate-pressure product, and NOR decreased,whereas left ventricular end-systolic volume index, cardiac index, and ejection fraction did not change in the 2 groups. Systemic vascular resistance decreased in group Th2–4, whereas it did not change in group Th2–3. Left ventricular end-diastolic volume index and stroke index increased in group Th2–3, whereas it did not change in group Th2–4. After ETS, rate-pressure product, systolic, diastolic, and mean blood pressures in group Th2–4 were smaller than those in group Th2–3, whereas other parameters were similar between the 2 groups. Among percent changes in all hemodynamic parameters and NOR occurring after ETS, only the percent decrease in systolic blood pressure in group Th2–4 was larger than that in group Th2–3 (–15 ± 12 % vs.–4±8%, respectively, p < 0.05). These findings suggest that only the change in blood pressure is related to the difference in the number of sympathetic segment operated.

Impact of left atrial size on isolation area in the acute phase of pulmonary vein isolation using 28 mm cryoballoon

The impact of left atrial (LA) size on isolation area (ISA) using a 28‐mm second‐generation cryoballoon (CB) in the acute phase after pulmonary vein isolation (PVI) and the differences of CB from contact force‐guided radiofrequency (RF) ablation have not been fully investigated.

Optimal lesion size index to prevent conduction gap during pulmonary vein isolation: KANAMORI et al.

A novel real‐time lesion size index (LSI) that incorporates contact force (CF), time, and power has been developed for safe and effective catheter ablation. The optimal LSI was evaluated to eliminate gap formation during pulmonary vein isolation (PVI).

A Case of Concealed WPW Syndrome, Accompanied with Coronary Sinus Orifice Atresia and Persistent Left Superior Vena Cava

A 58-year old man was transferred because of repetitive attacks of tachyarrhythmia and crescendo angina pectoris. Electrocardiogram during attack showed paroxysmal supraventricular tachycardia with down slope ST depression. After emergent PCI, catheter ablation was performed. We could not insert the electrode catheter to coronary sinus, and delayed phase of CAG showed sinus orifice atresia and coronary venous flow to innominate vein via left superior vena cava. We successfully blocked left-sided concealed accessory pathway with trans-septal approach. Asynptomatic venous anomaly sometimes results in complication of cardiac surgery, device implantation and catheter ablation. The hemodynamic circuits should be precisely recognized before and during these procedures.

The Rho/Rho-kinase Systems Are Involved in Rapid Pacing-induced Changes of Atrial Refractory Period in a Canine Model

Introduction: The Rho/Rho‐kinase pathway has been related to various physiological responses of the cardiovascular system. Previous reports have suggested a significant effect of Rho signals on the electrophysiological characteristics of the heart. We hypothesized that the Rho/Rho‐kinase system would contribute to the rapid pacing‐related change of atrial effective refractory period (AERP).