Toshiko Nakai | Nihon University (original) (raw)

Papers by Toshiko Nakai

Circulation, Apr 23, 2002

Background-Thromboembolism due to atrial fibrillation (AF) is a frequent cause of stroke. More th... more Background-Thromboembolism due to atrial fibrillation (AF) is a frequent cause of stroke. More than 90% of thrombi in AF form in the left atrial appendage (LAA). Obliteration of the appendage may prevent embolic complications. Methods and Results-We evaluated the feasibility and safety of implanting a novel device for percutaneous left atrial appendage transcatheter occlusion (PLAATO). LAA occlusion using the PLAATO system was attempted in 15 patients with chronic AF at high risk for stroke, who are poor candidates for long-term warfarin therapy. The implant consists of a self-expanding nitinol cage covered with a polymeric membrane (ePTFE). The LAA was successfully occluded in 15/15 patients (100%). Angiography and transesophageal echocardiography (TEE) during the procedure showed that the device was well-seated in all patients and that there was no evidence of perforation, device embolization, or interference with surrounding structures. In 1 patient, the first procedure was complicated by a hemopericardium, which occurred during LAA access. A second attempt 30 days later was successful with no untoward sequela. No other complications occurred. At 1-month follow-up, chest fluoroscopy and TEE revealed continued stable implant position with smooth atrial-facing surface and no evidence of thrombus. Conclusions-Thus, transcatheter closure of the LAA is feasible in humans. This novel implant technology may be appropriate for patients with AF who are not suitable candidates for anticoagulation therapy. Further trials are needed to show the long-term safety and its efficacy in reducing stroke. (Circulation. 2002;105:1887-1889.

Journal of the American College of Cardiology, Jul 1, 2005

These studies were conducted to evaluate the feasibility of percutaneous left atrial appendage (L... more These studies were conducted to evaluate the feasibility of percutaneous left atrial appendage (LAA) occlusion using the PLAATO system (ev3 Inc., Plymouth, Minnesota). BACKGROUND Patients with atrial fibrillation (AF) have a five-fold increased risk for stroke. Other studies have shown that more than 90% of atrial thrombi in patients with non-rheumatic AF originate in the LAA. Transvenous closure of the LAA is a new approach in preventing embolism in these patients. METHODS Within two prospective, multi-center trials, LAA occlusion was attempted in 111 patients (age 71 Ϯ 9 years). All patients had a contraindication for anticoagulation therapy and at least one additional risk factor for stroke. The primary end point was incidence of major adverse events (MAEs), a composite of stroke, cardiac or neurological death, myocardial infarction, and requirement for procedure-related cardiovascular surgery within the first month. RESULTS Implantation was successful in 108 of 111 patients (97.3%, 95% confidence interval [CI] 92.3% to 99.4%) who underwent 113 procedures. One patient (0.9%, 95% CI 0.02% to 4.9%) experienced two MAEs within the first 30 days: need for cardiovascular surgery and in-hospital neurological death. Three other patients underwent in-hospital pericardiocentesis due to a hemopericardium. Average follow-up was 9.8 months. Two patients experienced stroke. No migration or mobile thrombus was noted on transesophageal echocardiogram at one and six months after device implantation. CONCLUSIONS Closing the LAA using the PLAATO system is feasible and can be performed at acceptable risk. It may become an alternative in patients with AF and a contraindication for lifelong anticoagulation treatment. (J Am Coll Cardiol 2005;46:9-14) © 2005 by the American College of Cardiology Foundation Atrial fibrillation (AF) is responsible for more than 15% of all strokes (1-3). Besides irregular heart rate and possible lowered endurance, AF leads to insufficient contraction of the left atrium. Stagnation of blood flow within the left atrium leads to hypercoagulability and thus to an increased risk for thrombus formation (4). Several surgical, echocardiographic, and autopsy studies have shown that more than 90% of all thrombi in patients with non-rheumatic AF forming in the left atrium

Journal of Nihon University Medical Association, 2015

Background: Intra-isthmus reentry (IIR) denotes a reentry circuit within the cavotricuspid isthmu... more Background: Intra-isthmus reentry (IIR) denotes a reentry circuit within the cavotricuspid isthmus (CTI). The purpose of this study was to define the electrogram and surface ECG characteristics of IIR. Methods and Results: Three patients underwent electrophysiologic examination and were found to have IIR; the IIR in 1 patient was found during a redo procedure. Detailed electrogram mapping of the CTI and electroanatomic mapping (EAM) were performed in all 3 patients. Entrainment mapping in all patients during tachycardia proved reentry and showed that the anteroinferior CTI was outside the circuit and that the septal CTI was within the circuit. During tachycardia, fractionated or double potentials were recorded at either the septal CTI and/or the region of the coronary sinus ostium (CSos). The surface ECG showed a typical counterclockwise (CCW) pattern in 2 patients and an atypical pattern in 1 patient, and EAM showed a CCW pattern in 2 patients and a focal pattern in 1 patient. The one patient with atypical ECG pattern in spite of the CCW activation pattern showed a low voltage area at the inferolateral tricuspid annulus. Conclusions: IIR presents as a tachycardia circuit confined to the septal CTI/CSos region, and surface ECG characteristics show either typical CTI-dependent AFL or atypical AFL patterns.

Update of Non-Pharmacological Therapy for Heart Failure, 2020

Cardiac resynchronization therapy (CRT) is a standard therapy for patients with heart failure acc... more Cardiac resynchronization therapy (CRT) is a standard therapy for patients with heart failure accompanied by conduction disturbance and dyssynchrony. However, we feel that this therapy is not sufficiently utilized, even 15 years after first being implemented. Acceptance level of this treatment differs among physicians and across regions, possibly due to the invasive nature of CRT, which has led to failure to introduce this treatment properly. However, indication of CRT should not be determined solely by the interest and opinion of the physician in charge. CRT is often indispensable in cases with conduction disturbance and impaired cardiac function, similar to the necessity for commencing beta-blocker treatment for heart failure. Failure to introduce this treatment is a deviation from standard therapy and requires a sufficient explanation for the reasons not selecting this treatment. The objective of this chapter is to confirm the indications for CRT and to share its efficacy, in the hope that this will serve as a guidance to appropriate treatment of heart failure, without delays in the introduction of CRT.

The Annals of Thoracic Surgery, 2017

Clinical Case Reports, 2017

Right ventricular perforation leading to cardiac tamponade can occur during the chronic phase aft... more Right ventricular perforation leading to cardiac tamponade can occur during the chronic phase after cardiac device implantation. Physicians who manage the pacemaker clinic must be alert to the wide range of symptoms and signs that can accompany delayed right ventricular perforation. Surgical rather than percutaneous lead extraction may be prudent.

Anesthesia & Analgesia, 2004

Copyr ight © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibit... more Copyr ight © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited. ended up having CPB. Ideally, in this situation, results from both strategies, intent-to-treat and actual treatment, should be reported.

Journal of Clinical Medicine, 2021

Background: The definition of response to cardiac resynchronization therapy (CRT) varies across c... more Background: The definition of response to cardiac resynchronization therapy (CRT) varies across clinical trials. There are two main definitions, i.e., echocardiographic response and functional response. We assessed which definition was more reasonable. Methods: In this study of 260 patients who had undergone CRT, an echocardiographic response was defined as a reduction in a left ventricular end-systolic volume of greater than or equal to 15% or an improvement in left ventricular ejection fraction of greater than or equal to 5%. A functional response was defined as an improvement of at least one class category in the New York Heart Association functional classification. We assessed the response to CRT at 6 months after device implantation, based on each definition, and investigated the relationship between response and clinical outcomes. Results: The echocardiographic response rate was 74.2%. The functional response rate was 86.9%. Non-responder status, based on both definitions, was...

Heart and Vessels, 2019

A prolonged QRS duration (QRSd) is promising for a response to cardiac resynchronization therapy ... more A prolonged QRS duration (QRSd) is promising for a response to cardiac resynchronization therapy (CRT). The variation in human body sizes may affect the QRSd. We hypothesized that conduction disturbances may exist in Japanese even with a narrow (< 130 ms)-QRS complex; such patients could be CRT candidates. We investigated the relationships between QRSd and sex and body size in Japanese. We retrospectively analyzed the values of 338 patients without heart failure (HF) (controls) and 199 CRT patients: 12-lead electrocardiographically determined QRSd, left ventricular diastolic and systolic diameters (LVDd and LVDs), body surface area (BSA), body mass index (BMI), and LVEF. We investigated the relationships between the QRSd and BSA, BMI, and LVD. The men’s and women’s BSA values were 1.74 m2 and 1.48 m2 in the controls (p < 0.0001), and 1.70 m2 and 1.41 m2 in the CRT patients (p < 0.0001). The men’s and women’s QRSd values were 96.1 ms and 87.4 ms in the controls (p < 0.000...

Journal of arrhythmia, 2017

Clinical dilemmas arise when patients with a non-magnetic resonance (MR) conditional pacemaker ar... more Clinical dilemmas arise when patients with a non-magnetic resonance (MR) conditional pacemaker are required to undergo magnetic resonance imaging (MRI). We encountered a pacemaker patient with debilitating non-motor symptoms of Parkinson׳s disease, who required an MRI prior to deep brain stimulation (DBS) surgery. MRI was performed safely without adverse events despite the presence of a conventional pacemaker.

Journal of Nihon University Medical Association, 2014

Objective: Cardiac resynchronization therapy (CRT) is known to be effective for left ventricular ... more Objective: Cardiac resynchronization therapy (CRT) is known to be effective for left ventricular dysfunction associated with left bundle branch block. However, CRT does not necessarily decrease the risk of sudden cardiac death. Recent studies have shown that epicardial left ventricular pacing may lead to prolongation of the QT interval and the development of torsades de pointes. Microvolt T-wave alternans (TWA) has been associated with increased susceptibility to ventricular tachyarrhythmias. We compared the influence of right atrial pacing, right ventricular pacing, left ventricular pacing and biventricular pacing (RAP, RVP, LVP and BVP) on TWA. Methods: TWA was measured per pacing mode during incremental pacing from 70 to 120 bpm in 18 CRT patients with a mean ejection fraction of 32±5%. TWA was considered positive if alternans voltage (Valt)＞1.9 μV and alternans ratio (AR)＞3.0 were observed for at least 1 minute. The incidence of TWA is reported as the percentage of impulse applications during which it was observed.

Journal of arrhythmia, 2018

Limited data exist on indicators of durable pulmonary vein isolation (PVI) undergoing cryoballoon... more Limited data exist on indicators of durable pulmonary vein isolation (PVI) undergoing cryoballoon ablation (CBA) for atrial fibrillation (AF). We investigated whether balloon temperature and time to PVI can be used to predict early PV reconduction (EPVR), including residual PV conduction and adenosine triphosphate-induced dormant conduction and the relation between touch-up ablation of EPVR sites and mid-term recurrence of AF. We obtained procedural and outcome data from the records of 130 consecutive patients who underwent CBA and followed up for 13.4 months. EPVR was identified in 86 (17%) PVs of 61 (47%) patients. Balloon temperatures during 30 seconds (-27 ± 5.7°C vs -31 ± 5.5°C), 60 seconds (-36 ± 5.6°C vs -41 ± 5.4°C), and at the nadir point (-41 ± 7.4°C vs -49 ± 7.0°C) were significantly higher, and the time to PVI was longer (90 ± 50 seconds vs 52 ± 29 seconds) in PVs with EPVR than in those without ( < 0.0001 for all). Among PVs without EPVR, the time to PVI was longer a...

Journal of Arrhythmia, 2017

Background: Ablation targeting complex fractionated atrial electrograms (CFAEs) or high dominant ... more Background: Ablation targeting complex fractionated atrial electrograms (CFAEs) or high dominant frequency (DF) sites is generally effective for persistent atrial fibrillation (AF). CFAEs and/or high DF sites may exist in lowvoltage regions, which theoretically represent abnormal substrates. However, whether CFAEs or high DF sites reflect low voltage substrates during sinus rhythm (SR) is unknown. Methods: Sixteen patients with AF (8 with paroxysmal AF; 8, persistent AF) underwent high-density mapping of the left atrium (LA) with a 3-dimensional electroanatomic mapping system before ablation. The LA was divided into 7 segments and the mean bipolar voltage recorded during AF and SR, CFAEs (cycle lengths of 50-120 ms), and DF sites were assessed in each segment with either a duo-decapolar ring catheter (n¼ 10) or a 64-pole basket catheter (n¼ 6). Low-voltage areas were defined as those of o0.5 mV during AF and o1.0 mV during SR. Results: Regional mean voltage recorded from the basket catheter showed good correlation between AF and SR (r¼0.60, po0.01); however, the % low-voltage area in the LA recorded from the ring catheter showed weak correlation (r¼0.34, p¼ 0.05). Mean voltage was lower during AF than during SR (1.0 mV [IQR, 0.5-1.4] vs. 2.6 mV [IQR, 1.8-3.6], po0.01). The regional and overall % low-voltage area of the LA was greater during AF than during SR (20% vs. 11%, p¼ 0.05). CFAEs and high DF sites (48 Hz) did not correlate with % low-voltage sites during SR; however, CFAEs sites were located in high-voltage regions during AF and high DF sites were located in low voltage regions during AF. Conclusions: CFAEs and high DF areas during AF do not reflect damaged atrial myocardium as shown by the SR voltage. However, CFAEs and high DF sites may demonstrate different electrophysiologic properties because of different voltage amplitude during AF.

Journal of the American College of Cardiology, 2004

Journal of arrhythmia, 2017

The mechanisms underlying self-perpetuation of persistent atrial fibrillation (AF) are not well u... more The mechanisms underlying self-perpetuation of persistent atrial fibrillation (AF) are not well understood. To gain insight into these mechanisms, we conducted a study comparing left atrial (LA) electroanatomic maps obtained during sinus rhythm between patients with paroxysmal AF (PAF) and patients with persistent AF (PerAF). The study included 23 men with PAF (age, 56.3±12.1 years) and 13 men with PerAF (age, 54.3±13.4 years). LA voltage mapping was performed during sinus rhythm. The clinical and electroanatomic characteristics of the two groups were evaluated and analyzed statistically. The bipolar voltages at the LA septum, roof, and posterior wall, right superior pulmonary vein (PV) and its antrum, right superior PV carina, and right inferior PV antrum were significantly lower in patients with PerAF than in those with PAF. The bipolar voltages in other parts of the LA did not differ statistically between the two groups. PAF and PerAF seem to be characterized by differences in th...

International Heart Journal, 2015

Patients with atrial fibrillation (AF) are at risk of cardioembolism. 1,2) Atrial thrombus format... more Patients with atrial fibrillation (AF) are at risk of cardioembolism. 1,2) Atrial thrombus formation associated with AF typically occurs in the left atrial appendage (LAA); 3) therefore, transesophageal echocardiography (TEE) is important for detection of such a thrombus and measurement of LAA flow velocity. 4,5) LAA closure is routinely performed during mitral valve surgery in patients with AF to prevent cardiogenic stroke. 6) We report the case of a 65-year-old woman with severe mitral regurgitation (MR) and AF in whom a giant thrombus formed almost immediately after mitral and tricuspid valvuloplasty and concurrent LAA resection. No atrial thrombus or spontaneous echo contrast (SEC) was detected by TEE before the surgery. However, a giant intramural thrombus was detected in the left atrium 7 days after surgery. It was thought that the atrial dysfunction as well as the change in morphology of the left atrium resulting from the severe MR complicated by AF and congestive heart failure produced a thrombotic substrate. This case suggests that careful surveillance for thrombus formation and careful maintenance of anticoagulation therapy are needed throughout the perioperative period even if no SEC or thrombus is detected before surgery.

Journal of Arrhythmia

Background: The association between circulating adiponectin levels and atrial fibrillation (AF) i... more Background: The association between circulating adiponectin levels and atrial fibrillation (AF) is uncertain. We, therefore, investigated whether an increased serum adiponectin level is implicated in the longterm recurrence of AF after ablation therapy. Methods: Our study included 100 consecutive patients (88 men; median age, 57.97 10.9 years) who underwent catheter ablation for AF at our hospital between 2011 and 2013. The adiponectin and N-terminal pro-brain natriuretic peptide (NT-proBNP) levels were measured before ablation and compared between those in whom AF recurred and those in whom AF did not recur. Results: Elevation in adiponectin levels was significantly associated with female sex, non-paroxysmal AF, heart failure, higher NT-proBNP and matrix metallo-proteinase-2 levels, and lower body mass index. After a stepwise adjustment for any potential confounding variables, the adiponectin levels remained significantly associated with female sex (beta ¼ 0.2601, P ¼0.0041), non-paroxysmal AF (beta¼ 0.2708, P¼ 0.0080), and higher NT-proBNP levels (beta ¼0.2536, P ¼ 0.0138). During the median follow-up period of 26.2 months, AF recurred in 48 of the 100 patients. Stepwise multivariate adjustment showed that an increased log-transformed NT-proBNP (Hazard ratio [HR], 2.18; 95% confidence interval [CI] 1.25-4.00; P¼ 0.0055), longer duration of AF (HR, 1.87; 95%CI 1.01-3.76; P¼ 0.0465), and decreased left ventricular ejection fraction (HR, 0.96; 95%CI 0.93-0.99; P¼ 0.0391) were independent predictors of recurrent AF after catheter ablation, but adiponectin was not. Conclusions: Our data indicated that adiponectin was partially responsible for progression of AF, but the correlation between adiponectin levels and AF recurrence was not significant.

International heart journal, Jan 27, 2018

We report the case of a 38-year-old woman who was admitted for acute cerebral infarction linked t... more We report the case of a 38-year-old woman who was admitted for acute cerebral infarction linked to a cardiac calcified amorphous tumor (CAT) and related mitral annular calcification (MAC). The cardiac mass was removed, and mitral valve replacement surgery was performed. Pathological examination revealed an amorphous accumulation of degenerating material within both lesions, indicating that build-up of calcium along the mitral annulus and subsequent rupture of the fibrotic tissue may be involved in the initiation and progression of CAT.

Japanese Journal of Electrocardiology, 1999

Japanese Heart Journal, Apr 1, 2000

Circulation, Apr 23, 2002

Background-Thromboembolism due to atrial fibrillation (AF) is a frequent cause of stroke. More th... more Background-Thromboembolism due to atrial fibrillation (AF) is a frequent cause of stroke. More than 90% of thrombi in AF form in the left atrial appendage (LAA). Obliteration of the appendage may prevent embolic complications. Methods and Results-We evaluated the feasibility and safety of implanting a novel device for percutaneous left atrial appendage transcatheter occlusion (PLAATO). LAA occlusion using the PLAATO system was attempted in 15 patients with chronic AF at high risk for stroke, who are poor candidates for long-term warfarin therapy. The implant consists of a self-expanding nitinol cage covered with a polymeric membrane (ePTFE). The LAA was successfully occluded in 15/15 patients (100%). Angiography and transesophageal echocardiography (TEE) during the procedure showed that the device was well-seated in all patients and that there was no evidence of perforation, device embolization, or interference with surrounding structures. In 1 patient, the first procedure was complicated by a hemopericardium, which occurred during LAA access. A second attempt 30 days later was successful with no untoward sequela. No other complications occurred. At 1-month follow-up, chest fluoroscopy and TEE revealed continued stable implant position with smooth atrial-facing surface and no evidence of thrombus. Conclusions-Thus, transcatheter closure of the LAA is feasible in humans. This novel implant technology may be appropriate for patients with AF who are not suitable candidates for anticoagulation therapy. Further trials are needed to show the long-term safety and its efficacy in reducing stroke. (Circulation. 2002;105:1887-1889.

Journal of the American College of Cardiology, Jul 1, 2005

These studies were conducted to evaluate the feasibility of percutaneous left atrial appendage (L... more These studies were conducted to evaluate the feasibility of percutaneous left atrial appendage (LAA) occlusion using the PLAATO system (ev3 Inc., Plymouth, Minnesota). BACKGROUND Patients with atrial fibrillation (AF) have a five-fold increased risk for stroke. Other studies have shown that more than 90% of atrial thrombi in patients with non-rheumatic AF originate in the LAA. Transvenous closure of the LAA is a new approach in preventing embolism in these patients. METHODS Within two prospective, multi-center trials, LAA occlusion was attempted in 111 patients (age 71 Ϯ 9 years). All patients had a contraindication for anticoagulation therapy and at least one additional risk factor for stroke. The primary end point was incidence of major adverse events (MAEs), a composite of stroke, cardiac or neurological death, myocardial infarction, and requirement for procedure-related cardiovascular surgery within the first month. RESULTS Implantation was successful in 108 of 111 patients (97.3%, 95% confidence interval [CI] 92.3% to 99.4%) who underwent 113 procedures. One patient (0.9%, 95% CI 0.02% to 4.9%) experienced two MAEs within the first 30 days: need for cardiovascular surgery and in-hospital neurological death. Three other patients underwent in-hospital pericardiocentesis due to a hemopericardium. Average follow-up was 9.8 months. Two patients experienced stroke. No migration or mobile thrombus was noted on transesophageal echocardiogram at one and six months after device implantation. CONCLUSIONS Closing the LAA using the PLAATO system is feasible and can be performed at acceptable risk. It may become an alternative in patients with AF and a contraindication for lifelong anticoagulation treatment. (J Am Coll Cardiol 2005;46:9-14) © 2005 by the American College of Cardiology Foundation Atrial fibrillation (AF) is responsible for more than 15% of all strokes (1-3). Besides irregular heart rate and possible lowered endurance, AF leads to insufficient contraction of the left atrium. Stagnation of blood flow within the left atrium leads to hypercoagulability and thus to an increased risk for thrombus formation (4). Several surgical, echocardiographic, and autopsy studies have shown that more than 90% of all thrombi in patients with non-rheumatic AF forming in the left atrium

Journal of Nihon University Medical Association, 2015

Background: Intra-isthmus reentry (IIR) denotes a reentry circuit within the cavotricuspid isthmu... more Background: Intra-isthmus reentry (IIR) denotes a reentry circuit within the cavotricuspid isthmus (CTI). The purpose of this study was to define the electrogram and surface ECG characteristics of IIR. Methods and Results: Three patients underwent electrophysiologic examination and were found to have IIR; the IIR in 1 patient was found during a redo procedure. Detailed electrogram mapping of the CTI and electroanatomic mapping (EAM) were performed in all 3 patients. Entrainment mapping in all patients during tachycardia proved reentry and showed that the anteroinferior CTI was outside the circuit and that the septal CTI was within the circuit. During tachycardia, fractionated or double potentials were recorded at either the septal CTI and/or the region of the coronary sinus ostium (CSos). The surface ECG showed a typical counterclockwise (CCW) pattern in 2 patients and an atypical pattern in 1 patient, and EAM showed a CCW pattern in 2 patients and a focal pattern in 1 patient. The one patient with atypical ECG pattern in spite of the CCW activation pattern showed a low voltage area at the inferolateral tricuspid annulus. Conclusions: IIR presents as a tachycardia circuit confined to the septal CTI/CSos region, and surface ECG characteristics show either typical CTI-dependent AFL or atypical AFL patterns.

Update of Non-Pharmacological Therapy for Heart Failure, 2020

Cardiac resynchronization therapy (CRT) is a standard therapy for patients with heart failure acc... more Cardiac resynchronization therapy (CRT) is a standard therapy for patients with heart failure accompanied by conduction disturbance and dyssynchrony. However, we feel that this therapy is not sufficiently utilized, even 15 years after first being implemented. Acceptance level of this treatment differs among physicians and across regions, possibly due to the invasive nature of CRT, which has led to failure to introduce this treatment properly. However, indication of CRT should not be determined solely by the interest and opinion of the physician in charge. CRT is often indispensable in cases with conduction disturbance and impaired cardiac function, similar to the necessity for commencing beta-blocker treatment for heart failure. Failure to introduce this treatment is a deviation from standard therapy and requires a sufficient explanation for the reasons not selecting this treatment. The objective of this chapter is to confirm the indications for CRT and to share its efficacy, in the hope that this will serve as a guidance to appropriate treatment of heart failure, without delays in the introduction of CRT.

The Annals of Thoracic Surgery, 2017

Clinical Case Reports, 2017

Right ventricular perforation leading to cardiac tamponade can occur during the chronic phase aft... more Right ventricular perforation leading to cardiac tamponade can occur during the chronic phase after cardiac device implantation. Physicians who manage the pacemaker clinic must be alert to the wide range of symptoms and signs that can accompany delayed right ventricular perforation. Surgical rather than percutaneous lead extraction may be prudent.

Anesthesia & Analgesia, 2004

Copyr ight © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibit... more Copyr ight © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited. ended up having CPB. Ideally, in this situation, results from both strategies, intent-to-treat and actual treatment, should be reported.

Journal of Clinical Medicine, 2021

Background: The definition of response to cardiac resynchronization therapy (CRT) varies across c... more Background: The definition of response to cardiac resynchronization therapy (CRT) varies across clinical trials. There are two main definitions, i.e., echocardiographic response and functional response. We assessed which definition was more reasonable. Methods: In this study of 260 patients who had undergone CRT, an echocardiographic response was defined as a reduction in a left ventricular end-systolic volume of greater than or equal to 15% or an improvement in left ventricular ejection fraction of greater than or equal to 5%. A functional response was defined as an improvement of at least one class category in the New York Heart Association functional classification. We assessed the response to CRT at 6 months after device implantation, based on each definition, and investigated the relationship between response and clinical outcomes. Results: The echocardiographic response rate was 74.2%. The functional response rate was 86.9%. Non-responder status, based on both definitions, was...

Heart and Vessels, 2019

A prolonged QRS duration (QRSd) is promising for a response to cardiac resynchronization therapy ... more A prolonged QRS duration (QRSd) is promising for a response to cardiac resynchronization therapy (CRT). The variation in human body sizes may affect the QRSd. We hypothesized that conduction disturbances may exist in Japanese even with a narrow (< 130 ms)-QRS complex; such patients could be CRT candidates. We investigated the relationships between QRSd and sex and body size in Japanese. We retrospectively analyzed the values of 338 patients without heart failure (HF) (controls) and 199 CRT patients: 12-lead electrocardiographically determined QRSd, left ventricular diastolic and systolic diameters (LVDd and LVDs), body surface area (BSA), body mass index (BMI), and LVEF. We investigated the relationships between the QRSd and BSA, BMI, and LVD. The men’s and women’s BSA values were 1.74 m2 and 1.48 m2 in the controls (p < 0.0001), and 1.70 m2 and 1.41 m2 in the CRT patients (p < 0.0001). The men’s and women’s QRSd values were 96.1 ms and 87.4 ms in the controls (p < 0.000...

Journal of arrhythmia, 2017

Clinical dilemmas arise when patients with a non-magnetic resonance (MR) conditional pacemaker ar... more Clinical dilemmas arise when patients with a non-magnetic resonance (MR) conditional pacemaker are required to undergo magnetic resonance imaging (MRI). We encountered a pacemaker patient with debilitating non-motor symptoms of Parkinson׳s disease, who required an MRI prior to deep brain stimulation (DBS) surgery. MRI was performed safely without adverse events despite the presence of a conventional pacemaker.

Journal of Nihon University Medical Association, 2014

Objective: Cardiac resynchronization therapy (CRT) is known to be effective for left ventricular ... more Objective: Cardiac resynchronization therapy (CRT) is known to be effective for left ventricular dysfunction associated with left bundle branch block. However, CRT does not necessarily decrease the risk of sudden cardiac death. Recent studies have shown that epicardial left ventricular pacing may lead to prolongation of the QT interval and the development of torsades de pointes. Microvolt T-wave alternans (TWA) has been associated with increased susceptibility to ventricular tachyarrhythmias. We compared the influence of right atrial pacing, right ventricular pacing, left ventricular pacing and biventricular pacing (RAP, RVP, LVP and BVP) on TWA. Methods: TWA was measured per pacing mode during incremental pacing from 70 to 120 bpm in 18 CRT patients with a mean ejection fraction of 32±5%. TWA was considered positive if alternans voltage (Valt)＞1.9 μV and alternans ratio (AR)＞3.0 were observed for at least 1 minute. The incidence of TWA is reported as the percentage of impulse applications during which it was observed.

Journal of arrhythmia, 2018

Limited data exist on indicators of durable pulmonary vein isolation (PVI) undergoing cryoballoon... more Limited data exist on indicators of durable pulmonary vein isolation (PVI) undergoing cryoballoon ablation (CBA) for atrial fibrillation (AF). We investigated whether balloon temperature and time to PVI can be used to predict early PV reconduction (EPVR), including residual PV conduction and adenosine triphosphate-induced dormant conduction and the relation between touch-up ablation of EPVR sites and mid-term recurrence of AF. We obtained procedural and outcome data from the records of 130 consecutive patients who underwent CBA and followed up for 13.4 months. EPVR was identified in 86 (17%) PVs of 61 (47%) patients. Balloon temperatures during 30 seconds (-27 ± 5.7°C vs -31 ± 5.5°C), 60 seconds (-36 ± 5.6°C vs -41 ± 5.4°C), and at the nadir point (-41 ± 7.4°C vs -49 ± 7.0°C) were significantly higher, and the time to PVI was longer (90 ± 50 seconds vs 52 ± 29 seconds) in PVs with EPVR than in those without ( < 0.0001 for all). Among PVs without EPVR, the time to PVI was longer a...

Journal of Arrhythmia, 2017

Background: Ablation targeting complex fractionated atrial electrograms (CFAEs) or high dominant ... more Background: Ablation targeting complex fractionated atrial electrograms (CFAEs) or high dominant frequency (DF) sites is generally effective for persistent atrial fibrillation (AF). CFAEs and/or high DF sites may exist in lowvoltage regions, which theoretically represent abnormal substrates. However, whether CFAEs or high DF sites reflect low voltage substrates during sinus rhythm (SR) is unknown. Methods: Sixteen patients with AF (8 with paroxysmal AF; 8, persistent AF) underwent high-density mapping of the left atrium (LA) with a 3-dimensional electroanatomic mapping system before ablation. The LA was divided into 7 segments and the mean bipolar voltage recorded during AF and SR, CFAEs (cycle lengths of 50-120 ms), and DF sites were assessed in each segment with either a duo-decapolar ring catheter (n¼ 10) or a 64-pole basket catheter (n¼ 6). Low-voltage areas were defined as those of o0.5 mV during AF and o1.0 mV during SR. Results: Regional mean voltage recorded from the basket catheter showed good correlation between AF and SR (r¼0.60, po0.01); however, the % low-voltage area in the LA recorded from the ring catheter showed weak correlation (r¼0.34, p¼ 0.05). Mean voltage was lower during AF than during SR (1.0 mV [IQR, 0.5-1.4] vs. 2.6 mV [IQR, 1.8-3.6], po0.01). The regional and overall % low-voltage area of the LA was greater during AF than during SR (20% vs. 11%, p¼ 0.05). CFAEs and high DF sites (48 Hz) did not correlate with % low-voltage sites during SR; however, CFAEs sites were located in high-voltage regions during AF and high DF sites were located in low voltage regions during AF. Conclusions: CFAEs and high DF areas during AF do not reflect damaged atrial myocardium as shown by the SR voltage. However, CFAEs and high DF sites may demonstrate different electrophysiologic properties because of different voltage amplitude during AF.

Journal of the American College of Cardiology, 2004

Journal of arrhythmia, 2017

The mechanisms underlying self-perpetuation of persistent atrial fibrillation (AF) are not well u... more The mechanisms underlying self-perpetuation of persistent atrial fibrillation (AF) are not well understood. To gain insight into these mechanisms, we conducted a study comparing left atrial (LA) electroanatomic maps obtained during sinus rhythm between patients with paroxysmal AF (PAF) and patients with persistent AF (PerAF). The study included 23 men with PAF (age, 56.3±12.1 years) and 13 men with PerAF (age, 54.3±13.4 years). LA voltage mapping was performed during sinus rhythm. The clinical and electroanatomic characteristics of the two groups were evaluated and analyzed statistically. The bipolar voltages at the LA septum, roof, and posterior wall, right superior pulmonary vein (PV) and its antrum, right superior PV carina, and right inferior PV antrum were significantly lower in patients with PerAF than in those with PAF. The bipolar voltages in other parts of the LA did not differ statistically between the two groups. PAF and PerAF seem to be characterized by differences in th...

International Heart Journal, 2015

Patients with atrial fibrillation (AF) are at risk of cardioembolism. 1,2) Atrial thrombus format... more Patients with atrial fibrillation (AF) are at risk of cardioembolism. 1,2) Atrial thrombus formation associated with AF typically occurs in the left atrial appendage (LAA); 3) therefore, transesophageal echocardiography (TEE) is important for detection of such a thrombus and measurement of LAA flow velocity. 4,5) LAA closure is routinely performed during mitral valve surgery in patients with AF to prevent cardiogenic stroke. 6) We report the case of a 65-year-old woman with severe mitral regurgitation (MR) and AF in whom a giant thrombus formed almost immediately after mitral and tricuspid valvuloplasty and concurrent LAA resection. No atrial thrombus or spontaneous echo contrast (SEC) was detected by TEE before the surgery. However, a giant intramural thrombus was detected in the left atrium 7 days after surgery. It was thought that the atrial dysfunction as well as the change in morphology of the left atrium resulting from the severe MR complicated by AF and congestive heart failure produced a thrombotic substrate. This case suggests that careful surveillance for thrombus formation and careful maintenance of anticoagulation therapy are needed throughout the perioperative period even if no SEC or thrombus is detected before surgery.

Journal of Arrhythmia

Background: The association between circulating adiponectin levels and atrial fibrillation (AF) i... more Background: The association between circulating adiponectin levels and atrial fibrillation (AF) is uncertain. We, therefore, investigated whether an increased serum adiponectin level is implicated in the longterm recurrence of AF after ablation therapy. Methods: Our study included 100 consecutive patients (88 men; median age, 57.97 10.9 years) who underwent catheter ablation for AF at our hospital between 2011 and 2013. The adiponectin and N-terminal pro-brain natriuretic peptide (NT-proBNP) levels were measured before ablation and compared between those in whom AF recurred and those in whom AF did not recur. Results: Elevation in adiponectin levels was significantly associated with female sex, non-paroxysmal AF, heart failure, higher NT-proBNP and matrix metallo-proteinase-2 levels, and lower body mass index. After a stepwise adjustment for any potential confounding variables, the adiponectin levels remained significantly associated with female sex (beta ¼ 0.2601, P ¼0.0041), non-paroxysmal AF (beta¼ 0.2708, P¼ 0.0080), and higher NT-proBNP levels (beta ¼0.2536, P ¼ 0.0138). During the median follow-up period of 26.2 months, AF recurred in 48 of the 100 patients. Stepwise multivariate adjustment showed that an increased log-transformed NT-proBNP (Hazard ratio [HR], 2.18; 95% confidence interval [CI] 1.25-4.00; P¼ 0.0055), longer duration of AF (HR, 1.87; 95%CI 1.01-3.76; P¼ 0.0465), and decreased left ventricular ejection fraction (HR, 0.96; 95%CI 0.93-0.99; P¼ 0.0391) were independent predictors of recurrent AF after catheter ablation, but adiponectin was not. Conclusions: Our data indicated that adiponectin was partially responsible for progression of AF, but the correlation between adiponectin levels and AF recurrence was not significant.

International heart journal, Jan 27, 2018

We report the case of a 38-year-old woman who was admitted for acute cerebral infarction linked t... more We report the case of a 38-year-old woman who was admitted for acute cerebral infarction linked to a cardiac calcified amorphous tumor (CAT) and related mitral annular calcification (MAC). The cardiac mass was removed, and mitral valve replacement surgery was performed. Pathological examination revealed an amorphous accumulation of degenerating material within both lesions, indicating that build-up of calcium along the mitral annulus and subsequent rupture of the fibrotic tissue may be involved in the initiation and progression of CAT.

Japanese Journal of Electrocardiology, 1999

Japanese Heart Journal, Apr 1, 2000