Initial clinical experience with the novel POLARx FIT cryoballoon system for pulmonary vein isolation in patients with atrial fibrillation.

Background: The POLARx FIT system (Boston Scientific, MA, USA) is a novel cryoballoon (CB) ablation technology in which the balloon diameter can be expanded from 28 to 31 mm. The aim of this study was to compare the benefits and safety of the new POLARx FIT system to those of the existing POLARx system currently in use for pulmonary vein (PV) isolation (PVI) in patients with atrial fibrillation. Methods: The first 70 consecutive patients who underwent CB-based PVI with the POLARx FIT system were retrospectively compared with 200 consecutive patients treated with the POLARx system at Sakakibara Heart Institute from October 2021 to May 2023. Results: The POLARx FIT system yielded a higher mean ± standard deviation nadir temperature in the right inferior PV (-59.2 ± 5.29 °C vs. - 62.0 ± 5.08 °C, p = 0.006), but this required a balloon size reduction to 28 mm in 30 % of cases. No significant differences were detected in the time to isolation and thaw time of any PV between the two groups. After the CB-based PVI procedure, no residual PV carina potentials were observed with the POLARx FIT system, whereas 4/20 were with the POLARx system (p = 0.04). Conclusions: The POLARx FIT system had comparable effectiveness and safety to the basic POLARx system. This technology may improve the ablation area, including the PV carina. However, the 31-mm balloon alone was not sufficient to isolate certain PVs.

Inappropriate shock incidence in patients with subcutaneous implantable cardioverter-defibrillators with concomitant cardiac implantable electronic devices: A single-center cohort study.

BACKGROUND: Subcutaneous implantable cardioverter defibrillators (S-ICDs) are occasionally used in combination with other cardiac implantable electronic devices (CIEDs). However, whether the incidence of inappropriate shock increases in patients with S-ICDs and concomitant CIEDs remains unclear. This study aimed to investigate the association between the concomitant use of CIEDs and the incidence of inappropriate shock in patients with current-generation S-ICDs. METHODS: A total of 127 consecutive patients received an S-ICD. Patients were assigned to two groups depending on concomitant use of CIEDs at the time of S-ICD implantation: patients without other CIEDs (non-combined group, 106 patients) and patients with other CIEDs (combined group, 21 patients). CIEDs included pacemakers, implantable cardioverter defibrillators, cardiac resynchronization therapy pacemakers, and cardiac resynchronization therapy defibrillators. The primary outcome was inappropriate shock, defined as a shock other than ventricular arrhythmia. Hazard ratios and 95% confidence intervals were calculated using a time-varying Cox proportional hazards model which was adjusted for age because age differed between the groups and could be a confounder. RESULTS: During a median follow-up period of 2.2 years (interquartile range, 1.0-3.4 years), inappropriate shock events occurred in 17 (16%) and five (19%) patients of the non-combined and combined groups, respectively. While the age-adjusted hazard ratio for inappropriate shock was 24% higher in the combined than in the non-combined group (hazard ratio = 1.24, 95% confidence interval, 0.39-3.97), this difference was insignificant (p = .71). CONCLUSION: The incidence of inappropriate shock did not differ between patients with and without concomitant use of CIEDs, suggesting that S-ICDs could potentially be combined with other CIEDs without increasing the number of inappropriate shocks. Further studies are warranted to confirm the safety and feasibility of concomitant use of S-ICDs and CIEDs.

Safety and Performance of the Micra VR Leadless Pacemaker in a Japanese Cohort　- Comparison With Global Studies.

BACKGROUND: The Micra leadless pacemaker has demonstrated favorable outcomes in global trials, but its real-world performance and safety in a Japan-specific population is unknown.Methods and Results: Micra Acute Performance (MAP) Japan enrolled 300 patients undergoing Micra VR leadless pacemaker implantation in 15 centers. The primary endpoint was the acute (30-day) major complication rate. The 30-day and 6-month major complication rates were compared to global Micra studies. All patients underwent successful implantation with an average follow-up of 7.23±2.83 months. Compared with previous Micra studies, Japanese patients were older, smaller, more frequently female, and had a higher pericardial effusion risk score. 11 acute major complications were reported in 10 patients for an acute complication rate of 3.33% (95% confidence interval: 1.61-6.04%), which was in line with global Micra trials. Pericardial effusion occurred in 4 patients (1.33%; 3 major, 1 minor). No procedure or device-related deaths occurred. Frailty significantly improved from baseline to follow-up as assessed by Japan Cardiovascular Health Study criteria. CONCLUSIONS: In a Japanese cohort, implantation of the Micra leadless pacemaker had a high success rate and low major complication rate. Despite the Japan cohort being older, smaller, and at higher risk, the safety and performance was in line with global Micra trials.

High-risk imaging characteristics in left ventricular apex for the life-threatening arrhythmic events in Japanese hypertrophic cardiomyopathy patients.

Left ventricular (LV) apical aneurysm is known to be associated with the life-threatening arrhythmic events in hypertrophic cardiomyopathy (HCM). However, the current 2014 ESC guideline has not included apical aneurysm as a major risk factor for sudden cardiac death and 2018 JCS guideline includes it only as a modulator, while it has been included as a new major risk marker in 2020 AHA/ACC guideline. Therefore, we sought to identify high-risk imaging characteristics in LV apex which is associated with a higher occurrence of ventricular tachycardia/fibrillation (VT/VF). In 99 consecutive Japanese HCM patients (median age, 65 years; 59 males) undergoing implantable cardioverter-defibrillator (ICD) implantation for primary prevention following cardiac magnetic resonance including late gadolinium enhancement (LGE), the occurrence of appropriate ICD interventions for VT/VF was evaluated for 6.2 (median) years after ICD implantation. Overall, appropriate ICD interventions occurred in 43% with annual rates of 7.0% for appropriate interventions. Kaplan-Meier analysis demonstrated that the presence of LV apical aneurysm was significantly associated with a higher occurrence of appropriate interventions (annual rates 18.9% vs. 6.4%, P = 0.013). Similarly, patients with high LV mid-to-apex pressure gradient (annual rates 14.9% vs. 6.2%, P = 0.022) and presence of apical LGE (annual rates 10.9% vs. 4.0%, P = 0.001) experienced appropriate interventions more frequently. An aneurysm, high-pressure gradient, and LGE in an apex are associated with VT/VF. These characteristics in apex should be kept in mind when implanting ICD in Japanese HCM patients as a primary prevention.

Sick sinus syndrome concomitant with myopathy associated with anti-mitochondrial antibodies: a case report.

Background: Anti-mitochondrial antibody (AMA)-associated myopathy is known to be concomitant with primary biliary cirrhosis and to cause both skeletal muscle disorders and arrhythmias, myocardium disorders, and respiratory muscle disorders. We report a case of AMA-associated myopathy in which the bradycardia-related symptoms preceded the skeletal muscle symptoms. Case summary: A 59-year-old woman visited the emergency room in our hospital following a syncopal event. The patient was bradycardiac (45 b.p.m.) with a junctional rhythm resulting from sick sinus syndrome (SSS) and was suffering from heart failure. Blood tests revealed elevated creatine kinase (CK) and hepatic enzymes. She underwent permanent pacemaker implantation. However, it proved difficult to detect the electrical potential in the right atrium. Although successful atrial pacing was achieved at the lower right atrial septum, the atrial threshold was markedly high and she depended on ventricular pacing. One year later, neurological examination and muscle biopsy confirmed the diagnosis of AMA-associated myopathy. Following this diagnosis, steroid pulse therapy was initiated. Steroid administration relieved her symptoms and lowered the CK levels but the atrial standstill persisted. The patient takes low-dose prednisolone and has had an uneventful course for 3 years. Discussion: To the best of our knowledge, this is the first case of AMA-associated myopathy diagnosed by the first symptom related to bradycardia due to SSS. Patients with AMA-associated myopathy can experience a variety of cardiac symptoms, including arrhythmias, and initially complain of cardiac symptoms without symptoms of skeletal myopathy. This disease should be considered when diagnosing patients with arrhythmia and elevated CK.

Cephalic vein cut-down technique for severe venous spasm following axillary vein puncture at pacemaker implantation.

An 83-year-old male with complete atrioventricular block underwent dual-chamber pacemaker implantation. Venography showed normal anatomy of the left axillary vein. Following sedation with intravenous propofol, local anesthesia, and skin incision, we punctured the left axillary vein on the first limb. However, the guidewire could not be advanced despite blood backflow after the initial puncture. On venography, left axillary vein on the first limb totally disappeared with dilated collaterals. We diagnosed axillary vein spasm and injected 1000 µg of intravenous nitroglycerin. After 15 min, repeated venography showed slight contrast flow in the axillary vein. We alternatively punctured the axillary vein on the second limb. However, the axillary vein was spasmodically occluded again. We considered the possibility that puncture of the right axillary vein could also result in venous spasm. Since the left cephalic vein was identified after waiting time, we partially cut down the left cephalic vein and inserted guidewires into the vein. The ventricular and atrial leads were successfully implanted through sheaths in the right ventricular septum and right atrial appendage, respectively. Learning objective: Pacemaker implantation complicated with puncture-related axillary vein spasm is challenging. Severe venous spasms refractory to waiting time or nitroglycerin sometimes require conversion of access site. However, the bail-out technique from ipsilateral access remains unclear. Cut-down technique of the ipsilateral cephalic vein is one alternative to manage severe axillary vein spasm refractory to nitroglycerin and waiting time.

Radiofrequency Current Versus Balloon-Based Ablation for Atrial Fibrillation.

The basis for selection of contemporary ablation technologies for pulmonary vein isolation (PVI) in patients with atrial fibrillation (AF) remains unclear. We compared procedural data and efficacy in a propensity score-matched cohort treated with 4 ablation technologies in a center mainly using cryoballoon (CB). A total of 819 consecutive patients with AF underwent PVI, using radiofrequency current (RFC) (65 patients), CB (693 patients), hot balloon (HB) (74 patients), and laser balloon (LB) (52 patients). Fifty patients (82% paroxysmal AF) were selected from each group according to the propensity score. Procedural data and freedom from atrial tachyarrhythmia recurrence after the index procedure were compared. All pulmonary veins were isolated in all groups. Procedure time was shorter in CB and HB groups (RFC: 148 ± 53 vs CB: 85 ± 37 vs HB: 102 ± 31 vs LB: 140 ± 28 minutes, p <0.001). RFC touch-up was most commonly required for PVI in the HB group among balloon groups (40%) (p <0.001). Total complication rate was 4% to 18% without any statistical differences between groups (p = 0.123). Phrenic nerve injury occurred most often in the CB group (16%) (p <0.001). During a mean follow-up of 21 ± 6 months, there were no significant differences among groups for freedom from atrial tachyarrhythmia recurrence after the index procedure (RFC: 68% vs CB: 78% vs HB: 76% vs LB: 76%, p = 0.440). In conclusion, all the ablation technologies facilitate safe and efficient PVI, with slight differences in the procedural data and complications.

Evaluation of linear lesion formation and thermodynamics by dragging ablation with the third-generation laser balloon.

Background: The lesion formation properties of a motorized rotational delivery (RAPID) mode, third-generation laser balloon (LB3) ablation compared to point-by-point laser ablation in patients with atrial fibrillation remain unclear. Objective: The purpose of this study was to assess lesion characteristics and thermodynamics in LB3 ablation with a RAPID mode in vitro model. Methods: Chicken muscles were cauterized using LB3 in RAPID mode with 13 W and 15 W and 50% overlapped point-by-point fashion with 7 W/30 seconds, 8.5 W/20 seconds, 10 W/20 seconds, and 12 W/20 seconds. Lesion depth, width, and continuity were compared. Lesion continuity was classified by the visible gap degree categorized from 1 (perfect) to 3 (poor). Thermodynamics and maximum tissue temperatures were assessed under infrared thermographic monitoring. Fifteen and 5 lesions were evaluated per ablation protocol for measurement of lesion size and continuity and for thermographic assessment, respectively. Results: Lesion depth and width were smaller in RAPID mode laser ablation than point-by-point laser ablation (P <.001). However, RAPID mode laser ablation revealed sufficient mean lesion depth of 5 mm or more. Lesion continuity was 1 (perfect) in all samples in RAPID mode laser ablation and point-by-point laser ablation (P = 1). Infrared thermographic observation demonstrated fast and gapless linear lesion formation with thermal stacking in RAPID mode laser ablation. Maximum tissue temperature was lower in RAPID mode laser ablation than point-by-point laser ablation (P <.001). Conclusion: RAPID mode LB3 ablation could provide fast, gapless, and acceptable lesion formation with thermal stacking and moderate tissue temperature rise.

Prognostic predictors and echocardiographic time course after device replacement in patients treated chronically with cardiac resynchronization therapy devices.

The prognostic predictors of death or heart failure hospitalization and the echocardiographic response after initial cardiac resynchronization therapy (CRT) device replacement (CRT-r) remain unclear. We evaluated the predictors and the echocardiographic time course in patients after CRT-r. Consecutive 60 patients underwent CRT-r because of battery depletion. Patients were divided into two groups depending on the chronic echocardiographic response to CRT (left ventricular end-systolic volume [LVESV] reduction of ≥ 15%) at the time of CRT-r: CRT responders (group A; 35 patients) and CRT nonresponders (group B; 25 patients). The primary endpoint was a composite of death from any cause or heart failure hospitalization. Changes in LVESV and left ventricular ejection fraction (LVEF) after CRT-r were also analyzed. During the mean follow-up of 46 ± 33 months after CRT-r, the primary endpoint occurred more frequently in group B (group A versus group B; 8/35 [23%] patients versus 19/25 [76%] patients, p < 0.001). No significant changes in LVESV and LVEF were observed at the mean of 46 ± 29 months after CRT-r in both groups. A multivariate analysis identified echocardiographic nonresponse to CRT, chronic kidney disease, atrial fibrillation, and New York Heart Association functional class III or IV at the time of CRT-r as independent predictors of the primary endpoint in all patients. Residual echocardiographic nonresponse, comorbidities, and heart failure symptoms at the time of CRT-r predict the subsequent very long-term prognosis after CRT-r. No further echocardiographic response to CRT was found after CRT-r.

Evaluation of different ablation strategies verifying the optimal overlap ratio in point-by-point laser balloon ablation for patients with atrial fibrillation.

BACKGROUND: Optimal overlap ratio remains unclear in point-by-point laser balloon (LB) ablation. OBJECTIVE: This study sought to determine the optimal overlap strategy with target energies on the acute and chronic outcomes in LB pulmonary vein (PV) isolation (PVI). METHODS: Consecutive 38 patients (148 PVs) with atrial fibrillation underwent the first-generation LB PVI with the following protocols based on the overlap ratios for each PV anterior/posterior wall: 50%/50% (13 patients [49 PVs], group A), 50%/25% (15 patients [60 PVs], group B), and 25%/25% (10 patients [39 PVs], group C). High energies (240-255 J: 12 W / 20 seconds, 8.5 W / 30 seconds), moderate energies (200-210 J: 10 W / 20 seconds, 7 W / 30 seconds), and low-to-moderate energies (low, 165-170 J: 5.5 W / 30 seconds, 8.5 W / 20 seconds) were targeted for left PV anterior walls, right PV anterior walls, and bilateral PV posterior walls, respectively. First-pass PVI, the other procedure-related data, and atrial tachyarrhythmia recurrences were analyzed. RESULTS: First-pass PVI rate per PV was higher in group A (94%) than in group B (88%) and group C (62%) (P < .001). All PVs were finally isolated. First-pass time, total LB PVI time, complications, and atrial tachyarrhythmia recurrences during a mean follow-up of 11 ± 5 months did not differ between the groups. A few residual gaps after first-pass LB ablations were found for PV anterior walls even in group A and group B. CONCLUSION: Sufficiently overlapped LB ablation promises a high rate of first-pass PVI without adverse outcomes. High energy could be required for PV anterior walls.

Pacemaker implantation using the SelectSecure system for a patient with persistent left superior vena cava and absent right superior vena cava: Insights into techniques for stable lead fixation.

The techniques for successful pacemaker implantation via the PLSVC with the SelectSecure system (Medtronic, Minneapolis, Minnesota, USA) are unknown. Regarding the techniques, we presented a case in which we implanted a pacemaker via the PLSVC in patient with absent RSVC using the SelectSecure system.

Impact of a poor functional capacity on the clinical outcomes in patients with a pacemaker implantation -Results from the Japanese Heart Rhythm Society Registry.

BACKGROUND: Functional capacity (FC) correlates with mortality in various cardiovascular diseases. The aim of this study was to examine whether cardiac pacemaker implantations improve the FC and affect the prognosis. METHODS AND RESULTS: We prospectively enrolled 621 de novo pacemaker recipients (age 76 ± 9 years, 50.7% male). The FC was assessed by metabolic equivalents (METs) during the implantation and periodically thereafter. The patients were a priori classified into poor FC (<2 METs, n = 40), moderate FC (2 ≤ METs < 4, n = 239), and good FC (≥4 METs, n = 342). Three months after the pacemaker implantation, poor FC or moderate FC patients improved to a good FC by 43%. The distribution of the three FCs remained at those levels until after 1 year of follow-up (P = .18). During a median follow-up of 2.4 years, 71 patients (11%) had cardiovascular hospitalizations and 35 (5.6%) all-cause death. A multivariate Cox analysis revealed that a poor FC at baseline was an independent predictor of both cardiovascular hospitalization (hazard ratio [HR] 2.494, P = .012) and all-cause death (HR 3.338, P = .016). One year after the pacemaker implantation, the eight who remained with a poor FC had a high mortality rate of 37.5% (P < .01). CONCLUSION: Approximately half of the poor or moderate FC patients improved to good FC 3 months after the pacemaker implantation. The baseline FC predicted the prognosis, and patients with an improved FC after the pacemaker implantation had a better prognosis.

Comparison of dragging ablation and point-by-point ablation with a laser balloon on linear lesion formation.

INTRODUCTION: Lesion size and continuity in dragging laser balloon (LB) ablation, which may enable fast and durable pulmonary vein isolation for atrial fibrillation, are unknown. We evaluated the differences in size and continuity of linear lesions formed by dragging ablation and conventional point-by-point ablation using an LB in vitro model. METHODS AND RESULTS: Chicken muscles were cauterized using the first-generation LB in dragging and point-by-point fashion. Dragging ablation was manually performed with different dragging speeds (0.5-2°/s) using an overlap ratio of the beginning and last site during one application at 12 W/20 s and 8.5 W/30 s. Point-by-point ablation was performed with 25% and 50% overlap ratios at six energy settings (5.5 W/30 s to 12 W/20 s). Lesion depth, width, and continuity were compared. Lesion continuity was assessed by the surface and deep visible gap degree categorized from 1 (perfect) to 3 (poor). Twenty lesions were evaluated for each ablation protocol. Lesion depth and width in dragging ablation at high power (12 W) were comparable with most measurements in point-by-point ablation. Lesion depth and width were smaller at faster-dragging speed and lower power (8.5 W) in dragging ablation. The surface visible gap degree was better in dragging ablation at all dragging speeds than a 25% overlapped point-by-point ablation (p < .001). CONCLUSION: Dragging LB ablation at high power provides deep and continuous linear lesion formation comparable with that of point-by-point LB ablation. However, lesion depth and width depending on the dragging speed and power.

Prognostic value of cardiovascular magnetic resonance imaging for life-threatening arrhythmia detected by implantable cardioverter-defibrillator in Japanese patients with hypertrophic cardiomyopathy.

Implantable cardioverter-defibrillator (ICD) is effective to prevent sudden death in HCM patients. We reviewed ICD records to analyze the relation between life-threatening arrhythmia and late gadolinium enhancement (LGE) on cardiovascular magnetic resonance (CMR) in Japanese hypertrophic cardiomyopathy (HCM) patients. In 102 consecutive patients (median age 63 years, 63 males) implanted with an ICD after CMR with gadolinium enhancement (median follow-up 2.8 years), the outcome of life-threatening arrhythmic events (appropriate ICD interventions for ventricular tachycardia or ventricular fibrillation) was examined. Appropriate interventions rate were 10.3% per year for secondary prevention and 7.4% per year for primary prevention. The annualized ICD-related complication rate was 3.7%. 43/91 patients (47%) implanted ICD for primary prevention had maximum wall thickness ≥20 mm plus LGE in ≥4 of 17 left ventricular segments (cut-off value obtained from ROC curve); the appropriate ICD intervention rate was significantly higher in this group than in other patients group (annualized event rate, 11.1 vs. 4.6%; log-rank P = 0.038). A combination of myocardial hypertrophy and LGE is a useful outcome predictive factor for life-threatening ventricular arrhythmia in Japanese HCM patients.

Non-invasive diagnosis of coronary artery disease by 123I-BMIPP/201TlCl dual myocardial SPECT in patients with heart failure.

BACKGROUND/OBJECTIVES: Detecting the presence of coronary artery disease (CAD) is critically important in managing patients with heart failure of uncertain cause. The recently introduced 123I-BMIPP/201TlCl dual myocardial single-photon emission computed tomography (dual SPECT) is potentially a non-invasive diagnostic tool in detecting ischemic heart disease. The aim of our study is to evaluate the efficacy of detecting CAD by dual SPECT in patients with heart failure. METHODS: We studied 501 consecutive patients (366 males, mean age 68±12 years) who were admitted because of heart failure between January 2005 and April 2009. In all patients, the dual SPECT was performed in clinically stabilized states, followed by coronary angiography within 1 week. The polar map of the SPECT image was divided into 17 segments, each scored on a scale of 0-4 based on segmental percent uptake. The mismatch score was defined as the difference between 123I-BMIPP defect score and 201TlCI defect score. The uptake of 201TlCl and 123I-BMIPP was analyzed quantitatively using the Heart Score View software. RESULTS: The 201TlCI defect score and mismatch score were significantly higher in CAD patients than in non-CAD patients. The receiver operating characteristic (ROC) curve revealed that the mismatch score was a significantly more effective marker in detecting the presence of CAD than 201TlCl defect score (area under the curve: 0.84 versus 0.73, p<0.05). Using the mismatch score, the sensitivity and specificity of dual SPECT in detecting CAD were 84% and 83%, respectively. CONCLUSION: Dual SPECT is a useful non-invasive procedure for the detection of CAD in patients with heart failure.

Outcome of implantable cardioverter defibrillator therapy for congenital heart disease.

BACKGROUND: The use of implantable cardioverter defibrillator (ICD) therapy for congenital heart disease (CHD) has been increasing, but few studies have reported on the efficacy of ICD therapy in Japanese CHD patients. METHOD: Twelve CHD patients (median age, 35 years) with first ICD implantation were examined. Median follow-up duration was 2.9 years. Demographic information, implant electrical parameters, appropriate and inappropriate discharge data and complications were recorded for all implants from 2003 to 2010. RESULTS: Implant indication was primary prevention in two patients and secondary prevention in 10. Overall four patients received one or more discharges; three patients (25%) with secondary prevention received nine appropriate discharges. Inappropriate discharge attributed to sinus tachycardia occurred in two patients (16.7%). Only one patient experienced the late complication of skin erosion at the generator implantation site. CONCLUSIONS: Patients with CHD experienced significant rates of appropriate discharges and lower complications. But given that the indications of ICD implantation were mostly for secondary prevention, the ratio of appropriate shocks might be lower than in previous studies. In the primary prevention patients, the benefit of ICD was not clear because no appropriate discharges were seen during follow up. Although ICD implantation for CHD is beneficial for preventing sudden cardiac death, careful decision making and a large, long-term prospective study is required for the determination of the efficacy of ICD therapy in Japanese patients with CHD.

Late stent malapposition with marked positive vascular remodeling observed only at the site of drug-eluting stents after multivessel coronary stenting.

A 74-year-old woman presented with effort-induced chest pain. Diagnostic coronary angiography revealed three-vessel disease. A successful angioplasty was performed with two sirolimus-eluting stents placed in the left anterior descending artery (LAD) and left circumflex artery (LCX). The right coronary artery (RCA) was treated with a bare-metal stent. Follow-up angiography and intravascular ultrasound (IVUS) assessment were performed 8 months later, which showed late stent malapposition (LSM) with marked positive vascular remodeling around the drug-eluting stents (DES) in both LAD and LCX lesions, but there was no evidence of ectatic area around the BMS in the RCA lesion. Compared with the baseline IVUS, a significant increase in external elastic membrane (EEM) cross-sectional area was found. Twenty-seven months later, we performed repeat follow-up angiography. Intravascular ultrasound still showed vessel malapposition. A previous report showed that aneurysmal dilatation of the stented segment with severe localized hypersensitivity reaction could be a potential cause of late thrombosis after DES implantation. If LSM is related to hypersensitivity of the DES, it may have a potential risk of adverse events. Although there is a paucity of data regarding malapposition as the cause of adverse events, careful long-term follow-up of patients with vessel enlargement after DES placement is recommended.

Preoperative left atrial emptying fraction is a powerful predictor of successful maze procedure.

BACKGROUND: The maze procedure for the treatment of atrial fibrillation (AF) is a widely used adjunctive therapy. It is necessary to define the precise indications for the procedure based on preoperative factors, but definitive parameters in terms of atrial function have not been well determined. METHODS AND RESULTS: In the present study, 55 consecutive patients undergoing the maze procedure for persistent AF in combination with operations for organic heart diseases were evaluated. After dividing the patients into successful (n=41) and unsuccessful procedure (n=14) groups, based on the postoperative rhythm, the preoperative left atrial (LA) emptying fraction measured by transthoracic 2-dimensional echocardiogram was compared between groups. The LA emptying fraction was calculated as [(LA maximum volume - LA minimum volume)/LA maximum volume]x100. The preoperative LA emptying fraction was higher in the successful procedure group than in the unsuccessful procedure group (31.2+/-8.5 vs 21.4+/-10.9%, P=0.0011). Based on receiver-perating characteristic curve analyses, LA emptying fraction >26% predicted successful maze procedure with 70.7% sensitivity and 78.6% specificity. CONCLUSIONS: LA emptying fraction should be considered in the precise indications of the maze procedure as adjunctive therapy.