Novel indices representing heterogeneous distributions of myocardial perfusion imaging.

INTRODUCTION: Heterogeneous distribution in myocardial perfusion images (MPI) obtained by scintigraphy is often observed in cardiac diseases with normal myocardial perfusion. However, quantitative assessments of such heterogeneity have not been established. We hypothesized that the heterogeneity in MPI can be quantitatively evaluated through histogram analysis, calculating the standard deviation (SD), the 95% bandwidth (BW95%), and entropy. METHODS: We examined resting 99mTc-MIBI images in 20 healthy subjects and 29 patients with cardiac disease who had none or very-mild reduced myocardial perfusion evaluated as a low summed rest score (0 to 4, the range of the studied healthy subjects). Two nuclear medicine specialists blindly divided them into two groups: non-heterogeneity or heterogeneity group, based solely on their visual assessments of heterogeneity on splash and polar maps generated from single-photon emission computed tomography (SPECT) images. The %uptake was determined by dividing the tracer count of each pixel by the tracer count of the pixel with the highest value in the LV myocardium. SD, BW95%, and entropy from histogram patterns were analyzed from the polar map data array of each %uptake. We investigated whether heterogeneity could be assessed using SD, BW95, and entropy in two groups classified by visual assessments. Additionally, we evaluated the area under the curve (AUC) to identify heterogeneity in the receiver operating characteristic curve analysis. RESULTS: Based solely on visual assessments, 11 (22%) and 38 (78%) cases were classified into the non-heterogeneity and heterogeneity groups, respectively. The non-heterogeneity group consisted of only healthy subjects, and all patients with cardiac disease were classified into the heterogeneity group. The cases in the heterogeneity group had significantly higher values of heterogeneity indices (SD, BW95%, and entropy) in %uptake than those in the non-heterogeneity group (p < 0.05 for all). The AUCs of the heterogeneity indices were sufficiently high (AUCs > 0.90 for all) in distinguishing cases with visually heterogeneous distribution or patients with cardiac disease. CONCLUSIONS: Heterogeneity in MPI can be evaluated using SD, BW95%, and entropy through histogram analysis. These novel indices may help identify patients with subtle myocardial changes, even in images that show preserved perfusion (345/350).

Diverse distribution patterns of segmental longitudinal strain are associated with different clinical features and outcomes in dilated cardiomyopathy.

BACKGROUND: Dilated cardiomyopathy (DCM) presents with diverse clinical courses, hardly predictable solely by the left ventricular (LV) ejection fraction (EF). Longitudinal strain (LS) offers distinct information from LVEF and exhibits various distribution patterns. This study aimed to evaluate the clinical significance of LS distribution patterns in DCM. METHODS: We studied 139 patients with DCM (LVEF ≤ 35%) who were admitted for heart failure (HF). LS distribution was assessed using a bull's eye map and the relative apical LS index (RapLSI), calculated by dividing apical LS by the sum of basal and mid-LS values. We evaluated the associations of LS distribution with cardiac events (cardiac death, LV assist device implantation, or HF hospitalization) and LV reverse remodeling (LVRR), as indicated by subsequent LVEF changes. RESULTS: Twenty six (19%) and 29 (21%) patients exhibited a pattern of relatively apical impaired or preserved LS (defined by RapLSI < 0.25 or > 0.75, signifying a 50% decrease or increase in apical LS compared to other segments), and the remaining patients exhibited a scattered/homogeneously impaired LS pattern. The proportion of new-onset heart failure and LVEF differed between the three groups. During the median 595-day follow-up, patients with relatively-impaired apical LS had a higher rate of cardiac events (both log-rank p < 0.05) and a lower incidence of LVRR (both p < 0.01) compared to patients with other patterns. RapLSI was significantly associated with cardiac event rates after adjusting for age, sex, and new-onset HF or global LS. CONCLUSION: DCM patients with reduced EF and distinct distribution patterns of impaired LS experienced different outcomes.

Mitochondrial function and coronary flow reserve improvement after autologous myoblast patch transplantation for ischaemic cardiomyopathy: a case report.

Background: Autologous myoblast patch (AMP) transplantation has resulted in good clinical outcomes for end-stage ischaemic cardiomyopathy, but the mechanisms behind them are unclear. Herein, we report the relationship between mitochondrial function and coronary flow reserve (CFR) before and after AMP transplantation. Case summary: The patient was a 73-year-old man who underwent coronary artery bypass grafting (CABG). At that time, the left ventricular ejection fraction (LVEF) was 53%, but it declined to 25% after 6 years. He was diagnosed with ischaemic cardiomyopathy (ICM). Coronary flow reserve in NH3-positron emission tomography (NH3-PET) was impaired to 1.69. In Tc-99m MIBI scintigraphy, the washout rate (WR) was 17%, suggestive of impaired mitochondrial function. He was not a candidate for heart transplantation, and we performed AMP transplantation 6 years after CABG. One year after AMP transplantation, LVEF, CFR, and Tc-99m MIBI WR improved to 36%, 2.07, and 7%, respectively. The Tc-99m MIBI WR improved especially in the anterolateral region, and the CFR increased in almost all segments. Discussion: In this case, AMP transplantation for ICM improved cardiac function, CFR, and mitochondrial function. The mitochondrial transfer from the transplanted myoblasts to the damaged myocardium may have contributed to the mitochondrial function improvement. This probably induced myocardial energy metabolism recovery and decreased oxygen demand. AMP transplantation also has the potential to improve microvascular dysfunction, due to angiogenesis induction. These effects can lead to improved prognoses of ICM after AMP transplantation, highlighting its potential to cure refractory heart failure.

Evaluation of the efficacy and safety of an integrated telerehabilitation platform for home-based cardiac REHABilitation in patients with heart failure (E-REHAB): protocol for a randomised controlled trial.

INTRODUCTION: Cardiac rehabilitation (CR) is strongly recommended as a medical treatment to improve the prognosis and quality of life of patients with heart failure (HF); however, participation rates in CR are low compared with other evidence-based treatments. One reason for this is the geographical distance between patients' homes and hospitals. To address this issue, we developed an integrated telerehabilitation platform, RH-01, for home-based CR. We hypothesised that using the RH-01 platform for home-based CR would demonstrate non-inferiority compared with traditional centre-based CR. METHODS AND ANALYSIS: The E-REHAB trial aims to evaluate the efficacy and safety of RH-01 for home-based CR compared with traditional centre-based CR for patients with HF. This clinical trial will be conducted under a prospective, randomised, controlled and non-inferiority design with a primary focus on HF patients. Further, to assess the generalisability of the results in HF to other cardiovascular disease (CVD), the study will also include patients with other CVDs. The trial will enrol 108 patients with HF and 20 patients with other CVD. Eligible HF patients will be randomly assigned to either traditional centre-based CR or home-based CR in a 1:1 fashion. Patients with other CVDs will not be randomised, as safety assessment will be the primary focus. The intervention group will receive a 12-week programme conducted two or three times per week consisting of a remotely supervised home-based CR programme using RH-01, while the control group will receive a traditional centre-based CR programme. The primary endpoint of this trial is change in 6 min walk distance. ETHICS AND DISSEMINATION: The conduct of the study has been approved by an institutional review board at each participating site, and all patients will provide written informed consent before entry. The report of the study will be disseminated via scientific fora, including peer-reviewed publications and presentations at conferences. TRIAL REGISTRATION NUMBER: jRCT:2052200064.

Focal severe decrease in myocardial technetium-99 m sestamibi uptake indicates ventricular irreversibility in patients with dilated cardiomyopathy.

OBJECTIVE: Technetium-99 m sestamibi (99mTc-MIBI) scintigraphy can identify non-viable left ventricular (LV) myocardium. However, the optimal cut-off value and the details of decreased 99mTc-MIBI uptake of the non-viable LV myocardium in patients with dilated cardiomyopathy (DCM) have not been well established. This study aimed to evaluate the decrease in 99mTc-MIBI uptake in each segment and in the whole LV myocardium, and to determine cut-off values for identifying non-viable LV myocardium in DCM patients. METHODS: Overall, 53 DCM patients with reduced LV ejection fraction (LVEF ≤ 40%) who underwent 99mTc-MIBI scintigraphy and any optimization of heart failure treatments were evaluated. LV myocardium was classified as viable or non-viable based on the absolute increase in LVEF of ≥ 10% unit leading to an LVEF of > 40% at follow-up, respectively. The decrease in myocardial 99mTc-MIBI uptake in each of the 17 segments was evaluated using three indices determined by different thresholds or standard references: segmental %uptake, rest score, and defect extent. Changes in the whole LV myocardium were evaluated by the minimum %uptake, and the summed rest score (SRS) and extent of LV defect were obtained using summed data of 17 segments. RESULTS: Segmental evaluation indicated a mild decrease in 99mTc-MIBI uptake in 18 patients with viable LV myocardium, whereas focal severe decrease in uptake was observed in patients with non-viable LV myocardium. In the receiver-operating characteristic curve analysis, the cut-off values of minimum %uptake, SRS, and LV defect extent for predicting non-viable LV were 39% (p < 0.01, area under the curve [AUC]: 0.87), 10 (p < 0.01, AUC: 0.91), and 23% (p < 0.01, AUC: 0.92), respectively. CONCLUSIONS: In DCM patients, myocardial 99mTc-MIBI %uptake of < 40% indicated non-viable myocardium. The focal and severe decrease in uptake in approximately more than a quarter of the LV myocardium may indicate non-viable LV.

Diagnostic performance of coronary angiography utilizing intraprocedural 320-row computed tomography with minimal contrast medium.

Recently developed coronary angiography with intraprocedural 320-row computed tomography can be performed in a catheterization laboratory (XACT) by injecting contrast medium from a place close to the coronary arteries, thereby requiring a minimal amount of contrast medium. However, its clinical application has not yet been established. This study aimed to evaluate the diagnostic accuracy of XACT angiography with a minimal volume of contrast medium in patients with suspected coronary artery disease (CAD). A total of 167 coronary segments were analyzed in 14 patients (9 males, median age 70 years) with suspected CAD by XACT angiography with 7.5 ml of contrast medium and invasive coronary angiography (ICA) with standard techniques. The segmental-based diagnostic accuracy of XACT angiography in detecting stenosis of ≥ 50% and ≥ 75% and visualized by ICA was good (sensitivity: 74% and 62%, specificity: 99% and 99%, positive predictive value: 93% and 80%, and negative predictive value: 97% and 97%, respectively). These results suggest that XACT angiography with a very low amount of contrast medium may have strong clinical utility for screening coronary arteries in patients with renal dysfunction or undergoing clinical procedures such as pacemaker implantation.

Late gadolinium enhancement on cardiac magnetic resonance combined with 123I- metaiodobenzylguanidine scintigraphy strongly predicts long-term clinical outcome in patients with dilated cardiomyopathy.

Late gadolinium enhancement (LGE) on cardiac magnetic resonance (CMR) is limited in its ability to detect diffuse interstitial fibrosis, which is commonly found in idiopathic dilated cardiomyopathy (DCM). On the other hand, Washout rate (WR) by cardiac 123I- metaiodobenzylguanidine (123I-MIBG) scintigraphy which evaluates cardiac sympathetic nervous function, is a useful tool for predicting the prognosis in DCM. We investigated the predictive value of the combination of two different types of examinations, LGE on CMR and WR by 123I-MIBG scintigraphy for outcomes in DCM compared with LGE alone. One-hundred forty-eight DCM patients underwent CMR and 123I-MIBG scintigraphy. Patients were divided into 4 groups according to the presence or absence of LGE and WR cut-off value of 45% for predicting prognosis based on receiver operating characteristic curve analysis. Cardiac deaths, re-hospitalization for heart failure, implantation of a left ventricular assist device, and life-threatening ventricular arrhythmias were defined as clinical events. Forty-two DCM patients reached the clinical events during the median follow-up for 9.1 years (interquartile range, 8.0-9.2 years).Multivariable Cox regression analysis identified WR≥45%+LGE positive group as an independent predictor of cardiac events (HR 3.18, 95%CI 1.36-7.45, p = 0.008). Notably, there was no significance in the cardiac event-free survival rate between the WR<45%+LGE positive and WR≥45%+LGE negative groups (p = 0.89). The combination of WR by 123I-MIBG scintigraphy and LGE on CMR, which evaluate different type of cardiac deterioration, serves as a stronger predictor of long-term outcomes in DCM patients than LGE alone.

Improvement of left ventricular function assessment by global longitudinal strain after successful percutaneous coronary intervention for chronic total occlusion.

The benefit of revascularization of chronic total occlusion (CTO) in percutaneous coronary intervention (PCI) is controversial. On the other hand, left ventricular (LV) global longitudinal strain (GLS) is a more sensitive marker of LV myocardial ischemia and LV function than LV ejection fraction (EF). The purpose of this study was to investigate the impact of revascularization of CTO on LV function using LV GLS. A total of 70 consecutive patients (65.1±8.9 years, 59 males, LVEF 51.0±12.0%) with CTO who had a positive functional ischemia and underwent PCI, were included in this study. Echocardiography was performed before and 9 months after the procedure with conventional assessment including LV end-diastolic and end-systolic volume (LVEDV, LVESV), LVEF, and with 2DSTE analysis of GLS. Successful PCI was obtained in 60 patients (86%). There were no stent thromboses during follow-up. GLS showed a significant improvement 9 months after successful PCI (pre-PCI -12.4±4.1% vs. post-PCI -14.5±4.1%, P< 0.01), whereas in failed PCI group that did not change significantly (pre-PCI -13.2±4.2% vs. post-PCI -14.0±4.7%, P = 0.64). LVEF, LVEDV and LVESV did not change significantly during follow-up in both successful and failed groups. Successful PCI for CTO improved LV function, assessed by LV GLS.

Liver Stiffness Reflecting Right-Sided Filling Pressure Can Predict Adverse Outcomes in Patients With Heart Failure.

OBJECTIVES: This study sought to investigate whether elevated liver stiffness (LS) values at discharge reflect residual liver congestion and are associated with worse outcomes in patients with heart failure (HF). BACKGROUND: Transient elastography is a newly developed, noninvasive method for assessing LS, which can be highly reflective of right-sided filling pressure associated with passive liver congestion in patients with HF. METHODS: LS values were determined for 171 hospitalized patients with HF before discharge using a Fibroscan device. RESULTS: The median LS value was 5.6 kPa (interquartile range: 4.4 to 8.1 kPa; range 2.4 to 39.7 kPa) and that of right-sided filling pressure, which was estimated based on LS, was 5.7 mm Hg (interquartile range: 4.1 to 8.2 mm Hg; range 0.1 to 18.9 mm Hg). The patients in the highest LS tertile (>6.9 kPa, corresponding to an estimated right-sided filling pressure of >7.1 mm Hg) had advanced New York Heart Association functional class, high prevalence of jugular venous distention and moderate/severe tricuspid regurgitation, large inferior vena cava (IVC) diameter, low hemoglobin and hematocrit levels, high serum direct bilirubin level, and a similar left ventricular ejection fraction compared with the lower tertiles. During follow-up periods (median: 203 days), 8 (5%) deaths and 33 (19%) hospitalizations for HF were observed. The patients in the highest LS group had a significantly higher mortality rate and HF rehospitalization (hazard ratio: 3.57; 95% confidence interval: 1.93 to 6.83; p < 0.001) compared with the other tertiles. Although LS correlated with IVC diameter and serum direct bilirubin and brain natriuretic peptide levels, LS values were predictive of worse outcomes, even after adjustment for these indices. CONCLUSIONS: These data suggest that LS is a useful index for assessing systemic volume status and predicting the severity of HF, and that the presence of liver congestion at discharge is associated with worse outcomes in patients with HF.

Simple Electrocardiographic Score Can Predict Left Ventricular Reverse Remodeling in Patients With Non-Ischemic Cardiomyopathy.

Background: Left ventricular reverse remodeling (LVRR) is a favorable response in non-ischemic, non-valvular cardiomyopathy (NICM) patients. Recently, 18-lead body surface electrocardiography (ECG), the standard 12-lead ECG with synthesized right-sided/posterior chest leads, has been developed, but its predictive value for LVRR has not been evaluated. Methods and Results: Of 216 consecutive hospitalized NICM patients with LV ejection fraction (LVEF) ≤35%, we studied 125 who received optimization of their heart failure treatment and had 18-lead ECG and echocardiography data available for evaluating LVRR, defined as an absolute increase in LVEF ≥10% concomitant with LVEF ≥35% after 1-year optimized treatment. Most 18-lead ECG parameters in the NICM patients differed from those in 312 age- and body mass index-matched subjects with normal echocardiography. LVRR occurred in 59 NICM patients and they had a larger QRS amplitude in the limb leads (I, II, aVR, and aVF), precordial leads (V3-V6), and synthesized leads (syn-V4R-5R), decreased QRS axis and duration, and lower prevalence of fragmented QRS than those without LVRR. The ECG score using 3 selected parameters (QRS amplitude in aVR ≥675 µV; QRS duration <106 ms without fragmentation; and QRS axis <67°) was associated with the incidence of LVRR even after adjusting for optimized treatment. Conclusions: The standard 12-lead ECG parameters are sufficiently predictive of LVRR in NICM patients.

Ratio of pulmonary artery diameter to ascending aortic diameter and severity of heart failure.

BACKGROUND: Treatment decisions in dilated cardiomyopathy (DCM) patients with severe heart failure (HF) and short clinical history are challenging because of the difficulty of determining HF stage or prognosis in the acute HF phase. We hypothesized that persistent decreased systemic or increased pulmonary arterial pressure, including in the sub-clinical phase, might affect the main pulmonary artery diameter (PAD), ascending aortic diameter (AoD), and their ratio (PAD/AoD). This study assessed AoD, PAD, and PAD/AoD by non-contrast computed tomography scans in DCM patients in the acute phase of HF and examined the association of these parameters with their clinical course. METHODS: Of 261 screened individuals, we studied 110 consecutive hospitalized patients with DCM suspected of being in advanced stage of HF and 45 age-matched controls, assessing clinical data and later events (cardiac death or left ventricular assist device implantation). RESULTS: Compared with controls, DCM patients had smaller AoD (26.6 ± 4.4 vs 30.6 ± 2.7 mm) and larger PAD (27.7 ± 3.5 vs 25.4 ± 2.8 mm) and PAD/AoD (1.05 ± 0.14 vs 0.83 ± 0.08; all p < 0.01). DCM patients with high PAD/AoD (median, > 1.05) had more frequent past HF hospitalizations, lower blood pressure, stroke volume, and ejection fraction, higher brain natriuretic peptide levels, smaller AoD, and similar PAD compared with patients with a low PAD/AoD. A higher PAD/AoD was associated with poorer outcomes even after adjusting for age, blood pressure, ejection fraction, or number of hospitalizations. CONCLUSION: Assessment of AoD and PAD may have important clinical implications in determining whether DCM patients are in an advanced stage of HF with a poorer prognosis.

Non-Ischemic Heart Failure With Reduced Ejection Fraction Is Associated With Altered Intestinal Microbiota.

BACKGROUND: Research suggests that heart failure with reduced ejection fraction (HFrEF) is a state of systemic inflammation that may be triggered by microbial products passing into the bloodstream through a compromised intestinal barrier. However, whether the intestinal microbiota exhibits dysbiosis in HFrEF patients is largely unknown.Methods and Results:Twenty eight non-ischemic HFrEF patients and 19 healthy controls were assessed by 16S rRNA analysis of bacterial DNA extracted from stool samples. After processing of sequencing data, bacteria were taxonomically classified, diversity indices were used to examine microbial ecology, and relative abundances of common core genera were compared between groups. Furthermore, we predicted gene carriage for bacterial metabolic pathways and inferred microbial interaction networks on multiple taxonomic levels.Bacterial communities of both groups were dominated by the Firmicutes and Bacteroidetes phyla. The most abundant genus in both groups wasBacteroides. Although α diversity did not differ between groups, ordination by ß diversity metrics revealed a separation of the groups across components of variation.StreptococcusandVeillonellawere enriched in the common core microbiota of patients, whileSMB53was depleted. Gene families in amino acid, carbohydrate, vitamin, and xenobiotic metabolism showed significant differences between groups. Interaction networks revealed a higher degree of correlations between bacteria in patients. CONCLUSIONS: Non-ischemic HFrEF patients exhibited multidimensional differences in intestinal microbial communities compared with healthy subjects.

Longitudinal strain combined with delayed-enhancement magnetic resonance improves risk stratification in patients with dilated cardiomyopathy.

OBJECTIVE: Late gadolinium enhancement (LGE) on cardiac magnetic resonance (CMR) imaging has been reported to be associated with unfavourable outcomes; however, few studies have addressed the prognostic value of left ventricular (LV) deformation parameter indicated by global longitudinal strain (GLS) in two-dimensional speckle-tracking (2DST) echocardiography in patients with non-ischaemic dilated cardiomyopathy (DCM). This study aims to investigate whether the combination of GLS and LGE is useful in stratifying the risk in patients with DCM. METHODS: We studied 179 consecutive symptomatic patients with DCM (age, 61±15 years; 121 males; left ventricular ejection fraction (LVEF) 33%±9%; New York Heart Association (NYHA) class II: n=71, III: n=107, IV: n=1) who underwent CMR and echocardiography with conventional assessment and 2DST analysis. RESULTS: There were 40 rehospitalisations for heart failure, including 7 cardiac deaths and 2 implantations of LV assist device during follow-up (3.8±2.5 years). Univariable Cox proportional hazard regression analysis showed that NYHA class, blood pressure, B-type natriuretic peptide, LV end-diastolic and end-systolic volumes, LVEF, left atrium volume, GLS and LGE were significantly associated with long-term outcome. Multivariable analysis revealed that GLS and LGE were independently associated with long-term outcome (p<0.05, both). In additional analyses, we found independent associations between GLS and LV reverse remodelling after the optimal medical therapy, and between LGE and life-threatening arrhythmias (p<0.05, both). CONCLUSION: Combining GLS and LGE could be useful for risk stratification and prognostic assessment in patients with DCM.

Impact of esophageal temperature monitoring guided atrial fibrillation ablation on preventing asymptomatic excessive transmural injury.

BACKGROUND: Even with the use of a reduced energy setting (20-25 W), excessive transmural injury (ETI) following catheter ablation of atrial fibrillation (AF) is reported to develop in 10% of patients. However, the incidence of ETI depends on the pulmonary vein isolation (PVI) method and its esophageal temperature monitor setting. Data comparing the incidence of ETI following AF ablation with and without esophageal temperature monitoring (ETM) are still lacking. METHODS: This study was comprised of 160 patients with AF (54% paroxysmal, mean: 24.0±2.9 kg/m(2)). Eighty patients underwent ablation accompanied by ETM. The primary endpoint was defined as the occurrence of ETI assessed by endoscopy within 5 d after the AF ablation. The secondary endpoint was defined as AF recurrence after a single procedure. If the esophageal temperature probe registered >39 °C, the radiofrequency (RF) application was stopped immediately. RF applications could be performed in a point-by-point manner for a maximum of 20 s and 20 W. ETI was defined as any injury that resulted from AF ablation, including esophageal injury or periesophageal nerve injury (peri-ENI). RESULTS: The incidence of esophageal injury was significantly lower in patients whose AF ablation included ETM compared with patients without ETM (0 [0%] vs. 6 [7.5%], p=0.028), but not the incidence of peri-ENI (2 [2.5%] vs. 3 [3.8%], p=1.0). AF recurrence 12 months after the procedure was similar between the groups (20 [25%] in the ETM group vs. 19 [24%] in the non-ETM group, p=1.00). CONCLUSIONS: Catheter ablation using ETM may reduce the incidence of esophageal injury without increasing the incidence of AF recurrence but not the incidence of peri-ENI.

Usefulness of non-contrast-enhanced MRI with two-dimensional balanced steady-state free precession for the acquisition of the pulmonary venous and left atrial anatomy pre catheter ablation of atrial fibrillation: Comparison with contrast enhanced CT in clinical cases.

BACKGROUND: To investigate the feasibility of substituting non-contrast-enhanced MR (non-CE-MR) imaging with a two-dimensional (2D) balanced steady-state free precession (b-SSFP) sequence for contrast-enhanced computed tomography (CE-CT) for atrial fibrillation (AF) ablation. METHODS: Fifty-four patients that underwent AF ablation under the guidance of a 3D electro-anatomical mapping system with CE-CT (n = 27) or non-CE-MR images (n = 27) were studied. Procedural results were compared between the two groups. Furthermore, in 22 patients who underwent both CE-CT and non-CE-MRI, two cardiologists independently scored the multiplanar reformatted images on a scale of 1 to 4 (from 1, poor, to 4, excellent). RESULTS: The image score was nearly 0.5 point higher with the CE-CT method. However, the procedural results such as the surface registration error (1.0 [0.8-1.6] mm versus 1.0 [0.8-1.35] mm, P = 0.88) and procedure time (185 [159-199] min versus 185 [142-221] min, P = 0.86) did not significantly differ between the CE-CT and non-CE-MR groups. CONCLUSION: The non-CE-MR method with a 2D-b-SSFP sequence can give us adequate information on AF ablation without any radiation exposure or contrast medium usage

Incidence of esophageal injury after pulmonary vein isolation in patients with a low body mass index and esophageal temperature monitoring at a 39 °C setting.

BACKGROUND: Esophageal injury following catheter ablation of atrial fibrillation (AF) is reported to occur in 35% of patients. Even with a low energy setting (20-25 W), lesions develop in 10% of patients. Body mass index (BMI) has been reported to be a predictor of esophageal injury, indicating that patients with a low BMI (<24.9 kg/m(2)) are at a higher risk. We hypothesized that catheter ablation with a lower energy setting of 20 W controlled by esophageal temperature monitoring (ETM) at 39 °C could prevent esophageal injury even in patients with a BMI <24.9 kg/m(2). METHODS: Twenty patients with AF were included (age, 63±8 years; BMI, 22.9±1.3 kg/m(2), left atrium diameter, 44±11 mm). If the esophageal temperature probe registered a temperature of >39 °C, radiofrequency (RF) application was stopped immediately. RF application could be performed in a "point by point" manner for a maximum of 20 s. Endoscopy was performed 1-5 days after ablation. RESULTS: Esophageal mucosal injury was not observed in any patient in the study. CONCLUSIONS: Catheter ablation using ETM reduced the incidence of esophageal injuries, even in patients with a low BMI.

Visualizing radiofrequency lesions using delayed-enhancement magnetic resonance imaging in patients with atrial fibrillation: A modification of the method used by the University of Utah group.

BACKGROUND: Atrial tissue fibrosis has previously been identified using delayed-enhancement MRI (DE-MRI) in patients with atrial fibrillation (AF). Although the clinical importance of DE-MRI is well recognized, the visualization of atrial fibrosis and radiofrequency (RF) lesions has still not been achieved in Japan, primarily because of the differences in contrast agents, volume-rendering tools, and technical experience. The objective of this study was to visualize RF lesions by using commercially available tools. METHODS: DE-MRI was performed in 15 patients who had undergone AF ablation (age, 59±4 years, left atrium diameter, 40±2 mm). Specific parameters for MR scanning obtained from previous reports were modified. RESULTS: Of the 15 images, the images of three patients were uninterpretable owing to low image quality. RF lesions could be visualized in 8 (67%) of the 12 patients. CONCLUSIONS: In the current study, we successfully demonstrated that RF lesions could be visualized in Japanese patients using DE-MRI, although only commercially available tools were used.

Visualization of the radiofrequency lesion after pulmonary vein isolation using delayed enhancement magnetic resonance imaging fused with magnetic resonance angiography.

BACKGROUND: The radiofrequency (RF) lesions for atrial fibrillation (AF) ablation can be visualized by delayed enhancement magnetic resonance imaging (DE-MRI). However, the quality of anatomical information provided by DE-MRI is not adequate due to its spatial resolution. In contrast, magnetic resonance angiography (MRA) provides similar information regarding the left atrium (LA) and pulmonary veins (PVs) as computed tomography angiography. We hypothesized that DE-MRI fused with MRA will compensate for the inadequate image quality provided by DE-MRI. METHODS: DE-MRI and MRA were performed in 18 patients who underwent AF ablation (age, 60±9 years; LA diameter, 42±6 mm). Two observers independently assessed the DE-MRI and DE-MRI fused with MRA for visualization of the RF lesion (score 0-2; where 0: not visualized and 2: excellent in all 14 segments of the circular RF lesion). RESULTS: DE-MRI fused with MRA was successfully performed in all patients. The image quality score was significantly higher in DE-MRI fused with MRA compared to DE-MRI alone (observer 1: 22 (18, 25) vs 28 (28, 28), p<0.001; observer 2: 24 (23, 25) vs 28 (28, 28), p<0.001). CONCLUSIONS: DE-MRI fused with MRA was superior to DE-MRI for visualization of the RF lesion owing to the precise information on LA and PV anatomy provided by DE-MRI.

Acquisition of the pulmonary venous and left atrial anatomy with non-contrast-enhanced MRI for catheter ablation of atrial fibrillation: Usefulness of two-dimensional balanced steady-state free precession.

BACKGROUND: Usually, the pulmonary venous and left atrial (PV-LA) anatomy is assessed with contrast-enhanced computed tomographic imaging for catheter ablation of atrial fibrillation (AF). A non-contrast-enhanced magnetic resonance (MR) imaging method has not been established. Three-dimensional balanced steady-state free precession (3D b-SSFP) sequences cannot visualize the PV-LA anatomy simultaneously because of the signal intensity defect of pulmonary veins. We compared two-dimensional (2D) b-SSFP sequences with 3D b-SSFP sequences in depicting the PV-LA anatomy with non-contrast-enhanced MR imaging for AF ablation. METHODS: Eleven healthy volunteers underwent non-contrast-enhanced MR imaging with 3D b-SSFP and 2D b-SSFP sequences. The MR images were reconstructed on the 3D PV-LA surface image. Two experienced radiological technicians independently scored the multiplanar reformatted (MPR) images on a scale of 1-4 (from 1, not visualized, to 4, excellent definition). The overall score was a sum of 5 segments (LA and 4 PVs). RESULTS: In the 2D b-SSFP method, MR imaging was successfully performed, and the 3D PV-LA surface image was precisely reconstructed in all healthy volunteers. The image score was significantly higher in the 2D b-SSFP method compared to the 3D b-SSFP method (19 [19; 20] vs. 12 [11; 15], p=0.004, for both observers). No PV signal intensity defects occurred in the 2D b-SSFP method. CONCLUSIONS: The 2D b-SSFP sequence was more useful than the 3D b-SSFP sequence in adequately depicting the PV-LA anatomy.