The coronary artery calcium score correlates with left atrial low-voltage area: Sex differences.

INTRODUCTION: In patients with coronary artery disease, a high coronary artery calcium score (CACS) correlates with atrial fibrillation (AF); however, the association between left atrial (LA) remodeling progression and coronary arteriosclerosis is unclear. This study aimed to evaluate the relationship between LA remodeling progression and the CACS. METHODS: This retrospective study enrolled 148 patients with AF (paroxysmal AF, n = 94) who underwent catheter ablation. Voltage mapping for the left atrium and coronary computed tomography for CACS calculations were performed. The ratio of the LA low-voltage area (LA-LVA), defined by values less than 0.5 mV divided by the total LA surface without pulmonary veins, was calculated. Patients with LA-LVA (<0.5 mV) >5% and ≤5% were classified as the LVA (n = 30) and non-LVA (n = 118) groups, respectively. Patient characteristics and CACS values were compared between the two groups. RESULTS: LA volume, age, CHA2 DS2 VASc score, and percentage of female patients were significantly higher, and the estimated glomerular filtration rate was lower in the LVA group than in the non-LVA group. The CACS was significantly higher in the LVA group (248.4 vs. 13.2; p = .001). Multivariate analysis identified the LA volume index and CACS as independent predictors of LA-LVA (<0.5 mV) greater than 5%. The areas under the receiver operating characteristic curves for predicting LA-LVA (<0.5 mV) greater than 5% with CACS were 0.695 in the entire population, 0.782 in men, and 0.587 in women. CONCLUSION: Progression of LA remodeling and coronary artery calcification may occur in parallel. A high CACS may indicate advanced LA remodeling, especially in men.

Conduction slowing area during sinus rhythm harbors ventricular tachycardia isthmus.

INTRODUCTION: The voltage map during sinus rhythm (SR) is a cornerstone of substrate mapping (SM) in scar-related ventricular tachycardia (VT) and frequently used with pace mapping (PM). Where to conduct PM is unclear in cases of an extensive or unidentified substrate. Conduction properties are another aspect incorporated by SM, and conduction slowing has gained interest as being related to successful ablation, although its mechanism has not been elucidated. We aimed to investigate the relationship between SR conduction properties and VT isthmuses. METHODS: Nineteen patients (mean age, 62 years) who underwent VT ablation with voltage mapping and PM were reviewed. Isochronal late activation maps (ILAMs) with eight zones were reconstructed and sequentially named from one to eight according to the SR propagation. Good PM sites were superimposed on ILAMs, and the isthmus was defined using different pacing latencies. ILAM properties harboring isthmuses were investigated. RESULTS: Twenty-eight ILAMs (13 epicardium, 1 right ventricular [RV], and 14 left ventricular [LV] endocardium) were reviewed. Eighteen isthmuses of 24 target VTs were identified, in which the proximal ends were in a later zone than the distal ends (zone 6 vs 4; P < .001), suggesting a reverse isthmus vector to the SR. The conduction velocity of the zone involving the distal isthmus was significantly lower than that of the SR preceding zone (0.40 vs 1.30 m/s; P < .001). SR conduction velocity decelerated by 69.5% (range 59.7%-74.5%) before propagating into the isthmus area. CONCLUSION: Conduction slowing area during SR were related with the exit portion of the VT isthmuses.

Characteristics of ventricular intracardiac electrograms of ventricular tachycardias originating from the epicardia in patients with an implantable cardioverter defibrillator.

INTRODUCTION: While characteristic waveforms of 12-lead electrocardiograms have been reported to predict the epicardial origin of ventricular tachycardia (VT), it has not been fully examined whether ventricular intracardiac electrograms (VEGMs) recorded from the implantable cardioverter defibrillator (ICD) via telemetry can determine the origin of VT or not. The aim of this study was to investigate the VEGM characteristics of VT originating from the epicardia. METHOD AND RESULTS: Intracardiac VEGMs of the induced VTs, with detected sites of origin during the VT study, were recorded in 15 (23 VTs) of the 46 patients. The characteristics of the 23 VTs were evaluated using far-field and near-field VEGMs recorded via telemetry. Five of 23 VTs were found to be focused on the epicardial site (epi group) and 18 VTs were focused on the endocardium (endo group). VTs of the epi group had longer VEGM duration in far-field EGM than those of the endo group (epi group: 240 ± 49 ms vs endo group: 153 ± 45 ms; P = 0.002) and the duration from the onset to the peak of VEGM was also longer than that of the endo group (epi group: 153 ± 53 ms vs endo group: 63 ± 28 ms; P < 0.001). There was no difference in the V wave duration in tip-ring EGM between both groups (epi group: 122 ± 52 ms vs endo group: 98 ± 6 ms; P = 0.377). CONCLUSION: Evaluation of intracardiac VEGM before VT ablation may be helpful to predict the epicardial origin of VT in patients with an ICD.

The relationship between obstructive sleep apnea and recurrence of atrial fibrillation after pulmonary vein isolation using a contact force-sensing catheter.

PURPOSE: Our aim was to elucidate the relationship between obstructive sleep apnea (OSA) and atrial fibrillation (AF) recurrence after repeated pulmonary vein isolation (PVI). METHODS: We conducted a non-randomized observational study, with the data prospectively collected. One hundred patients (paroxysmal AF, n = 89) underwent PVI using a contact force-sensing catheter. All patients underwent an electrophysiological study and additional ablation for left atrium-pulmonary vein (PV) reconnection and non-PV foci, 6 months after the first treatment session, regardless of AF recurrence. Those with an apnea-hypopnea index ≥ 15 were diagnosed with OSA. Continuous positive air pressure (CPAP) therapy was initiated after the second treatment session, based on results of a sleep study. For analysis, patients were classified into the non-OSA (n = 66), treated OSA (OSA patients undergoing CPAP; n = 11), and untreated OSA (n = 23) groups, and between-group differences evaluated. RESULTS: After the first session, AF recurrence was observed in 18.2% (12/66) and 14.7% (5/34) of patients without and with OSA, respectively (P = 0.678). After the second procedure, the rate of AF recurrence was 12.1% (8/66) in the non-OSA group, 9.1% (1/11) in the treated OSA group, and 8.7% (2/23) in the untreated OSA group (log-rank P = 0.944). CONCLUSIONS: The rate of AF recurrence might not be greater in patients with untreated OSA than in those without OSA and those with treated OSA after repeated PVI, using a contact force-sensing catheter, for patients with paroxysmal or short-term persistent AF.

Macroreentrant atrial tachycardia detouring the epicardium at the anterior wall of the left atrium.

A 79-year-old woman with a history of pulmonary vein isolation for persistent atrial fibrillation was admitted for recurrence of atrial tachycardia, with a tachycardia cycle length of 236 milliseconds. The ultra-high-resolution mapping system revealed that tachycardia circuit detouring the epicardium at the anterior wall scar and breaking through to the endocardium below the left atrial appendage. Radiofrequency energy was applied to this site, which successfully terminated the tachycardia. This case suggests that epicardial conduction could occur even at the left atrial anterior wall and identifies a variation in epicardial conduction around the left atrium, which could be a tachycardia circuit.

Radiofrequency Catheter Ablation of Ventricular Tachycardia in Patients With Hypertrophic Cardiomyopathy and Apical Aneurysm.

OBJECTIVES: This study evaluated the characteristics and results of radiofrequency catheter ablation (RFCA) of ventricular tachycardia (VT) in patients with hypertrophic cardiomyopathy (HCM) and left ventricular apical aneurysm (AA). BACKGROUND: Monomorphic VT in patients with HCM and left ventricular AA has been reported. However, outcome data of RFCA are insufficient. METHODS: Fifteen patients with HCM and AA who underwent RFCA for VT at 5 different institutions were included in this study. The data were evaluated retrospectively. RESULTS: Endocardial voltage mapping showed a low-voltage area (LVA), and late potential in the AA was recorded in 12 patients (80%). Although epicardial or intramural origin of VT was suspected in 7 patients, endocardial RFCA successfully suppressed the VT at the LVA border (n = 10) or within the LVA (n = 2). In 2 of 3 patients without LVA at the endocardial site, linear RFCA at the anterior wall of the aneurysmal neck side was successful. In the remaining patient, endocardial RFCA of AA was not effective, and epicardial RFCA site was needed. In all patients, clinical VT became noninducible after RFCA. VT recurrence was observed in 2 patients (13.3%) during the 12-month follow-up period. One patient underwent a second endocardial RFCA, and no VT recurrence was noted. In the other patient, VT recurred 3 months after RFCA and was successfully terminated by antitachycardia pacing of the implantable cardioverter-defibrillator. CONCLUSIONS: In patients with HCM and AA, endocardial RFCA of AA effectively suppressed monomorphic VT which was related to AA and resulted in satisfactory outcomes.

Usefulness of epicardial impedance evaluation for epicardial mapping and determination of epicardial ablation site for ventricular tachycardia: A pilot study.

BACKGROUND: During epicardial mapping, determination of appropriate ablation sites in low voltage areas (LVA) is challenging because of large epicardial areas covered by adipose tissue. OBJECTIVE: To evaluate the impedance difference between epicardial fat and the epicardial LVA using multiple detector computed tomography (MDCT). METHODS: We enrolled patients who underwent ventricular tachycardia (VT) ablation via the epicardial approach after endocardial ablation failure. After the procedure, MDCT-derived images of epicardial fat were loaded to the mapping system. Then, all points acquired during sinus rhythm were retrospectively superimposed and analyzed. RESULTS: This study included data from 7 patients (62.5 ± 3.9 years old) who underwent eight epicardial VT ablation procedures. After the procedure, MDCT-derived images of epicardial fat were registered in eight procedures. Retrospective analysis of 1,595 mapping and 236 ablation points was performed. Of the 1,595 mapping points on the merged electroanatomical and epicardial fat maps, normal voltage area (NVA) and low voltage area (LVA) without fat had lower impedance than those with fat (NVA without fat 182 ± 46 Ω vs. NVA with fat 321 ± 164.0 Ω, P  =  0.001, LVA without fat 164 ± 69 Ω vs. LVA with fat 248 ± 89 Ω, P  =  0.002). Of the 236 ablation points, initial impedance before ablation was higher on epicardial fat than on epicardial LVA without fat (134 ± 16 Ω vs. 156 ± 28 Ω, P  =  0.01). CONCLUSIONS: Real time epicardial impedance evaluation may be useful to determine effective epicardial ablation sites and avoid adipose tissue. However, the number of patients in the present study is limited. Further investigation with a large number of patients is needed to confirm our result.

The radio frequency catheter ablation of inter-fascicular reentrant tachycardia: new insights into the electrophysiological and anatomical characteristics.

INTRODUCTION: Macro-reentrant ventricular tachycardias (VT) utilizing the bundle branches and Purkinje fibers have been reported as verapamil sensitive VT (idiopathic left VT), bundle branch reentrant VT (BBRT) and inter-fascicular reentrant tachycardia (inter-fascicular VT). However, diagnostic confusion exists with these VTs due to the difficulty in differentiating between them with conventional electrophysiological (EP) studies. The aim of this study was to clarify the EP and anatomical entity of inter-fascicular VT, and provide successful methods for the radio frequency catheter ablation (RFCA) of inter-fascicular VT. METHODS AND RESULTS: A total of nine patients were included in this study. All patients were diagnosed with idiopathic left VT in the first session, and underwent a second session after a failed RFCA. Detailed EP studies guided by a three-dimensional (3D) mapping system were performed to further analyze the VTs. All VTs were finally diagnosed as inter-fascicular VT. They were successfully cured with RFCA targeting the left anterior or posterior fascicle, which was regarded as a requisite part of the reentrant circuit of the inter-fascicular VT, using 3D and fluoroscopic images combined with a detailed EP investigation instead of the conventional RFCA method targeting Purkinje potentials for the RFCA of idiopathic left VT. CONCLUSIONS: Inter-fascicular VT could be misdiagnosed as idiopathic left VT due to the limitations of the conventional EP study. Failed RFCA in presumptive idiopathic left VT cases has to be carefully investigated by further analysis, and a tailored RFCA strategy targeting the requisite portions of the left fascicles in the inter-fascicular VT reentrant circuit will be required for the successful elimination of the inter-fascicular VT.

Ablation of swallowing-induced atrial tachycardia affects heart rate variability: a case report.

A 47-year-old man underwent slow pathway ablation for slow-fast atrioventricular nodal reentrant tachycardia. Following the procedure, he felt palpitations while swallowing, and swallowing-induced atrial tachycardia was diagnosed. Swallowing-induced atrial tachycardia arose from the right atrium-superior vena cava junction and was cured by catheter ablation. After the procedure, the patient's heart rate variability changed significantly, indicating suppression of parasympathetic nerve activity. In this case, swallowing-induced atrial tachycardia was related to the vagal nerve reflex. Analysis of heart rate variability may be helpful in elucidating the mechanism of swallowing-induced atrial tachycardia.

Prevalence and electrophysiological characteristics of typical atrial flutter in patients with atrial fibrillation and chronic obstructive pulmonary disease.

AIMS: Chronic obstructive pulmonary disease (COPD) is one of the important underlying diseases of atrial fibrillation (AF). However, the prevalence and electrophysiological characteristics of typical atrial flutter (AFL) in patients with AF and COPD remain unknown. The purpose of the present study was to investigate those characteristics. METHODS AND RESULTS: We investigated 181 consecutive patients who underwent catheter ablation of AF. Twenty-eight patients were diagnosed with COPD according to the Global Initiatives for Chronic Obstructive Lung Disease (GOLD) criteria. Forty patients with no lung disease served as a control group. We analysed the electrophysiological characteristics in these groups. Typical AFL was more common in the COPD group (19/28, 68%) than in the non-COPD group (13/40, 33%; P = 0.006). The prevalence of AFL increased with the severity of COPD: 4 (50%) of 8 patients with GOLD1, 13 (72%) of 18 patients with GOLD2, and 2 (100%) of 2 patients with GOLD3. Atrial flutter cycle length and conduction time from the coronary sinus (CS) ostium to the low lateral right atrium (RA) during CS ostium pacing before and after the cavotricuspid isthmus ablation were significantly longer in the COPD group than in the non-COPD group (285 vs. 236, 71 vs. 53, 164 vs. 134 ms; P = 0.009, 0.03, 0.002, respectively). CONCLUSION: In COPD patients with AF, conduction time of RA was prolonged and typical AFL was commonly observed.

Prophylactic catheter ablation for induced monomorphic ventricular tachycardia in patients with implantable cardioverter defibrillators as primary prevention.

AIMS: Prophylactic catheter ablation (CA) has been established to reduce the incidence of appropriate implantable cardioverter-defibrillator (ICD) therapy (anti-tachycardia pacing or shock) in secondary prevention patients. The aim of this study was to determine whether prophylactic CA for induced ventricular tachycardia (VT) reduces the incidence of appropriate ICD therapy in primary prevention patients. METHODS AND RESULTS: We retrospectively investigated 66 consecutive patients with structural heart disease who had undergone ICD implantation as primary prevention and electrophysiological study. Patients with hypertrophic cardiomyopathy or no inducible monomorphic VT had been excluded, and the remaining 38 patients were divided into two groups; those who had undergone prophylactic CA for induced monomorphic VT (the CA group, n = 18), and those who had not undergone CA (the non-CA group, n = 20). During a mean follow-up of 50 ± 38 months, 1 patient (5%) received appropriate ICD therapy in the CA group and 13 (65%) in the non-CA group. Kaplan-Meier survival analysis revealed a significantly higher event-free survival rates for appropriate ICD therapy in the CA group compared with the non-CA group (P = 0.003). Among the patients, one patient (5%) in the CA group and nine patients (45%) in the non-CA group suffered appropriate shock (P = 0.018). CONCLUSIONS: Prophylactic CA for induced monomorphic VT reduces the incidence of appropriate ICD therapy including shock in primary prevention patients. These results indicate that prophylactic CA may be considered for structural heart disease patients who are candidates for ICD implantation as primary prevention.

Macroreentrant atrial tachycardia in patients without previous atrial surgery or catheter ablation: clinical and electrophysiological characteristics of scar-related left atrial anterior wall reentry.

INTRODUCTION: Macroreentrant atrial tachycardia (MRAT) has been described most frequently in patients with prior cardiac surgery. Left atrial tachycardia and flutter are common in patients who undergo atrial fibrillation ablation; however, few reports describe left atrial MRAT involving the regions of spontaneous scarring. Here, we describe left atrial MRAT in patients without prior cardiac surgery or catheter ablation (CA) and discuss the clinical and electrophysiological characteristics of tachycardia and outcome of CA. METHODS AND RESULTS: An electrophysiological study and CA were performed in 6 patients (3 men; age 76 ± 6 years) with MRAT originating from the left atrial anterior wall (LAAW). No patient had a history of cardiac surgery or CA in the left atrium. Spontaneous scars (areas with bipolar voltage ≤ 0.05 mV) were observed in all patients. The activation map showed a figure-eight circuit with loops around the mitral annulus (4 counterclockwise and 2 clockwise) and a low-voltage area with LAAW scarring. The mean tachycardia cycle length was 303 ± 49 milliseconds. The conduction velocity was significantly slower in the isthmus between the scar in the LAAW and the mitral annulus than in the lateral mitral annulus (0.17 ± 0.05 m/s vs 0.94 ± 0.35 m/s; P = 0.003). Successful ablation of the isthmus caused interruption of the tachycardia and rendered it noninducible in all patients. CONCLUSION: Spontaneous LAAW scarring is an unusual cause of MRAT, showing activation patterns with a figure-eight configuration. Radiofrequency CA is a feasible and effective treatment in such cases.

Clinical and electrophysiological characteristics in patients with sustained monomorphic reentrant ventricular tachycardia associated with dilated-phase hypertrophic cardiomyopathy.

AIMS: Little is known about sustained monomorphic ventricular tachycardia (SMVT) associated with dilated-phase hypertrophic cardiomyopathy (DHCM). The purpose of this study was to clarify the clinical characteristics and effectiveness of catheter ablation for SMVTs in DHCM patients. METHODS AND RESULTS: Five patients with DHCM (mean age; 67.0 years old, five males) who underwent catheter ablation for drug-refractory SMVTs were included the study. Four of five patients suffered from electrical storm. When the endocardial ablation failed, epicardial and/or intracoronary ethanol ablation, or surgical cryoablation was performed. We reviewed all ablation procedures and electrocardiogram (ECG) of targeted SMVTs. A total of 13 SMVTs were targeted for ablation. Mechanism of all ventricular tachycardias (VTs) was diagnosed as reentry. Endocardial ablation successfully eliminated all VTs in two patients. The remaining three patients needed epicardial ablation, intracoronary ethanol ablation, and surgical cryoablation. All but one VT arose from the basal septum, basal anterior to anterolateral left ventricle (LV). Although the ECGs demonstrated similar features of idiopathic outflow or mitral annulus VTs reflecting the origins, there were characteristic multiple QRS deflections. Following the ablation, four (80%) of the five patients are free from VT recurrence during 18 months of the follow-up period. CONCLUSIONS: In DHCM patients, VT circuits predominantly distributed in the basal septum and the basal anterior to anterolateral LV. In addition to the endocardial ablation, alternative approaches were required in some patients.