The relationship between the incision line and position of the latissimus dorsi muscle for subcutaneous implantable cardioverter-defibrillator intermuscular implantations.

INTRODUCTION: Intermuscular implantations of subcutaneous implantable cardioverter-defibrillators (S-ICD) have been recommended, but the position of the anterior border of the latissimus dorsi muscle (LDM) has not previously been evaluated in establishing an incision line to facilitate the intermuscular approach. The objective of this study is to evalua the position and trend of the anterior border of the LDM in patients who are candidates for implantable cardioverter-defibrillators. METHODS: The distance from the back to the anterior border of the LDM (A) and the anterior-posterior width of the chest wall (B) were measured on computed tomography retrospectively, and the ratio (=A/B) was used as the position of the anterior border of the LDM. In addition, the variability and factors affecting the values were evaluated. RESULTS: An analysis was performed on 78 patients, and the position of the anterior border of the LDM (=A/B) exhibited a normal distribution, with a mean value of 0.53 ± 0.062 (0.41-0.69). The position of the anterior border of the LDM tended to be more anterior in younger, taller, male, primary prevention, nonheart failure, low brain natriuretic peptide level, and nondiabetic patients. CONCLUSION: The position of the anterior border of the LDM varied from case to case with variable results. Conventional incisions on the midaxillary line may be inappropriate for intermuscular implantations, and the position of the anterior border of the LDM should be evaluated in each individual case to establish the incision line.

The impact of the procedural parameters on the lesion characteristics associated with AF recurrence: Late-gadolinium enhancement magnetic resonance imaging (LGE-MRI) analysis.

BACKGROUND: Lesion gaps assessed by late-gadolinium enhancement magnetic resonance imaging (LGE-MRI) are associated with the atrial fibrillation (AF) recurrence after pulmonary vein isolation. Animal studies have demonstrated that the catheter-contact force (CF), stability, and orientation are strongly associated with lesion formation. However, the impact of those procedural factors on the lesion characteristics associated with AF recurrence has not been well discussed. METHODS: A total of 30 patients with paroxysmal AF who underwent catheter ablation were retrospectively enrolled. Radiofrequency (RF) applications were performed with 35 W for 30 s in a point-by-point fashion under esophageal temperature monitoring. The inter-lesion distance was 4 mm. The lesions were visualized by LGE-MRI 3 months postprocedure and assessed by the LGE volume (ml), gap number (GN), and average gap length (AGL [mm]). The gaps were defined as nonenhancement sites of >4 mm. The procedural factors including the catheter-CF, stability, and orientation were calculated on the NavX system. RESULTS: Six (20%) of 30 patients had AF recurrences 12 months postablation. A univariate analysis demonstrated that the AGL was associated with AF recurrence (hazard ratio [HR]: 1.20, confidence interval [CI]: 1.03-1.42, p = .02). All AF recurrence were found in patients with an AGL of >7 mm. The catheter-CF and stability were associated with an AGL of >7 mm, but not the orientation (CF-HR: 0.62, CI: 0.39-0.97, p = .038; stability-HR: 0.8, CI: 0.66-0.98, p = .027). CONCLUSIONS: RF ablation with a low CF and poor catheter stability has a potential risk of creating large lesion gaps associated with AF recurrence.

Factors related to the skin thickness of cardiovascular implantable electronic device pockets.

INTRODUCTION: The skin overlying cardiovascular implantable electronic devices (CIEDs) sometimes becomes very thin after implantations, which could cause a device erosion. The factors related to the skin thickness of device pockets have not been elucidated. This study aimed to evaluate the skin thickness of CIED pockets and search for the factors associated with the thickness. METHODS: Seventeen skin thickness points around the CIED pocket were measured through ultrasonography in each patient. RESULTS: A total of 101 patients (76 ± 11 years, 26 female) were enrolled. The median duration from the implantation to the examination was 95 months (quartile: 52.5-147.5). The median skin thickness overlying the device was 4.1 mm (3.3-5.9). Patients with heart failure and malignancy had thinner skin overlying the CIED than those without. A significant correlation existed between skin thickness and body mass index (BMI), hemoglobin, serum creatinine, estimated glomerular filtration rate (eGFR), and left ventricular ejection fraction. In contrast, age, gender, and device size did not exhibit a significant correlation with skin thickness. A multivariate logistic regression analysis revealed that chronic heart failure and a decrease in the eGFR and BMI were independent predictive factors of "very thin (≦3.3 mm)" skin of the CIED pocket late after an implantation. CONCLUSION: Aside from a low BMI, the comorbidities (low hemoglobin, heart failure, and renal dysfunction) had a stronger impact on the skin thickness overlying the device than the device size. A careful observation of the device pocket should be performed in patients with those risk factors.

Sex Differences in the Regional Analysis of Nonpulmonary Vein Foci and Epicardial Adipose Tissue in Patients With Atrial Fibrillation.

BACKGROUND: The mechanism underlying the sex differences in atrial fibrillation (AF) recurrence following pulmonary vein (PV) isolation is not fully understood. We hypothesized that non-PV foci and epicardial adipose tissue (EAT) play a key role.Methods and Results: Data from 304 consecutive patients (75% males) who underwent contrast-enhanced computed tomography and catheter ablation of AF were reviewed. The EAT around the atrium was measured separately in 4 parts of the atrium. All patients underwent high-dose isoproterenol infusions to assess the non-PV foci. Significantly more non-PV foci and less EAT around the atrium were observed in female patients than in male patients. In males, those with non-PV foci on the left atrial (LA) anterior wall had significantly greater EAT for the same lesions than those without non-PV foci. During a median follow-up of 27 months, the predictors of AF recurrence after first catheter ablation were female sex, presence of non-PV foci, LA diameter, and septal EAT index. A sex-specific analysis revealed that LA diameter was a predictor only in males and that the presence of non-PV foci in the septal region was a strong predictor in males (hazard ratio [HR]: 2.24) and females (HR: 3.65). CONCLUSIONS: Sex-specific differences were observed in non-PV foci sites and local EAT and in regard to the predictors of AF recurrence.

Development of a Visualization Deep Learning Model for Classifying Origins of Ventricular Arrhythmias.

BACKGROUND: Several algorithms have been proposed for differentiating the right and left outflow tracts (RVOT/LVOT) arrhythmia origins from 12-lead electrocardiograms (ECGs); however, the procedure is complicated. A deep learning (DL) model, a form of artificial intelligence, can directly use ECGs and depict the importance of the leads and waveforms. This study aimed to create a visualized DL model that could classify arrhythmia origins more accurately.Methods and Results: This study enrolled 80 patients who underwent catheter ablation. A convolutional neural network-based model that could classify arrhythmia origins with 12-lead ECGs and visualize the leads that contributed to the diagnosis using a gradient-weighted class activation mapping method was developed. The average prediction results of the origins by the DL model were 89.4% (88.2-90.6) for accuracy and 95.2% (94.3-96.2) for recall, which were significantly better than when a conventional algorithm is used. The ratio of the contribution to the prediction differed between RVOT and LVOT origins. Although leads V1 to V3 and the limb leads had a focused balance in the LVOT group, the contribution ratio of leads aVR, aVL, and aVF was higher in the RVOT group. CONCLUSIONS: This study diagnosed the arrhythmia origins more accurately than the conventional algorithm, and clarified which part of the 12-lead waveforms contributed to the diagnosis. The visualized DL model was convincing and may play a role in understanding the pathogenesis of arrhythmias.

Predictors of recurrence in patients without non-inducibility of ventricular tachycardia at the end of ablation.

Background: Ventricular tachycardia (VT) non-inducibility at the end of ablation is associated with a less likely VT recurrence. However, it is not clear whether we should use VT non-inducibility as a routine end point of VT ablation. The aim of this study was to evaluate VT recurrence in patients in whom VT non-inducibility was not achieved at the end of the radiofrequency (RF) ablation and the factors attributing to the VT recurrence. Methods: We analyzed that 62 patients in whom VT non-inducibility was not achieved at the end of the RF ablation were studied. Results: Over 2 years, 22 (35%) of the cases had VT recurrences. A multivariate analysis showed that an LVEF ≥35% (HR: 0.19; 95% CI: 0.06-0.49; p < .01) and elimination of the clinical VT as an acute ablation efficacy (HR: 0.23; 95% CI: 0.04-0.81; p = .02) were independent predictors of fewer VT recurrences. RF ablation was associated with a 91.1% reduction in VT episodes. Conclusion: Even if VT non-inducibility was not achieved, patients with an LVEF ≥35% or in whom the clinical VT could be eliminated might be prevented from having VT recurrences. The validity of the VT non-inducibility of any VT should be evaluated considering each patient's background and the results of the procedure.

Telehealth Follow-up Using a Real-Time Electrocardiogram Device Improves Electrocardiogram Monitoring Duration and Patient Satisfaction After Catheter Ablation.

Background: There is a strong demand for remote monitoring systems to gather health data. This study investigated the safety, usefulness, and patient satisfaction in outpatient care using telehealth with real-time electrocardiogram (ECG) monitoring after catheter ablation. Methods and Results: In all, 38 patients who underwent catheter ablation were followed up using telehealth. At the 3- and 6-month follow-up, a self-fitted Duranta ECG monitoring device was sent to the patient's home before the online consultation. Patients attached the devices themselves, and the doctors viewed the patients by video chat and performed real-time ECG monitoring. The frequency of hospital visits and the ECG monitoring duration were compared with conventional in-person follow-up data (n=102). The completion rate for telehealth follow-up was 32 of 38 patients (84%). The number of hospital visits during the 6 months was significantly lower with telehealth follow-up than with conventional follow-up (median [interquartile range] 1 [1-1] vs. 5 [3-5]; P<0.0001). However, the ECG monitoring duration was approximately 4-fold longer for the telehealth follow-up (median [interquartile range] 89 [64-117] vs. 24 [0.1-24] h; P<0.0001). No major adverse events were observed during the telehealth follow-up. Patient surveys showed high satisfaction with telehealth follow-up due to reduced hospital visits. Conclusions: A combination of telehealth follow-up with real-time ECG monitoring increased the ECG monitoring duration and patient satisfaction without any adverse events.

Impact of corticosteroid use on the clinical response and prognosis in patients with cardiac sarcoidosis who underwent an upgrade to cardiac resynchronization therapy.

Background: Corticosteroids are widely used in patients with cardiac sarcoidosis (CS). In addition, upgrading to cardiac resynchronization therapy (CRT) is sometimes needed. This study aimed to investigate the impact of corticosteroid use on the clinical outcomes following CRT upgrades. Methods: A total of 48 consecutive patients with non-ischemic cardiomyopathies who underwent CRT upgrades were retrospectively reviewed and divided into three groups: group 1 included CS patients taking corticosteroids before the CRT upgrade (n = 7), group 2, CS patients not taking corticosteroids before the CRT upgrade (n = 10), and group 3, non-CS patients (n = 31). The echocardiographic response, heart failure hospitalizations, and cardiovascular deaths were evaluated. Results: The baseline characteristics during CRT upgrades exhibited no significant differences in the echocardiographic data between the three groups. After the CRT upgrade, responses regarding the ejection fraction (EF) and end-systolic volume (ESV) were significantly lower in CS patients than non-CS patients (ΔEF: group 1, 6.7% vs. group 2, 7.7% vs. group 3, 13.6%; p = .039, ΔESV: 3.0 ml vs. -12.7 ml vs. -37.2 ml; p = .008). The rate of an echocardiographic response was lowest in group 1 (29%). There were, however, no significant differences in the cumulative freedom from a composite outcome among the three groups (p = .19). No cardiovascular deaths occurred in group 1. Conclusion: The echocardiographic response to an upgrade to CRT and the long-term prognosis in patients with CS should be carefully evaluated because of the complex etiologies and impact of immunosuppressive therapy.

Ventricular arrhythmia events in heart failure patients with cardiac resynchronization therapy with or without a defibrillator for primary prevention.

Background: It is uncertain whether cardiac resynchronization therapy with a defibrillator (CRT-D) provides better survival benefits than a CRT-pacemaker (CRT-P) in heart failure patients with a reduced ejection fraction (≦35%, HFrEF) treated with contemporary HF therapy. Methods: We retrospectively analyzed the ventricular arrhythmia (VAs; sustained ventricular tachycardia/fibrillation) events in HFrEF patients who underwent CRT without a prior history of VAs or aborted sudden cardiac death before the CRT implantation. Between January/2010 and December/2020, a CRT device was implanted in 79 HFrEF patients (mean age: 69 ± 12 years, male: 57, ischemic cardiomyopathy: 16). CRT-D and CRT-P devices were implanted in 50 and 29 patients, respectively, at each physician's discretion. CRT-Ds were indicated in younger patients than were CRT-Ps (66 ± 12 vs. 73 ± 12 years, p = 0.03), but the gender distribution did not differ (female, 24% [12 of 50] vs. 35% [10 of 29], p = 0.44). The VA events during a median follow-up of 3.5-years (interquartile range [IQR]:1.6-5.5) and their predictors were analyzed. Results: VA events occurred in 9 patients with CRT-Ds (18%) and one with a CRT-P (3%, p = 0.08). The VA event rate was significantly lower in patients without a prior non-sustained ventricular tachycardia (NSVT: ≥3 beats; rate, ≥120 bpm; lasting <30 s, HR 0.05; 95% CI 0.01-0.30; p < 0.01) and females (HR 0.11; 95% CI 0.01-0.93; p = 0.04). Of note, no female patients without a prior history of NSVT experienced VA events. Conclusion: HFrEF CRT candidates without a prior history of NSVT and females may obtain less benefit from a primary preventive defibrillator indication.