Behavior of the OptiVol2 fluid index and intrathoracic impedance on remote monitoring As a detector of subclinical device infection early after implantation.

We report the behavior of OptiVol2 fluid index (OVFI2) and intrathoracic impedance on remote monitoring before the appearance of signs of infection. A sustained rise in OVFI2 early after implantation reflects peri-device fluid retention.

Preoperative Prediction of Shock Impedance for Subcutaneous Implantable Cardioverter Defibrillator Using Chest Computed Tomography.

BACKGROUND: High shock impedance is associated with conversion failure among patients with subcutaneous implantable cardioverter defibrillators (S-ICD). Currently, there is no preoperative assessment method for predicting high shock impedance. This study examined the efficacy of chest computed tomography (CT) as a preoperative evaluation tool to assess the shock impedance of S-ICDs. METHODS AND RESULTS: The amount of adipose tissue adjacent to the device and anteroposterior diameter at the basal heart region were measured preoperatively using chest CT. We examined the correlation between these measurements and shock impedance at the conversion test. We enrolled 43 patients with S-ICDs (mean [±SD] age 54±15 years; body mass index 23±4 kg/m2; PRAETORIAN score 30-270 points; amount of adipose tissue 1,250±716 cm3), who underwent intraoperative conversion tests by inducing ventricular fibrillation, which was terminated with a 65-J shock. A sufficient concordance correlation coefficient was observed between the shock impedance and the amount of adipose tissue (r=0.616, P<0.01) and anteroposterior diameter (r=0.645, P<0.01). In multiple regression analysis, the amount of adipose tissue (ß=0.439, P=0.009) and anteroposterior diameter (ß=0.344, P=0.038) were identified as independent predictive factors of shock impedance. CONCLUSIONS: The preoperative CT-measured amount of adipose tissue and basal heart anteroposterior diameter are independent predictors of shock impedance. These parameters may be more accurate in identifying higher shock impedance in patients with S-ICDs.

ST-Segment Elevation During Percutaneous Left Atrial Appendage Closure.

A 70-year-old patient with paroxysmal atrial fibrillation underwent left atrial appendage closure. The patient experienced transient hypotension during device implantation. The procedure was abandoned because of ST-T-wave changes on electrocardiography and elevated coronary flow velocity on transesophageal echocardiography, which indicated that the device caused coronary artery compression.

Successful Epicardial Radiofrequency Ablation of Ventricular Tachycardia That Shared a Pathway with Bi-Directional Conduction in a Patient with Human Immunodeficiency Virus-Associated Cardiomyopathy.

A 59-year-old man who had been diagnosed with human immunodeficiency virus-associated cardiomyopathy was referred for catheter ablation of ventricular tachycardia (VT). An electrocardiogram (ECG) waveform revealed that the clinical VT originated from the epicardium. A deceleration zone (DZ) was identified on an isochronal late activation map. Moreover, 2 forms of monomorphic VT were induced by different cycle length burst pacings from near the DZ. The morphologies of the 2 VTs with an identical cycle length were very likely to use a shared common pathway with bi-directional conduction around the slow conduction area in the left ventricle posterolateral small epicardial surface area. After ablation of the DZ, the VT was uninducible.

Revisiting predictors of worse atrioventricular valve and left ventricular systolic function following pacemaker therapy.

BACKGROUND: Predictors of worsening atrioventricular valve regurgitation and left ventricular (LV) systolic function after implantation of a leadless pacemaker (LPM) remain unclear compared with those of a transvenous pacemaker (TPM). METHODS: We retrospectively analyzed 205 patients who were newly implanted with a permanent pacemaker (119 LPMs and 86 TPMs) and underwent transthoracic echocardiography before and 8 ± 5 months after implantation. We evaluated the worsening of tricuspid and mitral regurgitation (TR and MR), defined as at least one-grade aggravation in severity, and changes in LV ejection fraction (LVEF). RESULTS: Worsening TR occurred more frequently in the LPM group compared to the TPM group (33% vs. 20%, p = .04); however, there was no significant difference between the two groups regarding worsening MR (26% vs. 18%, p = .18) and LVEF change (-2 ± 10% vs. -3 ± 8%, p = .40). In multivariable analysis, independent predictors for worsening TR, MR, and LVEF after implantation were found to be (1) the change from sinus rhythm at baseline to atrioventricular asynchronous right ventricular (RV) pacing (odds ratio [OR]: 5.68, 95% confidence interval [CI]: 1.94-16.70, p < .01); (2) the change from non-pacing ventricular contraction at baseline to RV pacing (OR: 2.42, 95% CI: 1.12-5.24, p = .02); and (3) a higher RV pacing burden (ß: -0.05, 95% CI: -0.08--0.02, p < .01), respectively. CONCLUSION: Worsening TR, MR, and LVEF after pacemaker implantation were not associated with the type of pacing device but loss of atrioventricular synchrony or dependency on RV pacing.

Two-year Outcomes of Ventricular-demand Leadless Pacemaker Therapy for Heart Block After Transcatheter Aortic Valve Replacement.

Ventricular-demand leadless pacemakers (VVI-LPMs) have often been used as an alternative to atrioventricular (AV) synchronous transvenous pacemakers (DDD-TPMs) in patients with high-grade AV block following transcatheter aortic valve replacement (TAVR). However, the clinical outcomes of this unusual usage are not elucidated. Patients who received permanent pacemakers (PPMs) owing to new-onset high-grade AV block after TAVR from September 2017 to August 2020 at a high-volume center in Japan were included in the analysis, and the clinical courses of VVI-LPM and DDD-TPM implants through 2 years of follow-up were compared retrospectively. Out of 413 consecutive patients who underwent TAVR, 51 (12%) patients received a PPM. After excluding 8 patients with chronic atrial fibrillation (AF), 3 with sick sinus syndrome, and 1 with incomplete data, 17 VVI-LPMs and 22 DDD-TPMs were included in our final cohort. The VVI-LPM group had lower serum albumin levels (3.2 ± 0.5 vs. 3.9 ± 0.4 g/dL, P < .01) than the DDD-TPM group. Follow-up revealed no significant differences between the 2 groups in terms of the incidence of late device-related adverse events (0% vs. 5%, log-rank P = .38) and new-onset AF (6% vs. 9%, log-rank P = .75); however, there were increases in the rates of all-cause death (41% vs. 5%, log-rank P < .01) and heart failure rehospitalization (24% vs. 0%, log-rank P = .01) in the VVI-LPM group. This small retrospective study reveals favorable post-procedural complication rates but higher all-cause mortality with VVI-LPM compared to DDD-TPM therapy for high-grade AV block after TAVR at 2 years of follow-up.

Clinical Outcomes of Non-Atrial Fibrillation Bradyarrhythmias Treated With a Ventricular Demand Leadless Pacemaker Compared With an Atrioventricular Synchronous Transvenous Pacemaker　- A Propensity Score-Matched Analysis.

BACKGROUND: Implanting a ventricular demand leadless pacemaker (VVI-LPM) for patients with non-atrial fibrillation (AF) bradyarrhythmias such as sick sinus syndrome (SSS) or high-grade (i.e., second- or third-degree) atrioventricular (AV) block is not recommended unless they have limited vascular access or a high infection risk; nevertheless, an unexpectedly high number of VVI-LPM implantations have been performed. This study investigated the clinical outcomes of these unusual uses.Methods and Results:This study retrospectively analyzed 193 patients who were newly implanted with a VVI-LPM or an atrioventricular synchronous transvenous pacemaker (DDD-TPM) for non-AF bradyarrhythmias at a high-volume center in Japan from September 2017 to September 2020. Propensity score-matching produced 2 comparable cohorts treated with a VVI-LPM or DDD-TPM (n=58 each). Each group had 20 (34%) patients with SSS and 38 (66%) patients with high-grade AV block. During a median follow up of 733 (interquartile range 395-997) days, there were no significant differences between the VVI-LPM and DDD-TPM groups regarding late device-related adverse events (0% vs. 4%, log-rank P=0.155), but the VVI-LPM group had a significantly increased readmission rate for heart failure (HF) (29% vs. 2%, log-rank P=0.001) and a tendency to have higher all-cause mortality (28% vs. 4%, log-rank P=0.059). CONCLUSIONS: The implantation of a VVI-LPM for non-AF bradyarrhythmias increased the incidence of HF-related rehospitalization at the mid-term follow up compared to the use of a DDD-TPM.

Revisit to the Prognostic Value of Premature Atrial Contraction Burden in 24-h Holter Electrocardiography for Predicting Undiagnosed Atrial Fibrillation　- A Propensity Score-Matched Study.

BACKGROUND: The optimum cut-off value of premature atrial contraction (PAC) burden (CV-PACb) in 24-h Holter electrocardiography (24-h ECG) for predicting atrial fibrillation (AF) is debatable, with few validation data.Methods and Results:We retrospectively analyzed 61 patients already diagnosed with AF (AD-AF) and 147 patients never diagnosed with AF (ND-AF), aged ≥50 years, free of heart disease, and who had undergone 24-h ECG and transthoracic echocardiography (TTE). Receiver operating characteristic analysis demonstrated that 0.4% was the optimal CV-PACb differentiating AD-AF from ND-AF, with 69% sensitivity and 72% specificity (area under the curve [AUC] 0.72; 95% confidence interval [CI] 0.65-0.79); however, the left atrial volume index was not significant (AUC 0.60; 95% CI 0.51-0.68). To verify the CV-PACb, new propensity-matched cohorts (i.e., subjects with a PAC burden ≥0.4% and <0.4%; n=69 in each group) were compared based on new detection of AF at a median follow-up of 50 months (interquartile range 12-60 months) Multivariable Cox regression analysis revealed that among 24-h ECG and TTE findings, only PAC burden ≥0.4% was independently associated with incident AF (hazard ratio 5.28; 95% CI 1.28-26.11; P=0.023). CONCLUSIONS: A high PAC burden (≥0.4%) in 24-h ECG was a reliable indicator to identify undiagnosed AF, whereas TTE parameters did not show any predictive value.