Circulation. Arrhythmia and electrophysiology最新文献

Background: Over the past decades, hypertrophic cardiomyopathy has become a contemporary treatable disease. However, limited data exist on the global trends of implantable cardioverter defibrillator (ICD) utilization and its impact on mortality/morbidity burden reduction.

Methods: Electronic databases were systematically searched up to March 2024 for studies reporting on ICD utilization rates in hypertrophic cardiomyopathy. A random effects model was used to pool study estimates across time-era, geographic region, and age group. Primary outcome was global trends in ICD utilization. Secondary outcomes included trends of sudden cardiac death, appropriate/inappropriate shocks, and ICD-related complications.

Results: In total, 234 studies (N=92 500, 514 748 patient-years) met inclusion criteria. Mean age was 46.2 (12.4) years and 37.49% were women. A total of 12 139 patients (16.43%) received an ICD over 429 766 person-years of follow-up, with an ICD implantation rate of 2.79%/y ([95% CI, 2.35%-3.32%] I²=97.80%). Rates of ICD implantation steadily increased over time from 1990 (1.09%) to 2021 (4.01%; P=0.002), with noticeable geographic variation (P=0.008). The overall rate of appropriate ICD discharges and ICD-related complications was 3.44%/y ([95% CI, 3.08%-3.84%] I²=88.40%) and 1.98%/y ([95% CI, 1.52%-2.59%] I²=90.44%), respectively, with no significant trend over time. The overall rate of inappropriate discharges was 3.58%/y ([95% CI, 3.08%-4.16%] I²=88.03%), and declined significantly over time (P=0.044). There was a significant decline in the rates of sudden cardiac death from 1990 (0.84%/y) to 2020 (0.31%/y).

Conclusions: Dramatic increases in ICD utilization have occurred, representing a 3.7-fold increase, with appropriate therapies occurring in 3.44%/y. In parallel a significant reduction in sudden cardiac death was observed, but there are insufficient data to demonstrate that a causative relationship exists. Geographic disparities in ICD utilization were evident, highlighting the need to improve access to specialized care for patients with hypertrophic cardiomyopathy. Geographic disparities in ICD utilization were evident, highlighting the need to improve access to specialized care for patients with hypertrophic cardiomyopathy.

Registration: URL: https://www.crd.york.ac.uk/PROSPERO/; Unique identifier: CRD42023407126.

Background: It is difficult to identify patients with atrial fibrillation (AF) most likely to respond to ablation. While any arrhythmia patient may recur after acutely successful ablation, AF is unusual in that patients may have long-term arrhythmia freedom despite a lack of acute success. We hypothesized that acute and chronic AF ablation outcomes may reflect distinct physiology and used machine learning of multimodal data to identify their phenotypes.

Methods: We studied 561 consecutive patients in the Stanford AF ablation registry (66±10 years, 28% women, 67% nonparoxysmal), from whom we extracted 72 data features of electrograms, electrocardiogram, cardiac structure, lifestyle, and clinical variables. We compared 6 machine learning models to predict acute and long-term end points after ablation and used Shapley explainability analysis to contrast phenotypes. We validated our results in an independent external population of n=77 patients with AF.

Results: The 1-year success rate was 69.5%, and the acute termination rate was 49.6%, which correlated poorly on a patient-by-patient basis (φ coefficient=0.08). The best model for acute termination (area under the curve=0.86, Random Forest) was more predictive than for long-term outcomes (area under the curve=0.67, logistic regression; P<0.001). Phenotypes for long-term success reflected clinical and lifestyle features, while phenotypes for AF termination reflected electrical features. The need for AF induction predicted both phenotypes. The external validation cohort showed similar results (area under the curve=0.81 and 0.64, respectively) with similar phenotypes.

Conclusions: Long-term and acute responses to AF ablation reflect distinct clinical and electrical physiology, respectively. This de-linking of phenotypes raises the question of whether long-term success operates through factors such as attenuated AF progression. There remains an urgent need to develop procedural predictors of long-term AF ablation success.

Background: Power-controlled radiofrequency ablation with irrigated-tip catheters has been the norm for ventricular ablation for almost 2 decades. New catheter technology has recently integrated more accurate tissue temperature sensing enabling temperature-controlled irrigated ablation. We aimed to investigate the in vivo ablation parameters and lesion formation characteristics in ventricular myocardium using a novel temperature-controlled radiofrequency catheter.

Methods: Twenty canines were divided into 3 groups: 4 noninfarcted, acute (phase I); 8 noninfarcted, chronic (phase II); and 8 infarcted, chronic (phase III). Lesions were delivered with a temperature-controlled radiofrequency system utilizing a chemical vapor deposit diamond for efficient thermal diffusivity. In phase I, 17 ablation settings were tested (temperature set points, 50/60/70 °C; ablation duration, 15/30/60/90/120 s; and power limit, 30/50 W). Four and one of these sets of parameters were further tested in phases II and III, respectively. Lesions were assessed by ex vivo contrast-enhanced magnetic resonance imaging and gross pathology 5 weeks after ablation in phases II/III.

Results: Across all phases, 111 ablation lesions were delivered. Ablation with the power limit of 50 W, the temperature set point of 60 °C, and the duration of 60 s produced significantly larger and deeper lesions (mean, 569.2 mm³; mean maximal depth, 9.8 mm) compared with 50 W/60 °C/30 s (mean, 340.4 mm³; mean maximal depth, 8.3 mm) and 50 W/50 °C/60 s (mean, 227 mm³; mean maximal depth, 6.9 mm), with P<0.05 for all pairwise comparisons. Ablation of infarcted myocardium in phase III (50 W/60 °C/30 s) resulted in smaller impedance and bipolar electrogram amplitude changes and lesion size compared with ablation in normal myocardium with the same settings. No steam pop, myocardial perforation, or char formation was observed in any of the 111 ablations across all phases.

Conclusions: In vivo radiofrequency ablation in a canine model with a diamond-tip temperature-controlled catheter using a temperature set point of 60 °C and a power limit of 50 W created large lesions without steam pop risk in both normal and infarcted ventricular myocardia.

Background: Current clinical guidelines emphasize the significance of rhythm control with catheter ablation but lack guidance on the timing of atrial fibrillation (AF) ablation relative to the diagnosis time. We aim to investigate the latest evidence on the impact of diagnosis to ablation time (DAT) on clinical outcomes after AF ablation.

Methods: We searched PubMed, Web of Science, Scopus, Embase, and Cochrane Central Register of Controlled Trials through August 2024. Pairwise, prognostic, and reconstructed time-to-event data meta-analyses were conducted using R V. 4.3.1. Our primary end point was time to first AF recurrence, with secondary end points of all-cause mortality, tamponade, stroke, and heart failure.

Results: Our cohort included 23 studies with 43 711 patients. Shorter DAT was significantly associated with reduced AF recurrence across both paroxysmal and persistent AF subgroups (P<0.01). There was a significant decrease in benefit for paroxysmal AF over time and a slight decrease in benefit for persistent AF over time. However, the benefit remained significant in both over time. DAT per year was significantly associated with a 10% increased risk of AF recurrence. Reconstructed Kaplan-Meier analysis showed that DAT >1 year was significantly associated with a 70% increased risk of AF recurrence in paroxysmal AF and 30% in persistent AF. DAT ≤1 year was significantly associated with decreased all-cause mortality (P<0.01) and showed a trend toward an association with a lower incidence of stroke (P=0.08). However, there was no significant difference in heart failure between DAT ≤1 year and DAT >1 year.

Conclusions: Early ablation is more beneficial in paroxysmal AF, with a notable decrease in benefit over time, while in persistent AF, the benefit remains significant but slightly decreases over time. Shorter DAT was significantly associated with decreased all-cause mortality and showed a trend toward an association with a lower incidence of stroke.

Registration: URL: https://www.crd.york.ac.uk/prospero/display_record.php?; Unique identifier: CRD42024525542.

Background: QT correction (QTc) formulae are widely used in clinical and research settings but often underperform, possibly due to demographic influences on the QT-heart rate (HR) relationship. To address this limitation, we developed an adaptive QTc (QTcAd) formula, which adjusts for demographic factors like age, and compared its efficacy to other standard formulae.

Methods: The QTcAd formula was tested across diverse age groups with different HR in both humans and guinea pigs. Using retrospective ECG data from 1819 pediatric patients at Children's National Hospital and 2400 subjects from the Pediatric Heart Network database, alongside in vivo (N=55) and ex vivo (N=66) guinea pig ECG recordings, we evaluated the formula's effectiveness. Linear regression fit parameters of QTc-HR (slope and R²) were utilized for performance assessment. To evaluate the accuracy of the predicted QTc, we acquired epicardial electrical and optical voltage data from Langendorff-perfused guinea pig hearts.

Results: In both human subjects and guinea pigs, the QTcAd formula (QTcAd=QT+(|m|×(HR-HR_mean)) consistently outperformed other formulae across all age groups. For instance, in a 20-year-old human group, the QTcAd formula successfully nullified the inverse QT-HR relationship (R²=5.1×10^-10, slope=-3.5×10^-5), whereas the Bazett formula failed to achieve comparable effectiveness (R²=0.21, slope=0.91). Moreover, the QTcAd formula exhibited better accuracy than the age-specific Benatar QTc formula, which overcorrected QTc (1-week human QT: 263.8±14.8 ms, QTcAd: 263.8±7.3 ms, P=0.62; Benatar QTc: 422.5±7.3 ms, P<0.0001). The optically measured pseudo-QT interval (143±22.5 ms, n=44) was better approximated by QTcAd (180.6±17.0 ms) compared with all other formulae. Furthermore, we demonstrated that the QTcAd formula was not inferior to individual-specific QTc formulae.

Conclusions: The demography-based QTcAd formula showed superior performance across human and guinea pig age groups, which may enhance the efficacy of rate-corrected K.M.M. for cardiovascular disease diagnosis, risk stratification, and drug safety testing in children and adults.

Background: Sequential application of radiofrequency with pulsed field (PF) ablation may increase lesion depth while preserving the advantages of PF. The study's aim was to determine lesion dimensions of sequential, colocalized radiofrequency and PF ablation.

Methods: A preclinical study using swine (n=4) performed lesions in the right/left ventricles. Ablations were performed with a force-sensing 3.5-mm irrigated-tip ablation catheter using a generator delivering both radiofrequency and PF. PF was delivered using unipolar, biphasic pulses at a standard dose (PF index, 300) with 4-mL/min irrigation. Radiofrequency was delivered at 50 W for 10 s (15 mL/min). Lesions were created by applying colocalized radiofrequency followed by sequential application of PF on the same location, PF followed by sequential application of radiofrequency on the same location, PF alone, or radiofrequency alone. Tissue was collected after 2 hours for lesion assessment. Results are mean±SD.

Results: Forty-five lesions were analyzed. The lesion depth of radiofrequency alone was 4.9±0.8 mm. The mean lesion depth and width for PF alone were 3.5±0.6 and 5.1±1.8 mm. Lesion depths for combined applications were significantly greater versus PF alone (6.2±1.8 mm radiofrequency followed by sequential application of PF on the same location; 5.7±1.3 mm PF followed by sequential application of radiofrequency on the same location; P<0.0001 for both). Lesion widths were also significantly greater with combined therapy versus PF alone (8.6±1.8 mm radiofrequency followed by sequential application of PF on the same location; 8.9±2.1 mm PF followed by sequential application of radiofrequency on the same location; P<0.0001 for both). Histology for both combined lesions showed central thermal necrosis surrounded by a hemorrhagic and transitional PF zone.

Conclusions: Combined, colocalized radiofrequency and PF, irrespective of order, show significantly increased lesion size compared with the same dose of PF or radiofrequency alone.

Background: Superior vena cava (SVC) has been considered a specific trigger in atrial fibrillation development.

Methods: We investigated the efficacy and safety of combining cryoballoon pulmonary vein isolation (PVI) with SVC ablation compared with PVI alone in 100 patients with paroxysmal or non-long-standing persistent atrial fibrillation. Patients were randomly assigned to either the PVI+SVC ablation group or the PVI-only group. Each patient was given a mobile device to record a daily ECG and detect atrial tachyarrhythmias.

Results: The primary end point, freedom from any atrial tachyarrhythmia recurrence between 91 and 365 days post-catheter ablation, did not significantly differ between the 2 groups (62.9% versus 72%; P=0.41). However, the PVI+SVC group exhibited higher rates of phrenic nerve paralysis (20.8% versus 6%; P=0.003) and transient sinus node injury (18.8% versus 0%; P=0.001) compared with the PVI-only group. The median burden of atrial tachyarrhythmia showed no significant difference (P=0.91).

Conclusions: The addition of SVC ablation to PVI did not enhance freedom from atrial tachyarrhythmia at 12 months, and it led to increased complications. These findings do not support the routine inclusion of SVC ablation in cryoballoon procedures for first-time catheter ablation in patients with paroxysmal or non-long-standing persistent atrial fibrillation.