Publications

BACKGROUND: Multiple studies continue to evaluate the use of intracardiac echocardiography (ICE) and transesophageal echocardiography (TEE) for guiding left atrial appendage occlusion (LAAO).

OBJECTIVE: To conduct an updated meta-analysis comparing the effectiveness and safety outcomes of both imaging modalities.

METHODS: PubMed, Cochrane, and Embase were searched for studies comparing ICE vs TEE to guide LAAO. Odds ratios (OR) with 95% confidence intervals (CI) were pooled using a random-effects model. The primary effectiveness endpoint was procedural success. The primary safety endpoint included the overall complications rate. Additional safety outcomes were assessed as secondary endpoints. Subgroup analysis of primary endpoints was conducted according to device type (Amulet, LAmbre, Watchman, Watchman FLX) and study region (American, Asia, Europe). We used R version 4.3.1 for all statistical analyses.

RESULTS: Our meta-analysis included 19 observational studies encompassing 42,474 patients, of whom 4,415 (10.4%) underwent ICE-guided LAAO. Compared with TEE, ICE was associated with a marginally higher procedural success (OR 1.33; 95% CI: 1.01-1.76; p=0.04; I2=0%). There was no significant difference in the overall complications rate (OR 1.02; 95% CI: 0.77-1.36; p=0.89; I2=5%). However, ICE showed higher rates of pericardial effusion (OR 2.11; 95% CI: 1.47-3.03; p<0.001; I2=0%) and residual iatrogenic atrial septal defect (iASD) (OR 1.52; 95% CI: 1.15-2.03; p<0.004; I2=0%). Subgroup analysis revealed variations in procedural success within the ICE group across study regions (p=0.02).

CONCLUSION: In this updated meta-analysis, the increasing adoption of ICE-guided LAAO demonstrated higher procedural success rates compared to TEE, although with limited statistical significance. Overall complication rates were similar; however, ICE showed higher rates of pericardial effusion and residual iASD.

BACKGROUND: The current standard of practice for cremating patients with cardiac implantable electronic devices (CIEDs) is surgical explantation prior to cremation to mitigate the risk of device explosion. This surgery may conflict with patient or family beliefs, whereas cremation of CIEDs may create occupational hazards.

OBJECTIVES: This study sought to establish an ex-vivo model for screening CIED behavior during cremation.

METHODS: Seven CIED underwent testing including projectile/sound testing, impact testing, and gas analysis. In the projectile test, devices were heated until thermal failure (explosion) and filmed with a high-speed camera and microphone. For impact testing, brick structures were built to assess damage after explosion. Gas chromatography-mass spectrometry identified released gases. Findings were compared with occupational health standards, where available.

RESULTS: The implantable loop recorder and leadless pacemaker produced minimal kinetic energy and impact risk with thermal failure. The remaining devices demonstrated explosive disintegration at thermal temperatures <500°C. The pacemakers and implantable cardiac defibrillators produced sound levels >120 dB and resulted in damage to brick structures. Small quantities of benzene and hydrogren fluoride were produced but at quantities within acceptable occupational exposure limits in a cremation chamber.

CONCLUSIONS: All tested CIEDs experienced explosion at temperatures below crematorium standards. The smallest devices produced minimal risk of damage or injury suggesting they may safely remain in situ during cremation, while the larger devices produced more kinetic energy, testing chamber damage, and louder explosions suggesting potential risk with cremation. Cadaveric testing in full-sized cremation chambers is required to determine real-world risk.

BACKGROUND: Implantable cardioverter-defibrillator (ICD) intervention is an established prophylactic measure. Identifying high-benefit patients poses challenges.

PURPOSE: To assess the prognostic value of cardiac magnetic resonance imaging (MRI) parameters including myocardial deformation for risk stratification of ICD intervention in non-ischemic cardiomyopathy (NICM) while accounting for competing mortality risk.

STUDY TYPE: Retrospective and prospective.

POPULATION: One hundred and fifty-nine NICM patients eligible for primary ICD (117 male, 54 ± 13 years) and 49 control subjects (38 male, 53 ± 5 years).

FIELD STRENGTH/SEQUENCE: Balanced steady state free precession (bSSFP) and three-dimensional phase-sensitive inversion-recovery late gadolinium enhancement (LGE) sequences at 1.5 T or 3 T.

ASSESSMENT: Patients underwent MRI before ICD implantation and were followed up. Functional parameters, left ventricular global radial, circumferential and longitudinal strain, right ventricular free wall longitudinal strain (RV FWLS) and left atrial strain were measured (Circle, cvi42). LGE presence was assessed visually. The primary endpoint was appropriate ICD intervention. Models were developed to determine outcome, with and without accounting for competing risk (non-sudden cardiac death), and compared to a baseline model including LGE and clinical features.

STATISTICAL TESTS: Wilcoxon non-parametric test, Cox's proportional hazards regression, Fine-Gray competing risk model, and cumulative incidence functions. Harrell's c statistic was used for model selection. A P value <0.05 was considered statistically significant.

RESULTS: Follow-up duration was 1176 ± 960 days (median: 896). Twenty-six patients (16%) met the primary endpoint. RV FWLS demonstrated a significant difference between patients with and without events (-12.5% ± 5 vs. -16.4% ± 5.5). Univariable analyses showed LGE and RV FWLS were significantly associated with outcome (LGE: hazard ratio [HR] = 3.69, 95% CI = 1.28-10.62; RV FWLS: HR = 2.04, 95% CI = 1.30-3.22). RV FWLS significantly improved the prognostic value of baseline model and remained significant in multivariable analysis, accounting for competing risk (HR = 1.73, 95% CI = 1.12-2.66).

DATA CONCLUSIONS: In NICM, RV FWLS may provide additional predictive value for predicting appropriate ICD intervention.

LEVEL OF EVIDENCE: 2 TECHNICAL EFFICACY: Stage 5.

BACKGROUND: Frailty is associated with adverse cardiovascular outcomes independent of age and comorbidities, yet the independent influence of frailty progression on cardiovascular outcomes remains uncertain.

METHODS: To determine whether frailty progression is associated with adverse cardiovascular outcomes, independent of baseline frailty and age, we evaluated all Medicare Fee-for-Service beneficiaries ≥65 years at cohort inception with continuous enrollment from 2003 to 2015. Linear mixed effects models, adjusted for baseline frailty and age, were used to estimate change in a validated claims-based frailty index (CFI) over a 5-year period. Survival analysis was used to examine frailty progression and risk of adverse health outcomes.

RESULTS: There were 8.9 million unique patients identified, mean age 77.3 ± 7.2 years, 58.7% female, 10.9% non-White race. In total, 60% had frailty progression and 40% frailty regression over median follow-up of 2.4 years. Compared to those with frailty regression, when adjusting for age and baseline CFI, those with frailty progression had a significantly greater risk of incident major adverse cardiovascular and cerebrovascular events (MACCE) (hazard ratio [HR] 1.31, 95% confidence interval [CI] 1.31-1.31), all-cause mortality (HR 1.34, 95% CI 1.34-1.34), acute myocardial infarction (HR 1.08, 95% CI 1.07-1.09), heart failure exacerbation (HR 1.30, 95% CI 1.29-1.30), ischemic stroke (HR 1.14, 95% CI 1.14-1.15). There was also a graded increase in risk of each outcome with more rapid progression, as well as significantly fewer days alive at home (DAH) with more rapid progression compared to the slowest progression group (270.4 ± 112.3 vs. 308.6 ± 93.0 days, rate ratio 0.88, 95% CI 0.87-0.88, p < 0.001).

CONCLUSIONS: In this large, nationwide sample of older Medicare beneficiaries, frailty progression, independent of age and baseline frailty, was associated with fewer DAH and a graded risk of MACCE, all-cause mortality, myocardial infarction, heart failure, and ischemic stroke compared to those with frailty regression.

IMPORTANCE: Climate change may increase the risk of adverse cardiovascular outcomes by causing direct physiologic changes, psychological distress, and disruption of health-related infrastructure. Yet, the association between numerous climate change-related environmental stressors and the incidence of adverse cardiovascular events has not been systematically reviewed.

OBJECTIVE: To review the current evidence on the association between climate change-related environmental stressors and adverse cardiovascular outcomes.

EVIDENCE REVIEW: PubMed, Embase, Web of Science, and Cochrane Library were searched to identify peer-reviewed publications from January 1, 1970, through November 15, 2023, that evaluated associations between environmental exposures and cardiovascular mortality, acute cardiovascular events, and related health care utilization. Studies that examined only nonwildfire-sourced particulate air pollution were excluded. Two investigators independently screened 20 798 articles and selected 2564 for full-text review. Study quality was assessed using the Navigation Guide framework. Findings were qualitatively synthesized as substantial differences in study design precluded quantitative meta-analysis.

FINDINGS: Of 492 observational studies that met inclusion criteria, 182 examined extreme temperature, 210 ground-level ozone, 45 wildfire smoke, and 63 extreme weather events, such as hurricanes, dust storms, and droughts. These studies presented findings from 30 high-income countries, 17 middle-income countries, and 1 low-income country. The strength of evidence was rated as sufficient for extreme temperature; ground-level ozone; tropical storms, hurricanes, and cyclones; and dust storms. Evidence was limited for wildfire smoke and inadequate for drought and mudslides. Exposure to extreme temperature was associated with increased cardiovascular mortality and morbidity, but the magnitude varied with temperature and duration of exposure. Ground-level ozone amplified the risk associated with higher temperatures and vice versa. Extreme weather events, such as hurricanes, were associated with increased cardiovascular risk that persisted for many months after the initial event. Some studies noted a small increase in cardiovascular mortality, out-of-hospital cardiac arrests, and hospitalizations for ischemic heart disease after exposure to wildfire smoke, while others found no association. Older adults, racial and ethnic minoritized populations, and lower-wealth communities were disproportionately affected.

CONCLUSIONS AND RELEVANCE: Several environmental stressors that are predicted to increase in frequency and intensity with climate change are associated with increased cardiovascular risk, but data on outcomes in low-income countries are lacking. Urgent action is needed to mitigate climate change-associated cardiovascular risk, particularly in vulnerable populations.

BACKGROUND: Pulmonary vein isolation (PVI) is increasingly recommended as first-line therapy for atrial fibrillation. Recent data suggest growing PVI volumes but rising complication rates, although comprehensive real-world outcomes including both inpatient and outpatient encounters remain unclear.

OBJECTIVES: The purpose of this study was to evaluate patient characteristics, population rates, and 30-day outcomes of PVI in a nationwide sample of U.S. adults aged >65 years.

METHODS: First-time PVIs were identified among U.S. Medicare fee-for-service beneficiaries using Current Procedural Terminology procedural codes. Comorbidities were ascertained using International Classification of Diseases-10th Revision diagnosis codes associated with each procedural claim. Outcomes included periprocedural complications, all-cause hospitalizations, and mortality at 30 days.

RESULTS: From January 2017 through December 2021, a total of 227,133 patients underwent PVI (mean age 72.5 years, 42% women, 92.7% White) with an increasing comorbidity burden over time. PVI volume increased from 83.8 (2017) to 111.6 per 100,000 patient-years (2021), which was driven by outpatient procedures (87.8% of all PVIs). Concurrently, there was a significant decrease in complication rates (3.9% in 2017 vs 3.1% in 2021; P < 0.001) and hospitalizations (8.8% vs 7.0%; P < 0.001), with no significant change in mortality (0.4%; P = 0.08). The most common periprocedural complications were bleeding (1.8%), pericardial effusion (1.4%), and vascular access damage (0.8%).

CONCLUSIONS: The use of PVI has steadily increased among older patients in contemporary U.S. clinical practice; yet, cumulative complication and hospitalization rates at 30 days have decreased over time, with stably low rates of short-term mortality despite rising comorbidity burden among treated patients. These data may reassure patients and providers on the safety of PVI as an increasingly common first-line procedure for atrial fibrillation.

BACKGROUND: Subtle, prognostically important ECG features may not be apparent to physicians. In the course of supervised machine learning, thousands of ECG features are identified. These are not limited to conventional ECG parameters and morphology. We aimed to investigate whether neural network-derived ECG features could be used to predict future cardiovascular disease and mortality and have phenotypic and genotypic associations.

METHODS: We extracted 5120 neural network-derived ECG features from an artificial intelligence-enabled ECG model trained for 6 simple diagnoses and applied unsupervised machine learning to identify 3 phenogroups. Using the identified phenogroups, we externally validated our findings in 5 diverse cohorts from the United States, Brazil, and the United Kingdom. Data were collected between 2000 and 2023.

RESULTS: In total, 1 808 584 patients were included in this study. In the derivation cohort, the 3 phenogroups had significantly different mortality profiles. After adjusting for known covariates, phenogroup B had a 20% increase in long-term mortality compared with phenogroup A (hazard ratio, 1.20 [95% CI, 1.17-1.23]; P<0.0001; phenogroup A mortality, 2.2%; phenogroup B mortality, 6.1%). In univariate analyses, we found phenogroup B had a significantly greater risk of mortality in all cohorts (log-rank P<0.01 in all 5 cohorts). Phenome-wide association study showed phenogroup B had a higher rate of future atrial fibrillation (odds ratio, 2.89; P<0.00001), ventricular tachycardia (odds ratio, 2.00; P<0.00001), ischemic heart disease (odds ratio, 1.44; P<0.00001), and cardiomyopathy (odds ratio, 2.04; P<0.00001). A single-trait genome-wide association study yielded 4 loci. SCN10A, SCN5A, and CAV1 have roles in cardiac conduction and arrhythmia. ARHGAP24 does not have a clear cardiac role and may be a novel target.

CONCLUSIONS: Neural network-derived ECG features can be used to predict all-cause mortality and future cardiovascular diseases. We have identified biologically plausible and novel phenotypic and genotypic associations that describe mechanisms for the increased risk identified.

INTRODUCTION: Conduction system pacing (CSP), consisting of His bundle pacing (HBP) or left bundle branch area pacing (LBBAP) is a rapidly developing field. These pacing techniques result in single lead left ventricular resynchronisation. Understanding of the associated learning curve of the two techniques is an important consideration for new implanters/implanting centres.

METHODS: We conducted a review of the first 30 cases of both HBP and LBBAP at The Royal Brompton Hospital. The procedural duration and fluoroscopy time were used as surrogates for the learning curve of each technique.

RESULTS: Patient characteristics were similar in HBP and LBBAP groups; LV ejection fraction (46% vs 54%, p = 0.08), pre-procedural QRS duration (119 ms vs 128 ms, p = 0.32).Mean procedural duration was shorter for LBBAP than for HBP (87 vs 107mins, p = 0.04) and the drop in procedural duration was more marked in LBBAP, plateauing and remaining low at 80mins after the initial 10 cases. Fluoroscopic screening time mirrored procedural duration (8 min vs 16 min, p < 0.01).

DISCUSSION/CONCLUSION: Our data suggest that the CSP learning curve was shorter for LBBAP than for HBP and appears to plateaux after the first 10 cases, however the HBP learning curve is longer with continued improvement over the first 30 cases. The shorter learning curve of LBBAP in conjunction with the superior electrical parameters and simplified programming mean the establishment of a CSP program is potentially easier with LBBAP compared to with HBP.

PURPOSE OF REVIEW: The goal of the narrative review is to provide an overview of the epidemiology of frailty in cardiovascular disease and cardiovascular mortality and discuss applications of frailty in cardiovascular care of older adults.

RECENT FINDINGS: Frailty is highly prevalent in older adults with cardiovascular disease and is a robust, independent predictor of cardiovascular death. There is a growing interest in using frailty to inform management of cardiovascular disease either through pre- or post-treatment prognostication or by delineating treatment heterogeneity in which frailty serves to distinguish patients with differential harms or benefits from a given therapy. Frailty can enable more individualized treatment in older adults with cardiovascular disease. Future studies are needed to standardize frailty assessment across cardiovascular trials and enable implementation of frailty assessment in cardiovascular clinical practice.