Race and Ethnic and Sex Differences in Rhythm Control Treatment of Incident Atrial Fibrillation

Background

Atrial fibrillation (AF) is associated with considerable morbidity and mortality. Timely management and treatment is critical in alleviating AF disease burden. Variation in treatment by race and ethnic and sex could lead to inequities in health outcomes.

Objective

To identify racial and ethnic and sex differences in rhythm treatment for patients with incident AF.

Methods

Using 2010-2019 Optum Clinformatics database, an administrative claims data for commercially insured patients in the United States (US), incident AF patients ≥20 years old who were continuously enrolled 12-months pre- and post-index diagnosis were identified. Rhythm control treatment (ablation, antiarrhythmic drugs [AAD], and cardioversion) for AF were compared by patient race and ethnicity (Asian, Hispanic, Black vs White) and sex (female vs male). Multivariable regression analysis was used to examine the relationship of race and ethnicity and sex with rhythm control AF treatment.

Results

A total of 77,932 patients were identified with incident AF. Black and Hispanic female patients had the highest CHA2DS2VASc scores (4.3 ± 1.8) and Elixhauser scores (4.1 ± 2.8 and 4.0 ± 6.7), respectively. Black males were less likely to receive AAD treatment (adjusted odds ratio [aOR] 0.87; 95% confidence interval [CI], 0.79-0.96) or ablation (aOR, 0.72; 95% CI, 0.58-0.90). Compared to White males, all groups had lower likelihood of receiving cardioversion with Asian females having the lowest [aOR, 0.48; 95% CI, (0.37-0.63)].

Conclusion

Black patients were less likely to receive pharmacologic and procedural rhythm control therapies. Further research is needed to understand the drivers of undertreatment among racial and ethnic groups and females with AF.

Racial/ethnic and sex differences in safety outcomes and atrial fibrillation/atrial flutter-related acute healthcare utilization after catheter ablation of atrial fibrillation

Background

Catheter ablation is recommended for the treatment of symptomatic atrial fibrillation (AF) refractory to medical therapy.

Objective

The study sought to examine racial/ethnic and sex differences in complications and AF/atrial flutter (AFL)-related acute healthcare utilization following catheter ablation for AF.

Methods

We performed a retrospective analysis using data from the Centers for Medicare and Medicaid Services Medicare Standard Analytical Files (October 1, 2014, to September 30, 2019) among patients ≥65 years of age with AF who underwent catheter ablation for rhythm control. The risk of any complication within 30 days and AF/AFL-related acute healthcare utilization within 1 year of ablation by race, ethnicity, and sex were assessed using multivariable Cox regression modeling.

Results

We identified 95,394 patients for analysis of postablation complications and 68,408 patients for analysis of AF/AFL-related acute healthcare utilization. Both cohorts were ∼95% White and 52% male. Female patients had a slightly elevated risk of complications compared with male patients (adjusted hazard ratio [aHR] 1.07, 95% confidence interval [CI] 1.03-1.12). Black (aHR 0.78, 95% CI 0.77-1.00) and Asian (aHR 0.67, 95% CI 0.50-0.89) patients had lower utilization compared with White patients. Specifically, Asian men (aHR 0.58, 95% CI 0.38-0.91) had lower utilization compared with White men.

Conclusion

Differences in safety and healthcare utilization after catheter ablation for AF were observed by race/ethnicity and sex groups. Underrepresented racial and ethnic groups with AF had a lower risk of AF/AFL-related acute healthcare utilization postablation.

The clinical and genetic spectrum of catecholaminergic polymorphic ventricular tachycardia: findings from an international multicentre registry

Aims

Catecholaminergic polymorphic ventricular tachycardia (CPVT) is an ion channelopathy characterized by ventricular arrhythmia during exertion or stress. Mutations in RYR2-coded Ryanodine Receptor-2 (RyR2) and CASQ2-coded Calsequestrin-2 (CASQ2) genes underlie CPVT1 and CPVT2, respectively. However, prognostic markers are scarce. We sought to better characterize the phenotypic and genotypic spectrum of CPVT, and utilize molecular modelling to help account for clinical phenotypes.

Methods and results

This is a Pediatric and Congenital Electrophysiology Society multicentre, retrospective cohort study of CPVT patients diagnosed at <19 years of age and their first-degree relatives. Genetic testing was undertaken in 194 of 236 subjects (82%) during 3.5 (1.4-5.3) years of follow-up. The majority (60%) had RyR2-associated CPVT1. Variant locations were predicted based on a 3D structural model of RyR2. Specific residues appear to have key structural importance, supported by an association between cardiac arrest and mutations in the intersubunit interface of the N-terminus, and the S4-S5 linker and helices S5 and S6 of the RyR2 C-terminus. In approximately one quarter of symptomatic patients, cardiac events were precipitated by only normal wakeful activities.

Conclusion

This large, multicentre study identifies contemporary challenges related to the diagnosis and prognostication of CPVT patients. Structural modelling of RyR2 can improve our understanding severe CPVT phenotypes. Wakeful rest, rather than exertion, often precipitated life-threatening cardiac events.

Nonfluoroscopic Ablation in the Setting of Congenital Heart Disease

In this case series, we demonstrate the performance of nonfluoroscopic ablation in the congenital heart disease population. Techniques for procedural safety and the benefits of three-dimensional mapping in the setting of structural heart disease are reviewed.

Analysis of Screening Electrocardiogram for the Subcutaneous Defibrillator in Adults with Congenital Heart Disease

Candidates for the subcutaneous implantable cardioverter-defibrillator (S-ICD) are screened using an electrocardiogram (S-ECG) tool to measure appropriate detection. We sought to define the S-ICD candidacy of congenital heart disease patients using the S-ECG tool. We also analyzed the reliability of the (S-ECG) tool between measurers in this population. Patients above the age of 12 and with a diagnosis associated with either a higher incidence of cardiac arrest or vascular access challenges were asked to undergo screening. S-ECGs were then analyzed by a pediatric electrophysiologist, an S-ICD device engineer, and an S-ICD clinical representative for candidacy. Results were compared for interobserver variability and S-ECGs were analyzed by t test to determine variables that differ among passing and failing leads. Thirty-one patients underwent screening. Two of the 31 (6.5%) patients failed S-ICD screening. Analysis of the screening leads demonstrated the highest passing rates using lead III at a 5 mm/mV amplitude setting with 71 and 62% pass rate in the supine and standing positions, respectively. Interobserver analysis correlated well among the three measurers. There was a higher amplitude difference between QRS and T waves among passing versus failing S-ECG. Congenital heart disease patients have acceptable passage rates utilizing the S-ECG algorithm. Interobserver measurements were well correlated and these data suggest that the proximal coil to device (lead III) vector would be best utilized in this patient population. A larger difference between QRS and T wave amplitudes was associated with a higher S-ECG passing rate.

Catecholaminergic polymorphic ventricular tachycardia in children: analysis of therapeutic strategies and outcomes from an international multicenter registry

BACKGROUND

Catecholaminergic polymorphic ventricular tachycardia is an uncommon, potentially lethal, ion channelopathy. Standard therapies have high failure rates and little is known about treatment in children. Newer options such as flecainide and left cardiac sympathetic denervation are not well validated. We sought to define treatment outcomes in children with catecholaminergic polymorphic ventricular tachycardia.

METHODS AND RESULTS

This is a Pediatric and Congenital Electrophysiology Society multicenter, retrospective cohort study of catecholaminergic polymorphic ventricular tachycardia patients diagnosed before 19 years of age. The cohort included 226 patients, including 170 probands and 56 relatives. Symptomatic presentation was reported in 176 (78%). Symptom onset occurred at 10.8 (interquartile range, 6.8-13.2) years with a delay to diagnosis of 0.5 (0-2.6) years. Syncope (P<0.001), cardiac arrest (P<0.001), and treatment failure (P=0.008) occurred more often in probands. β-Blockers were prescribed in 205 of 211 patients (97%) on medication, and 25% experienced at least 1 treatment failure event. Implantable cardioverter defibrillators were placed in 121 (54%) and was associated with electrical storm in 22 (18%). Flecainide was used in 24% and left cardiac sympathetic denervation in 8%. Six deaths (3%) occurred during a cumulative follow-up of 788 patient-years.

CONCLUSIONS

This study demonstrates a malignant phenotype and lengthy delay to diagnosis in catecholaminergic polymorphic ventricular tachycardia. Probands were typically severely affected. β-Blockers were almost universally initiated; however, treatment failure, noncompliance and subtherapeutic dosing were often reported. Implantable cardioverter defibrillators were common despite numerous device-related complications. Treatment failure was rare in the quarter of patients on flecainide. Left cardiac sympathetic denervation was not uncommon although the indication was variable.

Measures of dyssynchrony in the left ventricle of healthy children and young patients with dilated cardiomyopathy

BACKGROUND

Doppler tissue imaging may help identify children with dyssynchrony who could benefit from resynchronization therapy. However, few studies have quantified dyssynchrony measures in children; no study has investigated the relationship among age, heart rate, and dyssynchrony measures in children; and no study has quantified cross-correlation delay in children. The aim of this study was to test the hypotheses that measures of left ventricular dyssynchrony would correlate with age, primarily because of the correlation between heart rate and age, and that children with cardiomyopathy would have left ventricular dyssynchrony.

METHODS

Sixty healthy children and 11 children with dilated cardiomyopathy were prospectively enrolled. Seven dyssynchrony measures were quantified: septal-to-lateral delay, peak velocity difference, the standard deviations of times to peak in 12 segments in systole and diastole, and cross-correlation delay in systole, diastole, and the whole cycle.

RESULTS

The seven dyssynchrony measures were either not correlated with age or only weakly correlated with age after correcting for heart rate using Bazett's formula. Septal-to-lateral delay, peak velocity difference, and the standard deviation of times to peak in 12 segments in systole showed dyssynchrony in 57% to 85% of normal controls, compared with 20% for cross-correlation delay in the whole cycle and 3% for the standard deviation of times to peak in 12 segments in diastole. Cross-correlation delay in systole, cross-correlation delay in diastole, cross-correlation delay in the whole cycle, and the standard deviation of times to peak in 12 segments in diastole were elevated in children with dilated cardiomyopathy compared with controls.

CONCLUSIONS

Echocardiographic dyssynchrony measures should be corrected for heart rate using Bazett's formula in children. Time-to-peak Doppler tissue imaging dyssynchrony measures classify many healthy children as having abnormalities with the timing of left ventricular contraction, which suggests that the methodology is not accurate in children. In preliminary studies, cross-correlation dyssynchrony measures show elevated systolic and diastolic measures of dyssynchrony in children with dilated cardiomyopathy compared with controls, which deserves further investigation to help identify children who may benefit from resynchronization therapy.

Cardioversion of intraatrial reentrant tachycardia using rate response

Intraatrial reentrant tachycardia (IART) is the most common long-term, surgical arrhythmia sequela in patients with complex congenital heart disease. The management of IART is challenging. Medications, catheter ablation therapy, and pacemaker therapy have all been utilized as treatment options. Slower tachycardia cycle lengths and 1:1 atrioventricular conduction provide even more challenges with regard to detection and antitachycardia pacing. We describe the use of the rate response feature as a means of patient-initiated cardioversion.

Glutathione and associated enzymes in toxic cataractogenesis-selenite model

Glutathione, gamma-glutamyl cysteine synthetase (gamma -GCS) and glutathione reductase (GSH-R) activity were determined biochemically in the lens during various stages after subcutaneous administration of sodium selenite in multiple low dosages and single high dosages. The GSH concentration and gamma-GCS and GSH-R activity declined progressively after the selenite administration. The changes observed were discussed in relation to the possible role of selenite interaction with GSH and the enzymes.

Selenite cataract and its attenuation by vitamin E in Wistar rats

PURPOSE

To study the role of vitamin E in preventing cataract formation in experimental animals.

METHODS

An experimental model (selenite cataract) was selected for this study. Selenite cataract was produced in rats by subcutaneous administration of sodium selenite. Biochemical and histological changes following induction of selenite cataract in weanling Wistar rats were studied vis-a-vis the role of vitamin E in attenuating or preventing cataractogenesis.

RESULTS

Vitamin E was capable of preventing selenite cataractogenesis. Selenite cataract did not develop in 91.6% (11 of 12) and 76.7% (8 of 12) vitamin E treated rats, when administered on the 12th and 10th post partum day respectively.

CONCLUSION

The study confirmed that selenite induced cataract in Wistar rats is attenuated by vitamin E.

Predictions of the impacts of changes in population size and environmental variablitity on Leadbeater's possum, Gymnobelideus leadbeateri McCoy (Marsupialia: Petauridae) using population viability analysis: an application of the computer program VORTEX

Population Viability Analysis (PVA) uses computer modelling to simulate interacting deterministic and stochastic factors (e.g. demographic, genetic, spatial, environmental and catastrophic processes) that act on small populations and assess their long-term vulnerability to extinction. The computer program VORTEX was used in a PVA of Leadbeater's possum, Gymnobelideus leadbeateri McCoy, an endangered arboreal marsupial that is restricted to the montane ash forests of the central highlands of Victoria. PVA was used to examine the impacts of changes in the size of subpopulations and the effects of environmental variation. Our analyses demonstrated that an annual linear decline in the carrying capacity in all or parts of the habitat will lead to the extinction of G. leadbeateri in those areas. Mean time to extinction was related to the rate of annual decrease. This conclusion is of practical and management importance as there is presently a decline in suitable habitat because of an annual loss of more than 3.5% of trees with hollows, which provide nest sites for G. leadbeateri. Because nest sites are a factor that limits populations of G. leadbeateri, the species could be lost from large areas within the next 50 years. PVA was also used to determine the viability of populations in areas, such as oldgrowth forest, where there is not likely to be a steady decline in habitat carrying capacity resulting from the loss of trees with hollows. This allowed an analysis of the cumulative impacts of small population size, environmental variation and genetic factors, which showed that, for a 100-year projection, simulated populations of 200 animals or more remained demographically stable and experienced a less than 10% decline in predicted genetic variability. However, the relatively simplified nature of population modelling and the suite of assumptions that underpin VORTEX mean that the probability of extinction of populations of this size may be greater than determined in this study. As a result, it is possible that only populations of more than 200 animals may persist in the long term where suitable habitat can be conserved or established and subsequently maintained without a reduction in carrying capacity.