Therapeutic implications of gender differences in supraventricular cardiac arrhythmias: lessons of life cannot be learned in a day

Atrioventricular accessory pathways in 89 dogs: Clinical features and outcome after radiofrequency catheter ablation

Background

Atrioventricular accessory pathways (APs) in dogs have been reported rarely. Data regarding clinical presentation and long‐term outcome after radiofrequency catheter ablation (RFCA) are limited.

Hypothesis/Objectives

To study clinical features, electrophysiologic characteristics, and outcome of RFCA in dogs with APs.

Animals

Eighty‐nine dogs presented consecutively for RFCA of APs.

Methods

Case series.

Results

Labrador retrievers (47.2% of dogs) and male dogs (67.4% of dogs) were most commonly affected. Labrador retrievers were more likely to be male than non‐Labrador breeds (P = .043). Clinical signs were nonspecific and most commonly included lethargy and gastrointestinal signs. Concealed APs were more prevalent in Labrador retrievers than other breeds (P = .001). Right‐sided APs (91.7%) predominated over left‐sided (8.3%). Tachycardia‐induced cardiomyopathy (TICM) occurred in 46.1% of dogs, with complete resolution or substantial improvement noted on one‐month postablation echocardiograms. Radiofrequency catheter ablation successfully eliminated AP conduction long term in 98.8% of dogs in which it was performed. Complications occurred in 5/89 dogs. Recurrence in 3 dogs was eliminated long term with a second procedure.

Clinical Importance/Conclusions

Accessory pathways are challenging to recognize in dogs because of nonspecific clinical signs, frequency of concealed APs that show no evidence of their presence during sinus rhythm, and intermittent occurrence of tachyarrhythmias resulting from APs. Tachycardia‐induced cardiomyopathy commonly occurs with AP‐mediated tachycardias and should be considered in any dog presenting with a dilated cardiomyopathic phenotype because of its good long‐term prognosis with rhythm control. Radiofrequency catheter ablation is a highly effective method for eliminating AP conduction and providing long‐term resolution.

Patient's age rather than severity of the arrhythmia influences the cost of medical treatment of atrioventricular nodal or atrioventricular reciprocating tachycardia

Purpose

Radiofrequency ablation (RFA) is considered the treatment of choice in cases of atrioventricular nodal reciprocating tachycardia (AVNRT) and atrioventricular reciprocating tachycardia (AVRT). Published studies suggest a considerable time gap between the onset of the arrhythmia, correct diagnosis, and RFA which may reach 10–15 years. The cost of medical treatment during that period may be substantial. The aim of the study was to calculate the annual direct medical cost of medical treatment of patients with AVNRT and AVRT and identify potential factors influencing this cost.

Methods

Based on the consumption of particular resources and the unit costs of services in 2013, we calculated the annual direct medical cost of care for patients with AVNRT and AVRT in Poland. We adopted the public payer’s and societal perspectives. Data on health resources was collected with a structured questionnaire and medical records of patients scheduled for RFA. Additional analyses were performed to identify factors influencing this cost.

Results

We enrolled 82 patients: mean age 43.9 ± 14.1 years old and mean symptom duration before the RFA 13.0 ± 11.3 years. The median annual cost of medical treatment was 546 USD [312–957], 411 € [278–786], and 616 USD [369–1044], 464 € [235–721], for the public payer and the common perspective, respectively, with hospitalizations being the main cost component. In multivariate analysis, only the age of the patient significantly influenced this cost.

Conclusions

The annual cost of medical treatment of AVNRT or AVRT is substantial and dependent on the age of the patient rather than the severity of the arrhythmia (NCT01594814).

Predictors of sustained ventricular arrhythmia episodes in patients with primary ICD indication: male gender and AF in primary ICD prophylaxis

AIMS

Implantable cardioverter-defibrillators (ICD) reduce mortality in patients with severely impaired left ventricular function. In randomized studies, female patients are underrepresented and data on ICD therapy is limited. Atrial fibrillation (AF) is a determinant of poor prognosis but has not been consistently evaluated. We evaluated the risk factors for the occurrence of ventricular arrhythmia episodes in patients with primary ICD prophylaxis.

METHODS

Consecutive patients after ICD implantation for primary prophylaxis were followed. During follow-up, detected sustained episodes of ventricular arrhythmia were documented. Multivariate analysis controlled for propensity score was used to evaluate the correlation between gender, history of AF, and the occurrence of ventricular arrhythmia episodes.

RESULTS

A total of 400 patients (19.8% female; n = 79) were included. During follow-up, 64 patients (16%) had appropriate ICD therapy episodes. Men (18%) had significantly more often episodes than women (8%; p = 0.025). Patients with a history of AF (102, 25.5%) had significantly more often episodes (30%) compared to patients without a history of AF (11%; p < 0.001). In a multivariate model, only gender (p = 0.02) and history of AF (p < 0.001) were significantly associated predictors of the occurrence of appropriate ICD therapies during follow-up. Based on the propensity score model, the adjusted hazard ratio for male gender was 2.7 (p = 0.02) and 2.6 (p = 0.0004) for history of AF.

CONCLUSION

Male gender and history of AF are independent predictors for the occurrence of sustained ventricular arrhythmia in primary ICD prophylaxis. Further studies need to evaluate whether history of AF in female patients might be an indicator for higher risk of sudden cardiac arrhythmic death.