The effects of gender on electrical therapies for the heart: procedural considerations, results and complications: A report from the XII Congress of the Italian Association on Arrhythmology and Cardiostimulation (AIAC).

Use of cardiac implantable devices and catheter ablation is steadily increasing in Western countries following the positive results of clinical trials. Despite the advances in scientific knowledge, tools development, and techniques improvement we still have some grey area in the field of electrical therapies for the heart. In particular, several reports highlighted differences both in medical behaviour and procedural outcomes between female and male candidates. Women are referred later for catheter ablation of supraventricular arrhythmias, especially atrial fibrillation, leading to suboptimal results. On the opposite females present greater response to cardiac resynchronization, while the benefit of implantable defibrillator in primary prevention seems to be less pronounced. Differences on aetiology, clinical profile, and development of myocardial scarring are the more plausible causes. This review will discuss all these aspects together with gender-related differences in terms of acute/late complications. We will also provide useful hints on plausible mechanisms and practical procedural aspects.

The effects of gender on electrical therapies for the heart: physiology, epidemiology, and access to therapies.

The difference between men and women is clear even just by looking at an electrocardiogram: females present higher resting heart rate, a shorter QRS complex length and greater corrected QT interval. The development of these differences from pubertal age onward suggests that sexual hormones play a key role, although their effect is far from being completely understood. Different incidences between sexes have been reported for many arrhythmias, both ventricular and supraventricular, and also for sudden cardiac death. Moreover, arrhythmias are an important issue during pregnancy, both for diagnosis and treatment. Interestingly, cardiovascular structural and electrophysiological remodelling promoted by exercise training enhances this 'gender effect'. Despite all these relevant issues, we lack gender specific recommendations in the current guidelines for electrical therapies for heart rhythm disorders and heart failure. Even more, we continue to see that fewer women are included in clinical trials and are less referred than men for these treatments.

Primary prevention of sudden cardiac death: can we afford the cost of cardioverter-defibrillators? Data from the Search-MI Registry-Italian sub-study.

BACKGROUND: Large randomized trials show that in appropriately selected patients with left ventricular dysfunction, implantable cardioverter-defibrillators (ICDs) can improve overall survival at 2-5 years. Since direct implementation of the criteria used in the MADIT II and SCD-HeFT will lead to a marked rise in ICD implants, there is a growing fear that increased use of ICDs may cause a dramatic burden to health care systems. The ICD has traditionally been seen as an expensive form of treatment, which is difficult to accept at the first look. This is mainly due to the nonlinear character of the ICD investment, characterized by high initial expenditure, followed by a deferred pay-off in terms of clinical benefits. Cost-effectiveness analysis may help provide a different perspective on the problem of ICD cost, as may estimation of the daily cost of ICD treatment, assuming a time horizon of 5-7 years--a particularly interesting subject for further registry studies. METHODS AND RESULTS: Based on real expenditure data from 2002 to 2005, as recorded in the Search-MI Registry-Italian Sub-study of patients implanted on MADIT II indications, we estimated the daily costs associated with the device and leads. Over a 5-7 year time horizon, the average daily cost was estimated to be euro 4.60-euro 6.70. Translation of these figures into U.S. market conditions suggests a daily cost of around $7.90-$11.40. CONCLUSIONS: These findings appear useful to help evaluate the affordability of ICD in comparison with other therapeutic options in a context of limited available economic resources.

Temporal variability of atrial tachyarrhythmia burden in bradycardia-tachycardia syndrome patients.

AIMS: Several studies have tested non-pharmacological therapies for atrial tachyarrhythmias (ATs) by measuring the cumulative time (burden) the patient spends in arrhythmia. Contradictory results questioned either therapy efficacy or statistical power of the trials. We studied AT burden variability in patients paced for sinus node disease (SND) in order to interpret currently published data appropriately and to evaluate reliable sample sizes. METHODS AND RESULTS: One hundred and five patients with AT and SND received a dual chamber pacemaker with antitachyarrhythmia-pacing capability, and were followed for 13 months. Seventy-eight patients (74%) suffered AT recurrences. Device-gathered diagnostic measures were used to simulate results of randomized studies both with crossover and parallel design. The sample size required for statistically significant results was calculated as a function of the expected therapy-induced burden reduction. AT burden intra-patient variability was high: 43% of patients showed intrinsic fluctuations hiding any therapy-induced burden reduction lower than 30%. Demonstrating therapeutic breakthrough through a 6 month study would require 290 patients with crossover design and 5800 patients with parallel design. Doubling the study period requires 400 and 3000 patients, respectively. CONCLUSION: Patients with AT and paced for SND showed high intra-patient burden variability, which could possibly hide an AT burden reduction induced by a therapy. Previous studies involving non-pharmacological therapies utilizing AT burden endpoints could lack the power to reach statistical significance.