S. Badia

Mid-Term Results of Surgical Treatment of Atrial Fibrillation in Valvular Heart Disease Assesed by Speckle Tracking Echocardiography

Background Atrial fibrillation frequently affects patients with valvular heart disease. Ablation of atrial fibrillation during valvular surgery is an alternative for restoring sinus rhythm. Objectives This study aimed to evaluate mid-term results of successful atrial fibrillation surgical ablation during valvular heart disease surgery, to explore left atrium post-ablation mechanics and to identify predictors of recurrence. Methods Fifty-three consecutive candidates were included. Eligibility criteria for ablation included persistent atrial fibrillation <10 years and left atrium diameter < 6.0 cm. Three months after surgery, echocardiogram, 24-hour Holter monitoring and electrocardiograms were performed in all candidates who maintained sinus rhythm (44 patients). Echo-study included left atrial deformation parameters (strain and strain rate), using 2-dimensional speckle-tracking echocardiography. Simultaneously, 30 healthy individuals (controls) were analyzed with the same protocol for left atrial performance. Significance was considered with a P value of < 0.05. Results After a mean follow up of 17 ± 2 months, 13 new post-operative cases of recurrent atrial fibrillation were identified. A total of 1,245 left atrial segments were analysed. Left atrium was severely dilated in the post-surgery group and, mechanical properties of left atrium did not recover after surgery when compared with normal values. Left atrial volume (≥ 64 mL/m2) was the only independent predictor of atrial fibrillation recurrence (p = 0.03). Conclusions Left atrial volume was larger in patients with atrial fibrillation recurrence and emerges as the main predictor of recurrences, thereby improving the selection of candidates for this therapy; however, no differences were found regarding myocardial deformation parameters. Despite electrical maintenance of sinus rhythm, left atrium mechanics did not recover after atrial fibrillation ablation performed during valvular heart disease surgery.

Indications for Ventricle Assist Devices

Despite widespread use of evidence-based therapies the morbidity and mortality of heart failure has not changed, and it remains the most common hospital discharge diagnosis for patients older than 65 years old of age. Approximately 5 million patients in the United States of America have cardiac failure, and over 550,000 patients are diagnosed with heart failure for the first time each year (Levy et al, 2002; Hunt et al, 2005). The European Society of Cardiology represents countries with a population of more than 900 million, and in their last guidelines they reported that there are at least 15 million patients suffering this disease in those 51 countries (Dickstein et al, 2008). Heart failure is primarily a condition of the elderly (Kannel & Belanger, 1991), and thus the widely recognized “aging of the population” also contributes to the increasing incidence of heart disease. The incidence of cardiac failure approaches 10 per 1,000 population after age 65 years, and approximately about 80% of patients hospitalized with heart failure are older than 65 years old (Masoudi & Havranek, 2002). There are several reasons that may explain why the prevalence of heart failure is increasing: ageing of the population, the success in prolonging survival in coronary patients, and the success in postponing coronary events by effective prevention in those patients at high risk or those patients who have already survived a first event (secondary prevention) (Senni et al, 1999). Advances in medical therapy have resulted in improved survival in patients with moderate and severe heart failure, but the prognosis for end-stage heart failure patients still remains poor. The conclusion of all these aspects is that there is a change in the demographics of heart failure patients in recent years, and an increased survival of older patients with heart disease. At present time, cardiac transplantation remains the gold standard of cardiac replacement therapy. However, the supply of donor hearts is limited and therefore is not an option for many patients because of age and other comorbid conditions. Alternative forms of cardiac replacement therapy are being investigating. This includes cell therapy, xenotransplantation, ventricle assist devices implantation and total artificial heart. Although initially the indications for heart mechanical assistance are similar to those developed in the1960s for the use of intra-aortic balloon pumps the indications have developed into more complex cases which must be considered. Ventricle assist devices are more and more reliable and its size is becoming smaller with the passing of time, improving patient’s outcomes.