Atrial arrhythmia after surgical closure of atrial septal defects in adults

BACKGROUND: Atrial flutter and atrial fibrillation are causes of morbidity in adults with an atrial septal defect. In this study, we attempted to identify risk factors for atrial flutter and fibrillation both before and after the surgical closure of an atrial septal defect. METHODS: We searched for preoperative and postoperative atrial flutter or fibrillation in 213 adult patients (82 men and 131 women) who underwent surgical closure of atrial septal defects because of symptoms, a substantial left-to-right shunt (ratio of pulmonary to systemic blood flow, >1.5:1), or both at Toronto Hospital between 1986 and 1997. RESULTS: Forty patients (19 percent) had sustained atrial flutter or fibrillation before surgery. As compared with the patients who did not have atrial flutter or fibrillation before surgery, those who did were older (59+/-11 vs. 37+/-13 years, P<0.001) and had higher mean pulmonary arterial pressures (25.0+/-9.7 vs. 19.7+/-8.2 mm Hg, P=0.001). There were no perioperative deaths. After a mean follow-up period of 3.8+/-2.5 years, 24 of the 40 patients (60 percent) continued to have atrial flutter or fibrillation. The mean age of these patients was greater than that of the 16 who converted to sinus rhythm (P=0.02). New-onset atrial flutter or atrial fibrillation was more likely to have developed at follow-up in patients who were older than 40 years at the time of surgery than in those who were 40 or younger (5 of 67 vs. 0 of 106, P=0.008). Late events (those occurring more than one month after surgery) included stroke in six patients (all but one with atrial flutter or fibrillation, one of whom died) and death from noncardiac causes in two patients. Multivariate analysis showed that older age (>40 years) at the time of surgery (P=0.001), the presence of preoperative atrial flutter or fibrillation (P<0.001), and the presence of postoperative atrial flutter or fibrillation or junctional rhythm (P=0.02) were predictive of late postoperative atrial flutter or fibrillation. CONCLUSIONS: The risk of atrial flutter or atrial fibrillation in adults with atrial septal defects is related to the age at the time of surgical repair and the pulmonary arterial pressure. To reduce the morbidity associated with atrial flutter and fibrillation, the timely closure of atrial septal defects is warranted.     

Radiofrequency Catheter Ablation of Posteroseptal Accessory Pathways–Results of a Step-by-Step Ablation Approach

Introduction: Transcatheter radiofrequency ablation of posteroseptal accessory pathways (AP) is challenging. A number of different interventional approaches have been suggested by different groups. The selection of the initial approach is crucial in order to reduce radiation exposure and the number of unsuccessful lesions applied. We present our ablation technique as guided by a simplified electrocardiographic analysis of the delta wave polarity and the electrophysiologic mapping results. Methods and Results: Out of 35 manifest APs encountered in the right (n=17) or the left posteroseptum (n=18) in 35 patients, 34 were successfully ablated. Despite their left sided location, 7 of the 18 left sided APs were ablated after switching from an initial arterial to a venous approach looking for an appropriate target site in the right posteroseptal space or within the coronary sinus network. The other 11 left sided APs were ablated in the mitral ring, on 2 occasions, on their atrial aspect through a retrograde transmitral approach. On the contrary, 16 of the 17 right sided APs were successfully ablated exclusively through a venous approach. Fourteen of these were ablated in the right posteroseptum, in 2 cases, only after reaching their ventricular aspect. Two right sided APs were interrupted in the coronary sinus os and the middle cardiac vein respectively. Conclusion: It appears that even though the electrocardiographic and electrophysiologic location of the AP in the posteroseptal space helps select the appropriate initial approach, it does not always guarantee a successful ablation procedure in the expected site of the corresponding atrioventricular ring. Not uncommonly, it will be necessary to look after intermediate target sites within the coronary sinus to improve the overall ablation success rate.     

Atrial High-Rate Episodes in Patients with Devices Without a History of Atrial Fibrillation: a Systematic Review and Meta-analysis

Cardiovascular Drugs and Therapy - Atrial high-rate episodes (AHREs) recorded with cardiac implantable electronic devices (CIEDs) have been associated with the development of clinical atrial...     

Ventilatory responses to exercise in adults after repair of tetralogy of Fallot.

BACKGROUND--Adult patients with total correction of tetralogy of Fallot may have poor exercise capacity associated with impaired right heart function and in particular pulmonary regurgitation. The ventilatory responses to exercise were studied in a group of such patients to assess relations between ventilation, exercise capacity, and right ventricular function. METHODS--30 patients (7 female) (aged 27.8 (6.0) years) and 30 (7 female) controls of a similar age range were studied prospectively. All underwent exercise testing with metabolic gas exchange to determine peak oxygen consumption (peak VO2), and (as indices of the ventilatory response) the slope of the relation between both respiratory rate (RR) and ventilation (VE) against carbon dioxide production (VCO2). Patients were studied with pulsed wave Doppler echocardiography to determine pulmonary arterial systolic and diastolic flow characteristics. Patients were defined as having restrictive right ventricular function where diastolic pulmonary forward flow was seen coincident with atrial systole. RESULTS--In the group with tetralogy of Fallot mean (SD) peak VO2 was 35.3 (7.5) ml/kg/min (93.6 (15.3) % of expected for age, weight, height and sex). The RR/VCO2 slope was steeper in the Fallot group (6.8 (2.6) v 9.6 (4.7), P < 0.02). Those with restrictive right ventricles achieved a higher peak VO2 than those without (82.5 (10.1) % v 100.9 (13.8), P < 0.001). In the Fallot group alone, there was an inverse relation between ventilatory response and peak VO2 (RR/VCO2 v peak VO2; r = -0.63, P = 0.003: VE/VCO2 v peak VO2; r = -0.62, P < 0.001). CONCLUSIONS--Many of these patients with repaired tetralogy of Fallot had near normal exercise capacity, but as exercise capacity decreased, the ventilatory response to exercise increased. This was not due to alterations in pulmonary function tests or to the effects of cardiac size causing decreased lung volume. It may be that the increased ventilatory rate at a given level of carbon dioxide production acts as a respiratory pump aiding right ventricular function.