Left ventricular function and right ventricular pacing for isolated congenital heart block.

BACKGROUND: Right ventricular pacing has been the treatment of choice in patients with congenital complete atrioventricular block (CAVB). However, the effect of chronic right ventricular pacing on left ventricular function in young patients is still controversial. AIM: The aim of the study was to assess the change in left ventricular systolic function in young patients (age ≤20 years) paced for isolated CAVB and to identify possible predictors of left ventricular systolic dysfunction. METHODS: We studied 55 young patients who underwent permanent right ventricular pacemaker implantation for CAVB in the absence of significant structural heart disease. We excluded patients affected by any condition known to affect left ventricular function. Echocardiographic data prior to and after pacemaker implantation were obtained. RESULTS: The mean age at the time of pacemaker implantation was 20 months, range 2.3-72 months. The mean duration of follow-up was 94.86 (range: 2-268 months). Chronic right ventricular pacing affected left ventricular shortening fraction (LVSF) significantly (pre = 37.8 ±â€Š7.8 vs. post = 32.8 ±â€Š5.5%, P = 0.0036). In 14 patients (25.4%), LVSF decreased by at least 7% (group A). The only parameter studied able to significantly discriminate the two groups was a better baseline LVSF in group A (baseline LVSF: 42.1 ±â€Š5.2 vs. 32.2 ±â€Š2.2%, P = 0.019; cut-off value >39%, P <0.0001; area under the curve = 0.887). CONCLUSION: Chronic right ventricular pacing in young patients without significant structural heart disease is responsible for a significant reduction in left ventricular systolic function, especially in patients with a good baseline LVSF. These patients need close follow-up not only for pacing parameters but also for left ventricular functional evaluation.

Fontan completion without surgery.

OBJECTIVE: There are several modifications introduced in the preparation for a subsequent non-surgical transcatheter completion of the Fontan procedure. We report our experience with one type of the modification and the short-term results following its implementation. METHODS: During bidirectional cavopulmonary connection (BCPC) an intra-atrial lateral tunnel is additionally created, as intended for a Fontan procedure but fenestrated with a 10-14 mm aperture. The cardiac end of the superior vena cava (SVC) is then patched to maintain the physiology of BCPC. During the interventional transcatheter completion procedure, the SVC patch is perforated using radio-frequency (RF) energy, balloon-dilated, and stented as well. The aperture is closed with a device when required. Paired t-test was used to compare data before and after the Fontan completion. RESULTS: From June 2003 to February 2006, 16 patients (9 boys and 7 girls, mean age 12 months) underwent the surgical procedure described. The mean bypass time was 137 min and the mean ischemic time was 77 min. There were no operative deaths. One patient with bilateral SVC required a take down due to recurrent effusions. Ten months later, nine patients underwent completion (mean age 20 months, mean weight 10.6 kg). The stents were dilated to a mean diameter of 14.4mm. All except one aperture was closed with a device. The mean fluoroscopy time was 41 min. Oxygen saturation increased from 85 to 94% (p=0.001). Pulmonary artery pressures remained normal (16 mmHg before and 19 mmHg after, p=0.12). No patients required mechanical ventilation and none developed pleural effusions or arrhythmias. All were discharged from hospital within 6 days of the Fontan completion. Twenty-two months after Fontan, all were well. Echocardiography revealed no gradients across the stents. Two patients had minor leaks across the aperture. One underwent further stent dilatation a year later. CONCLUSIONS: Fontan completion without surgery is suitable in patients with single ventricles with lower mortality and morbidity, avoids multiple surgical interventions while maintaining the staged approach and allows for successive dilatation of the Fontan pathway to accommodate for growth.