Ventricular pacing from the coronary sinus of a patient with a Fontan circulation.

Permanent pacing of the left ventricle was achieved by transvenous implantation of a steroid-eluting electrode into the coronary sinus in a patient who had undergone a Fontan operation. This approach to endocardial pacemaker implantation is potentially of considerable value in patients who do not have transvenous access to the right ventricle.     

Case Report: Permanent Ventricular Pacing from Coronary Sinus after Fontan Operation Using Newly Designed Left Ventricular Lead

The functional single ventricles in Fontan procedures are isolated from the systemic return and thereby precluding conventional endocardial ventricular pacing. We reported a young patient who underwent Fontan operation at the age of 8 years old. He presented with significant bradyarrhythmias 13 years later requiring pacing therapy. A specially designed self-retained left ventricular (LV) pacing lead was implanted successfully through the coronary sinus and its anterolateral branch with satisfactory and stable chronic thresholds by one year's follow-up.     

Transhepatic approach to create stent fenestration in the extracardiac fontan conduit in a child with dextrocardia and interrupted inferior vena cava with azygos continuation

Plastic bronchitis is a rare life‐threatening complication of Fontan operation. When medical treatment is ineffective in the setting of high systemic venous pressures, Fontan fenestration may be considered to decompress venous pressures and improve cardiac output by creation of the right‐to‐left shunting. However, transcatheter approach can be difficult in patients with complex venous anatomy. We report a 4‐year‐old girl born with hypoplastic left ventricle and heterotaxy syndrome, who developed plastic bronchitis following extracardiac Fontan procedure. Her venous anatomy was complex with dextrocardia and interrupted inferior vena cava with azygos continuation. Stent fenestration was successfully performed via transhepatic approach, which was selected based on the anatomical relationship (between extracardiac conduit, left atrium, and hepatic veins) delineated by pre‐catheterization cardiac MRI. Simultaneous transesophageal echocardiography guided the intervention. Her plastic bronchitis improved significantly in 3 months but slowly progressed after the stent fenestration. At her 8‐month follow‐up, stent fenestration remains open and she is currently under heart transplantation evaluation due to persistent plastic bronchitis. Treatment of plastic bronchitis can be undertaken with Fontan fenestration, with pre‐procedural MRI playing an essential role in patients with complex venous anatomy. © 2012 Wiley Periodicals, Inc.     

Transvenous right atrial and left ventricular pacing after the Fontan operation: long-term hemodynamic and electrophysiologic benefit of early atrioventricular resynchronization

We report a case of long-term, successful, endocardial atrioventricular pacing in a 32-year-old man who had severe heart failure and ascites after having undergone a Fontan procedure for tricuspid atresia 9 years earlier. The patient was referred to our hospital for Fontan revision. However, electroanatomic mapping of the right atrium revealed viable tissue at the interatrial septum above the os of the coronary sinus, and it appeared that the left ventricle could be paced from a coronary sinus branch. Therefore, instead of Fontan revision, an endocardial atrioventricular pacemaker was implanted transvenously. On 5-year follow-up, the patient remained in New York Heart Association functional class I and had not been readmitted to the hospital for congestive heart failure or arrhythmias. His atrial and ventricular leads continued to show excellent pacing and sensing results.     

Salvage of an epicardial lead in a pacemaker‐dependent patient with Fontan palliation using an IS‐1 extender

We present a case report of severed epicardial atrial lead salvage using an IS‐1 lead extender. A 37‐year‐old male with single ventricle physiology, Fontan palliation, sinus node dysfunction, recurrent atrial tachycardias, and atrial fibrillation resulting in failing Fontan physiology presented with failure of the atrial pacing lead. The patient was initially paced with an epicardial system that had to be removed due to pocket infection, and the epicardial leads were cut and abandoned. Given his significant sinus node dysfunction he required atrial pacing to allow for rhythm control. The failing Fontan physiology of the patient precluded him from undergoing surgery for epicardial lead placement or a complex intravascular lead placement procedure (although anatomically feasible). We considered the option of salvaging the existing epicardial atrial leads to provide atrial pacing, allowing for rhythm control and improvement of his failing Fontan physiology as a bridge to a more permanent pacing solution. This case report is important because it demonstrates how a lead extender can be used to salvage a severed pacemaker lead. This may be useful for patients in whom implantation of new leads is not promptly feasible due to patient anatomy and/or clinical status.     

Permanent pacing using a coronary sinus lead in a patient with univentricular physiology: an extended application of biventricular pacing technology.

In the past, patients requiring permanent pacing with difficult right ventricular (RV) access were usually subjected to epicardial pacing by a surgical approach. This report describes a young patient with univentricular physiology following repeated palliative surgery for complex congenital heart disease. The patient had symptomatic complete heart block and a dual chamber pacemaker with transvenous atrial and ventricular leads was implanted successfully. The ventricle was paced through the posterolateral cardiac vein with a lead specially designed for cardiac resynchronization therapy. This case illustrates an extended application of the recently developed coronary sinus lead in selected patients, when conventional RV endocardial pacing is impossible.     

A rare cause of stroke in a patient with a cardiac pacemaker

The authors report the case of a 78 year old woman admitted to hospital for recurrent cerebrovascular accidents, the initial investigation of which was normal. This pacemaker patient had a displacement of the definitive ventricular pacing catheter which was positioned in the left ventricle through a patent foramen ovale. The diagnosis was suspected on clinical and echocardiographic examination and confirmed by transthoracic and transoesophageal echocardiography. In view of the risk of systemic embolism, the pacing catheter was repositioned by an endovascular approach in the right ventricle.     

Surgical Options for Endocardial Lead Placement when Upper Veins are Obstructed or Nonusable

In 35 patients (24 adults, 11 children), two techniques were used to implant endocardial pacemaker or defibrillator leads in the presence of complete occlusion or nonusability of upper veins. The obstructed veins were the subclavian, innominate, and superior vena cava (SVC). Most of the obstructions occurred secondary to previous implant of multiple leads. Twenty-four patients had occlusion of the subclavian veins; 7 of both the subclavians and innominates; 4 had stenosis of the SVC. Twenty-seven patients with obstructed subclavian veins, but with patent innominates, underwent direct implants via cut-down internal jugular vein for one or two leads, as needed. Eight patients with obstructed innominate veins or SVC underwent a direct transthoracic transatrial approach (TTTA). This method involves a parasternal extrapleural route through the mediastinum to directly puncture the right atrium. The leads are then implanted endocardially, under fluoroscopy. There were no complications with either method, and the implanted units have been working well during up to 14 years follow-up. These two techniques circumvent the problem of obstructed upper veins--which limits the options for implanting endocardial pacing systems.     

Hemodynamic responses to isolated increments in heart rate by atrial pacing after a Fontan procedure

The physiologic role of the right ventricle has long been a subject of interest to physiologists. The Fontan operation provides a human model for studying the circulation in series devoid of a subpulmonic right ventricle. The hemodynamic response to isotonic exercise in this setting has been established, and differs appreciably from normal. However, the physiologic response to an increase in heart rate (atrial pacing) as an isolated variable has not been examined and compared to atrial pacing in hearts with two concordant subarterial ventricles. Accordingly, we compared the supine bicycle exercise response to rate-equivalent right atrial pacing in nine patients after atriopulmonary anastomoses (the Fontan operation) for single ventricle or tricuspid atresia. Cardiac index increased 77% with exercise (rest 2.6 L/min/m2; exercise 4.6 L/min/m2) but decreased 12% with atrial pacing (rest 2.5 L/min/m2; pacing 2.2 L/min/m2). Pulmonary arterial oxygen saturation declined significantly during exercise (rest 68%; exercise 31%) and during atrial pacing (control 72%; pacing 64%). The mean increment in pulmonary arterial pressure was 1.3 times greater with exercise (rest 14 mm Hg; exercise 20 mm Hg) than with pacing (control 12 mm Hg; pacing 16 mm Hg). Peak systemic arterial systolic pressure increased 14% with exercise but was unchanged by pacing. Systemic and pulmonary vascular resistances fell with exercise but changed insignificantly during atrial pacing. Stroke volume rose slightly with exercise but fell significantly with pacing.(ABSTRACT TRUNCATED AT 250 WORDS)     

Long-term endocardial atrial pacing in children with postoperative bradycardia-tachycardia syndrome and limited ventricular access

Permanent pacing in children, including those with postoperative bradycardia-tachycardia syndrome, has been compromised by the availability of pulse generators, electrode leads and implantation techniques designed for the adult patient. Recent technologic improvements and simplified implantation techniques have reduced many of these barriers and have made endocardial as well as epicardial ventricular pacing more feasible. However, in some children, ventricular pacing may be impeded by anatomic abnormalities due to congenital anomalies or prior cardiac operations. In these instances, endocardial atrial pacing may provide an alternative therapeutic approach in selected patients. This report describes the use of endocardial atrial demand pacing in four children with postoperative bradycardia-tachycardia syndrome and restricted ventricular access. This approach controls symptomatic bradycardia, helps prevent and convert paroxysmal intraatrial tachycardia and overcomes the problem of limited ventricular access.     

Two problems and a single solution: Covered stent implantation to close an anterograde pulmonary flow and treat hypoplastic left pulmonary artery after Fontan operation

Several issues may impact on the function of a Fontan circulation including accessory source of pulmonary blood flow and pulmonary artery anatomy. Here we report on a 5.5‐year‐old boy who showed failing Fontan circulation due to left pulmonary artery stenosis/hypoplasia and significant forward pulmonary blood flow through the native pulmonary artery. Successful implantation of a 34‐mm CP covered stent in the left pulmonary artery in a Fontan patient was useful for simultaneous successful treatment of residual antegrade flow from the systemic ventricle to the pulmonary artery and enlargement of hypoplastic left pulmonary artery. © 2015 Wiley Periodicals, Inc.     

Hybrid approach to pulmonary vein stenting after Fontan palliation

Pulmonary vein stenosis is poorly tolerated in patients who have undergone Fontan palliation and typically requires surgical or transcatheter intervention. Percutaneous transcatheter approaches to intervention can be technically difficult due to challenging anatomy. A hybrid per-atrial transcatheter approach for stenting pulmonary veins provides a direct approach to the pulmonary veins and has the potential to improve safety and efficacy of this complex intervention. We describe our experience with hybrid per-atrial pulmonary vein stenting in three patients with pulmonary vein stenosis following Fontan palliation.     

Reversal of protein losing enteropathy with prednisone in adults with modified Fontan operations: long term palliation or bridge to cardiac transplantation?

Protein losing enteropathy (PLE), defined as severe loss of serum protein into the intestine, occurs in 4-13% of patients after the Fontan procedure and carries a dismal prognosis with a five year survival between 46% and 59%. Chronically raised systemic venous pressure is thought to be responsible for the development of PLE in these patients, with perhaps superimposed immunological or inflammatory factors. The success rate of contemporary medical, transcatheter, and surgical treatments attempting to reduce systemic venous pressure ranges from 19% to 40%. Prednisone treatment for PLE has been tried, with variable success rates reported in children. The effect of prednisone in adult patients with PLE after the Fontan procedure is largely unknown. Two cases of PLE in adults (a 39 year old woman and a 25 year old man) after modified Fontan procedure who responded dramatically to oral prednisone treatment are reported, suggesting that a trial of this "non-invasive" treatment should be considered as long term palliation or bridge to cardiac transplantation.     

Major intrahepatic veno-venous fistula after modified Fontan operation treated by transcatheter implantation of amplatzer septal occluder

Patients with complex congenital cardiac malformations who have been converted to the Fontan circulation with partial exclusion of the hepatic veins may develop progressive cyanosis because of formation of intrahepatic veno-venous malformations. We describe transcatheter closure of a major intrahepatic fistula in such a setting using an Amplatzer septal occluder delivered by the left jugular venous approach in a 5 year old boy.     

Electrophysiologic study of the left ventricle: indications and safety.

Eighty patients (69 with documented or suspected recurrent ventricular tachycardia or fibrillation, ten with left bundle-branch block, and one with the Wolff-Parkinson-White syndrome) underwent both right ventricular and left ventricular programmed electrical stimulation, including ventricular pacing and the introduction of one or two ventricular extrastimuli or electrode catheter mapping of the left ventricle (or both). Left ventricular catheters were introduced precutaneously via the femoral artery (of 61 patients, one required secondary repair) or via brachial arteriotomy (of 19 patients, two required secondary repair). All patients received an intravenously administered bolus of hep arin (5,000 units) following the insertion of the left ventricular catheter and then 1,000 units/hr after the first hour of study. No patients had cerebrovascular, systemic thromboembolic, or cardiac sequelae. In four (12 percent) of 34 patients with inductible ventricular tachycardia, programmed electrical stimulation of the left ventricle was required for initiation. Extensive left ventricular endocardial mapping was performed in 45 patients. Our experience suggests that (1) electrophysiologic study of the left ventricle can be performed safely, (2) programmed electrical stimulation of the left ventricle is indicated when a suspected ventricular tachyarrhythmia cannot be induced from the right ventricle, and (3) endocardial mapping of the left ventricle is indicated when surgery is being considered to abolish recurrent sustained ventricular tachycardia.     

Ventricular function in the single ventricle before and after Fontan surgery

To better delineate the importance of ventricular function in patients with a single ventricle and assess its relation to outcome after the Fontan procedure, 47 patients with a single ventricle were studied. Ventricular ejection fraction was estimated by radionuclide angiocardiography. Before Fontan surgery, ejection fraction was 0.57 ± 0.10 (mean ± standard deviation). This differed significantly from the normal mean left ventricular ejection fraction of 0.68 ± 0.09 (p < 0.001) derived in our laboratory by radionuclide angiocardiographic methods. Age, ventricular morphology and the presence of pulmonary artery band or systemic to pulmonary artery shunts had no statistical relation to ventricular ejection fraction in patients with a single ventricle. Serial preoperative evaluation in 15 patients over 3.8 ±1.3 years revealed no significant change in ventricular ejection fraction; however, increased atrioventricular valve regurgitation was documented in 4 of these 15. Modified Fontan procedure was performed in 24 of the 47 study patients; 7 have died, 1 has undergone cardiac transplantation and 1 faces possible transplantation. No difference was noted in preoperative ejection fraction between survivors and nonsurvivors. Ventricular morphology, age at Fontan surgery and operative factors such as bypass and cross-clamp time were not related to functional outcome. Preoperative ejection fraction of 0.52 ± 0.08 decreased to 0.39 ± 0.11 (p < 0.001) when evaluated 1.16 ± 0.44 years after Fontan surgery. In patients with a single ventricle (1) ventricular ejection fraction is less than that of the normal systemic ventricle; (2) during childhood, ejection fraction is not related to age or ventricular morphology; and (3) ventricular ejection fraction frequently decreases after a Fontan repair. Thus, long-term studies of clinical course and ventricular function are essential before altering recommendations for pursuing the Fontan repair.     

Transthoracic percutaneous access for electroanatomic mapping and catheter ablation of atrial tachycardia in patients with a lateral tunnel Fontan

BACKGROUND: The incidence of atrial tachycardia following Fontan surgery is high, but access to the pulmonary venous atrium, a frequent site of arrhythmia origin, is limited. OBJECTIVES: The purpose of this study is to report our results with a novel transthoracic percutaneous technique that provides direct access to the pulmonary venous atrium for electrophysiologic procedures. METHODS: Six transthoracic ablation procedures were performed in five patients (age 1.2-17 years, weight 9.2-68.4 kg) with a lateral tunnel Fontan. Under biplane fluoroscopy, a percutaneous needle was advanced at the selected intercostal space toward the pulmonary venous atrium. Once access was confirmed, a sheath was placed over a wire and a Navistar CARTO catheter advanced for mapping and ablation. Additional catheters were placed in the baffle and esophagus for pacing and reference. Atrial tachycardia was induced, electroanatomic mapping performed, and candidate areas tested with entrainment techniques. Radiofrequency ablation was performed and success defined as the inability to reinduce tachycardia using the initiating protocol. RESULTS: All tachycardias were ablated. Procedure time ranged from 3.7 to 4.9 hours, and fluoroscopy time ranged from 31 to 70 minutes. Hospital stay was 2 days. One patient had a pneumothorax and two had a hemothorax that was drained. Tachycardia recurred in one patient at 3 months. Ablation was repeated successfully. Four patients are free of tachycardia at follow-up ranging from 6 to 29 months. Follow-up is not available for one child. CONCLUSION: Transthoracic percutaneous access provided a direct route to the pulmonary venous atrium for successful mapping and radiofrequency ablation in Fontan patients.     

Cardiac Implantable Electronic Devices in the Fontan Patient

As a result of remarkable progress in operative techniques and cardiology care during childhood, Fontan patients continue to age and require team-based multidisciplinary expertise to manage complications encountered in adulthood. They face particular challenges in terms of altered hemodynamic stressors, cardiac and hepatic failure, and arrhythmias. Arrhythmias in Fontan patients are highly prevalent and associated with underlying anatomy, surgical technique, and postoperative sequelae. Diagnostic tools, treatments, and device strategies for arrhythmias in Fontan patients should be adapted to the specific anatomy, type of surgical repair, and clinical status. Great strides in our understanding of arrhythmia mechanisms, options and techniques to obtain access to relevant cardiac structures, and application of both old and new technologies have contributed to improving cardiac implantable electronic device (CIED) therapies for this unique population. In this state-of-the-art review, we discuss the various arrhythmias encountered in Fontan patients, their diagnosis, and options for treatment and prevention, with a focus on CIEDs. Throughout, access challenges particular to the Fontan circulation are considered. Recently developed technologies, such as the subcutaneous implantable cardioverter defibrillator, carry the potential to be transformative but require awareness of Fontan-specific issues. Moreover, new leadless pacing technology represents a promising strategy that may soon become applicable to Fontan patients with sinus-node dysfunction. CIEDs are essential tools in managing Fontan patients, but the complex clinical scenarios that arise in this patient population are among the most challenging for the electrophysiologist treating patients with congenital heart disease.     

Termination of sustained ventricular tachycardia by external noninvasive pacing

Cardiac pacing has proven useful in the termination of sustained ventricular tachycardia (VT). In this study, the effectiveness of external noninvasive temporary pacing was compared with traditional endocardial burst ventricular pacing for the termination of sustained and hemodynamically stable VT. In 14 patients, 16 VT morphologies induced by programmed right ventricular extrastimulation were reproducibly terminated by endocardial burst pacing (3 to 9 complexes). VT cycle lengths averaged 392 +/- 97 ms (standard deviation) and ranged from 300 to 690 ms. The endocardial burst pacing cycle length used to terminate VT averaged 298 +/- 93 ms (range 220 to 600 ms). External burst pacing terminated 14 of 16 VT morphologies (88%). The pacing cycle length used to terminate these 14 VTs averaged 282 +/- 44 ms. The number of ventricular captures ranged from 5 to 20 beats. Failure to terminate 2 VT morphologies probably represented a failure of the device to capture the ventricle. Acceleration of VT occurred in 1 patient with burst external noninvasive pacing. These observations suggest that external burst pacing may be an effective means of terminating sustained VT in some patients.     

Early experiences of endocardial catheter mapping of the left ventricle in patients with sustained ventricular tachycardia--efficacy, safety and complications

In 23 patients with recurrent sustained ventricular tachycardia (VT) which originated from the left ventricle, endocardial catheter mapping has performed. In an additional 14 patients we also stimulated their left ventricle for non-sustained VT. Multiple sites could be mapped for the recording of local electrical activity, for pacing and for the induction of VT. These procedures could be done without complication. A careful, reasonable, and safe method of endocardial mapping will facilitate clinical electrophysiologic study.