Preventing sudden cardiac death in athletes: in search of evidence-based, cost-effective screening.

Sudden cardiac death in athletes is a recurrent phenomenon at sporting events and during training. Recent studies have associated sudden cardiac death with such cardiovascular conditions as coronary artery anomalies, cardiomyopathies, and electrocardiographic abnormalities, most of which are screenable with modern imaging techniques. We recently inaugurated the Center for Coronary Artery Anomalies at the Texas Heart Institute, which is dedicated to preventing sudden cardiac death in the young and investigating coronary artery anomalies. There, we are conducting 2 cross-sectional studies intended to firmly establish and quantify, in a large group of individuals from a general population, risk factors for sudden cardiac death that arise from specific cardiovascular conditions. In a pilot screening study, we are using a brief, focused clinical questionnaire, electrocardiography, and a simplified novel cardiovascular magnetic resonance screening protocol in approximately 10,000 unselected 11- to 15-year-old children. Concurrently, we are prospectively studying the prevalence of these same conditions, their severity, and their relation to exercise and mode of death in approximately 6,500 consecutive necropsy cases referred to a large forensic center. Eventually, we hope to use our findings to develop a more efficient method of preventing sudden cardiac death in athletes. We believe that these studies will help quantify sudden cardiac death risk factors and the relevance of associated physical activities--crucial information in evaluating the feasibility and affordability of cardiovascular magnetic resonance-based screening. We discuss the rationale for and methods of this long-term endeavor, in advance of reporting the results.

Conservative management of infected pacemaker and implantable defibrillator sites with a closed antimicrobial irrigation system.

AIMS: Current guidelines recommend that patients with infected cardiac rhythm management device (CRMD) sites undergo removal of all system components (pulse-generator and leads). However, lead removal may not be an option for patients who lack access to state-of-the-art technology, lack the necessary financial resources, or are at very high risk because of age or concomitant disease. In this case series, we report our successful experience with conservative treatment of five such patients, who had CRMD infections localized to the device pocket. METHODS AND RESULTS: The device pocket and remaining hardware were completely sterilized to successfully eradicate the infection. First, all non-viable tissue, chronically inflamed tissue, granulation tissue, and scar tissue were completely removed, with special attention to complete haemostasis. Secondly, all non-essential foreign materials, including old sutures and plastic suture anchoring sleeves, were removed, and the remaining hardware was completely sterilized. To achieve this goal, we used mechanical means (scrubbing and pulsed lavage), as well as a closed antimicrobial irrigation system. In all five cases, the pulse-generator site was saved, lead removal was avoided, and the patients were free of local or systemic infection for a minimum of 1 year after treatment. CONCLUSION: Our conservative approach to the management of infected CRMD sites is feasible and beneficial in selected patients who are at very high risk for lead removal or who lack access to the technology necessary for safe performance of this procedure, provided that the infection is limited to the implant site.

Morphological, compositional, structural, and optical properties of Si-nc embedded in SiOx films.

Structural, compositional, morphological, and optical properties of silicon nanocrystal (Si-nc) embedded in a matrix of non-stoichiometric silicon oxide (SiOx) films were studied. SiOx films were prepared by hot filament chemical vapor deposition technique in the 900 to 1,400°C range. Different microscopic and spectroscopic characterization techniques were used. The film composition changes with the growth temperature as Fourier transform infrared spectroscopy, energy dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy reveal. High-resolution transmission electron microscopy supports the existence of Si-ncs with a diameter from 1 to 6.5 nm in the matrix of SiOx films. The films emit in a wide photoluminescent spectrum, and the maximum peak emission shows a blueshift as the growth temperature decreases. On the other hand, transmittance spectra showed a wavelength shift of the absorption border, indicating an increase in the energy optical bandgap, when the growth temperature decreases. A relationship between composition, Si-nc size, energy bandgap, PL, and surface morphology was obtained. According to these results, we have analyzed the dependence of PL on the composition, structure, and morphology of the Si-ncs embedded in a matrix of non-stoichiometric SiOx films.

Implantable cardioverter defibrillator lead placement in the middle cardiac vein after tricuspid valve surgery.

AIMS: Pacing and defibrillation with an implantable cardioverter defibrillator (ICD) after tricuspid valve surgery can be challenging if right ventricular (RV) lead placement is contraindicated or safe lead placement in the RV apex is impossible. METHODS AND RESULTS: In six patients for whom RV lead placement and repeat thoracotomy were contraindicated, ventricular pacing and sensing were achieved with bipolar leads placed in the lateral branch of the coronary sinus or in the atrialized portion of the RV or without helix exposure of the pace-sense electrodes of the defibrillator leads. After cannulation of the middle cardiac vein (MCV), a defibrillator coil lead was delivered there and placed in the farthest apical position. An 'active can' pulse generator was implanted in the left retromammary region. Biphasic shocks were delivered between the MCV coil, SVC coil, and the 'active can', or between the MCV coil, azygous vein coil, and the 'active can'. All six patients underwent successful implantation. All patients had a defibrillation safety margin of at least 10 J (at least two successful shocks at 25 J). During follow-up, one patient received a successful internal shock for ventricular fibrillation, and two received successful overdrive ventricular pacing for ventricular tachycardia. Three patients underwent defibrillation threshold testing to evaluate safety margins. No late complications have been reported at 60 months' follow-up. CONCLUSION: Defibrillator coil lead placement in the MCV is a safe alternative to epicardial lead placement via a thoracotomy in selected patients for whom RV lead placement is contraindicated or impossible.

Treatment of an infected pacemaker pocket with an antimicrobial envelope.

This article reports the successful treatment of an infected permanent pacemaker pocket after pulse generator replacement in an immunosuppressed patient by means of localized surgical revision of the pulse generator pocket and placement of a sustained-release combination antibacterial envelope in the revised pocket.

Total transvenous approach to pacing and defibrillation after Ebstein's anomaly.

We describe the successful use of a percutaneous, transvenous endocardial approach to atrioventricular pacing and cardiac defibrillation in an adult born with Ebstein's anomaly who had undergone tricuspid valve repair. The patient has systolic left ventricular dysfunction, congestive heart failure, and sinus node dysfunction. Ventricular pacing and sensing was obtained with a bipolar lead placed in the inferolateral cardiac vein; atrial pacing was obtained at the low interatrial septum. Internal cardiac defibrillation was achieved with a coil lead placed in the middle cardiac vein and the active can in the left retro mammary pre-pectoral position. With this approach, we avoided a thoracotomy and epicardial patch in a patient whose previous tricuspid valve surgery precluded an endocardial right ventricular lead position.

Cardiac resynchronization therapy may improve symptoms of congestive heart failure in patients without electrical or mechanical dyssynchrony.

AIMS: Cardiac resynchronization therapy (CRT) has reportedly not been effective in the absence of electrical or mechanical dyssynchrony. We present six patients with severe left ventricular (LV) dilation, mitral regurgitation (MR), and non-ischaemic cardiomyopathy who underwent CRT. We assessed the effects of CRT on LV ejection fraction (EF), LV dimensions, mitral valve regurgitant fraction (RF), pulmonary arterial pressures (PAP), and serum levels of B-natriuretic peptide (BNP). METHODS AND RESULTS: All patients had severe LV dilation (>/=6.8 cm) and no electrical or mechanical dyssynchrony. All patients underwent CRT-D (with defibrillator) without complications. Average echocardiographic follow-up was 4.6 months. Mean LVEF increased significantly from 20.8 +/- 3.4 to 28.3 +/- 2.9% after CRT (P < 0.01). Mean LV end-diastolic dimension decreased significantly from 6.9 +/- 0.15 to 6.45 +/- 0.33 cm after CRT (P = 0.03); mean BNP serum level decreased from 1738 +/- 526 to 1040 +/- 768 pg/mL (P = 0.07). Baseline RF decreased from 45 +/- 12.2 to 20 +/- 10.9% after CRT-D (P = 0.009). Mean PAP decreased from 48.5 +/- 5.8 to 42.6 +/- 5.2 (P = 0.03). In five patients, New York Heart Association class symptoms improved by at least one level. No patients required assist devices or transplantation. One patient was hospitalized during follow-up. CONCLUSION: We describe six patients with severe LV dilation without evidence of electrical or mechanical dyssynchrony who improved with CRT, possibly due to improvement in MR.

Transvenous biventricular pacing for cardiac resynchronization therapy in patients with persistent left superior vena cava and right superior vena cava atresia.

Biventricular pacing for cardiac resynchronization therapy is an effective adjunctive therapy for the treatment of symptomatic moderate and severe congestive heart failure. However, experience with transvenous cardiac resynchronization therapy in patients who have both persistent left superior vena cava and right superior vena cava atresia is extremely limited. We successfully performed cardiac resynchronization therapy in 2 patients who had persistent left superior vena cava, right superior vena cava atresia, and congestive heart failure. Our 2 cases demonstrate the possibility of a total transvenous approach for left ventricular pacing despite the presence of serious cardiac venous anomalies. This approach enables clinicians to avoid the riskier epicardial lead placement, which requires a thoracotomy under general anesthesia.

New transvenous implantable cardioverter defibrillator configuration for use after tricuspid valve surgery.

A 57-year-old patient with a tricuspid valve (TV) prosthesis underwent successful atrioventricular pacing and internal defibrillation via a totally transvenous approach without crossing the TV. Ventricular pacing and sensing were obtained with a bipolar lead in the lateral cardiac vein. Internal defibrillation was obtained with a coil lead in the middle cardiac vein and an 'active can' pulse generator in the left infraclavicular region.

A novel approach to transvenous dual-chamber pacing lead placement and cardiac defibrillator implantation after tricuspid valve replacement.

Pacing and Defibrillation Therapy. We report the successful use of a percutaneous, totally transvenous endocardial approach to atrioventricular pacing and internal cardiac defibrillation in an adult patient with tetralogy of Fallot who had undergone three previous cardiac operations, including a tricuspid valve replacement. Ventricular pacing and sensing were achieved with a bipolar lead in the lateral cardiac vein, and atrial pacing was attained in the region of Bachmann's bundle. Internal defibrillation was achieved with a coil lead in the middle cardiac vein and an "active can" pulse generator in the retromammary position. This minimally invasive method has significant potential benefits because it avoids epicardial placement via a thoracotomy and allows endocardial placement without crossing the tricuspid valve.

Use of a transvenous dual-chamber ICD after a mustard operation for d-transposition of the great vessels.

A 40-year-old man was admitted to our institution with mild heart failure symptoms, including palpitations and near syncope. Twenty-eight years earlier, he had undergone a Mustard operation to correct d-transposition of the great vessels. At the present admission, echocardiography revealed severe right (systemic) ventricular dysfunction. Continuous monitoring also showed sinus-node dysfunction, sinus bradycardia, and nonsustained ventricular tachycardia. The patient underwent successful transvenous placement of a dual-chamber implantable cardioverter-defibrillator for pacing of the atria and prevention of sudden cardiac death. To our knowledge, there have been no previous reports of transvenous placement of an implantable cardioverter-defibrillator after surgery for d-transposition of the great vessels in the English-language medical literature.

Transvenous bifocal left ventricular pacing after mechanical prosthetic tricuspid valve replacement with use of echocardiography to optimize pacing parameters.

A 56-year-old woman underwent placement of a permanent pacemaker to treat symptomatic bradycardia; she had a documented, severe atrioventricular (AV) conduction abnormality and was not taking any AV node-blocking drugs. She had a mechanical prosthetic valve in the tricuspid position, which had been implanted for severe valvular insufficiency caused by rheumatic heart disease. Pacing leads were successfully placed transvenously in the anterior cardiac and a posterolateral vein, which avoided the need for repeat thoracotomy. Echocardiographic and Doppler parameters were used to optimize interventricular as well as septal-to-lateral left ventricular (LV) time delay and reduce or avoid interventricular and LV mechanical dyssynchrony.

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.

Transvenous implantation of a coronary sinus lead for left ventricular pacing after cutting balloon angioplasty.

We describe a patient in whom a localized proximal vein stenosis at the only possible target vein precluded placement of a coronary sinus lead for left ventricular (LV) pacing. After multiple attempts to perform venoplasty with both compliant and noncompliant balloons, a cutting balloon relieved the obstruction, and an LV pacing lead was successfully placed in the midportion of this lateral vein.

Successful use of transvenous atrial and bifocal left ventricular pacing in Ebstein's anomaly after tricuspid prosthetic valve surgery.

A 62-year-old woman with Ebstein's anomaly and a tricuspid valve prosthesis underwent placement of a permanent atrioventricular pacemaker to treat highly symptomatic sinus node dysfunction and atrioventricular block. Transvenous bipolar leads were placed in the anterior cardiac and lateral coronary veins and were set to optimal ventricular pacing parameters to preserve prosthetic valve function, back-up ventricular pacing, and maintain atrioventricular and interventricular synchrony. An atrial septal lead was placed to control atrial pacing. Interventricular and atrioventricular timing were optimized with the use of tissue Doppler imaging and the Doppler-derived stroke volume.

Successful use of a transvenous dual-chamber automatic implantable cardiac defibrillator after a classic Fontan operation for tricuspid atresia.

We report the first successful totally percutaneous pacing and defibrillation of a single ventricle in a 52-year-old woman who had undergone a classic Fontan operation (atriopulmonary connection) for tricuspid atresia 21 years earlier. Left ventricular pacing and sensing was obtained with a bipolar lead in the lateral cardiac vein, and defibrillation was obtained with a coronary sinus coil lead and an "active can" in the retromammary position to optimize the current vector. This approach has significant potential benefits because it avoids a repeat thoracotomy, with its associated mortality and morbidity.

Balloon occlusion technique to cannulate angulated and tortuous coronary sinus branches in cardiac resynchronization therapy.

We present two cases that demonstrate a new technique to cannulate angulated and tortuous coronary sinus branches during left ventricular lead placement for cardiac resynchronization therapy. The technique uses an occlusive pulmonary artery balloon just beyond the takeoff of the coronary sinus branch to assist in the cannulation of the branch.