Venovenous extracorporeal membrane oxygenation in patients with atrial septal defects.

Two patients presented in profound respiratory distress unresponsive to maximal support and were placed on venovenous ECMO. Subsequently, both were found to have a patent foramen ovale and high pulmonary artery pressures, resulting in a right to left shunt. Both patients had a better than expected response to ECMO, likely related to their shunts allowing oxygenated blood to bypass the high pulmonary artery pressures and go directly to the left heart. Both patients were successfully weaned from ECMO and discharged to home in good condition.

Transmission of Donor-Derived Trypanosoma cruzi and Subsequent Development of Chagas Disease in a Lung Transplant Recipient.

Donor infection status should be considered when accepting an organ for transplant. Here we present a case of Chagas disease developing after a lung transplant where the donor was known to be Trypanosoma cruzi antibody positive. The recipient developed acute Trypanosoma cruzi infection with reactivation after treatment. Chagas disease-positive donors are likely to be encountered in the United States; donor targeted screening is needed to guide decisions regarding organ transplant and posttransplant monitoring.

Impact of electrical cardioversion for atrial fibrillation on left atrial appendage function and spontaneous echo contrast: characterization by simultaneous transesophageal echocardiography.

OBJECTIVES: This study assessed the function of the left atrial appendage in the pericardioversion period to gain insights into mechanisms involved in thromboembolism after cardioversion of atrial fibrillation. BACKGROUND: Systemic embolization associated with electrical cardioversion of atrial fibrillation is thought to originate from the left atrium or left atrial appendage, or both. However, the mechanism involved is poorly understood. METHODS: We studied left atrial appendage function with transesophageal echocardiography in 20 patients with atrial fibrillation before and after successful electrical cardioversion. We measured left atrial appendage emptying and filling velocities by pulsed wave Doppler echocardiography, characterized Doppler emptying patterns, measured atrial appendage areas and assessed the presence or absence of spontaneous echo contrast or thrombus. RESULTS: Organized left atrial appendage function returned in 16 (80%) of 20 patients immediately after cardioversion. Atrial appendage emptying velocities before cardioversion were greater in patients without (0.39 +/- 0.02 m/s) than in those with (0.25 +/- 0.12 m/s) spontaneous echo contrast (p = 0.045). Furthermore, emptying velocities before cardioversion were significantly greater than late diastolic emptying velocities after cardioversion (0.31 +/- 0.15 vs. 0.14 +/- 0.12 m/s, p = 0.0001), as well as in both the group with (0.25 +/- 0.12 vs. 0.13 +/- 0.13 m/s, p = 0.001) and the group without (0.39 +/- 0.02 vs. 0.15 +/- 0.12 m/s, p = 0.01) spontaneous echo contrast. In addition, left atrial and atrial appendage spontaneous echo contrast developed in 4 of 20 patients and increased in intensity in 3 of 20 patients in the immediate postcardioversion period. CONCLUSIONS: Organized left atrial appendage function returns in most patients immediately after cardioversion of atrial fibrillation. However, its function is impaired compared with that before cardioversion. Furthermore, spontaneous echo contrast increased in 7 (35%) of 20 patients after cardioversion. These observations suggest that stunned left atrial appendage function after cardioversion may predispose the chamber to thrombus formation, which may play a role in the mechanism involved in the occurrence of embolization after cardioversion.

Clinical investigation of antiarrhythmic devices. A statement for healthcare professionals from a joint task force of the North American Society of Pacing and Electrophysiology, the American College of Cardiology, the American Heart Association, and the Working Groups on Arrhythmias and Cardiac Pacing of the European Society of Cardiology.

The goal of radiofrequency catheter ablation and the criterion for efficacy is the elimination of arrhythmogenic myocardium. The application of radiofrequency current in the heart clearly results in lower morbidity and mortality rates than thoracic and cardiac surgical procedures in general, and comparisons of therapy with radiofrequency catheter ablation and therapy with thoracic and cardiac surgical procedures in randomized clinical trials is unwarranted. Trials of radiofrequency catheter ablation versus medical or implantable cardioverter-defibrillator therapy may be indicated in certain conditions, such as ventricular tachycardia associated with coronary artery disease. Randomized trials are recommended for new and radical departures in technology that aim to accomplish the same goals as radiofrequency catheter ablation. Surveillance using registries and/or databases is necessary in the assessment of long-term safety and efficacy.

Radiofrequency catheter ablation for management of symptomatic ventricular ectopic activity.

OBJECTIVES: This study assessed the useful role of intracardiac mapping and radiofrequency catheter ablation in eliminating drug-refractory monomorphic ventricular ectopic beats in severely symptomatic patients. BACKGROUND: Ventricular ectopic activity is commonly encountered in clinical practice. Usually, it is not associated with life-threatening consequences in the absence of significant structural heart disease. However, frequent ventricular ectopic beats can be extremely symptomatic and even incapacitating in some patients. Currently, reassurance and pharmacologic therapy are the mainstays of treatment. There has been little information on the use of catheter ablation in such patients. METHODS: Ten patients with frequent and severely symptomatic monomorphic ventricular ectopic beats were selected from three tertiary care centers. The mean frequency +/- SD of ventricular ectopic activity was 1,065 +/- 631 beats/h (range 280 to 2,094) as documented by baseline 24-h ambulatory electrocardiographic (ECG) monitoring. No other spontaneous arrhythmias were documented. These patients had previously been unable to tolerate or had been unsuccessfully treated with a mean of 5 +/- 3 antiarrhythmic drugs. The site of origin of ventricular ectopic activity was accurately mapped by using earliest endocardial activation time during ectopic activity or pace mapping, or both. RESULTS: During electrophysiologic study, no patient had inducible ventricular tachycardia. The ectopic focus was located in the right ventricular outflow tract in nine patients and in the left ventricular posteroseptal region in one patient. Frequent ventricular ectopic beats were successfully eliminated by catheter-delivered radiofrequency energy in all 10 patients. The mean number of radiofrequency applications was 2.6 +/- 1.3 (range 1 to 5). No complications were encountered. During a mean follow-up period of 10 +/- 4 months, no patient had a recurrence of symptomatic ectopic activity, and 24-h ambulatory ECG monitoring showed that the frequency of ventricular ectopic activity was 0 beat/h in seven patients, 1 beat/h in two patients and 2 beats/h in one patient. CONCLUSIONS: Radiofrequency catheter ablation can be successfully used to eliminate monomorphic ventricular ectopic activity. It may therefore be a reasonable alternative for the treatment of severely symptomatic, drug-resistant monomorphic ventricular ectopic activity in patients without significant structural heart disease.

Cardioinhibitory carotid sinus hypersensitivity. Intracardiac recordings and clinical assessment.

Cardioinhibitory carotid sinus hypersensitivity most frequently occurs in elderly men, predominantly during right carotid massage. Resting sinus bradycardia and aortic stenosis may be unusually prevalent in this subgroup of patients. Ventricular arrest occurs abruptly and may be preceded by brief prolongation of sinus cycle lengths and atrioventricular nodal conduction times. Gradual recovery of the sinoatrial rate follows resumption of sinus rhythm and is preceded by atrioventricular nodal recovery. His bundle electrocardiography is valuable in excluding other potential causes of syncope in patients with carotid sinus hypersensitivity. Despite a history of syncope, permanent pacing may not be indicated in the management of patients with carotid sinus hypersensitivity and otherwise normal electrophysiologic study.

Concealed retrograde bypass tracts and enhanced atrioventricular nodal conduction. An unusual subset of patients with refractory paroxysmal supraventricular tachycardia.

The clinical and electrophysiologic features of eight patients with unusually rapid, medically refractory paroxysmal supraventricular tachycardia are described. Exercise induction of tachycardia and functional bundle branch block patterns during tachycardia were common. Tachycardia resulted from anterograde enhanced atrioventricular nodal conduction combined with retrograde conduction by a concealed left atrial-left ventricular accessory pathway producing rates ranging from 200 to 300 beats/min. Management and late follow-up study were characterized by generally unsuccessful electrophysiologic-pharmacologic testing and inconsistent rhythm control with continued drug therapy. Three patients underwent successful surgical interruption of the concealed accessory pathway, with elimination of recurrent tachycardias. These patients represent a unique subgroup with an identifiable electrophysiologic basis for unusually rapid tachycardias, potentially benefiting from invasive study and aggressive therapy.

Clinical presentation of endocardial pacing lead malfunction.

This study highlights the wide spectrum of manifestation of pacing lead malfunction. Patients judged to be pacer dependent or in whom ventricular lead malfunction is suspected, and patients with severe symptoms before pacemaker implantation, should be considered at high risk for the development of hemodynamic compromise; prompt hospital admission and pacing lead replacement should be performed.

Hemodynamic benefits of atrioventricular sequential pacing after cardiac surgery.

The hemodynamic effects of atrioventricular (A-V) sequential pacing were assessed and compared with those of ventricular and of atrial pacing in 10 patients with and without heart block after cardiac surgery. Ventricular pacing alone was either hemodynamically detrimental or of no benefit in six of the eight patients who initially had sinus or accelerated junctional rhythms. Atrial pacing alone produced significant improvement in cardiac output in all patients who were not pacemaker-dependent. However, five of the eight patients with intact A-V conduction had further increases in cardiac output through A-V sequential pacing at shorter than intrinsic A-V intervals. Optimal A-V intervals for maximal cardiac output could be identified in all patients and varied widely. Significant changes in cardiac output occurred with relatively small diviations in the A-V interval. In selected patients after cardiac surgery, temporary A-V sequential pacing is a workable and valuable adjunctive form of hemodynamic support and is preferable to ventricular or atrial pacing.

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 postoperatively bradycardia-tachycardia syndrome and restricted ventricular access. This approach controls symptomatic bradycardia, helps prevent and convert paroxysmal intraatrial tachycardia and overcomes the problems of limited ventricular access.

Chronic transvenous pacemaker lead removal using a unique, sequential transvenous system.

Transvenous removal of 43 consecutive chronic pacemaker leads was successful in 28 patients. For leads not removed by traction at the pacemaker connection terminal, a unique locking stylet was advanced through the inner coil lumen and engaged at the tip to allow traction without lead elongation. Leads not extracted with the locking stylet alone had traction maintained on the stylet as sheaths were advanced over the lead to dilate and detach any fibrous tissue adherent to the lead. By applying traction at the pacemaker connection terminal, 2 leads were removed. The locking stylet alone extracted 9 leads. Both the locking stylet and sheaths were necessary to explant 32 leads. There were 15 right atrial and 22 right ventricular leads completely removed. Additionally, 6 right ventricular leads were subtotally removed leaving only the tip in the right ventricular apex. Avulsed myocardium was removed with the lead in 1 patient without sequelae. A subacute hemothorax developed in 1 patient 18 days after discharge requiring drainage, and subclavian vein thrombosis developed in another, which was successfully treated with anticoagulation. Hypotension occurred in 1 patient during final positioning of new leads, which responded to conservative treatment. Chronic pacemaker leads can be reliably removed without thoracotomy. Both a unique locking stylet to allow traction without lead elongation and a sheath to dilate and detach adherent fibrous tissue are needed for consistent success. Recognized complications included myocardial avulsion without sequelae, subacute hemothorax, subclavian vein thrombosis and transient hypotension.

Single-chamber ventricular pacing is not associated with worsening heart failure in sick sinus syndrome.

Ventricular pacing (with loss of normal atrioventricular synchrony) has been considered to have a role in the development or progression of congestive heart failure (CHF) in patients with sick sinus syndrome (SSS). No rigorous study has tested this hypothesis. Five hundred seven consecutive patients with SSS who received an initial pacemaker from January 1980 to December 1989 were studied. Atrial or dual-chamber pacemakers were implanted in 395 patients and ventricular pacemakers in 112. After a mean follow-up of 65 +/- 37 months, 97 patients (19%) developed new CHF or increased their New York Heart Association functional class. By univariate analysis, preimplant predictors for these events were left ventricular dysfunction (p < 0.001), valvular heart disease (p = 0.004), peripheral vascular disease (p = 0.005), diabetes (p = 0.02), coronary artery disease (p = 0.02), high New York Heart Association functional class (p = 0.03) and complex ventricular arrhythmia (p = 0.03). By multivariate analysis (logistic regression), the only predictors for CHF were valvular heart disease (p = 0.002; odds ratio [OR] 2.51), peripheral vascular disease (p = 0.003; OR 1.7) and complex ventricular arrhythmia (p = 0.027; OR 2.74). When the analysis was restricted to patients who had preimplant assessment of left ventricular function, independent predictors for CHF were left ventricular dysfunction (p < 0.001; OR 1.66), and complex ventricular arrhythmia (p < 0.001; OR 1.75). In conclusion, progressive or new-onset CHF is a consequence of the underlying cardiovascular disease. In the present population of patients with SSS, ventricular pacing mode was not associated with an increased incidence of CHF.

Catheter ablation of the atrioventricular junction using radiofrequency energy and a bilateral cardiac approach.

Radiofrequency current catheter ablation was used successfully to create complete atrioventricular (AV) block in 60 of 61 patients (98%) with drug refractory supraventricular tachyarrhythmias. The remaining patient developed Mobitz I AV block and is clinically improved (clinical efficacy 100%). In 54 patients (89%), complete AV block was achieved using a right-sided approach. Patients aged > 60 years needed significantly fewer right-sided radiofrequency applications to produce complete AV block (5.3 +/- 5.3 vs 11.1 +/- 10.0; p = 0.009). In 6 of 7 patients with unsuccessful right-sided ablation, a left ventricular approach was used. In each case, 1 to 4 additional radiofrequency applications produced complete AV block. Patients with unsuccessful right-sided ablation were generally younger than those with successful ablation (50 +/- 16 vs 64 +/- 11; p = 0.007). It is concluded that catheter ablation using radiofrequency current is an extremely effective means of producing complete AV block. Older patients appear to be more susceptible to right-sided radiofrequency approaches. Left ventricular ablation easily produces complete AV block in patients refractory to right-sided attempts.

Permanent pacemaker infections: characterization and management.

From January 1974 to June 1980, a total of 46 patients were treated for infections involving permanent pacing systems. Demographic characteristics, types of infecting organisms, specific clinical features, significance of an infected foreign body and various medical and surgical treatment methods are described. Likely infecting organisms depend on the mode of presentation and the time course of the infection. Optimal treatment for the large majority of patients requires removal of the entire infected pacing system. In a subgroup of patients, a short course of antibiotic therapy followed by one stage surgery involving implantation of a new pacing system and concurrent explanation of the infected pacemaker was used safely with excellent results.

Influence of left ventricular function on survival and mode of death after implantable defibrillator therapy (Cleveland Clinic Foundation and Montefiore Medical Center experience).

To determine the influence of left ventricular (LV) function on survival and mode of death in patients with an implantable cardioverter-defibrillator (ICD), sudden death, surgical mortality, total arrhythmia-related death, total cardiac death and total death were retrospectively evaluated in 377 consecutive patients. The outcomes were also compared between patients with an LV ejection fraction > or = 30% (214 patients, group 1) and < 30% (148 patients, group 2). Surgical mortality was 3.9% (1.8% in group 1, 7% in group 2). During the follow-up of 25 +/- 20 months, actuarial survival rates of all patients at 3 years were 96% for sudden deaths, 81% for total cardiac deaths and 74% for total mortality. When the 2 groups were compared, survival rates of groups 1 and 2 at 3 years, respectively, were 99 and 90% for sudden death (p < 0.05), 97 and 84% for sudden death and surgical mortality (p < 0.01), 94 and 80% for the total arrhythmia-related death (p < 0.001), 88 and 68% for total cardiac death (p < 0.0001), and 81 and 62% for total mortality (p < 0.002). In group 2, 73% of total cardiac deaths within 1 year were causally related to the arrhythmia. Thus, in patients with an ICD, sudden death rates were very low. However, total cardiac death and total death rates were relatively higher. The outcomes of patients with an ICD were strongly influenced by the degree of LV dysfunction.(ABSTRACT TRUNCATED AT 250 WORDS)

Supra-his alternate-beat Wenckebach dysrhythmia.

Alternate-beat Wenckebach, an uncommon dysrhythmia, usually is attributed to block within the His bundle or bundle branches (or in both). A patient with features of the "sick sinus" syndrome demonstrated A-V nodal (supra-His) alternate-beat Wenckebach during atrial pacing and His bundle electrocardiography. Electrophysiologic mechanisms are proposed.

Programmed ventricular stimulation in management of recurrent ventricular tachycardia.

Programmed ventricular stimulation was used effectively in the clinical management of six patients with medically refractory, chronic, recurrent ventricular tachycardia. Critically timed ventricular stimuli reliably terminated episodes of ventricular tachycardia and thus obviated repeated countershocks. Critically timed stimuli also reliably induced reentrant ventricular tachycardia. This provided a "clinical model" allowing immediate determination of optimal suppressive drug regimens. The technique has practical application in selected patients with recurrent ventricular tachycardia and can be safely performed within the intensive-care unit.

Contribution of the electroencephalogram in monitoring cardiac dysrhythmias.

It is often difficult to distinguish between episodic cerebral symptoms resulting from primary disorders of the brain and those resulting from cardiac dysrhythmias. When patients with such symptoms are referred for electroencephalography, the electrocardiographic activity recorded concurrently can provide additional useful diagnostic information. Two cases are presented to illustrate the contribution of the electroencephalogram in the diagnosis of significant cardiac dysrhythmias.

Surgical repair of Ebstein's anomaly.

Ebstein's anomaly is a complex malformation that has been treated by various surgical techniques, with variable results. We have developed a repair-by plication of the free wall of the atrialized portion of the right ventricle, posterior tricuspid annuloplasty, and right atrial reduction--that has been used since 1972 in 16 patients. The repair is based on the construction of a monocusp valve by the use of the anterior leaflet of the tricuspid valve, which is usually enlarged in this anomaly. There were 14 operative survivors and no instances of complete heart block. Two patients with refractory dysrhythmias due to the Wolff-Parkinson-White syndrome underwent successful intraoperative epicardial and endocardial mapping and surgical division of accessory pathways. This repair has resulted in improvement in the operative mortality and in gratifying early and late results in most patients.

The use of the percutaneous subclavian technique for permanent cardiac pacing in childhood.

The use of the percutaneous subclavian approach for permanent tranvenous cardiac pacing is described in an 8.6-kg, 18-month-old child with symptomatic congenital heart block. This approach may facilitate the use of permanent transvenous cardiac pacing in infancy and childhood.