Bone marrow transplantation in the treatment of thalassemia

OBJECTIVE: To investigate the long-term results of the corridor operation in the treatment of symptomatic atrial fibrillation refractory to drug treatment. BACKGROUND: The corridor operation is designed to isolate from the left and right atrium a conduit of atrial tissue connecting the sinus node area with the atrioventricular node region in order to preserve physiological ventricular drive. The excluded atria can fibrillate without affecting the ventricular rhythm. This surgical method offers an alternative treatment when atrial fibrillation becomes refractory to drug treatment. PATIENTS: From 1987 to 1993, 36 patients with drug refractory symptomatic paroxysmal atrial fibrillation underwent surgery. The in hospital rhythm was followed thereafter by continuous rhythm monitoring and with epicardial electrograms. After discharge Holter recording and stress testing were regularly carried out to evaluate the sinus node function and to detect arrhythmias; whereas Doppler echocardiography was used to measure atrial contraction and size. MAIN OUTCOME MEASURES: Maintained absence of atrial fibrillation without drug treatment after operation; preservation of normal chronotropic response in the sinus node. RESULTS: The corridor procedure was successful in 31 (86%) of the 36 patients. After a mean (SD) follow up of 41 (16) months 25 (69%) of the 36 patients were free of arrhythmias without taking drugs (mean (SE) actuarial freedom at four years 72 (9)%)). Paroxysmal atrial fibrillation recurred in three patients; paroxysmal atrial flutter (two patients) and atrial tachycardia (one patient) developed in the corridor in three others. Among the 31 patients in whom the operation was successful sinus node function at rest and during exercise remained undisturbed in 26 and 25 patients respectively (mean (SE) actuarial freedom of sinus node dysfunction at four years (81(7)%)). Pacemakers were needed in five (16%) of the 31 patients for insufficient sinus node rhythm at rest only. Doppler echocardiography showed maintenance of right atrial contribution to right ventricle filling in 26 of the 31 patients after operation in contrast to the left atrium, which never showed such contribution. His bundle ablation was performed and a pacemaker implanted in the five patients in whom the corridor operation was unsuccessful. CONCLUSION: These results substantiate the idea of this surgical procedure. Modification of the technique is, however, needed to achieve a reliable isolation between left atrium and corridor, which would make this experimental surgery widely applicable in the treatment of drug refractory atrial fibrillation.     

Electrophysiological properties in patients undergoing atrial compartment operation for chronic atrial fibrillation with mitral valve disease

AIMS: Surgical treatment for atrial fibrillation is now feasible in selective cases. The aim of this study was to assess the electrophysiological properties of patients undergoing atrial compartment operation for chronic atrial fibrillation. METHODS AND RESULTS: Electrophysiological studies were performed in 20 mitral valve patients with atrial fibrillation who had been maintained in sinus rhythm for more than 1 year after atrial compartment operation. Intra-cardiac recording and programmed electrical stimulation were performed in various atrial compartments. The parameters studied included sinus node function, atrial conduction and refractoriness, atrioventricular conduction function and inducible arrhythmias if any. Intra-cardiac recordings showed that the rhythm was of sinus origin in all cases, with the earliest atrial activity located in the high right atrium. The mean sinus cycle length was 750 +/- 110 ms, AH time 106 +/- 29 ms, and HV time 53 +/- 7 ms. The sinus node function was normal in 18 patients (90%), and only two patients had prolonged sinus node recovery and sino-atrial conduction. The right atrial appendage compartment was driven by the sinus node in all patients. However, the conduction time from the high right atrium to the right atrial appendage compartment was markedly prolonged in 12 of 15 patients (80%) undergoing the three-compartment operation in which an incision was placed between the high right atrium and right atrial appendage compartments. On the other hand, the electrical activities in the left atrial compartment were much more varied. In 13 of 20 patients (65%), the left atrial compartment was driven by the sinus node; 11 of the 13 patients had a normal or mildly prolonged conduction time (ranged 75 to 146 ms), whereas two patients had a marked delay in conduction (200 ms and 266 ms, respectively). In the remaining seven patients, the left atrial compartments were dissociated from the rest of the heart; five of them had a quiescent left atrium, one a fluttering left atrial rhythm, and one a slow left atrial rhythm. The effective refractory period was longer in the left atrial compartment (242 +/- 47 ms) as compared to that of the high right atrium (224 +/- 26 ms, P < 0.01) and right atrial appendage compartments (219 +/- 25 ms, P < 0.01). Programmed electrical stimulation could not induce atrial fibrillation in any patient, whereas two patients had inducible atrial flutter and three repetitive atrial responses. CONCLUSIONS: (1) Atrial compartment operation does not impair sinus node function in most cases. (2) Elimination of atrial fibrillation while maintaining the electrical connection between different atrial compartments is feasible.     

Revision of previous Fontan connections to extracardiac or intraatrial conduit cavopulmonary anastomosis

BACKGROUND: In patients who have received an atriopulmonary Fontan connection, complications such as right pulmonary vein obstruction, atrial arrhythmias, and thromboembolism are often secondary to right atrial enlargement. When such complications develop despite good ventricular function, there are few management options available. Extracardiac or intraatrial conduit cavopulmonary anastomosis, which improves central systemic venous flow patterns, avoids atrial distention, and does not involve the extensive atrial suturing required by other forms of cavopulmonary anastomosis, may provide relief for this group of patients. METHODS: Between October 1992 and October 1995, 7 patients presented 8 to 20 years after atriopulmonary connection with severe right atrial dilatation (7), Fontan pathway obstruction (4), progressive congestive heart failure (4), atrial tachydysrhythmias (3), right atrial thrombus (1), obstruction of right pulmonary veins by an enlarged right atrium (1), and subaortic stenosis (1). After evaluation of the options, they underwent revision of the atriopulmonary connection to extracardiac (5) or intraatrial (2) conduit cavopulmonary anastomosis. RESULTS: One patient with severe cachexia, in whom transplantation was contraindicated for social reasons, died in the early postoperative period of massive effusions. Two patients eventually required permanent pacing for atrial dysrhythmias (1) or complete heart block secondary to subaortic fibromuscular resection (1), and 2 demonstrated marked improvement in unstable preoperative rhythm disturbances. At a median follow-up of 17 months, 4 of the 6 survivors were functioning at higher New York Heart Association levels than preoperatively, and 1 had recently undergone heart transplantation. CONCLUSIONS: In properly selected patients with atrial complications, revision of a prior Fontan connection to extracardiac or intraatrial conduit cavopulmonary anastomosis appears to be a viable option.     

Prevention of unbalanced lung perfusion and atrial arrhythmias after the lateral tunnel operation

BACKGROUND: The lateral tunnel operation has become increasingly popular with pediatric cardiac surgeons, as it is technically reproducible, is relatively easy to perform, and can be used in a variety of patients with single-ventricle physiology. The main drawbacks of the original operation are uneven blood flow distribution to the lungs and increasing incidence of supraventricular arrhythmias over time. METHODS: In 1988, we modified this technique by avoiding narrowing of the tunnel at the superior vena cava-atrial junction, avoiding incorporation of the crista terminalis in the baffle suture line, and minimizing damage to the sinoatrial node. Between 1988 and 1995, 19 patients underwent this operation at Marie-Lannelongue Hospital in Paris. RESULTS: There was one early death and no late deaths. At a mean follow-up of 5.2 years, all survivors are in New York Heart Association class I. Early atrial flutter, related to atrial scarring secondary to multiple previous surgical procedures, developed in 1 patient, and late atrial flutter developed in 1 patient who had a previous Blalock-Hanlon atrial septectomy. All patients are currently in sinus rhythm. Atrial flutter did not occur in 17 patients who had had no previous atrial wall surgical procedure. CONCLUSIONS: We believe that the good long-term clinical results are directly attributable to our modifications, which ensure optimal hemodynamics and absence of rhythm disturbances. All patients who had not previously undergone operation on the atrial wall were free from supraventricular tachyarrhythmias at a mean follow-up of 5.2 years. This is a consequence of protecting the sinus node, crista terminalis, and Bachmann's bundle.     

A 7-day activity diary for assessment of daily energy expenditure validated by the doubly labelled water method in adolescents

Several authors have reported the single atrioventricular (AV) electrode, comprising an atrial dipole floating in the right atrium, to be a system capable of providing results which are just as satisfactory as those of conventional systems (DDD). Between August 1992 and March 1995, a VDD single electrode pacemaker was implanted in 65 patients (mean age: 73 years +/- 17.2). The indication for implantation was isolated high degree AVB with no apparent sinus dysfunction. Four pacemakers were used: Vitatron (n = 24), Intermedics (n = 23), Medico (n = 13), Biotronik (n = 5). Intraoperative atrial endocavitary recording was 1.8 mV +/- 0.74. 17 patients died from a cause unrelated to pacemaker dysfunction. 4 patients were lost to follow-up. The remaining 44 patients were reviewed in our centre with a mean follow-up of 14.5 months +/- 7 months. Seven pacemakers (16%) were reprogrammed in VVI or VVI (R) mode, because of permanent atrial fibrillation in 3 cases, complete loss of atrial reception in 2 cases and late onset sinus dysfunction in 1 case. In the 41 patients in sinus atrial rhythm, the atrioventricular synchronization rate was greater than 90% in 88% of patients, equal to 76.3% in 2.4% of patients and atrioventricular synchronization was impossible in 9.6% of cases. CONCLUSION: The overall results of our preliminary experience of VDD mode single electrode pacemaker are moderate. The poor results essentially concerned patients with paroxysmal atrial arrhythmias prior to pacing.     

Right atrial isolation for atrial fibrillation associated with atrial septal defect

Two patients with atrial fibrillation associated with an atrial septal defect underwent simultaneous surgical correction of the atrial septal defect and right atrial isolation. The right atrium was surgically isolated while the continuity with the sinoatrial node was preserved in the remainder of the heart. After the operation, the patients maintained normal sinus rhythm for 99 and 65 months. Thus, right atrial isolation offers an alternative to the current surgical treatment for atrial fibrillation associated with an atrial septal defect.     

Echocardiographic factors predicting the maintenance of sinus rhythm one year after cardioversion for non-valvular atrial arrhythmias]

Echocardiographic factors predictive of the maintenance of sinus rhythm after successful cardioversion were investigated in 94 patients with non-valvular atrial arrhythmias of recent onset. Seventy-five patients with atrial fibrillation and 19 with atrial flutter admitted for reduction of their arrhythmias underwent transthoracic and transoesophageal echocardiography. After excluding a thrombus in the left atrial appendage or checking that it had disappeared (5 patients), and electrical (n = 74) or pharmacological (n = 20) cardioversion was successfully performed. The maintenance of sinus rhythm (n = 44) or recurrence of arrhythmia (n = 50) were controlled every 3 months for one year. The mean value of the peak positive blood flow in the left atrial appendage was 38 +/- 20 cm/s for the whole group. It was not possible to identify an echocardiographic parameter predictive of maintenance of sinus rhythm at one year either in the whole group or in the subgroups with atrial flutter or atrial fibrillation. In the group in atrial flutter, the mean value of the peak positive blood flow in the left atrial appendage was significantly greater than in the group with atrial fibrillation: 49 +/- 22 cm/s vs 35 +/- 18 cm/s, respectively; p < 0.05. The peak of positive flow in the left atrial appendage was statistically related to indirect parameters of left atrial function and of left ventricular function in the group with atrial fibrillation but only with parameters of left ventricular function in the smaller group with atrial flutter.     

The conversion of a modified Fontan procedure to a total extracardiac cavo-pulmonary conduit. The Medico-Surgical Cardiology Group

BACKGROUND: After a modified Fontan procedure with atriopulmonary or atrioventricular conduit, some patients present stress intolerance, supraventricular arrhythmia, recurrent pleuropericardial or ascitic effusions, and protein-losing enteropathy, all of which are signs that the previous procedure has failed. The aim of this study was to evaluate the midterm outcome after surgical therapy for this condition. MATERIAL AND METHODS: Between August 1994 and December 1997, nine patients (6 males and 3 females), age 10 to 39 (mean 21.5) years, underwent conversion of previous modified Fontan procedure to total extracardiac cavo-pulmonary connection. Time from the previous procedure was 6 to 18 years (mean 10). Diagnosis was tricuspid atresia with pulmonary stenosis (n = 2), double-inlet left ventricle and concordant ventriculoarterial connection (n = 3), double-inlet left ventricle and discordant ventriculoarterial connection (n = 3), Holmes heart (n = 1). Nine patients presented decreased stress tolerance, seven had arrhythmia, five had pleuropericardial effusions and two had protein-losing enteropathy. In all but one patient, right atrial pressure was higher than 15 mmHg, while in six patients the cardiac index was less than 2 l/min/m2. A polytetrafluoroethylene non-valved conduit was interposed between the inferior vena cava and the right pulmonary artery for conversion in all patients. A bidirectional cavo-pulmonary anastomosis (modified Glenn) was associated in all patients. Evaluation was done by NYHA Class and by an arbitrary score assigned to patients based on 7 parameters. RESULTS: There was no perioperative mortality. All patients were clinically improved at a mean follow-up of 24 months (range: 3 to 46). No patient had effusions, and the arrhythmias disappeared in 4 patients and were controlled by medical therapy in one. The two patients with protein-losing enteropathy improved markedly within 30 days and the score dropped below 10 points. CONCLUSIONS: The conversion of the modified Fontan procedure to total extracardiac cavo-pulmonary connection improves clinical condition by decreasing the right atrium-pulmonary gradient and right atrial preload, and by providing a laminar cavo-pulmonary flow without any need for intracardiac anastomoses. This procedure should be undertaken early in this subset of patients, before ventricular failure ensues.     

Radiofrequency and cryoablation of atrial fibrillation in patients undergoing valvular operations

BACKGROUND: Previous studies have shown that the maze operation can restore sinus rhythm and atrial transport function in patients with chronic atrial fibrillation. The purpose of this study was to test the feasibility of the application of radiofrequency and cryoablation as an alternative to the classic maze operation. METHODS: Twelve patients undergoing mitral valve procedures were included in this study. Radiofrequency and cryoablation were applied to create lesions in both atria to simulate the classic maze operation. RESULTS: There were two surgical deaths. At the mean follow-up of 10.25 months for the remaining 10 patients; 6 were in sinus rhythm, 2 in atrial rhythm, 1 in paroxysmal atrial tachycardia, and 1 in atrial fibrillation. Doppler echocardiography at 6-month follow-up showed emergence of biatrial transport function in 3 patients and right atrial contractility in 8. At 12-month follow-up of 5 patients, Doppler echocardiography showed biatrial transport function in 3 and right atrial contractility in 4. CONCLUSIONS: Our modified maze procedure during valvular operation is effective for achieving an acceptable success rate to restore sinus rhythm and atrial transport function in patients with chronic atrial fibrillation.     

Long-term reproducibility of programmed atrial stimulation

Programmed atrial stimulation is a technique increasingly used to assess different pathologies but the reproducibility of the results is totally unknown. The aim of this study was to determine its reproducibility. Two electrophysiological studies were undertaken without antiarrhythmic therapy in an interval of one to three months (average 18 months) in 48 patients. The programmed atrial stimulation used 1 and 2 extrastimuli delivered in sinus rhythm and then three paced rhythms (sinus cycle -10%, 600 ms, 400 ms). Twenty-one patients had documented atrial arrhythmias (atrial fibrillation n = 13, flutter n = 3 or tachycardia n = 5) (group 1) and the 27 other patients had no spontaneous arrhythmias (group II). In group I, clinical tachycardial was reproduced in 18 patients during the initial stimulation procedure. During the second investigation, 17 remained inducible and in the 3 in whom stimulation was negative, it remained so in 2 of the cases. The reproducibility was therefore 90%. In group II, 12 patients had inducible sustained (for over 1 minute) tachycardia during the first procedure (44%) but this only remained inducible in 6 patients. In the other 15 subjects, stimulation was negative during the first procedure but 7 of them had inducible tachycardial during the second procedure. The reproducibility of the technique was therefore only of 52%. The authors conclude that the reproducibility of programmed atrial stimulation in patients with documented spontaneous paroxysmal arrhythmias is excellent. However, the reproducibility is mediocre in subjects without spontaneous arrhythmias and the induction of tachycardial in this group of patients should be interpreted with caution given the variability of the response to programmed atrial stimulation.     

Transposition of the great arteries and isolated origin of the sinus node artery

We report the cases of 2 newborns who underwent at 7 days of age an arterial switch operation for transposition of the great arteries with a rare coronary anomaly: the left and right coronary arteries originated with a single ostium from sinus 1 and the sinus node artery had an isolated origin from sinus 2. The sinus node artery was reimplanted into the new aorta in both patients. Both babies were discharged in sinus rhythm. Preserving the vascularization of the sinus node may avoid the occurrence of postoperative atrial rhythm disturbances.     

Atrioverter: an implantable device for the treatment of atrial fibrillation

BACKGROUND: During atrial fibrillation, electrophysiological changes occur in atrial tissue that favor the maintenance of the arrhythmia and facilitate recurrence after conversion to sinus rhythm. An implantable defibrillator connected to right atrial and coronary sinus defibrillation leads allows prompt restoration of sinus rhythm by a low-energy shock. The safety and efficacy of this system, called the Atrioverter, were evaluated in a prospective, multicenter study. METHODS AND RESULTS: The study included 51 patients with recurrent atrial fibrillation who had not responded to antiarrhythmic drugs, were in New York Heart Association Heart failure class I or II, and were at low risk for ventricular arrhythmias. The atrial defibrillation threshold had to be 相似文献   

Atrial arrhythmias in adults after repair of tetralogy of Fallot. Correlations with clinical, exercise, and echocardiographic findings

BACKGROUND: The long-term success of intracardiac repair of tetralogy of Fallot is hampered by the occurrence of arrhythmias. Numerous studies have stressed the potential role of ventricular arrhythmias. However, the importance of other arrhythmias in the morbidity of these patients appears to be underestimated. Furthermore, most follow-up studies have been limited to children or adolescents, whereas many patients have reached adulthood after earlier repair of tetralogy of Fallot. The aim of the present study was to determine the incidence of atrial fibrillation, atrial flutter, and other supraventricular arrhythmias in adult patients after intracardiac repair for tetralogy of Fallot and their correlation with surgical and clinical findings. METHODS AND RESULTS: The study group consisted of 53 consecutive patients referred to the Thoraxcenter adult congenital heart disease clinic. They underwent repair at a mean age of 9.1 years (range, 0.7 to 55 years). The median age at the time of study was 23.2 years (range, 15 to 57 years; mean age, 26.6 years), and the mean duration of follow-up of 17.5 years (range, 1.4 to 32 years) after surgery. Records were reviewed extensively for evidence of arrhythmias. The follow-up study included routine 12-lead ECG, 24-hour continuous ambulatory monitoring, and echocardiography, and 46 patients underwent exercise testing. Sinus node dysfunction was recorded in 19 patients (36%), of whom 4 required a permanent pacemaker. Atrial fibrillation or flutter was found in 12 patients, and other supraventricular tachycardias were found in 6. The former were more frequently of older age at follow-up. Antiarrhythmic therapy and cardioversion were typically directed at control of atrial (and not ventricular) tachyarrhythmias. Ten patients (19%) showed nonsustained ventricular tachycardia; they were older at initial surgery and older at follow-up and had more intracardiac repairs and longer cardiopulmonary bypass times. CONCLUSIONS: Despite an emphasis on ventricular ectopy in past series, the main sources of morbidity in adult patients after surgical correction of tetralogy of Fallot emanated from atrial arrhythmias, which were present in one third of the patients.     

Right-sided maze procedure for right atrial arrhythmias in congenital heart disease

BACKGROUND: Atrial fibrillation and flutter, commonly associated with congenital heart anomalies that cause right atrial dilatation, may cause significant morbidity and reduction of quality of life, even after surgical repair of the anomalies. METHODS: In an effort to reduce the incidence of atrial tachyarrhythmias after repair of right-sided congenital heart disease, we performed a concomitant right-sided maze procedure. RESULTS: Eighteen patients with paroxysmal atrial fibrillation or flutter (n = 12) or chronic atrial fibrillation or flutter (n = 6) aged 10.9 to 68.4 years (mean 34.9 years) underwent a right-sided maze in association with repair of Ebstein's anomaly (n = 15), congenital tricuspid insufficiency (n = 2), and isolated atrial septal defect (n = 1). There were no early deaths, reoperations, or complete heart block. Discharge rhythm was sinus (n = 16) or junctional (n = 2). Follow-up was complete in all 18 patients and ranged from 3.1 to 17.2 months (mean 8.1 months); all are in New York Heart Association class I. Early postoperative arrhythmias developed in 3 patients (all were converted to sinus rhythm by antiarrhythmic drugs). There were no late deaths or reoperations. CONCLUSIONS: The inclusion of a right-sided maze procedure with cardiac repair in patients having congenital heart anomalies that cause right atrial dilatation and associated atrial tachyarrhythmias is effective in eliminating or reducing the incidence of those arrhythmias.     

The effect of Ro 11-1781, a calciumantagonist, on atrioventricular conduction (author's transl)

The effect of an intravenous bolus of 1 mg/kg Ro 11-1781, a new calciumantagonist, on sinus node automaticity and intracardiac conduction was studied by His-bundle electrography and atrial stimulation. During sinus rhythm, no significant action of Ro 11-1781 on rate, P-A-interval, A-H interval, and H-V-interval was observed. The sinus node recovery time remained unaltered. On atrial stimulation, the St-H-interval was significantly (p less than 0.001) prolonged after Ro 11-1781. Wenckebach Periods occurred at lower stimulation rates in all patients after Ro 11-1781. It is concluded that Ro 11-1781 prolongs av nodal conduction and may be of therapeutic value in the treatment of supraventricular arrhythmias.     

Comparison of the effects of atrial and ventricular stimulation on sinus node function in man

Although sinus node function has been evaluated during premature atrial stimulation, no study of retrograde ventriculoatrial sinus node activation following premature ventricular stimuli has been reported. The purpose of this study was to investigate the production of compensatory and noncompensatory pauses by premature ventricular contractions through a comparison of the effects of atrial and ventricular stimulation on sinus node function. Eleven patients in sinus rhythm were studied with programmed introduction of premature atrial and ventricular stimuli outside the ventricular vulnerable period. The onset of sinus node reset, duration of return sinus cycle (A2-A3) during reset, and estimated sinoatrial conduction times were recorded. Sinus node function during premature ventricular stimulation was approximated by utilizing the interval between the last sinus beat and onset of retrograde atrial depolarization (A1-A2 interval). The return cycle length (A2-A3) during sinus reset compared at equal A1-A2 intervals was significantly less with ventriculoatrial conduction (1,145 +/- 52 msec. atrial vs. 1,076 +/- 52 msec ventriculoatrial; P less than 0.01 by paired t test) and the estimated sinoatrial conduction time was significantly less with ventriculoatrial conduction (71 +/- 7 msec. atrial vs. 25 +/- 7 msec. ventriculoatrial; P less than 0.01 by paired t test). Ventriculoatrial sinus reset occurred later in the sinus cycle than atrial reset in three of seven patients with sinus reset produced by both atrial and ventricular prematures. This study shows that the effects of ventriculoatrial conduction on sinus node function are significantly different from those of atrial stimulation alone. The return sinus cycle length during reset and estimated sinoatrial conduction time are significantly reduced with ventriculoatrial conduction. Although the zones of sinus reset with atrial and ventricular stimulation are approximately equal, ventriculoatrial depolarization may produce sinus reset later in the sinus cycle in some cases.     

Thromboembolism in chronic atrial flutter: is the risk underestimated?

OBJECTIVES: We sought to evaluate the risk of thromboembolic events in the presence of chronic atrial flutter and to determine the impact of anticoagulation therapy, if any, on this risk. BACKGROUND: Thromboembolic events are thought to be rare after cardioversion of atrial flutter. METHODS: This study was a retrospective analysis of 110 consecutive patients referred to the electrophysiology laboratory for cardioversion of chronic atrial flutter from 1986 to 1996. Atrial flutter was present for at least 6 months. Of the 110 patients reviewed, 100 had adequate information available regarding the effectiveness of anticoagulation (mean age 64 years, range 27 to 86; 75 men, 25 women; mean left ventricular ejection fraction 42%). RESULTS: Thirteen patients (13%) had a thromboembolic event. Of these, seven were attributable to causes other than atrial flutter. In the remaining six patients (6%), thromboembolic events occurred during a rhythm of atrial flutter or after cardioversion to sinus rhythm. Other causes of thromboembolism were excluded. Effective anticoagulation was associated with a decreased risk of thromboembolism (p = 0.026). CONCLUSIONS: Patients with chronic atrial flutter are at an increased risk of thromboembolic events. Effective anticoagulation may decrease this risk.     

Usefulness of PKHs for studying cell proliferation

INTRODUCTION AND OBJECTIVES: The MAZE procedure was developed as a surgical approach to the management of patients with atrial fibrillation refractory to medical treatment. This study seeks to identify the risk and benefits of adding the MAZE procedure in patients with atrial fibrillation undergoing surgery for underlying organic cardiac disorders. MATERIAL AND METHODS: Since november 1993, we have performed 10 interventions with the MAZE procedure, for the treatment of refractory atrial fibrillation. The indication to perform the technique was systemic embolism in 5 patients, contraindication for the anticoagulant treatment in two cases and no response to antiarrhythmic treatment in 5 cases. Two patients had more than one indication. In all the cases another surgical procedure was performed, 5 replacements of mitral valve, a mitral repair, one tricuspid repair and tree repairs of an atrial septal defect. RESULTS: Soon after surgery 9 patients were in sinus rhythm, and one in atrial fibrillation. Four patients needed atrial pacing during the first days. One patient required a pacemaker due to symptomatic sinus bradycardia. During the first 3 months, 4 patients had episodes of paroxysmal atrial fibrillation and flutter. One patient died suddenly one month after surgery. Seven patients have completed two years of follow-up, and are in stable sinus rhythm, in functional class I and free of antiarrhythmic drugs. All of them have echocardiographic evidence of mechanical activity in both atria. Left atrium had been reduced from 5.3 +/- 0.7 cm to 4.5 +/- 0.7 cm (p < 0.05). No patient has presented new embolic events. CONCLUSIONS: The MAZE procedure is a good choice in selected patients with atrial fibrillation refractory to medical treatment, or a precedent of systemic embolism. However, several problems can complicate the patient's course.     

Actinic superficial folliculitis

BACKGROUND: The maze operation is effective for the restoration of sinus rhythm; however, restoration of atrial mechanical function has not been demonstrated in all patients. METHODS: Maze operations were performed in 32 patients (13 men, 19 women; mean age 47.1 +/- 9.0 years) combined with valvular surgery (n = 25), coronary artery bypass graft (CABG) (n = 3), and others (n = 4). At 1 week, 3 months, 6 months, and 1 year after the operation, prospective serial Doppler echocardiographic examination was carried out to determine the presence of atrial mechanical function. RESULTS: Sinus rhythm was restored and maintained during the follow-up period in 26 (81%) patients; in 22 patients this was due solely to the operation, whereas in four patients an antiarrhythmic agent was needed to maintain sinus rhythm. Another four patients showed paroxysmal atrial fibrillation (AF) despite treatment with an antiarrhythmic agent. Right atrial mechanical function was restored in all 30 patients with sinus rhythm or paroxysmal AF; in 19 (63%) of these, left atrial mechanical function was restored. In patients with restored left atrial mechanical function, peak A velocity (A) and A/E ratio (A/E) of mitral inflow were significantly lower than in the 16 postoperative control patients (A: 0.46 +/- 0.14 m/sec vs 0. 75 +/- 0.29 m/sec, p < 0.01; A/E: 0.40 vs 0.80, p < 0.01). In patients with left atrial mechanical function, the duration of AF was significantly shorter than in patients without left atrial mechanical function (1.9 +/- 2.9 years vs 7.1 +/- 3.0 years, p < 0. 01), but there were no significant differences in left atrial size and volume. CONCLUSIONS: The maze operation could be safely added to standard open heart surgery for the correction of underlying structural heart disease. The rate of conversion to sinus rhythm resulting solely from the operation might be lower than the rates previously reported with only the duration of AF adversely affecting the restoration of left atrial mechanical function. Considering the fact that not all patients converted to sinus rhythm show atrial mechanical function, the role of the maze operation in the prevention of systemic embolism, with subsequent improvement in survival, requires further study.     

Spectral analysis of short term R-Tapex interval variability during sinus rhythm and fixed atrial rate

Analysis of heart rate variability has been proven useful in stratifying post myocardial patients at risk and in evaluating autonomic dysfunction. Recently augmented inter-lead variability of the QT interval has been associated with increased mortality as a result of arrhythmia and proposed as a marker of dispersion of ventricular repolarization. As the duration of the QT interval is largely dependent upon the length of the preceding cardiac cycle it is tempting to analyse whether neural mechanisms might also directly exert additional modulation. Using autoregressive algorithms we therefore analysed RR and R-Tapex interval variabilities in 15 normal subjects during sinus rhythm and in six patients with a fixed atrial rate. In controls mean R-Tapex interval and variance measured on the vector magnitude were, respectively, 245 +/- 6 ms and 5.1 +/- 0.7 ms2. Spectral analysis of R-Tapex indicated the presence of two spectral components which corresponded to the low and high frequency components of heart rate variability. In R-Tapex variability, high frequency (44 +/- 4 nu) was predominant over low frequency (29 +/- 4 nu). During controlled respiration, a manoeuvre associated with enhanced vagal modulation of sinus node, there was a further increase in high frequency (58 +/- 4 nu) whereas during tilt the low frequency component of R-Tapex variability became predominant (57 +/- 6 nu). In patients with a fixed atrial rate, variance was extremely low (3 +/- 0.9 ms2) and only a respiration-related high frequency component was recognizable in spectral analysis of RR and R-Tapex variabilities. This component was likely to depend upon mechanically induced changes in cardiac vector orientation. These data indicate that during sinus rhythm short-term R-Tapex interval variability is characterized by the same rhythmical components present in RR variability. However, the presence of a very low variance and of only a high frequency component in patients in whom the physiological variability of sinus node is abolished by atrial pacing. suggests that neural modulatory mechanisms do not exert a direct effect on the length of the R-Tapex interval.