Anatomy of atrioventricular attachments, connections and junction: in medio stat virtus.
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Atrioventricular Node↗
Biomedical subjects
G M Guiraudon
Publications and source records attributed to G M Guiraudon.
Intraoperative mapping is not necessary for VT surgery.
Surgical ablation of ventricular tachycardia is generally guided by the results of pre- and intraoperative cardiac mapping. However, in certain situations intraoperative cardiac mapping may not be possible and, therefore, surgery has to be based on information obtained preoperatively. This raises the question whether intraoperative mapping is necessary for the success of this approach. We describe our experience with encircling endocardial cryoablation for ischemic VT and examine the contribution of intraoperative mapping for this procedure. Thirty-three patients with inducible VT refractory to medical therapy and a well defined anatomic scar were considered for surgery. All patients underwent baseline electrophysiology study and intraoperative mapping was attempted during normothermic cardiopulmonary bypass. In 14 patients, VT was inducible intraoperatively (Group 1) and surgical ablation was guided by this information, whereas in 19 patients, VT could not be mapped for various reasons (Group 2). Reasons for failure to obtain intraoperative map included noninducibility (3), nonsustained VT (8), polymorphic VT (4), VF (3), and incessant VT with hemodynamic collapse and cardiac arrest (1). The two groups did not differ with respect to age, location of myocardial infarction, or preoperative left ventricular ejection fraction. The operative procedures were similar in the two groups with respect to aortic cross clamp time, cardiopulmonary bypass time, number of cryoablation lesions, concomitant revascularization, aneurysmectomy, and ICD implantation. Encircling endocardial cryoablation was performed in 32 patients and one patient underwent partial right ventricular free wall disconnection (RV infarct). Thirteen patients underwent concomitant coronary artery bypass grafting (5 in Group 1 and 8 in group 2). One patient had prophylactic ICD patches (Group 1).(ABSTRACT TRUNCATED AT 250 WORDS)
Cardiac Pacing, Artificial↗
Long-term results of the corridor operation for atrial fibrillation.
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.
Atrial Fibrillation↗
Aprotinin significantly decreases bleeding and transfusion requirements in patients receiving aspirin and undergoing cardiac operations.
BACKGROUND: Patients with heart disease are frequently maintained on a regimen of aspirin because of its ability to decrease thrombotic complications and reduce the prevalence of unstable angina and myocardial infarction. Aspirin-induced platelet acetylation also increases bleeding caused by impairment of platelet function during cardiac surgery. METHODS: Between October 1990 and November 1991 this double-blind, randomized, placebo-controlled, parallel group interventional study examined the efficacy of high-dose aprotinin administration (up to 7 million KIU) to decrease blood loss and transfusion requirements in patients receiving aspirin within 48 hours of undergoing coronary bypass or valvular heart operations. Primary outcome measures in this study were total volume of blood loss (intraoperative blood loss plus postoperative chest tube drainage) and volume of transfusion during hospitalization. RESULTS: Patients treated with aprotinin (n = 29) had significantly lower total blood loss (1409 +/- 232 ml versus 2765 +/- 248 ml; p = 0.0002), intraoperative blood loss (503 +/- 53 ml versus 1055 +/- 199 ml; p = 0.0001), postoperative blood loss (906 +/- 204 ml versus 1710 +/- 202 ml; p = 0.0074), and prevalence of transfusion (59% versus 88% of patients; p = 0.016) than the placebo group (n = 25). The prevalence of complications including myocardial infarction was similar in the two groups. CONCLUSIONS: High-dose aprotinin significantly reduces blood loss and red blood cell transfusions in patients receiving aspirin who undergo cardiac operations.
Aged↗
Complications of radiofrequency catheter ablation: a review.
Radiofrequency catheter ablation has revolutionized the management of patients with supraventricular tachycardias. Although initial reports were very favourable, it is becoming apparent that radiofrequency catheter ablation may lead to some potentially serious complications. Complication rate for accessory pathway ablation ranges from 1.8 to 4% and the risk of atrioventricular (AV) block for 'AV nodal modification' ranges from 1.3 to 8%. It is likely that complications are underreported and the true incidence may be higher. Some of these complications are probably related to operator experience or the volume of ablations performed at the centre, but other complications, such as systemic embolism, may be sporadic and unrelated to experience or volume. Although radiofrequency catheter ablation has emerged as an excellent therapeutic tool, the potential complications and limitations should be recognized.
Catheter Ablation↗
Biphasic versus sequential pulse defibrillation: a direct comparison in humans.
It has been demonstrated recently that both biphasic and sequential pulse defibrillation shocks are superior to monophasic defibrillation shocks in animals and humans. There is little information directly comparing these two waveforms when pulse characteristics, subjects, and total electrode surface areas are kept constant. We determined the defibrillation threshold intraoperatively in 12 patients undergoing arrhythmia surgery, with the use of two or three patch electrodes (Medtronic 6891 and 6892), while keeping the electrode surface area constant. Patients were randomized in a crossover design for determinations of defibrillation threshold by means of biphasic and sequential pulse shocks. Leading-edge delivered current and delivered energy were significantly lower with sequential pulse shocks than with biphasic shocks (delivered energy means +/- SEM 3.6 +/- 0.7 joules vs 5.5 +/- 0.9 joules, respectively). We conclude that sequential pulse defibrillation with three defibrillating electrodes provides an important current delivery system not matched by biphasic shocks with two electrodes when subjects, waveform characteristics, and total electrode surface areas are kept constant.
Adult↗
Supraventricular tachycardias: the role of surgery.
Because of its high efficacy and low morbidity radiofrequency energy catheter ablation techniques have toppled the hierarchy of choice in the electrophysiological intervention armamentum. This review assesses current role of surgery and its foreseeable future. Most accessory AV pathways can be attained by endocardial manipulation and ablated. Surgical dissection of accessory pathways on the beating heart had documented that most pathways were paraannular, although right-sided pathways may be distant to the annulus. Results of accessory pathway ablation have shown that right-sided pathways are difficult to approach and ablate. Surgical ablation may currently be considered after failed catheter ablation. AV nodal modification using catheter ablation also yields excellent results. Radiofrequency energy creates a discrete lesion associated with discrete electrophysiological alteration. Surgical dissection is associated with more diffuse and extensive anatomical and electrophysiological changes and is no longer used even after failed catheter ablation. The arrhythmogenic anatomical substrate associated with atrial flutter is not yet well delineated in the coronary sinus os region. How to extend tissue modification for uniform success here is not yet known. Further surgical approach combined with extensive intraoperative cardiac mapping may ultimately prove a valuable guide for subsequent catheter technique. Atrial fibrillation is the last surgical frontier unchallenged by catheter techniques. Arrhythmogenic anatomical substrate is diffuse spreading over the entire atrial myocardium without a discrete target. The associated pathology is diffuse, severe, and progressive and present even in the so-called lone atrial fibrillation. Progression of underlying pathology can nullify the best designed surgical rationale in terms of sinus node chronotropic function, and atrial contractility. Currently used surgical techniques, i.e., the corridor and the Maze operations, have contributed to a better selection of patients. Surgery is still associated with significant morbidity and relative efficacy, and may be improved before becoming the electrophysiological intervention of choice for atrial fibrillation. In conclusion, atrial fibrillation is a greater surgical challenge, but has to be met with the same standard used for other supraventricular tachycardias.
Atrial Fibrillation↗
Comparative atrioventricular node properties after radiofrequency ablation and operative therapy of atrioventricular node reentry.
The anatomical substrate for atrioventricular (AV) node reentry is unclear. To gain insights into the mechanism of cure of AV node reentry by nonpharmacological techniques, we compared AV node properties in 53 patients undergoing operative therapy (perinodal dissection) and 43 undergoing radiofrequency ablation (28 posterior approach, 15 anterior approach). Anterior radiofrequency ablation was associated with significant AH prolongation (62 +/- 18 msec vs 136 +/- 64 msec, P < 0.0001), loss of "fast" pathway physiology, and no change in the anterograde refractory period of the AV node (273 +/- 24 msec vs 268 +/- 28 msec, P = NS). Posterior radiofrequency ablation did not change the AH interval (67 +/- 17 msec vs 68 +/- 17 msec, P = NS), prolonged AV node effective refractory period (275 +/- 48 msec vs 320 +/- 55 msec, P < 0.0001), and was associated with loss of "slow pathway" physiology. Operative treatment prolonged the AH interval (66 +/- 18 msec vs 83 +/- 37 msec, P < 0.0001) and the AV node effective refractory period (264 +/- 52 msec vs 364 +/- 112 msec, P < 0.0001), and affected dual pathway physiology inconsistently. These data support the view that the "fast" and "slow" pathways are distinct perinodal entities that can be selectively ablated. The operative approach causes more diffuse and variable injury to the AV node region.
Adolescent↗
Heart transplantation after cardioverter-defibrillator implantation. A case control study.
A case control study was performed to determine whether previous implantable cardioverter-defibrillator (ICD) insertion adversely affects outcome after heart transplantation. Six male heart transplant recipients who had undergone ICD insertion 12 +/- 5 months before heart transplantation were compared to a cohort of six heart transplant recipients who were matched according to age, preoperative status and hemodynamics, date of transplantation, graft ischemic time, history of a previous cardiac operation, and duration of follow-up. There were no significant differences in operating room time, chest tube drainage, time to extubation, and the duration of intensive care unit or hospital stay between the two groups. Furthermore, there were no significant differences in the number of units of packed cells, fresh frozen plasma, platelets and cryoprecipitate transfused. The number of treated rejection episodes and the number of patients requiring intravenous antibiotics for infection in the first 90 days was identical between groups. It was concluded that heart transplantation after ICD implantation did not appear to carry more risk than heart transplantation after a previous cardiac operation. Our limited experience supports the potential use of the ICD in patients with life-threatening ventricular dysrhythmias who are awaiting transplantation.
Blood Loss, Surgical↗
Surgical treatment of atrial fibrillation.
Recently, two new rationale for surgical treatment of atrial fibrillation have been developed which have been used, initially, primarily in patients with lone atrial fibrillation. We performed the "corridor" operation in eleven patients with paroxysmal or chronic atrial fibrillation. Postoperatively, eight patients had normal sinus rhythm, one had a junctional rhythm, one patient had atrial tachycardia and one had intermittent atrial flutter/fibrillation with sinus bradycardia. During a mean observation period of 18 months, recurrent intermittent atrial fibrillation occurred in two patients. Another study reported the results of 20 patients with paroxysmal atrial fibrillation. During a mean observation period of 32 +/- 14 months, one patient had a brief episode of atrial fibrillation and three patients had atrial tachycardia amenable to antiarrhythmic drug treatment. The "Maze" operation was performed in 22 patients with resistant lone atrial fibrillation or atrial flutter. Postoperatively, eight patients had atrial flutter/fibrillation which, however, could be controlled in three with antiarrhythmic drug treatment. In all patients serious symptoms were improved but adjunctive measures and/or antiarrhythmic drugs were required frequently. There was no intraoperative mortality with either the corridor or the Maze operation but substantial postoperative morbidity was observed which, currently, exceeds that of the natural history or other ablative techniques.
Atrial Fibrillation↗
Surgical therapy of paroxysmal atrial fibrillation with the "corridor" operation.
Patients with paroxysmal atrial fibrillation may be extremely disabled despite medical therapy. Based on recent concepts of atrial fibrillation, a surgical open heart procedure was designed to isolate a "corridor" from the right and the left atrium. The corridor consists of the sinus node area, the atrioventricular nodal junction, and the connecting right atrial mass, small enough to prevent atrial fibrillation. Between 1987 and 1990, 20 patients with severely disabling symptoms due to frequent paroxysmal atrial fibrillation underwent the corridor operation, with permanent success in 16 patients. In 8 patients, left atrium to corridor conduction reappeared shortly after the procedure. Reoperation was performed in these patients without extracorporeal circulation. The site of persistent conduction between the left atrium and the corridor could consistently be localized adjacent to the coronary sinus. Nevertheless, reoperation failed to isolate permanently the corridor in 4 patients. During a mean follow-up of 20 months, atrial fibrillation dominating the ventricles was never observed nor inducible in the corridor in the 16 patients with a successful operation. In all cured patients, sinus node function remained undisturbed. Paroxysmal atrial flutter inside the corridor arose in 1 patient and a paroxysmal focal tachycardia in another. All 16 cured patients experienced a clear improvement in quality of life. Refinement of the surgical technique to obtain persistent isolation between the left atrium and the corridor is needed. These results demonstrate that the concept of the corridor operation is sound and justify its use in the treatment of drug-refractory paroxysmal atrial fibrillation.
Adult↗
Coronary artery bypass grafting in the management of ventricular arrhythmias in patients with coronary artery disease.
This review analyzes the role of coronary artery bypass grafting in ventricular arrhythmia associated with exertion, problematic sustained ventricular tachycardia, and sudden cardiac death associated with documented ventricular arrhythmia, or first manifestation of coronary artery disease. Specifically discussed is the role of acute ischemia in initiating and perpetuating ventricular arrhythmia. Coronary artery bypass grafting is indicated as a curative intervention for ventricular arrhythmia, but in only one rare instance: exercise-induced ischemia associated with problematic sustained ventricular arrhythmia, when the tachycardia is documented as being induced by acute ischemia. In other instances, indications for coronary artery bypass grafting follow the current guidelines based on clinical trials. Patients with the most severely damaged coronary artery anatomy associated with impaired left ventricular dysfunction have their life expectancy significantly prolonged after coronary artery bypass grafting. These results have been presented as evidence that coronary artery bypass grafting prevents ventricular arrhythmia and sudden cardiac death by modifying the two most powerful predicting factors of sudden cardiac death: coronary artery anatomy and left ventricular function.
Arrhythmias, Cardiac↗
A permanent transvenous lead system for an implantable pacemaker cardioverter-defibrillator. Nonthoracotomy approach to implantation.
A transvenous lead system for implantable defibrillators would obviate a surgical thoracotomy and reduce the morbidity and mortality associated with implantation. We evaluated the clinical performance of a new nonthoracotomy lead system that included a defibrillation lead in the coronary sinus. At the time of defibrillator implantation, transvenous defibrillation leads were inserted percutaneously through the left subclavian vein into the right ventricular apex (RVA), superior vena cava (SVC), and distal coronary sinus (CS) under fluoroscopic guidance. A subcutaneous patch electrode (SQ) was also available if required. The first single- or dual-pathway electrode configuration that successfully terminated three of four ventricular fibrillation episodes using 18 J or less was implanted. Eleven men and three women aged 39-77 years (60.0 +/- 10.1 years) with left ventricular ejection fraction ranging from 16% to 63% (33.4 +/- 13.1%) were evaluated. Nine presented with ventricular tachycardia, three had ventricular fibrillation, and two had both. A totally transvenous lead system (RVA/CS/SVC) was implanted in seven patients (50%) with a mean defibrillation threshold of 15.6 +/- 2.9 J (10-18 J). Four patients received a partial transvenous lead system (RVA/CS/SQ). An effective nonthoracotomy lead system was not found in three patients; they received epicardial electrodes. After cumulative follow-up of 73 patient-months, nine patients remain alive and free of problems related to the implanted nonthoracotomy leads. One patient died of respiratory failure 3 months after defibrillator implant, and the leads from another patient were removed at 9 months because of bacterial infection. A transvenous lead system that includes a defibrillation lead in the coronary sinus is a safe, reliable, and, at least in the short term, effective nonthoracotomy approach for automatic defibrillator implantation.
Adult↗
Surgery for supraventricular tachyarrhythmias.
Since the first successful surgical intervention for Wolff-Parkinson-White syndrome by W. C. Sealy, a surgical electrophysiological intervention has been developed for every single supraventricular arrhythmia. The surgical rationale is based on the site of the mechanism of the arrhythmia and associated pathology which characterizes the "arrhythmogenic substrate". Wolff-Parkinson-White syndrome is a congenital heart disease characterized by an accessory atrioventricular connection distinct from the AV node-His bundle system. It is associated with AV reentrant tachycardia and/or atrial fibrillation with fast ventricular responses via the accessory pathway. The current surgical management is ablation of the accessory pathway using either an endocardial dissection or epicardial approach. Surgical ablation is associated with high efficacy and low morbidity. Epicardial dissection of the accessory pathway on the beating heart has helped to localize variant accessory pathways associated with Coumel's tachycardia or Mahaim's fiber electrophysiological entity. AV nodal reentrant tachycardia can be cured using direct AV nodal dissection (or perinodal cryoablation). Atrial flutter can be interrupted by cryoablation of the arrhythmogenic substrate located in the coronary sinus orifice of the region modifying atrial inputs. Chronotropic atrial function abolished by chronic or paroxysmal idiopathic atrial fibrillation can be restored using the corridor operation (sinus node-AV node insulation). Surgery is an alternative in patients with resistant atrial tachycardias. Currently surgery is indicated only after other non-invasive EP interventions have been either attempted or rejected.
Atrial Fibrillation↗
Radiofrequency catheter ablation of accessory pathways: a learning experience.
Success rates of approximately 90% have recently been reported with radiofrequency catheter ablation of accessory pathways. This study determined whether this success could be repeated using a conservative approach generally limiting fluoroscopy time to 1 hour. Consecutive patients referred for management of arrhythmias associated with accessory atrioventricular pathways were included over a 9-month period. Ablation was attempted in 75 patients with 84 pathways. Overall success rate (including second attempts in 9 patients) was 60 of 84 accessory pathways (71%). Success rates for the first 3 months (n = 23) were 52%, the second 3 months (n = 23) 60% and the last 3 months (n = 38) 90%. Success rate varied with pathway location, with left lateral pathways having the best early success rates. Mean fluoroscopy time for successful procedures of 33 +/- 21 minutes was shorter than the time for unsuccessful procedures of 63 +/- 24 minutes (p = 0.001). There were no major complications and no patients with successful procedures (n = 53) have had recurrence of accessory pathway conduction or reciprocating tachycardia (follow-up 1 to 10 months). A conservative approach can yield success rates approaching 90% in a short time. The absence of major complications supports earlier reports suggesting that radiofrequency catheter ablation of accessory pathways is a reasonable first-line therapy in the Wolff-Parkinson-White syndrome.
Adolescent↗
Epicardial mapping in patients with "nodoventricular" accessory pathways.
Some patients with electrophysiologic features suggesting nodoventricular fibers have been shown to have right parietal atrioventricular (AV) accessory pathways with decremental conduction properties intraoperatively. The experience with 11 patients (7 women and 4 men, mean age +/- standard deviation 25 +/- 5 years) who had electrophysiologic features consistent with a nodoventricular pathway and who underwent operative correction was reviewed. At electrophysiologic study, all patients had absent or minimal preexcitation in sinus rhythm. During atrial pacing and extrastimulus testing, maximal preexcitation with left bundle branch block morphology developed and the AH and AV intervals progressively prolonged. Preexcited tachycardia was initiated in all patients (AV reentrant tachycardia in 10 patients and AV node reentrant tachycardia in 1 patient). At operation all patients had a right parietal accessory pathway demonstrated. Intraoperative mapping demonstrated the earliest site of ventricular activation during anterograde preexcitation to be at the midanterior right ventricle, consistent with insertion of these pathways into the right bundle branch system, in 7 patients. The ventricular insertion was at the AV groove in 4 patients, in keeping with the typical Wolff-Parkinson-White syndrome. Retrograde conduction over the pathway was not demonstrated in any patient. Two patients had evidence of a second accessory AV pathway in the left paraseptal region. Operative AV node ablation was electively performed in 2 patients without affecting preexcitation in either case. In 1 of these patients, accessory pathway conduction was temporarily abolished by ice mapping in the right anterolateral AV groove.(ABSTRACT TRUNCATED AT 250 WORDS)
Adolescent↗
Multiple accessory pathways in the Wolff-Parkinson-White syndrome as a risk factor for ventricular fibrillation.
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Adult↗
Closed heart cryoablation of the His bundle using an anterior septal approach.
His bundle cryosurgical ablation using a closed heart anterior septal approach was used in 6 patients. There were 3 men and 3 women, aged 24 to 73 years. Three patients had atrial fibrillation and 2 patients had atrial flutter (2 with combined episodes of atrial tachycardia). One patient had atrial tachycardia. Five patients had no structural heart disease and 1 patient had left ventricular dilatation (ejection fraction, 0.35). All patients undergoing His bundle cryosurgical ablation had permanent heart block without intraoperative complications (mean follow-up, 25 months). Closed heart anteroseptal cryoablation of the His bundle is effective and is an alternative to attempted catheter ablation.
Adult↗