Surgical alternatives for supraventricular tachycardias

Since Sealy's pioneering surgical intervention for Wolff-Parkinson-White syndrome, surgical electrophysiologic interventions have been developed for all supraventricular arrhythmias. The surgical rationales are based on the site of origin of the arrhythmic mechanism and the associated pathology that characterizes the "arrhythmogenic substrate." The Wolff-Parkinson-White syndrome is characterized by an accessory atrioventricular (AV) connection distinct from the AV node-His bundle system. It is associated with AV reentrant tachycardia or atrial fibrillation, or both, with fast ventricular responses through the accessory pathway. The current surgical management involves ablation of the accessory pathway using either an endocardial or an epicardial approach. Surgical ablation is associated with high efficiency 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 the Mahaim fiber. 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 region. The chronotropic atrial function, abolished by incessant or paroxysmal idiopathic atrial fibrillation, can be restored using the corridor operation (sinus node-AV node insulation). The success of surgical intervention in atrial tachycardias is uncertain, but it may be an option in selected patients with resistant atrial tachycardias.

Operative therapy of atrioventricular node reentry and results of an anatomically guided procedure

Operative therapy for atrioventricular (AV) node reentrant tachycardia consisting of dissection guided by anatomic landmarks is described. Of the 21 patients studied, 17 had the common type ("slow-fast") and 4 had the uncommon type ("fast-slow") of AV node reentry. Under normothermic cardio-pulmonary bypass, perinodal dissection was performed guided by anatomic landmarks: the atrial membranous septum, posterior superior process of the left ventricle, tendon of Todaro and os of the coronary sinus. There were no deaths or major complications. Seven to 10 days postoperatively, all patients had normal AV conduction except for one who continued to have AV node Wenckebach-type block. Postoperatively, the shortest cycle length capable of 1:1 conduction over the AV node changed from 323 +/- 66 to 421 +/- 90 ms (p less than 0.0001) anterogradely and from 330 +/- 86 to 449 +/- 164 ms (p = 0.004) retrogradely. Anterograde effective refractory period of the AV node prolonged from 264 +/- 49 to 358 +/- 107 ms (p = 0.012). Discontinuous AV conduction curves were no longer seen in 14 of 17 patients and 5 patients lost retrograde conduction. During follow-up (14.8 +/- 8.2 months), 19 patients have been free of arrhythmia without medication. Two patients required a second operation for recurrent tachycardia with success. No patient required a permanent pacemaker. These data show that operative therapy of AV node reentrant tachycardia can be guided by anatomic landmarks. Successful cure of tachycardia with perinodal dissection while preserving AV node conduction supports the view that the reentrant circuit is, at least in part, perinodal.

Localization of accessory pathways in the Wolff-Parkinson-White syndrome

Operative and ablative therapy in the Wolff-Parkinson-White syndrome requires accurate localization of accessory atrioventricular pathways. A reasonable first approximation to pathway location can be obtained by noninvasive techniques, the 12-lead electrocardiogram being the most readily available of these. Accurate characterization of the number and anatomic localization of accessory pathways still requires invasive electrophysiological assessment. The most useful technique for accessory pathway localization remains endocardial atrial mapping of the tricuspid and mitral (via the coronary sinus) ring during atrioventricular reciprocating tachycardia and ventricular pacing. Other techniques provide important confirmatory evidence and may be the only guides to accessory pathway location in selected individuals.

Surgical therapy for arrhythmogenic right ventricular adiposis

Arrhythmogenic right ventricular adiposis, formerly dysplasia, was identified when the first patients underwent map-guided surgery for treatment of their ventricular tachycardia. We report our experience with 12 patients operated on using a conservative approach between 1973 and 1981 (Paris). Subsequently, we used a more comprehensive approach in five patients (London, Canada); the right ventricular free wall disconnection was used to confine all potential right ventricular tachycardias within the excluded right ventricular wall.

Mitral valve function after cryoablation of the posterior papillary muscle in the dog

Extensive cryoablation of an arrhythmogenic left ventricular posterior papillary muscle associated with ventricular arrhythmias may affect mitral valve function. We studied the long-term effects of extensive cryoablation of the posterior papillary muscle and its ventricular attachment in 10 dogs. The dogs had hemodynamic, electrophysiological, and angiographic testing 1 month after operation. Seven dogs were then killed, and the hearts were examined at that time. Three dogs had repeat assessments 2 and 3 months after operation before they were killed. At 1 month, left ventricular angiography showed normal mitral valve function in all dogs. Pathological examination revealed that the posterior papillary muscle and its left ventricular attachment were replaced by a discrete dense, fibrous scar. The fibrous process involved the mitral valve in 2 dogs. At 3 months, pathological examination showed a marked fibrous scar with chondroid metaplasia and fibrous involvement of the mitral valve chordae and posterior leaflet in all 3 dogs. We conclude that extensive cryoablation of the posterior papillary muscle is not associated with long-term mitral valve dysfunction, and may be the best surgical technique to ablate an arrhythmogenic papillary muscle.

Results of operative therapy in the permanent form of junctional reciprocating tachycardia

To assess the results of operative therapy for permanent junctional reciprocating tachycardia, a type of incessant tachycardia, the clinical and electrophysiologic data of 8 such patients referred for management of tachycardia were reviewed. The duration of incessant tachycardia was 14 +/- 10 years (range 2 to 30). The heart rate at rest during tachycardia ranged from 120 to 150 beats/min. Four of 8 patients had cardiomegaly or depressed ejection fraction (16 +/- 10%, range 5 to 27) at presentation and, of these, 2 had symptoms of congestive heart failure. Exertional dyspnea despite normal left ventricular function was noted in 1 patient, 2 had chronic palpitations and 3 were asymptomatic. Electrophysiologic data confirmed the presence of a posteroseptal pathway with atrioventricular node-like properties conducting slowly in the retrograde direction only. Seven patients underwent successful surgical ablation of the accessory pathway. Hypothermic cardiopulmonary bypass was used in 2 and a closed heart technique without cardiopulmonary bypass in the other 5. Three of 4 patients with reduced left ventricular function showed an improvement in ejection fraction to 34 +/- 20% (range 16 to 63) after control of dysrhythmia. Three patients had no evidence of cardiomegaly despite equivalent periods of incessant tachycardia. Another patient with normal left ventricular function despite incessant tachycardia for over 30 years underwent spontaneous remission to sinus rhythm and did not undergo surgery. These data suggest that permanent junctional reciprocating tachycardia has a variable presentation and that congestive heart failure is not an infrequent presenting symptom. The substrate is invariably an accessory atrioventricular pathway with a long conduction time and decremental properties conducting only in the retrograde direction.(ABSTRACT TRUNCATED AT 250 WORDS)

"Atypical" posteroseptal accessory pathway in Wolff-Parkinson-White syndrome

The posteroseptal accessory pathway in the Wolff-Parkinson-White syndrome is associated with a delta wave that is negative in the inferior electrocardiographic (ECG) leads and the occurrence of the earliest retrograde atrial activation near the orifice of the coronary sinus during atrioventricular (AV) reentrant tachycardia. Seventy-two patients with a posteroseptal accessory pathway underwent epicardial mapping before operative ablation. The earliest epicardial activation occurred at the posterosuperior process of the left ventricle in all patients. Dissection of the posteroseptal region (right atrial-left ventricular sulcus) resulted in permanent loss of preexcitation in 69 patients and failure to abolish preexcitation permanently in 3. At reoperation in two patients, preexcitation was abolished by discrete cryoablation of the left side of the interatrial septum near the AV node approached through the atrial septum in the normothermic beating heart. At reoperation, one patient had extensive AV node dissection. All patients have had permanent loss of preexcitation. The vast majority of posteroseptal accessory pathways ("typical") are epicardial and ablated by dissection of the posteroseptal region. Rarely, posteroseptal accessory pathways are "atypical" in that they are intraseptally located near the AV node on the left atrial endocardial surface.

Prediction of defibrillation success from a single defibrillation threshold measurement with sequential pulses and two current pathways in humans

The ultimate aim of defibrillation testing is to predict consistent defibrillation. This study tested the hypothesis that defibrillation success could be predicted from a single measurement of defibrillation threshold. We measured defibrillation threshold by using three patch electrodes and a standard protocol intraoperatively in 49 patients undergoing arrhythmia surgery. Each patient was then assigned to one of five energy subgroups (0.5, 1.0, 1.5, 2.0, or 2.5 times defibrillation threshold) for a single shock (followed by a rescue shock if necessary) for a subsequent ventricular fibrillation episode. A curve relating percent success to energy was then constructed for the group. Defibrillation threshold averaged 4.7 +/- 2.98 J for the group (mean +/- SD). There was a curvilinear relation between the energy of the defibrillation threshold ratio test shock and percent success: 33.3%, 58.3%, 81.8%, 91.7%, and 100% at mean defibrillation threshold ratios of 0.56 +/- 0.14, 1.02 +/- 0.07, 1.53 +/- 0.14, 1.88 +/- 0.09, and 2.60 +/- 0.14, respectively. We conclude that consistent defibrillation is predictable from a single measurement of defibrillation threshold. Furthermore, for an individual patient, a safety margin of 2.6 times defibrillation threshold should approximate 100% successful defibrillation for a single test shock.

Anaesthetic management for surgical cryoablation of accessory conducting pathways: a review and report of 181 cases

Pre-excitation disorders have an estimated prevalence of 0.15 per cent. Advances in electrophysiological mapping and the increasing sophistication of surgical techniques have resulted in an increasing role for definitive surgical treatment. A retrospective chart review of 181 patients undergoing 197 procedures for surgical ablation of accessory atrioventricular pathways between June 1981 to June 1986 was performed. Mean age of the patients was 30 years (range 6-66) with a preponderance of males (59 per cent). Associated cardiac disease was found in 18 (9.9 per cent) patients. Induction of anaesthesia employed either a barbiturate-relaxant (83 per cent) or a narcotic-benzodiazepine-relaxant (17 per cent) and was uneventful in all cases. In 14 per cent of cases a pure narcotic relaxant technique was employed for maintenance of anaesthesia, whereas a balanced technique with isoflurane (29 per cent), enflurane (34 per cent), or halothane (22 per cent) was utilized for the remainder. Muscle relaxation was provided by d-tubocurarine in 35 (18 per cent) procedures and pancuronium in the remaining 162 (82 per cent) procedures. There was no significant correlation between intraoperative arrhythmias and type of anaesthetic used. Although recognizing the potential for malignant arrhythmias, our experience (within the confines of a retrospective analysis) suggests that the majority of these patients can be managed successfully using standard anaesthetic techniques.

The coronary sinus diverticulum: a pathologic entity associated with the Wolff-Parkinson-White syndrome

Of 65 patients with posterior septal accessory pathways, 6 were found intraoperatively to have a previously unrecognized pathologic entity: a coronary sinus (CS) diverticulum in the posterior septal region. The CS diverticulum is a venous pouch within the left ventricular wall, with a neck opening into the CS. The pouch, 2 to 5 cm in diameter, has a deep wall corresponding to the left ventricular wall, with venous channel openings and a thin superficial wall made of myocardium. The CS diverticulum neck is 5 to 10-mm wide, opens into the CS and is proximal to the midcardiac vein. Using an epicardial approach during normothermic bypass, the neck of the CS diverticulum was identified, separated from the left ventricle and then closed. Accessory pathway conduction disappeared only after separation of the CS diverticulum neck. The accessory pathway is intimately related to the diverticulum. The latter is a bridge between the left ventricle and the right or left atrium. The accessory pathways associated with CS diverticula had short anterograde refractory periods and were associated with potentially malignant arrhythmias. An epicardial operative approach with division of the neck of the diverticulum is recommended when surgery is indicated.

Cryosurgery for ventricular bigeminy using a transaortic closed ventricular approach

Disabling monomorphic ventricular bigeminy has not been described as an indication for surgery. Three young patients with this arrhythmia sometimes deteriorating into ventricular tachyarrhythmias and in whom drug therapy failed completely were accepted for surgical ablation of the arrhythmogenic area. The earliest endocardial site of origin was located preoperatively by catheter mapping of the spontaneously occurring ventricular bigeminy in the left and right ventricles. For maximum preservation of myocardial muscle and function, the preoperative mapping and surgical procedure were performed through the aortic root; mapping by transaortic multipolar balloon was done during normothermic coronary perfusion and cryocoagulation was done during cardioplegic arrest. Cryocoagulation of the endocardial site was performed using the transaortic approach and epicardial cryocoagulation at the opposite site was done afterwards. In the two patients in whom the preoperative mapping results were consistent with those of preoperative catheter mapping, the arrhythmia could be abolished, as documented during long-term follow-up. In the only patient in whom the mapping results were not in agreement, the ventricular arrhythmia reoccurred and was the cause of death at five months after surgery. Postoperative wall-motion studies performed in the two surviving patients showed limited scars in the area of cryocoagulation and minor damage to the coronary arteries in that area. The transaortic approach can be considered as a new and important surgical option for endocardial mapping and cryocoagulation which prevents the damaging effects of a left ventriculotomy.

Epicardial reflection as a cause of incessant ventricular bigeminy

Incessant monomorphic ventricular bigeminy was studied in a young patient with no organic heart disease. The arrhythmia could not be controlled by drug therapy. Spontaneous and artificial variation of the heart rate showed that reentry was the most likely arrhythmogenic mechanism. Peroperative epicardial and transmural mapping revealed an epicardial focal origin which was cryoablated. Reflected reentry occurring in a small area of working myocardial cells appeared to be the most likely explanation for this arrhythmia.

Surgical therapy for sinoatrial reentrant tachycardia

Sinoatrial reentry is an uncommon cause of paroxysmal supraventricular tachycardia. This paper presents a case of supraventricular tachycardia, refractory to medical therapy, in which the sinus node formed part or all of the reentrant circuit. The mechanism of the arrhythmia was confirmed by catheter mapping during electrophysiological study and by intraoperative epicardial mapping. Cryosurgical ablation of the right atrium in the region of the sinus node has led to cure of her arrhythmia and emergence of a stable ectopic atrial pacemaker rhythm.

"Nodoventricular" accessory pathway: evidence for a distinct accessory atrioventricular pathway with atrioventricular node-like properties

Two patients are described with recurrent pre-excited tachycardia and electrophysiologic characteristics typically ascribed to a nodoventricular accessory connection. The accessory pathway in each case demonstrated rate-dependent prolongation of conduction time and a low right ventricular insertion site; it was associated with a left bundle branch block configuration during pre-excitation. Intraoperatively, the pathway was demonstrated to originate at the anterior right atrioventricular (AV) anulus and not at the AV node. These data suggest that a "typical" nodoventricular pathway, by electrophysiologic criteria, may in fact be an AV pathway with AV node-like conduction properties and a distal right ventricular insertion site.

Sequential pulse defibrillation in humans: orthogonal sequential pulse defibrillation with epicardial electrodes

A newly described sequential pulse technique, using four mesh electrodes positioned to approximate a true orthogonal system around the heart, was compared with a single pulse system using two of these same electrodes, which were located in positions that would be used for an automatic implantable defibrillator. The influence of electrode size was also assessed. The minimal energy necessary for defibrillation (defibrillation threshold) was determined intraoperatively in 21 volunteer patients undergoing accessory pathway ablation of Wolff-Parkinson-White syndrome. Ventricular fibrillation was induced with alternating current. Ten seconds after fibrillation onset defibrillation shocks were begun using either the single or the sequential pulse technique with stored voltage incremented until defibrillation was accomplished (defibrillation threshold). Selection of the use of a single or sequential pulse technique for the initial attempt was randomized. Defibrillation thresholds were determined in three groups of patients: 1) those with four small mesh electrodes (6 cm2), 2) those with two small and two large (13 cm2) mesh electrodes, and 3) those with four large mesh electrodes. In all cases, the average minimal energy needed for sequential pulse defibrillation was less than that required for single pulse defibrillation in the same patients with the same electrodes (four small, 24.8 +/- 24.7 J single versus 6.7 +/- 8.3 J sequential; two small plus two large, 11.4 +/- 15.0 J single versus 2.7 +/- 1.4 J sequential; four large, 8.1 +/- 5.3 J single versus 3.9 +/- 2.6 J sequential). Using the 6 cm2 electrodes for single pulse defibrillation energies delivered at greater than 45 J in two patients failed to defibrillate the heart.(ABSTRACT TRUNCATED AT 250 WORDS)

Surgical approach to anterior septal accessory pathways in 20 patients with the Wolff-Parkinson-White syndrome

Right anterior septal accessory pathways in the Wolff-Parkinson-White syndrome are generally defined by electrophysiological criteria, the most important being that earliest retrograde atrial activation during AV reciprocating tachycardia occurs at the anterior medial segment of the tricuspid annulus (His bundle catheter). The purpose of our study is to describe intraoperative mapping in 20 patients with anterior septal accessory pathways, and to assess if intraoperative mapping contributes to the operative approach. At surgery, all patients had identical early ventricular activation during pre-excitation at the infundibulum. However, two groups could be identified on the basis of retrograde atrial epicardial activation during AV reciprocating tachycardia or right ventricular pacing. Group 1 comprised 16 patients with earliest activation at the interatrial septum adjacent to the His bundle. Epicardial dissection failed to affect accessory pathway conduction. The accessory pathway was only ablated when a discrete endocardial approach to the atrial septum was used. Group 2 comprised 4 patients with early atrial activation "paraseptally" in the right coronary fossa. These accessory pathways were ablated by an epicardial approach without using cardiopulmonary bypass. We conclude that right anterior septal accessory pathways as defined by electrophysiological criteria can be divided into two groups on the basis of the atrial activation sequence: (1) right septal accessory pathways in the septal para-Hissian region and (2) right anterior 'paraseptal' accessory pathways. This classification is of practical importance because the latter can be ablated using an epicardial approach without the need for cardiopulmonary bypass or atriotomy.

Classification of supraventricular tachycardias

An ideal approach to classification of supraventricular arrhythmias would be based on exact knowledge of the pathophysiology and mechanism of the arrhythmia. Unfortunately, the mechanism may not be apparent from electrocardiographic data or indeed may not be known after extensive invasive and non-invasive studies. Difficulties are encountered in applying and extrapolating to patients criteria that are known to exist in experimental preparations. The traditional methods of classification have used electrocardiographic features and atrial rate. Although such classifications are simple, the criteria are arbitrary and electrocardiographically similar arrhythmias may have different mechanisms. A realistic classification must incorporate both electrocardiographic description and mechanism. The classification should be such that it can readily incorporate new knowledge in an additive way without completely restructuring the classification. A classification fulfilling these requirements would begin with electrocardiographic descriptors and end with mechanism, known or unknown. For example, a tachycardia may be characterized as supraventricular, atrial rate 300, 1:1 atrioventricular relation, with atrioventricular nodal reentry mechanism. It could then be qualified by further clinical descriptors such as incessant, paroxysmal or repetitive. With this approach, the initial descriptive category will always be constant and the mechanism known or unknown. As more data are obtained in future years, the "mechanism" segment of the descriptor may be added or revised.

Cryosurgical modification of the atrioventricular node: a closed heart approach in the dog

Intraoperative modification of the atrioventricular (AV) node to prolong refractoriness could be an alternative to His bundle ablation in patients with refractory supraventricular arrhythmias. It was postulated that a cryosurgical lesion at the posterior interatrial septum in the closed heart could achieve this. An electrophysiologic study was performed in anesthetized dogs. The AV fat pad was mobilized to expose the posteroseptal region. A cryoprobe cooled to 0 to -10 degrees C was moved in the exposed region until reversible AV block indicated proximity of the AV node. The probe was then cooled to -70 degrees C for 30 seconds. Four weeks later, five dogs had a favorable result with a mean prolongation of Wenckebach cycle length of 45 +/- 7% (p less than 0.05). Two dogs had complete heart block. Decreased (one dog) or increased (one dog) duration of freezing resulted in no change and complete heart block, respectively. Histologic examination verified partial damage to the AV node with preservation of the His bundle. Thus, controlled cryoinjury to modify AV node function is feasible in the closed heart; preservation of AV conduction provides an advantage over His bundle ablation.

Pharmacologic EEG suppression during cardiopulmonary bypass: cerebral hemodynamic and metabolic effects of thiopental or isoflurane during hypothermia and normothermia

We have determined the effects of thiopental or isoflurane upon cerebral blood flow (CBF) and the cerebral metabolic rate for oxygen (CMRO2) when these agents are used in sufficient dose to attain a deep burst suppression pattern on the electroencephalogram (EEG) during hypothermic and normothermic cardiopulmonary bypass (CPB). Thirty-one patients undergoing coronary artery bypass graft surgery were anesthetized with fentanyl 0.1 mg X kg-1, and were randomly allocated to one of three groups: control (no further anesthetics during bypass and continuous EEG activity), thiopental treatment (EEG suppression), or isoflurane treatment (EEG suppression). Hypothermia (25-29 degrees C) was routinely induced at onset of nonpulsatile cardiopulmonary bypass. In the treatment groups, thiopental or isoflurane were used during bypass to achieve a deep burst suppression pattern. Cerebral blood flow and cerebral metabolic rate for oxygen were determined during hypothermia and upon rewarming to normothermia (37 degrees C). Pharmacologic EEG suppression with either isoflurane or thiopental was associated with lower cerebral metabolic rate than control values during both hypothermic and normothermic bypass. However, only thiopental-induced EEG suppression was associated with lower cerebral blood flow than control. Cerebral blood flow during isoflurane-induced EEG suppression was similar to control values in spite of the reduced cerebral metabolic rate.

Sequential pulse defibrillation in man: comparison of thresholds in normal subjects and those with cardiac disease

We compared the parameters describing the defibrillation threshold in patients with normal hearts and in patients with ischemic heart disease, using a special electrode system and sequential pulses of current. Twenty-eight patients consented to the study (mean age: 36.6 +/- 10.1 years; mean mass: 80.7 +/- 13.8 kg). Twenty-one patients underwent surgery for Wolff-Parkinson-White syndrome (relatively normal hearts). Six patients had a history of previous myocardial infarction and aneurysm or coronary artery disease; and one patient had been resuscitated from an episode of sudden death, without evidence of consequent myocardial damage. For 26 patients, defibrillation thresholds were determined intraoperatively by passing sequential pulses through a catheter electrode and epicardial mesh electrode. For 2 patients defibrillation thresholds were determined during electrophysiologic study, after ventricular fibrillation was induced by programmed stimulation, by passing sequential pulses through a catheter and skin-patch electrode. Parameters for sequential pulse defibrillation thresholds between the two groups did not differ appreciably. Total energy for patients with normal hearts averaged 9.9 +/- 6.3 J compared to 8.9 +/- 4.6 J for patients with cardiac disease. No patient with cardiac disease had defibrillation parameters that exceeded the range of the normal patients. These results suggest that the presence of cardiac disease may not significantly alter the parameters necessary for successful defibrillation when using sequential pulses for delivery of energy.

An algorithm for the electrocardiographic localization of accessory pathways in the Wolff-Parkinson-White syndrome

Accessory pathway location in the Wolff-Parkinson-White syndrome influences the success and morbidity of nonpharmacological therapies, so that an estimate of accessory pathway location is relevant to the practicing physician. We derived an algorithm for accessory pathway localization based on the surface electrocardiogram; we tested it in a population of 141 patients with the Wolff-Parkinson-White syndrome in whom accessory pathway localization was made by electrophysiological and/or intraoperative mapping. The goal of the algorithm was to localize the accessory pathway to one of four anatomic regions, namely, left free wall, posteroseptal, anteroseptal or right free wall by using a simple, easy-to-apply scheme. Each of two observers, blinded to the results of mapping, correctly identified the anatomic location of 91% and 90% of pathways, respectively. We conclude that a simple algorithm utilizing the 12-lead electrocardiogram can provide a valuable first approximation of accessory pathway location in the Wolff-Parkinson-White syndrome.

Closed-heart technique for Wolff-Parkinson-White syndrome: further experience and potential limitations

We have described a closed-heart technique for division of atrioventricular (AV) pathways in Wolff-Parkinson-White (WPW) syndrome. The technique involves dissection and mobilization of the AV fat pad with exposure and cryoablation of the AV junction at the site of the AV pathways. One hundred five consecutive patients with WPW syndrome with left ventricular free wall (74), posterior septal (23), and right ventricular free wall AV pathways (11) were operated on between July, 1982, and September, 1985. Three patients had multiple accessory pathways, and 9 had associated cardiac disease. Electrophysiological testing to determine the presence and site of the AV pathway was performed before and after dissection of the fat pad and again after cryoablation of the AV junction. All AV pathways but 1 were successfully ablated. There were no deaths and no incident of AV block. One hundred four patients remain free from arrhythmia in the absence of drugs after a mean follow-up of 18 months (range, 2 to 42 months). Four patients required a second operation within the first few weeks for recurrence of AV pathway conduction, and 1 patient required a third operation. In 3 of these patients, AV pathway conduction persisted after extensive dissection and exposure of the AV junction and disappeared only after cryoablation. Recurrence of AV pathway conduction in the latter patients suggests the presence of a subendocardial pathway protected from cryoablation by the warm, circulating blood pool. The closed-heart technique appears safe and efficacious. A potential limitation may be the presence of subendocardial AV pathways, which may require an alternative surgical approach at the site of the pathway to attain uniform primary success.

Surgical treatment of supraventricular tachycardia: a five-year experience

Two hundred and eight patients underwent operative therapy of supraventricular tachycardia between June 1984 and June 1986. There were 196 patients with Wolff-Parkinson-White syndrome, one with AV nodal reentry, two with atrial flutter, one with ectopic atrial tachycardia, three with paroxysmal sinus tachycardia, and five with atrial fibrillation. Map guided or direct surgery was performed in all patients except the three with atrial fibrillation. Direct surgery was generally successful with failures including one patient with Wolff-Parkinson-White syndrome, one with atrial flutter, and the three patients with paroxysmal sinus tachycardia. There was no mortality. Major complications were uncommon and included three resternotomies for bleeding, one chylopericardium. Six patients required reoperation.

Retrograde coronary sinus versus aortic root perfusion with cold cardioplegia: randomized study of levels of cardiac enzymes in 40 patients

Myocardial injury was assessed with the use of enzyme indexes in 40 patients randomly assigned to one of two groups undergoing coronary artery bypass surgery. Twenty patients received cold cardioplegia delivered by retrograde coronary sinus perfusion and 20 received cardioplegic solution by anterograde aortic root perfusion. Creatine kinase isoenzyme MB and lactate dehydrogenese isoenzyme 1 and isoenzyme 2 assays were carried out on blood samples obtained from the coronary sinus before aortic cross-clamping and 0, 5, and 30 min after aortic unclamping. Levels of these enzymes were also obtained from venous blood samples before aortic cross-clamping and 3, 8, 14, and 20 hr after aortic unclamping and 2, 3, 4, and 5 days after surgery. Preoperative and postoperative hemodynamic measurements (Swan-Ganz catheter) and radionuclide wall motion studies were also obtained for comparison. There was no overall significant difference between the two groups postoperatively in terms of enzyme indexes, hemodynamic measurements, or results of wall motion studies. We conclude that retrograde coronary sinus perfusion is an alternative to aortic root perfusion in delivering cold cardioplegia. More studies are required to determine which subgroup of patients with coronary artery disease may benefit from retrograde coronary perfusion.

Surgical ablation of posterior septal accessory pathways in the Wolff-Parkinson-White syndrome by a closed heart technique

The conventional technique for surgical ablation of posterior septal accessory pathways in the Wolff-Parkinson-White syndrome has been associated with a significant incidence of inadvertent permanent atrioventricular block. We report our experience with the ablation of posterior septal accessory pathways by a closed heart technique that combines mobilization of the posterior septal atrioventricular fat pad and exposure and cryoablation of the atrioventricular junction. The operation is performed on the normothermic beating heart. Consequently, atrioventricular node-His bundle conduction and accessory pathway conduction can be continuously monitored to avoid inadvertent injury to the atrioventricular node-His bundle system. This technique for ablation of posterior septal accessory pathways was used in 13 patients (four female and nine male patients, aged 14 to 59 years). The heart was exposed via a median sternotomy. Epicardial mapping was used to determine the insertion of the accessory pathway either to the left ventricular process or the immediately adjacent right or left ventricular free wall. Normothermic cardiopulmonary bypass was used in nine patients and omitted in four. Accessory pathway conduction disappeared in the course of dissecting the fat pad from the atrial wall and atrioventricular sulcus in all patients. Cryosurgical lesions were then applied to the atrioventricular sulcus in the area of interest (while monitoring atrioventricular conduction) to ensure transmural fibrosis of the atrioventricular ring. All patients tolerated the procedure well. There were no complications and, specifically, not a single instance of atrioventricular block. All patients remain arrhythmia free after a follow-up period of 10 months. This closed heart approach allows the ablation of posterior septal accessory pathways while the electrocardiogram is being monitored. It obviates the need for aortic cross-clamping and minimize the risk of inadvertent heart block.

Surgery for Wolff-Parkinson-White syndrome: further experience with an epicardial approach

We have previously reported the use of an epicardial approach for ablation of left ventricular free wall accessory atrioventricular pathways. The technique involves mobilization of the atrioventricular fat pad and exposure and cryoablation of the atrioventricular junction at the site of the accessory pathway on the normothermic beating heart. Here we describe our further experience with left ventricular free wall accessory pathways and right ventricular free wall accessory pathways. Our experience is based on 53 consecutive patients. There were 35 male and 18 female subjects, 6 to 52 (mean 41.4) years old. Forty-eight patients had a left ventricular free wall accessory pathway, and five had a right ventricular free wall accessory pathway. Two patients had an associated anterior septal accessory pathway. Five patients had associated cardiac abnormalities, including atrial septal defect, aortic insufficiency, mitral valve prolapse, Ebstein's anomaly, and cardiomyopathy. The accessory pathway was ablated in 52 patients who remain arrhythmia free without medication after a mean follow-up period of 12 months. The accessory pathway was permanently modified in one patient. There were no postoperative complications. This epicardial approach can be performed with normothermic cardiopulmonary bypass or without bypass. It does not require cross-clamping of the aorta, allowing a greater margin of safety when this is required for concomitant procedures.

Demonstration of macroreentry and feasibility of operative therapy in the common type of atrial flutter

Two patients are described who had recurrent and long-standing atrial flutter of the common type and were referred for electrophysiologic testing and surgical management. In both patients, atrial flutter could be initiated and terminated by programmed stimulation. Atrial endocardial mapping showed earliest activation during flutter at the orifice of the coronary sinus, with activity proceeding to the low atrial septum, high lateral right atrium and low right atrium, respectively. Programmed atrial extrasystoles from the high right atrium at a time when the atrial septal region was refractory advanced atrial flutter in proportion to prematurity of the extrastimulus, while maintaining the low to high activation sequence. Intraoperatively, epicardial atrial mapping revealed a large right atrial reentrant circuit beginning in the posteroseptal region and proceeding superiorly and laterally through the right atrial free wall before returning to its starting point. The narrowest part of the circuit and that showing relatively slow conduction during atrial flutter was observed in the low right atrial tissue between the tricuspid valve ring and the orifices of the inferior vena cava and proximal coronary sinus, respectively. Cryosurgical ablation around the orifice of the coronary sinus and surrounding atrial wall has prevented recurrent atrial flutter over short term follow-up in both patients, although 1 of the patients has required antiarrhythmic therapy for postoperative atrial fibrillation.

Internal cardiac defibrillation in man: pronounced improvement with sequential pulse delivery to two different lead orientations

Wider applicability of an implantable automatic defibrillator depends on achieving internal cardiac defibrillation consistently with the lowest possible energy. In animal studies, we have found that the cardiac defibrillation threshold could be reduced when sequential shocks separated in time and spacially arranged were delivered to the heart. We compared internal cardiac defibrillation using a single pulse shock delivered through an intravascular catheter with this new method for internal cardiac defibrillation in patients undergoing cardiac surgery for the correction of arrhythmias. For the single pulse shock and the first pulse of the sequential pulse shock, current was passed through an intravascular catheter with the catheter cathode at the apex of the right ventricle and the anode at the superior vena cava-atrial junction region. The second pulse of the sequential pulse countershock was delivered between the catheter cathode in the right ventricular apex and an oval plaque electrode secured on the laterobasal left ventricular epicardium as anode. With the single pulse alone for shock delivery, 12 patients could be defibrillated with an average of 20.1 +/- 16.8 J, with a corresponding leading-edge peak voltage and current of 836 +/- 319 V and 9.4 +/- 4.5 A, respectively. However, two of the patients could not be defibrillated with energies below 50 J. With the sequential pulse shock delivery, a significant reduction in all values were recorded. Mean total energy for defibrillation averaged 7.7 +/- 6.0 J. Leading-edge peak voltage and current from the catheter averaged 430 +/- 148 V and 5.0 +/- 2.8 A, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Controlled cryothermal injury to the AV node: feasibility for AV nodal modification

Elective subtotal injury to the AV node-His bundle region may create a negative dromotropic effect to provide a therapeutic advantage in some patients with supraventricular tachycardia without creating complete AV block. We examined the effects of cryosurgery to the AV nodal region, varying temperature and time using a 15 mm circular cryoprobe applied directly to the canine AV node-His bundle region. Twelve dogs were anesthetized and the heart was exposed through a right thoracotomy. Electrophysiological data obtained included conduction intervals, incremental pacing, and extrastimulus testing. Under inflow occlusion, the cryoprobe was positioned over the AV node-His bundle region using anatomical landmarks and a single freeze was applied (-15 degrees C to -60 degrees C, 15 to 60 seconds). Dogs were allowed to recover for 1 month, after which time electrophysiological testing was repeated under similar conditions; then the animals were sacrificed. With probe temperatures of -60 degrees C for 15 to 60 seconds, five of six dogs experienced complete heart block with dense fibrosis observed in the AV nodal-His bundle region. After freezing with higher temperatures, the remaining seven dogs had return of atrioventricular conduction postoperatively with prolongation of AH time observed in five and marked prolongation of the Wenckebach cycle length in three of the five. We conclude that controlled cryothermal injury to the AV node-His bundle region may be useful to create a desirable negative dromotropic response without creating complete AV block.

Atrial fibrillation in patients with Wolff-Parkinson-White syndrome: incidence after surgical ablation of the accessory pathway

The effect of surgical ablation of ablation of atrioventricular accessory pathways on the incidence of atrial fibrillation in patients with Wolff-Parkinson-White syndrome was examined and the results of preoperative electrophysiologic testing were studied to determine factors predictive of outcome. Among 50 consecutive surgical cases, 19 patients were identified with a past history of at least one episode of spontaneous atrial fibrillation documented by electrocardiogram before surgery. The mean number of episodes of atrial fibrillation was 1.97/patient/year during a mean symptomatic period of 6.9 years before surgery. These patients were compared with 19 consecutive patients undergoing surgery during the same time period who had a history of only reciprocating tachycardia. Patients with atrial fibrillation had a significantly shorter antegrade accessory pathway effective refractory period (270 +/- 39 vs 330 +/- 107 msec; p less than .05) and much faster ventricular rates during induced atrial fibrillation (shortest RR interval 219 +/- 73 vs 294 +/- 60 msec, p less than .005; average RR interval 324 +/- 109 vs 405 +/- 127 msec, p less than .01). Patients with atrial fibrillation also had longer PA intervals (47 +/- 13 vs 37 +/- 7 msec; p less than .02). At preoperative electrophysiologic testing, 18 patients with atrial fibrillation had atrial fibrillation induced and 14 sustained the arrhythmia for longer than 10 min. In contrast, atrial fibrillation, although induced in 14 of 19 patients with reciprocating tachycardia, was not sustained in any. Thus electrophysiologic testing suggested that both accessory pathway properties and atrial vulnerability may predispose to atrial fibrillation.(ABSTRACT TRUNCATED AT 250 WORDS)

Marked paradoxical septal motion associated with an early diastolic heart sound

The findings in four patients with marked paradoxical septal motion and an unusual early diastolic sound are presented. Each patient had markedly abnormal right ventricular function. Phonocardiograms, apexcardiograms, and echocardiograms showed the sound to precede the expected timing of a third heart sound and to coincide with the peak leftward displacement of the paradoxically moving septum in early diastole. In two patients the sound was also accompanied by third and fourth heart sounds, revealing a total of five heart sounds on phonocardiographic studies. The sound appeared to originate from the sudden deceleration of the septal mass as it moved leftward during ventricular relaxation.

[Surgical section of the bundle of Kent in the closed heart]

The conventional operation for ablation of accessory pathways (AP) in the WPW syndrome requires an endocardial approach and necessitates cardiopulmonary bypass and hypothermic cardiac arrest. Cryosurgical ablation of AP from the epicardial surface has been described but was limited to superficial AP. We report a new closed-heart technique combining dissection of AV pad and cryosurgery. Eight patients with WPW syndrome, aged 6-56, underwent surgery for ablation of AP associated with disabling tachyarrhythmia refractory to medical management. All AP were located in the left lateral AV sulcus as determined by preoperative and intraoperative electrophysiological assessment. The heart was exposed through a median sternotomy. The AV fat pad and its vascular contents were dissected away from the atrium at the site of the AP, sacrificing some atrial vessels. The dissection left some fat adherent to the thin-walled atrium close to the level of the mitral annulus. A small segment of the ventricle adjacent to the sulcus was exposed. The fat pad was retracted to avoid cryo-injury to the coronary vessels. A cryoprobe (1.5 cm diameter) was applied to the exposed AV junction (-60 degrees C for 2 minutes) to create transmural fibrosis. After verification of AP ablation, the chest was closed. All 8 patients have remained free of preexcitation during short term follow-up (1 to 8 months). This simplified technique is applicable to patients with free-wall AP, a group constituting the majority of symptomatic WPW patients at our institution.

Total disconnection of the right ventricular free wall: physiological consequences in the dog

We recently described a new surgical procedure involving total disconnection and subsequent reattachment of the right ventricular free wall ( RVFW ) to confine electrically induced arrhythmic activity to the diffusely diseased RVFW of patients with arrhythmogenic right ventricular (RV) dysplasia. Although no major adverse effects were noted in patients with previously akinetic right ventricles, the consequences of this procedure are unknown in patients with a normally contractile RVFW . This study examined the physiologic consequences of RVFW disconnection in 15 mongrel dogs. Measurements were obtained before surgery, at 30 minutes following surgery, and following a 15-day recovery period. After surgery, the RVFW was electrically isolated from sinus rhythm. At follow-up, left ventricular (LV) pressure, dP/dt, and cardiac output were reduced to 52 mm Hg, 704 mm Hg/sec, and 1.18 L/min, respectively, during sinus rhythm. These values were increased to 76.2 mm Hg, 890 mm Hg/sec, and 1.69 L/min, respectively, when the RVFW was paced in synchrony with sinus rhythm. These studies show that the loss of RVFW contraction depressed hemodynamic function of the normal heart, which is partially compensated by contraction of the left ventricle. Electrical stimulation of the RVFW synchronously with the left ventricle returned cardiac performance toward normal. Finally, this preparation provides a model for independent assessment of the contribution of the RVFW to cardiac function.

Refractory paroxysmal sinus tachycardia: management by subtotal right atrial exclusion

A 27 year old woman presented with recurrent episodes of disabling paroxysmal sinus tachycardia (150 to 180 beats/min) in the absence of identifiable organic disease. Tachycardia was resistant to all drug therapy. Programmed stimulation could not induce the tachycardia but high dose propranolol therapy failed to suppress sinus tachycardia in response to isoproterenol infusion. Because of the disability resulting from refractory tachycardia, the patient underwent a new operative procedure to create exit block around the region of abnormal impulse formation. This resulted in the appearance of a stable junctional escape rhythm at 60 beats/min. No adverse effects occurred and the patient has remained free of symptoms after a follow-up period of 10 months.

Surgical correction of the Wolff-Parkinson-White syndrome in the closed heart using cryosurgery: a simplified approach

The conventional operation for ablation of accessory atrioventricular (AV) pathways in the Wolff-Parkinson-White syndrome requires an endocardial approach to the AV groove and necessitates the use of cardiopulmonary bypass and induced cardiac arrest. The feasibility of creating transmural atrial fibrosis at the level of the AV anulus in the closed heart in dogs without damaging the vascular contents of the AV fat pad was demonstrated. This was done by dissecting the fat pad from the atrium and applying a cryoprobe to the exposed atrial-anular region after retraction of the fat pad. The technique was then applied to successfully ablate 12 left parietal wall accessory pathways in 11 patients with the Wolff-Parkinson-White syndrome. This simplified approach to any parietal wall accessory pathway does not require cardiopulmonary bypass or induced cardiac arrest and may broaden the indications for this operation.

Surgical repair of Wolff-Parkinson-White syndrome: a new closed-heart technique

The conventional operation for ablation of accessory pathways in Wolff-Parkinson-White (WPW) syndrome requires an endocardial approach and necessitates cardiopulmonary bypass and hypothermic cardiac arrest. Cryosurgical ablation of these pathways from the epicardial surface has been described but limited to superficial accessory pathways. We report a new closed-heart technique combining dissection of the atrioventricular (AV) pad and cryosurgery. Six patients with WPW syndrome underwent operation for ablation of accessory pathways associated with disabling tachyarrhythmia refractory to medical management. All pathways were located in the left lateral AV sulcus as determined by preoperative and intraoperative electrophysiological assessment. The heart was exposed through a median sternotomy. The AV fat pad and its vascular contents were dissected away from the atrium at the site of the pathway. A small segment of the ventricle adjacent to the sulcus was exposed. The fat pad was retracted to avoid cryoinjury to the coronary vessels. A cryoprobe, 1.5 cm in diameter, was applied to the exposed AV junction (-60 degrees C for 2 minutes) to create transmural fibrosis. After ablation of the pathway was verified, the chest was closed. All 6 patients have remained free from preexcitation during short-term follow-up. This simplified technique is applicable to patients with free wall accessory pathways. This group constitutes the majority of symptomatic patients with WPW syndrome at our institution.

Surgical therapy of cardiac arrhythmias

Surgery guided by a greater understanding of the mechanism of arrhythmias has assumed an important role in managing recurrent tachycardia. Further progress will continue to broaden surgery's indications beyond the patient with life-threatening tachycardias refractory to all other forms of surgery.

Surgical treatment of Wolff--Parkinson--White syndrome

The Wolff--Parkinson--White syndrome may be associated with life-threatening or disabling tachyarrhythmia, owing to the presence of an atrioventricular accessory pathway (Kent bundle). The first division of a Kent bundle was reported in 1969, but this surgery is still confined to a few centres. Between September 1981 and October 1982, 19 patients (13 men, 6 women) aged 16 to 46 years (mean 25 years) with the Wolff--Parkinson--White syndrome associated with refractory arrhythmia underwent surgery. Kent bundles were localized in the electrophysiology laboratory and by intraoperative cardiac mapping. The 19 patients had a total of 22 distinct Kent bundles. The bundles were divided using open-heart (13 patients) or closed-heart (6 patients) technique. All Kent bundles were confirmed as nonfunctioning before discharge. A delta wave recurred in two patients. The Kent bundle was not functional in one patient. The other is controlled by a drug that was previously ineffective. There were no complications or deaths. Kent bundles can be divided with minimal morbidity and a high success rate (more than 90%). Surgery is indicated in patients with refractory arrhythmias or in young patients who would be required to take medication for life.

Total disconnection of the right ventricular free wall: surgical treatment of right ventricular tachycardia associated with right ventricular dysplasia

Arrhythmogenic right ventricular dysplasia is a myopathy that affects the right ventricular free wall (RVFW) and gives rise to recurrent reentrant ventricular tachycardia (VT). Because the entire right ventricle is potentially arrhythmogenic, ablating a single site of VT may not eliminate the arrhythmia. We developed an operation to confine any arrhythmic activity arising from the right ventricle to that chamber: total disconnection of the RVFW from the left ventricle. We performed RVFW disconnection in two patients with refractory VT associated with arrhythmogenic right ventricular dysplasia. At least two sites or origin of morphologically distinct VT were identified in the RVFW in each patient. RVFW disconnection was carried out under normothermic cardiopulmonary bypass. An encircling incision was made along the attachment of the RVFW to the aortoventricular unit and the tricuspid annulus; the right coronary artery and its RVFW branches were left intact. Electrical activity of the two chambers became dissociated, and VT arising from the RVFW was confined to that chamber. Postoperatively, there was no clinical evidence of hemodynamic impairment (follow-up 4 months and 3 months). Left ventricular function was unchanged and right ventricular flow was maintained by atrial contraction and motion of the septum toward the RVFW during left ventricular systole. One patient had incessant right ventricular tachycardia confined to the RVFW for 3 weeks. We conclude that RVFW disconnection is feasible and applicable to patients with refractory VT originating in the diffusely diseased RVFW.