Surgical treatment of supraventricular tachyarrhythmias

The surgical treatment of supraventricular tachyarrhythmias has undergone considerable evolution since its inception in 1968 with the treatment of a patient with Wolff-Parkinson-White syndrome. At present, Wolff-Parkinson-White syndrome, atrioventricular node re-entry, and ectopic atrial foci that can be localized are all amenable to surgical therapy.     

Surgical treatment of supraventricular tachyarrhythmias.

In this report, we have outlined our experiences with the direct surgical treatment of 16 patients with supraventricular tachyarrhythmias (SVTA). Re-entry supraventricular tachycardia (SVT) was demonstrated by the 4 patients who had retrograde-conducting Kent pathways. The SVT was corrected by the successful division of the Kent bundle in 3 and a partially successful His bundle division in one patient. The remaining 9 patients with re-entry, which included 6 with Kent pathways and WPW, all had His bundle section. The remaining 3 with His interruption had focal tachycardias associated with dysfunction of the atrioventricular (AV) node. Of the 13 His bundle interruptions, nine were successful, three resulted in questionable AV conduction, and one failed. Problems with suture ligation and cautery explained the failures. Cryothermia was the most successful procedure used. However, excision of that portion of the atrium containing the AV node shows promise of being satisfactory. The possibility is discussed of using measures much more precise and less destructive than His bundle interruption for SVTA.     

Transesophageal atrial pacing in the management of re-entry supraventricular tachyarrhythmias occurring during general anesthesia

BACKGROUND: Supraventricular tachyarrhythmias (SVTs) represent an intraoperative risk factor that should be always prevented/managed. The commonly used anti-arrhythmic drugs are accompanied by intrinsic hazards, such as pro-arrhythmic and toxic effects or unpredictable onset and duration of action. We underline the therapeutic use of transesophageal atrial pacing (TAP) for the interruption of particular re-entry SVTs occurred during surgical procedures in general anaesthesia. METHODS: Our study was carried out in 25 patients characterized by a personal clinical history of transient tachyarrhythmic episodes, subjected to general anaesthesia obtained by midazolam, propofol, N2O e O2, sevoflurane, fentanil and vecuronium bromide. We used TAP bursts of 3-5 sec, their minimal pacing rate being equivalent to the tachyarrhythmia cycle length, with an impulse intensity ranging from 18 to 25 mA. In such conditions, the re-entry was interrupted by the induction of refractoriness of the wave-front that sustained the underlying arrhythmogenic circuit. RESULTS: During the study, the following arrhythmias occurred in 7 out of all patients: 1 type I atrial flutter, 3 nodal tachycardias, 1 antidromic and 2 orthodromic atrioventricular tachycardias, respectively. TAP assured either atrial capture or prompt suppression of arrhythmias in all cases. Low intensity impulses did not ever allow ventricular capture. CONCLUSIONS: TAP can be considered as a valid therapeutic device for the management of re-entry SVTs occurred during general anaesthesia, resulting it effective, safe and easy-practicable.     

Persistent atrial activity during cardioplegic arrest: a possible factor in the etiology of postoperative supraventricular tachyarrhythmias

We assessed the relationship between the duration of atrial activity during the cross-clamp period and the postoperative occurrence of supraventricular tachyarrhythmias in 50 patients undergoing elective coronary bypass operation. The atrial electrical activity was monitored continuously by means of a bipolar atrial electrogram from the onset of cardioplegic administration until removal of the aortic cross-clamp. While ventricular arrest was induced promptly and maintained in all patients, sustained atrial activity was observed in 44 out of 50 patients during the cross-clamp period. In the postoperative period, supraventricular tachyarrhythmias developed in 15 patients (Group 1). Thirty-five patients (Group 2) were free from such tachyarrhythmias. There was no significant difference between the two groups with respect to cross-clamp time, bypass time, amount of cardioplegic solution used, or number of grafts per patient. The mean duration of atrial activity during cardioplegic arrest, however, was significantly longer in Group 1 than in Group 2 (46 +/- 4.7 minutes versus 22.6 +/- 4.0 minutes, respectively, p less than 0.001). None of the 6 patients in whom atrial activity was completely abolished experienced supraventricular tachyarrhythmias. The strong correlation observed between the duration of atrial activity during cardioplegic arrest and the incidence of postoperative supraventricular tachyarrhythmias suggests the possibility that these arrhythmias may be a manifestation of inadequate atrial protection during global myocardial ischemia.     

Cryoablation of septal pathways in patients with supraventricular tachyarrhythmias

Eighteen patients with supraventricular tachycardia refractory to medical therapy underwent preoperative electrophysiological study and subsequent operation. There were 6 female and 12 male patients ranging in age from 1.5 to 31.6 years (mean age, 11.9 +/- 7.8 years). Eleven had classic Wolff-Parkinson-White syndrome with intermittent tachycardia, and 7 had a form of permanent junctional reciprocating tachycardia. Five had impaired left ventricular function preoperatively. The location of the accessory conduction pathway was anteroseptal in 3, posteroseptal in 12, and both anteroseptal and posteroseptal in 3 patients. Pathway location was confirmed by intraoperative mapping in all patients. The pathways were ablated utilizing a cryoprobe at -70 degrees C. All patients survived the operation, had immediate abolishment of delta waves and tachycardia, and were considered cured at the time of hospital discharge. Sixteen (89%) remain cured at a mean follow-up of 16.9 months. One patient with a posteroseptal pathway no longer has a delta wave but has had poorly documented episodes of tachycardia and is taking medication. One other patient with both anteroseptal and posteroseptal pathways had a recurrent delta wave 6 months postoperatively but has had no tachycardia and is asymptomatic without medication. No patient experienced heart block. Ventricular function has returned to normal in all 5 patients with impaired function preoperatively. Cryoablation is an effective method of abolishing accessory conduction pathways located in the anteroseptal or posteroseptal region. The method is easy, and results are comparable with those of other techniques previously described.     

Thoracic epidural bupivacaine attenuates supraventricular tachyarrhythmias after pulmonary resection

Supraventricular tachyarrhythmias after pulmonary surgery are well described. Some investigators suggest that tachyarrhythmias after thoracic operations may result from the relative sympathotonic status produced by injury to the cardiac parasympathetic nerves. We examined whether postoperative thoracic sympathetic blockade by thoracic epidural bupivacaine might reduce the tachyarrhythmias after pulmonary resection. Fifty patients with lung cancer were randomized to receive epidural bupivacaine (Group B) or epidural morphine (Group M). Patients in Group B were given 6 to 10 mL of 0.25% bupivacaine epidurally, followed by epidural infusion at 3 to 5 mL/h for 3 days, and patients in Group M were given 2 to 3 mg morphine epidurally, followed by morphine infusion at a rate of 0.2 mg/h. Tachyarrhythmias were diagnosed by using the continuous heart rate trend and arrhythmia trend with a central monitoring system. Postoperative analgesia was not statistically different between groups. However, the incidence of postoperative tachyarrhythmias in Group B was significantly less than in Group M (1 of 23 vs 7 of 25, P = 0.0497, Fisher's exact test). The continuous infusion of thoracic epidural bupivacaine can reduce supraventricular tachyarrhythmias compared with epidural morphine infusion, presumably because of attenuation of the sympathotonic status after pulmonary resection. IMPLICATIONS: We examined whether postoperative thoracic sympathetic blockade by thoracic epidural bupivacaine after pulmonary resection might reduce the tachyarrhythmias that may result from the relative sympathotonic status produced by injury to the cardiac parasympathetic nerves. The continuous infusion of thoracic epidural bupivacaine was shown to reduce supraventricular tachyarrhythmias.     

Successful surgical treatment of atrial tachyarrhythmias

Three cases with ectopic atrial tachycardia and two cases with atrial flutter (AF), unresponsive to drugs, are described clinically and electrophysiologically. The three patients of ectopic atrial tachycardia were treated by surgical removal of ectopic focus and cryocoagulation of the adjacent area, not using cardiopulmonary bypass. All of them have been in sinus rhythm and had shown no tachycardia since the operation. In one patient of AF, cryosurgical ablation around the atrioventricular (AV) node and His bundle has prevented AF without AV block. Another patient of AF underwent cryoablation around the orifice of the coronary sinus, which was the earliest activation area during AF in endocardial mapping. In this patient, AF reappeared, so cryoablation around the AV node and His bundle was performed. His heart rate decreased to 120 beat/min from 270 beats/min during AF and a radiofrequency pacemaker (Atricon) was implanted to interrupt the remaining AF. This cryosurgical procedure is successful to modify and preserve AV conduction.     

Computerized global electrophysiological mapping of the atrium in a patient with multiple supraventricular tachyarrhythmias

The first clinical experience and the potential benefit of intraoperative global atrial-activation mapping recorded from 156 electrodes simultaneously are demonstrated in a 14-year-old girl with an ectopic (automatic) right atrial tachycardia, junctional tachycardia, and atrial flutter secondary to a previous atriotomy. Cryoablation of the right atrial focus terminated the automatic tachycardia, and surgical interruption of the atrial flutter pathway temporarily terminated this arrhythmia. Persistence of the junctional tachycardia necessitated elective cryoablation of the bundle of His.     

Nonpharmacologic treatment of supraventricular and ventricular tachyarrhythmias. A review of 249 consecutive patients.

Incapacitating or life-threatening tachyarrhythmias were treated nonpharmacologically in 249 patients from 1982 to 1991. Among 92 patients surgically treated for supraventricular tachycardia the cure rate was 93% and the complication rate 12%. Radiofrequency catheter ablation gave an equal cure rate in 51 patients, but with no major complications or mortality. Direct-current catheter ablation of the His bundle was successful in 96% of 27 patients with drug-refractory atrial fibrillation or other supraventricular tachyarrhythmias. Among 64 patients undergoing surgery for ventricular tachycardia/ventricular fibrillation, the perioperative mortality was 9%, estimated 5-year survival 69% and estimated 5-year freedom from the preoperative arrhythmias 72%. Of 18 patients treated with implantable cardioverter defibrillator, three (18%) died of heart failure during follow-up. Nonpharmacologic treatment of tachyarrhythmias is concluded to be effective and often definitively curative. The safety-risk ratio is improving as new treatment modalities are developed.     

Decreased incidence of supraventricular arrhythmias achieved by selective atrial cooling during aortic valve replacement

Inadequate atrial hypothermia and subsequent ischemic injury have been recognized as the major causes of supraventricular arrhythmias (SVAs) and conduction defects following cold chemical cardioplegia. This study was designed to assess the effects of right atrial cooling (15 degrees-20 degrees C) during cardioplegic arrest upon the incidence of postoperative SVAs and conduction defects in 40 consecutive patients undergoing isolated aortic valve replacement. Atrial preservation was ensured by combining systemic (24 degrees C) and topical hypothermia with snared double caval cannulation during arrest. Myocardial temperatures in the right atrial septum and anterior wall of the right ventricle were recorded before and after each cardioplegic infusion and upon release of caval tapes. Postoperatively, the incidence of SVAs and conduction defects was assessed by continuous rhythm monitoring, bipolar atrial electrograms and, in ten patients, 24-h Holter recordings during the first postoperative day. With the venae cavae snared, temperatures in the right atrial septum were not significantly different from those measured simultaneously in the right ventricle. Release of caval tapes resulted in right atrial temperatures increasing to systemic temperature (from 17.1 +/- 2.9 degrees C to 25.9 +/- 5.6 degrees C [m +/- SD]; P less than 0.01). Atrial rewarming between cardioplegic infusions did not exceed 2.9 degrees +/- 3.2 degrees C. Postoperatively, four patients (10%) developed sustained atrial fibrillation. One additional patient had a single episode of paroxysmal atrial fibrillation and two patients experienced asymptomatic episodes of junctional rhythm.(ABSTRACT TRUNCATED AT 250 WORDS)     

Efficacy of low-dose propranolol in preventing postoperative supraventricular tachyarrhythmias: a prospective, randomized study.

A prospective, randomized study was performed in 100 consecutive patients undergoing coronary artery bypass surgery to assess the efficacy of the early reinstitution of propranolol in reducing the incidence of postoperative supraventricular tachyarrhythmias (SVT). Patients were randomized to receive propranolol 10 mg every 6 hours enterally starting the morning after surgery (Group I, 50 patients) or to serve as controls (Group II, 50 patients). No patient was excluded because of poor ventricular function, need for urgent revascularization, or transient necessity for ionotropic support. Both groups had a comparable incidence of risk factors, previous infarction, unstable angina, and abnormal ventricular function. The extent of coronary disease, preoperative propranolol dose, and number of grafts performed were also similar. SVT occurred in 3/50 (6%) patients in Group I compared with 14/50 (28%) in Group II (p less than 0.01). There were no preoperative or intraoperative discriminators to predict the occurrence of SVT. In addition, perioperative infarction and the need for mechanical or pharmacologic circulatory support did not predispose to SVT. The data indicate that early administration of propranolol should be given to all patients after myocardial revascularization to decrease the incidence of these postoperative rhythm disturbances.