Preoperative Electrophysiological Study Research Articles

상완신경총에 발생하는 질환의 수술에서 수술중신경계의 검사와 감시

The brachial plexus disease is anatomically complex. Moreover, each patient’s neurological condition is highly variable and the decision-making during surgery is challenging. Thus, the surgical approach should be individualized. Sufficient evaluation, including preoperative electrophysiological study and radiological examination is essential; however, these evaluations have some limitations. Intraoperative neurophysiological monitoring is introduced in brachial plexus surgeries and offers additional benefits. This technique is not different from the intraoperative neurophysiological monitoring technique for peripheral nerve surgeries; however, special monitoring systems are required in brachial plexus surgeries. In traumatic brachial plexus injuries, differentiating the preganglionic or postganglionic lesions can provide decisive information in determining the surgical method. Although there is a lack of clinical evidence on the benefits of intraoperative neurophysiological monitoring in the surgery for brachial plexus disease, it is necessary to investigate the benefits through a well-designed prospective study based on a detailed evaluation of neurological deficits before and after surgeries.

Impact of preoperative electrophysiological intervention on occurrence of peri/postoperative supraventricular tachycardia following Fontan surgery

Little is known about the effects of preoperative electrophysiological study (EPS) and catheter ablation (CA) in Fontan surgery candidates with supraventricular tachycardia (SVT). The purpose of this study was to investigate the clinical impact of EPS-guided intervention in Fontan surgery candidates with preceding SVT events. A total of 109 consecutive patients with a history of SVT before Fontan surgery were divided into 3 groups: 44 in whom EPS with CA was attempted (CA group); 21 in whom EPS without CA was attempted (EPS group); and 44 in whom EPS was not performed (N group). The incidence and diagnosis of SVT, acute success rate of CA, and risk factors of peri/postoperative SVT were retrospectively investigated. The total incidence of SVT within 1 year after Fontan surgery was 34% (n = 37), with 91% of cases occurring within 1 month. Among the 71 SVT incidences diagnosed with EPS, 31 were atrioventricular reentrant tachycardias (AVRTs) involving twin atrioventricular nodes, 12 were atrioventricular nodal reentrant tachycardias, 12 were atrial tachycardias, 7 were orthodromic AVRTs via the accessory pathway, 7 were atrial flutters, and 2 werejunctional tachycardias. The acute success rate of CA was 91% (48/53). The rate of peri/postoperative atrioventricular reciprocating SVT was significantly lower in the CA group than in the N or EPS group (11% vs 43% or 43%; P <.05). No/unsuccessful CA significantly increased the risk of peri/postoperative SVT in multivariate analysis (odds ratio 4.43; 95% confidence interval 1.69-11.59). Preoperative CA reduces peri/postoperative SVT occurrence in Fontan surgery candidates at high risk for SVT.

OC44 VENTRICULAR TACHYCARDIA SURGICAL ABLATION IN REPAIRED TETRALOGY OF FALLOT PATIENTS

Background and Aim: Arrhythmias are the main causes of mortality in repaired TOF patients and ventricular tachycardia, due to abnormal electrical conduction near patches and surgical incisions, is refractory to medical therapy. The aim of the study is to evaluate the effectiveness of surgical ventricular RF ablation during pulmonary valve replacement. Methods: 20 patients (median age 37,5 y) in 2004–2013 underwent re-operation for symptomatic pulmonary valve regurgitation with RF ablation, 28 (16–39) years after first repair. Inducible VT was demonstrated during preoperative electrophysiological study in all. Median QRS was 178 (100–268) ms. Right ventricular dilation and dysfunction were present in all, with moderate-to-severe tricuspid regurgitation in 20%. Eleven patients showed spontaneous ventricular arrhythmia, 5 had preoperative ICD, and one presented out-of-hospital cardiac arrest. Surgical ablation of the slow-conducting isthmus between the VSD patch and the pulmonary annulus was performed with linear RF lesions. All patients underwent clinical evaluation, echocardiography and Holter-ECG at 1-3-6 months together with electrophysiological study after 6 months. Results: 16 patients underwent RVOT reduction and 4 TV repair. Median follow-up of 6.5 years was complete. 1 patient with pulmonary artery occlusion died on V-V ECMO for respiratory failure. No late mortality was observed. Residual inducible VT was present in 3/19 patients, whom received ICD as primary prevention. Freedom from ventricular arrhythmia was respectively 94% and 89.5% at 1 and 5 years of follow-up. Conclusion: Pulmonary regurgitation and ventricular dysfunction are correlated with SCD. Ablation of slow-conducting isthmus between the pulmonary valve and VSD patch prevents ventricular arrhythmias.

Utility of preoperative electrophysiologic studies in patients with Ebstein’s anomaly undergoing the Cone procedure

Ebstein's anomaly is associated with a high incidence of atrial and ventricular arrhythmias. The Cone procedure has become an effective hemodynamic intervention for this malformation. In response to two late postoperative sudden deaths in our early institutional Cone experience, a standardized plan for aggressive rhythm evaluation was instituted, including preoperative electrophysiologic studies (EPS) and intraoperative implantable loop recorder (ILR) placement. The purpose of this study was to measure the yield of this diagnostic protocol for patients with Ebstein's anomaly undergoing surgical repair and to describe its influence on patient management. All patients at Boston Children's Hospital with Ebstein's anomaly who underwent the Cone procedure from December 2006 to September 2012 were reviewed. Pre- and postoperative arrhythmias and therapies were documented. For patients who underwent preoperative EPS, all arrhythmia substrates and interventions were recorded. A total of 74 patients were included, 42 of whom underwent preoperative EPS. Significant findings were documented during EPS in 29 of the 42 patients (69%), including eight patients with no prior suspicion of arrhythmias. Seventeen patients had successful catheter ablation during EPS, and EPS data guided one or more intraoperative rhythm interventions for the remainder. During follow-up, diagnostic yield from ILR was low. Since implementing a more aggressive diagnostic strategy, no further sudden deaths have occurred. Preoperative EPS has a high diagnostic and therapeutic yield in patients with Ebstein's anomaly undergoing the Cone operation. It is reasonable to recommend EPS as a routine preoperative test for this population.

Assessment of the Macula in Keratoconus: An Optical Coherence Tomography and Multifocal Electroretinography Study

Purpose: The purpose of our study was to assess the macular thickness and the electrophysiological changes in keratoconic patients without any systemic or ocular disorders. Methods: 64 eyes of 32 keratoconus patients as well as 60 eyes of 30 controls participated in the study. All participants underwent a complete ophthalmological examination, including best-corrected visual acuity (BCVA) assessment, color vision testing, fundus examination, intraocular pressure measurement, central foveal thickness (CFT) measurement by optical coherence tomography (OCT) scan, and multifocal-electroretinogram (mf-ERG) recording. CFT, retinal response density (RRD) and P₁ latency were measured. Results: There was no statistically significant difference between the two groups concerning CFT and P₁ latency in mf-ERG. The RRD in mf-ERG differed significantly between keratoconus patients and controls. Of note, BCVA was positively associated with RRD in keratoconus patients. Conclusion: In some cases of keratoconus, a macular dysfunction not visible ophthalmoscopically may coexist and the low visual acuity could be due not only to the corneal abnormality, but also to the photoreceptor dysfunction. As a result, the preoperative electrophysiological study of patients with keratoconus is crucial to avoid a needless corneal transplantation.

Surgical ventricular reconstruction with endocardectomy along radiofrequency ablation-induced markings

The objective of this study was to evaluate the efficacy of a novel approach for endocardectomy during coronary artery bypass graft with surgical ventricular restoration in patients with postinfarction left ventricular aneurysm. One hundred sixty-eight patients underwent coronary artery bypass graft with surgical ventricular restoration from 2005 to 2011. Endocardectomy was performed as an integral part of surgical ventricular restoration for the prevention of ventricular tachycardia. The experimental group (surgical ventricular restoration-endocardectomy group; n=74) underwent preoperative electrophysiologic study with electroanatomic left ventricular mapping. Radiofrequency ablation-induced markings were placed and were used later as guides for performing endocardectomy during coronary artery bypass graft with surgical ventricular restoration. The control group (surgical ventricular restoration group; n=94) underwent surgical ventricular restoration without endocardectomy. The 1-year mortality rates in the surgical ventricular restoration-endocardectomy and surgical ventricular restoration (control) groups were 5% and 13%, respectively. During the postoperative period, 3% of patients in the surgical ventricular restoration-endocardectomy group and 38% of patients in the surgical ventricular restoration group experienced ventricular tachycardia events (P<.05). Automatic implantable cardioverter-defibrillators were implanted in 11 patients in the surgical ventricular restoration group and in 1 patient of the surgical ventricular restoration-endocardectomy group for secondary prevention of sudden cardiac death. When performed as an integral part of surgical ventricular restoration, endocardectomy was crucial in preventing postoperative ventricular tachycardia. Use of radiofrequency ablation-induced markings allowed clear visualization of the reentry zones for efficient endocardectomy during coronary artery bypass graft with surgical ventricular restoration, resulting in better patient outcomes.

Minimally Invasive Epicardial Ablation of Lone Atrial Fibrillation in Pediatric Patient

We describe a case of epicardial surgical ablation of drug refractory lone atrial fibrillation in a pediatric patient. Minimally invasive radiofrequency equipment was used off-pump through a right mini-thoracotomy. Electrical isolation of the pulmonary veins cuffs was obtained. The preoperative electrophysiological study identified a macro re-entrant circuit around the pulmonary veins orifices as the mechanism of arrhythmia triggering. At follow-up, the patient is in stable sinus rhythm and there is no evidence of pulmonary vein stenosis. The minimally invasive, off-pump ablation of lone atrial fibrillation is feasible and reliable, even in children who may pose incremental technical challenges. This technique may represent an additional tool for the current treatment algorithms to treat lone atrial fibrillation.

Surgical ablation of post-infarction ventricular tachycardia guided by mapping in sinus rhythm: long term results.

Some patients after myocardial infarction have an increased risk of malignant ventricular tachyarrhythmias (VTA) or sudden cardiac death. The aim of the study was to evaluate long-term results of surgical ablation of an arrhythmogenic substrate guided by simplified intraoperative mapping of pathological ventricular electrograms during sinus rhythm. The study population consisted of 77 patients (9 women; mean age 62.4+/-8.5 years) with previous Q-wave myocardial infarction and at least one documented episode of sustained VT/VF more than one month after the last infarction. The left ventricular ejection fraction was 31.3+/-8.8%. All but eight patients had clinical indication for concomitant coronary artery bypass surgery. All underwent preoperative electrophysiologic study. Intraoperative epicardial and endocardial mapping during sinus rhythm was performed using a multielectrode with 16 bipolar electrodes in combination with a multichannel recording system. Myocardial regions revealing fractionated, low amplitude signals lasting > or =130 ms were surgically excised or cryoablated. All surviving patients were restudied within one to two weeks after surgery using identical programmed electrical stimulation protocol. Five (6.5%) patients died in the perioperative (30-days) period. In the remaining cohort, inducibility of any sustained VTA after surgical procedure was observed in 21 subjects (29.2%). An implantable cardioverter-defibrillator (ICD) was implanted in these patients. Recurrence of sustained VTA was documented during follow-up period in two patients who were noninducible after the surgery (at the month 10 and 22, respectively), and both received ICD as well. No patient died of sudden cardiac death. In 14 ICD patients, no significant VTA was documented during the mean follow-up of 37.3+/-23.2 months. Altogether, 61 from the 72 patients surviving the surgery (84.7%) remained free of spontaneous recurrences of VTA during the follow-up. Surgical ablation of an arrhythmogenic substrate guided by simplified intraoperative mapping in normothermic heart during sinus rhythm appears to be both safe and efficacious procedure that prevents recurrences of VTA in a substantial proportion of patients.

Hearing improvement after middle fossa resection of vestibular schwannoma.

The preoperative, intraoperative, and postoperative variables of patients experiencing hearing improvement after middle fossa resection of vestibular schwannomas were evaluated as potential prognostic indicators. Retrospective case review with new objective postoperative data collected on patients with documented hearing improvement. California Ear Institute at Stanford and Stanford University Hospital, a tertiary referral center. The patient group consisted of 30 consecutive patients undergoing middle fossa approach to vestibular schwannoma between October 24, 1994, and November 11, 1998. Hearing preservation surgery via the middle cranial fossa approach was performed on all patients. Pure-tone averages (PTAs) and speech discrimination scores (SDS) were used to document hearing preoperatively and postoperatively. Preoperative electrophysiologic studies of auditory brainstem response, electronystagmography, electrical neuronography, transient evoked otoacoustic emissions, and distortion product otoacoustic emissions were evaluated. Intraoperative continuous nerve action potential and auditory brainstem response tracings were reviewed. Postoperative auditory brainstem response and transient evoked otoacoustic emissions were obtained when possible on patients whose hearing improved. Statistical analysis was completed using Student's t test and chi-square test. Seventeen (57%) of 30 patients with tumors ranging from 2 to 31 mm maintained hearing postoperatively. Among patients with hearing preservation, 7 (41% or 23% of the overall group) exhibited hearing improvement (PTA 2 improved by > or =5 dB and/or SDS improved by > or =12%). Three of these 7 patients moved from nonfunctional (AAOHNS class C/D) to functional (AAOHNS class A/B) categories. All patients who enjoyed postoperative hearing improvement had preoperative absence or abnormality of ABRs. No patient with normal preoperative ABR experienced hearing improvement. Hearing improvement patients also had lower preoperative caloric function on electronystagmography compared with the entire group (p < 0.02) and were more likely to have superior vestibular nerve tumors. No differences were noted for electrical neurography and otoacoustic emissions. Middle fossa resection of vestibular schwannoma offers patients the possibility of hearing improvement after treatment. The chance of hearing improvement is significantly higher than with other forms of treatment such as radiation therapy or translabyrinthine surgery. Although preoperative ABR abnormality may be an indicator of poor prognosis for hearing preservation, those patients who enjoy hearing improvement come from the group of patients with abnormal preoperative ABRs. Other factors identified as associated with hearing improvement include poor SDS with more normal PTA 2, and significantly decreased electronystagmographic caloric function (as an indicator of superior vestibular nerve tumors). Hearing improvement to the functional range after surgical resection is possible in some patients previously thought to be poor candidates for hearing preservation attempts. Hearing improvement may continue for many months after surgery.

Surgical cryoablation for frequent premature ventricular contraction originating in the left sinus of Valsalva.

Cryoablation in the left ventricular outflow tract and aortic valve replacement were conducted in a 70-year-old man with frequent premature ventricular contraction and nonsustained ventricular tachycardia complicated by Sellers grade 4 aortic regurgitation. The earliest endocardial activation site during premature ventricular contraction was confirmed by a preoperative electrophysiological study of the left sinus of Valsalva. Cryoablation preceded valvulectomy followed by aortic valve replacement. Clinical symptoms of premature ventricular contraction disappeared immediately after surgery.

The Long‐Term Outcome of Visually Directed Subendocardial Resection in Patients Without Inducible or Mappable Ventricular Tachycardia at the Time of Surgery

In prior studies, 20% to 40% of patients undergoing subendocardial resection (SER) for ventricular tachycardia (VT) could not be mapped intraoperatively because the VT was either noninducible or nonmappable following the ventriculotomy. The optimal surgical approach to such patients is not known. In this study, we retrospectively compared the long-term survival and functional outcome of 29 patients with VT and prior myocardial infarction who were either noninducible or nonmappable intraoperatively and underwent a visually directed extended SER. These results were then compared to 85 patients who had inducible VT intraoperatively and underwent a map-guided sequential SER. The two patient groups had different clinical characteristics. The visually directed cohort was more likely to be male, experienced fewer VT episodes before surgery, and underwent fewer antiarrhythmic drug trials prior to resection. In addition, the visually directed group had slower VT induced at a preoperative electrophysiologic study and was less likely to present to the operating room in shock or incessant VT than the map-guided group. The postoperative VT clinical recurrence or inducibility rate was 14% in both the visually directed and map-guided groups. The long-term actuarial survival at 1, 3, and 5 years was 93%, 86%, and 75%, respectively, in the visually directed group, compared to 77%, 58%, and 58%, respectively, in the map-guided group (P = 0.06). There were no documented nonfatal recurrences of VT in either group. At 24 months following surgery, 77% of patients who had a visually directed SER were in New York Heart Association Functional Class I or II, compared to 46% of patients who underwent a map-guided SER (P < 0.05). In patients with VT and prior myocardial infarction, the inability to induce or map the VT in the operating room does not preclude a favorable long-term outcome if a visually directed extended SER technique is used.

Multiple Myocardial Hamartomas Causing Ventricular Tachycardia in Young Children: Combined Surgical Modification and Medical Treatment

To describe two cases of incessant ventricular tachycardia caused by multiple myocardial hamartomas. Two infants, 13 and 14 months old, who had had multiple episodes of symptomatic tachycardia were referred to our institution. Incessant ventricular tachycardia was diagnosed. Initially, the patients received pharmacologic therapy. The recurrent tachycardia resulted in notable hemodynamic instability. No structural abnormalities were detected on the echocardiograms. In one patient, an electrophysiologic study revealed that the site of ventricular ectopic beats was in the anterolateral wall of the left ventricle, midway between the apex and the base. In the other patient, a preoperative electrophysiologic study was not undertaken because of the inability to obtain central venous access. Diffuse hamartomas were found throughout the ventricular myocardium in both patients. Surgical resection and cryoablation of the lesions in combination with medical therapy helped control the tachyarrhythmia. At 7 and 17 months postoperatively, the patients were in normal sinus rhythm and were receiving medication. In young children who have incessant ventricular tachycardia but no lesion evident on echocardiography, angiography, or other imaging modalities, a myocardial tumor should be suspected, and pharmacologic therapy should be instituted. If the medical regimen fails, surgical intervention should be undertaken, directed at areas localized by inspection and by preoperative and intraoperative electrophysiologic studies.

Alfentanil-midazolam anaesthesia has no electrophysiological effects upon the normal conduction system or accessory pathways in patients with Wolff-Parkinson-White syndrome.

The effects of alfentanil-midazolam anaesthesia upon the electrophysiologic (EP) properties of normal atrioventricular (A-V) and accessory pathway (AP) conduction were studied in eight patients with Wolff-Parkinson-White syndrome during accessory pathway surgical ablation. The presence of an AP was confirmed by preoperative EP studies. Anaesthesia was induced with alfentanil (50 micrograms.kg-1) and midazolam (0.15 mg.kg-1) and maintained with an alfentanil infusion (2 micrograms.kg-1.min-1) and intermittent boluses of midazolam (1-2 mg q 15 min, PRN). Following sternotomy, a baseline EP study was performed which consisted of effective refractory period (ERP) and shortest cycle length (SCC) measurement during antegrade conduction in the AV and AP, as well as during retrograde conduction in the AP. Comparison with preoperative EP studies indicated that the administration of alfentanil-midazolam anaesthesia had no effect upon conduction or ERP in either pathway. Haemodynamic stability occurred throughout the surgical procedure with no tachyarrhythmias. We conclude that a combination of alfentanil-midazolam is suitable for general anaesthesia in patients undergoing ablative procedures for accessory pathways.

Ventricular tachycardia after surgical repair of tetralogy of Fallot: Results of intraoperative mapping studies

Objectives. Four patients with previous repair of tetralogy of Fallot and ventricular tachycardia underwent map-guided surgery to ablate the arrhythmias.Background. Although patients with repaired tetralogy of Fallot are at increased risk of sudden death due to ventricular tachycardia, little is known of the origin and mechanism of this arrhythmia.Methods. A customized right ventricular balloon with 112 electrodes was used to record endocardial activation and, where possible, simultaneous epicardial recordings were obtained with a sock electrode array. Three patients had an aneurysm of the right ventricular outflow tract and one had a septal aneurysm. All had moderate to severe pulmonary valve insufficiency. Preoperative electrophysiologic study demonstrated inducible rapid (cycle length 180 to 300 ms) hemodynamically unstable monoform ventricular tachycardias.Results. Intraoperatively, five different tachycardias (two in one patient) were induced and mapped. The sites of earliest activation were located in the subendocardium of the right ventricular outflow tract in all, but they varied widely among the septum, free wall and parietal band and could not be identified by visible scar. All were due to a macroreentrant circuit initiated by a critical delay in activation beyond a functional arc of block. Two patients treated by cryoablation while the heart was beating and perfused at normal temperature had inducible ventricular tachycardia postoperatively. In the two subsequent patients, the application of cryoablation under anoxic cardiac arrest resulted in noninducibility of arrhythmia.Conclusions. Ventricular tachycardia in tetralogy of Fallot in these four patients was caused by macroreentry in the right ventricular outflow tract. Surgical success depends on detailed mapping and cryoablation under anoxic cardiac arrest. In patients at risk of sudden death, map-directed surgery may offer distinct advantages over either implantable devices or drug therapy.

Prophylactic implantable defibrillator patches in patients at high risk for malignant ventricular dysrhythmias.

The indications for prophylactically placing implantable cardioverter defibrillator (ICD) patches at cardiac surgery are unclear. Over the past 4 years, 25 patients have undergone placement of prophylactic ICD patches at the authors' institution. Indications were severe coronary artery disease with ventricular tachycardia (VT) (n = 14) or ventricular fibrillation (VF) (n = 2), and left ventricular aneurysmectomy and/or subendocardial resection (SER) (n = 9). Four patients died in-hospital, three from refractory VT (which could be transthoracically cardioverted until recurrence was unremitting), and one from congestive heart failure (CHF). All of the remaining 21 patients underwent post-operative electrophysiologic studies (EPS), and 12 had inducible VT (8/14 CABG, 4/7 SER). Eight of the 12 inducible patients had generators implanted, whereas 3 patients were controlled medically. One patient refused generator implantation and died at home from sudden cardiac death, and one initially non-inducible patient required late ICD generator placement, yielding a total of nine patients who received generators. All nine of these patients are currently alive at 14 +/- 7 months follow-up, and five have subsequently received appropriate ICD discharges. In patients undergoing cardiac surgery considered preoperatively or intraoperatively to be at increased risk for VT/VF and too unstable for preoperative EPS, prophylactic ICD patches should be considered.

Dimensions of the human posterior septal space and coronary sinus

Accurate anatomic localization of accessory pathways during preoperative electrophysiologic study and during operative mapping depends on a knowledge of the dimensions of the posterior septal space and the left free wall. These dimensions were therefore studied in 48 human cadaver hearts. Mean distance from the coronary sinus orifice to the left margin of the posterior septal space was 2.3 ± 0.4 cm and mean length of the left free wall was 5.0 ± 1.0 cm. The posterior septal space at the level of the valve anuli extended a mean of 3.4 ± 0.5 cm around the epicardium. The width of the posterior septum measured in the coronary sinus was related to heart weight and a combination of body weight and patient age (p < 0.05). The probability of an accessory pathway being located in the left free wall or the posterior septum during catheter mapping was calculated for various distances from the coronary sinus orifice for adults of different ages and body weights. In adults, accessory pathways located in the proximal 1.5 cm of the coronary sinus are almost always in the posterior septum. Those located between 1.5 and 3 cm from the coronary sinus orifice may be in either the left free wall or the posterior septum, and those located >3 cm from the coronary sinus orifice are almost invariably in the left free wall.

Sinus node-atrioventricular node isolation: Long-term results with the “corridor” operation for atrial fibrillation

The “corridor” operation is designed to restore sinus rhythm to patients with atrial fibrillation by electrically isolating the sinus node, a band of atrial tissue and the atrioventricular (AV) node from the remaining atrial tissue. Nine patients with drug-refractory atrial fibrillation underwent this operation; four patients had chronic atrial fibrillation and five had paroxysmal atrial fibrillation; the mean duration of symptoms was 12 ± 8 years. Patient ages ranged from 25 to 68 years (mean 48 ± 12). At preoperative electrophysiologic study, no patient had evidence of an accessory AV pathway or AV node reentry. Sinus node recovery time could not be determined in five patients because of recurrent atrial fibrillation during or before programmed stimulation.At operation the corridor of atrial tissue connecting the sinus and AV nodes was successfully isolated from the remaining left and right atrial tissue in all patients. One patient required early reoperation for recurrent atrial fibrillation before hospital discharge. At the predischarge electrophysiologic study, the corridor remained isolated in all patients except for one patient who had intermittent conduction between the corridor and excluded right atrium. One patient had nonsustained atrial fibrillation and one had atrial tachycardia evident in the corridor. Atypical AV node reentry of uncertain significance was induced in one other patient.Over a total follow-up of 191 patient months (mean 21 ± 20), seven patients remained free of atrial fibrillation. Two patients had recurrent atrial fibrillation, which in one patient was effectively controlled by a single antiarrhythmic agent. A permanent pacemaker was implanted in four patients for sinus node dysfunction.These initial results demonstrate that the corridor operation can maintain sinus rhythm in patients with atrial fibrillation. However, sinus node dysfunction may necessitate pacemaker implantation in some patients.

Diagnosis and surgical treatment of ectopic atrial tachycardia

Eighty-two patients with ectopic atrial tachycardia (EAT) were subjected to radical closed heart surgery (without cardiopulmonary bypass). The age of the patients ranged from 1 to 51 years. Permanent EAT was present in 19 patients, incessant EAT in 14, and paroxysmal EAT in 49 patients. Preoperative electrophysiological study included computed analysis of the P wave vector. Ectopic foci were established in the right atrium in 34 patients, in the left atrium in 11, in the interatrial septum in 32, and extracardially in 5 patients. For ablation or isolation of the foci, the cryogenic technique was used in 74 patients, cryo- and laser techniques in 4, and the laser technique alone in 1 patient. In 3 patients resection of the atrial auricles including the ectopic focus was undertaken. In 4 patients complete AV block was induced and a cardiac pacemaker implanted. After primary surgery, favourable results were obtained in 71 patients. In 11 patients recurrences were observed; 8 of these patients underwent successful repeat surgery. In 3 patients medical treatment was effective. Finally, the follow-up results have been promising-79 patients (96.4%) (including 4 patients in whom a complete AV block was created) have become arrhythmia-free. When EAT is resistant to medical treatment, closed heart ablation of the ectopic focus has proved to be safe (no mortality or morbidity) and effective. It can therefore be recommended not only for the termination of EAT but also for the prevention of dilated cardiomyopathy.

Surgical coronary revascularization in survivors of prehospital cardiac arrest: Its effect on inducible ventricular arrhythmias and long-term survival

In a selected subgroup of 50 survivors of cardiac arrest, the impact of surgical myocardial revascularization on inducible arrhythmias, arrhythmia recurrence and long-term survival was examined. The effects of several clinical, angiographic and electrophysiologic variables on arrhythmia recurrence and survival were also analyzed. All patients had a prehospital cardiac arrest and severe operable coronary artery disease and underwent myocardial revascularization. Preoperative electrophysiologic study was performed in 41 patients; 33 (80%) had inducible ventricular arrhythmias. Of 42 patients studied off antiarrhythmic drugs postoperatively, 19 (45%) had inducible ventricular arrhythmias. Thirty patients with inducible arrhythmias preoperatively underwent postoperative testing off antiarrhythmic drugs; arrhythmia induction was suppressed in 14 (47%). By multivariate analysis, the induction of ventricular fibrillation at the preoperative electrophysiologic study was the only significant predictor of induced ventricular arrhythmia suppression by coronary surgery (p less than 0.001). Inducible ventricular fibrillation was not present postoperatively in any of the 11 patients who manifested this arrhythmia preoperatively. In contrast, inducible ventricular tachycardia persisted in 80% of patients in whom preoperative testing induced this arrhythmia. Patients were followed up for 39 +/- 29 months. There were four arrhythmia recurrences; one was fatal. There were three nonsudden cardiac deaths and three noncardiac deaths. By life-table analysis, 5 year survival, cardiac survival and arrhythmia-free survival rates were 88%, 98%, and 88%, respectively. Depressed left ventricular ejection fraction and advanced age were predictive of death (p = 0.015 and 0.026, respectively) and cardiac death (p = 0.037 and 0.05, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

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 °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.