Evolving patterns in the surgical treatment of malignant ventricular tachyarrhythmias

Evaluation and Management of Sudden Death Survivors

Only 20% of patients survive a cardiac arrest. Up to 80% of patients have a cardiac arrest secondary to a ventricular tachyarrhythmia. In the adult population, over 70% of the above patients have obstructive coronary artery disease; thus, coronary arteriography should be performed in all survivors of cardiac arrest. Once reversible causes have been treated, antiarrhythmic therapy is usually guided by Holter monitoring, electrophysiologic testing or both. Due to high recurrence rates on antiarrhythmic drugs, many patients are now treated with implantable cardioverter defibrillators. Although these devices appear to improve sudden death survival, long-term overall survival may not be superior to “best drug therapy.” This hypothesis is currently being tested in two prospective randomized, multicenter trials.

Perioperative and long-term results with mapping-guided subendocardial resection and left ventricular endoaneurysmorrhaphy

BACKGROUND

Surgical ablation of the arrhythmogenic focus in patients with life-threatening ventricular tachyarrhythmias can be curative. However, the surgical techniques have been plagued by a high perioperative mortality rate (averaging approximately 12%). Reconstruction of the left ventricle may reduce mortality.

METHODS AND RESULTS

Reconstruction of the left ventricle with a pericardial patch, or endoaneurysmorrhaphy, was performed with mapping-guided subendocardial resection for recurrent ventricular tachycardia in 25 patients over a 5-year period. Postoperatively, electrophysiological studies were conducted to assess the results of surgery, which were further evaluated during long-term follow-up with survival analyses. The study included 25 patients, 60 +/- 9 years of age, with coronary artery disease, discrete left ventricle aneurysms, and malignant ventricular tacharrhythmias. Left ventricular ejection fraction was 24 +/- 6% preoperatively. Left ventricular endocardial mapping, endocardial resection, and endoaneurysmorrhaphy were performed in all patients. There was no operative or postoperative (30-day) mortality. Postoperative ventricular tachycardia was induced in 2 of the 25 patients (8%); left ventricular function increased to 32 +/- 9% (range, 19% to 52%). At a mean follow-up of 37 +/- 16 months (range, 6 to 65 months), there had been 6 deaths, including 1 sudden cardiac death, 2 congestive heart failure deaths, and 3 noncardiac deaths. Analysis of multiple variables failed to identify predictors of postoperative inducibility, sudden cardiac death, cardiac death, or total mortality.

CONCLUSIONS

Endoaneurysmorrhaphy with a pericardial patch combined with mapping-guided subendocardial resection frequently cures recurrent ventricular tachycardia with low operative mortality and improvement of ventricular function. Long-term follow-up demonstrates low sudden cardiac death rates.

The role of coronary revascularization in recipients of an implantable cardioverter-defibrillator

The impact of adjuvant coronary revascularization was studied in a group of 138 recipients of an implantable cardioverter-defibrillator, all of whom had ischemic heart disease as the cause of their arrhythmias. Patients chosen for revascularization had more severe anatomic, symptomatic, or physiologic evidence of active ischemia. There were no operative deaths among 23 patients who actually underwent coronary artery bypass combined with cardioverter-defibrillator implantation; however, operative mortality by the intention-to-treat principle was 8% (2/25). Total cardiac survival was better for patients who underwent revascularization than for those patients who had "high-risk" characteristics and did not undergo revascularization. Stratified subgroup analysis demonstrated significant survival advantages favoring revascularization in patients with three-vessel or left main coronary artery disease, class III or IV angina, and an ejection fraction greater than 25%. Multivariate analysis revealed that low ejection fraction and left main coronary artery disease were independent predictors of decreased survival.

Implantation and follow-up of a third-generation cardioverter defibrillator: comparison of epicardial and nonthoracotomy defibrillation lead system

OBJECTIVE

The intraoperative and follow-up results were compared in 67 patients with ventricular tachyarrhythmias who underwent implantation of the Ventritex Cadence defibrillator with either epicardial patch (EPI, 25 patients) or nonthoracotomy CPI Endotak (ENDO, 42 patients) defibrillation lead systems.

RESULTS

There was no significant difference between groups in age, sex, structural heart disease, ejection fraction, arrhythmia history, or drug therapy. Successful implantation was accomplished in all patients using either lead system. In the ENDO group, 35 patients (83%) had a defibrillation threshold < or = 550 V and did not require a subcutaneous patch. Intraoperatively, the defibrillation threshold was 453 +/- 139 V (13 +/- 9 J) for EPI and 490 +/- 113 V (15 +/- 8 J) for ENDO (P = NS). There were no perioperative deaths in either group. At predischarge testing, the defibrillation threshold was 445 +/- 183 V (14 +/- 12 J) for EPI and 439 +/- 133 V (13 +/- 7 J) for ENDO (P = NS). During a mean follow-up of 16 +/- 8 months, there were no sudden deaths, and four patients died from congestive heart failure (3 EPI, 1 ENDO). During follow-up, 916 spontaneous arrhythmia episodes occurred in 16 of 25 EPI patients (64%) and 967 episodes occurred in 31 of 42 ENDO patients (74%) (P = NS). The number of episodes detected as ventricular fibrillation were 192 for EPI (21%) and 232 for ENDO (24%), with first shock success in 76% and 75%, respectively; all episodes were successfully terminated by the device. In the remaining episodes detected as ventricular tachycardia, antitachycardia pacing was attempted and was successful in 672 of 724 episodes (93%) with EPI and 666 of 735 episodes (91%) with ENDO lead systems (P = NS). Acceleration of ventricular tachycardia with antitachycardia pacing occurred in 21 episodes (3%) with EPI and in 37 episodes (5%) with ENDO leads (P = NS).

CONCLUSIONS

A nonthoracotomy approach using the third generation cardioverter defibrillator Cadence V-100 is safe and effective and has clinical results that are not significantly different from epicardial defibrillation lead systems.

Risk and benefit of additional aortocoronary bypass grafting in patients undergoing cardioverter-defibrillator implantation

It is unclear whether additional aortocoronary bypass grafting should be performed in patients who need an automatic implantable cardioverter defibrillator (ICD) in one- or two-step procedures. Therefore we studied the follow-up of 139 patients who underwent epicardial implantation of the cardioverter defibrillator (CD). All patients had coronary artery disease and recurrent ventricular tachycardia or fibrillation. Eighty-nine patients had implantation of the CD without additional surgical approaches (group G1), and 50 patients had concomitant aortocoronary bypass grafting (group G2). Perioperative mortality (within 30 days after CD implant) was 1 (1%) of 89 patients in G1 and 6 (12%) of 50 patients in G2 (p < 0.01). During the mean follow-up of 26 +/- 20 months, sudden death occurred in four (4%) of 89 patients in G1 and two (4%) of 50 patients in G2. Twenty-three (17%) patients died of cardiac failure (18 [20%] patients in G1 and 5 [10%] patients in G2). ICD discharges occurred in 69 (78%) of 89 patients in G1 and in 36 (72%) of 50 patients in G2. The mean incidence of ICD discharges was 23 +/- 69 shocks per patient in G1 and 18 +/- 25 shocks per patient in G2 (p = NS). We conclude that concomitant aortocoronary bypass grafting during CD implantation leads to a higher perioperative mortality. Avoidance of myocardial ischemia does not significantly influence sudden death mortality nor markedly reduce the number of ICD discharges.

Coronary artery bypass in patients with previously placed implantable defibrillators

Four patients with previously placed implantable defibrillators required coronary revascularization several years after the original device was inserted. Three patients had a conventional system of epicardial patches and leads, and one patient had a nonthoracotomy system placed. All four patients were successfully revascularized without evidence of perioperative infarction or significant morbidity. The patient with the nonthoracotomy device did require manipulation of the endocardial lead at a separate setting. This limited experience suggests that patients needing revascularization after placement of an implantable defibrillator can be successfully bypassed.

Comparison of the usefulness of the implantable cardioverter-defibrillator and subendocardial resection in patients with sustained ventricular arrhythmias and poor regional wall motion associated with coronary artery disease

The implantable cardioverter-defibrillator (ICD) and subendocardial resection are effective forms of therapy for sustained ventricular arrhythmias associated with coronary artery disease in selected patients. The relative efficacy of these 2 treatments in equivalently matched patients is not known. A regional wall motion score has been shown to be a powerful predictor of long-term outcome after both ICD implantation and subendocardial resection. This study retrospectively analyzed the long-term outcome of patients with coronary artery disease and ventricular arrhythmias treated during the same period with an ICD (n = 53) or by subendocardial resection (n = 65). Treatment outcomes were compared in subgroups determined by preoperative regional wall motion scores of either < or = 16 or > 16%. The 3-year cardiac mortality of the 2 therapies was not significantly different among patients with a wall motion score of > 16% (0% ICD vs 11% endocardial resection) or of < or = 16% (41% ICD vs 35% endocardial resection). Similarly, the 3-year sudden cardiac death mortality was similar among patients with a score of > 16% (0% for both ICD and endocardial resection) or of < or = 16% (9% ICD vs 14% endocardial resection, p = NS). At 24 months after hospital discharge, the percentage of patients who were in New York Heart Association functional class I or II was similar among patients with a wall motion score of > 16% (75% ICD vs 86% endocardial resection, p = NS) or with a wall motion score of < or = 16% (26% ICD vs 45% endocardial resection, p = NS).(ABSTRACT TRUNCATED AT 250 WORDS)

Linear left ventricular aneurysmectomy: modern imaging studies reveal improved morphology and function

It remains uncertain whether left ventricular aneurysmectomy (LVA) improves ventricular function and whether LVA improves or distorts left ventricular contour. We applied the powerful imaging techniques of multiple-gated acquisition scanning, intraoperative transesophageal echocardiography, and magnetic resonance imaging to assess functional and morphologic changes after LVA in 75 consecutive patients undergoing LVA by conventional resection and linear closure. Fifty-two patients (69%) underwent concomitant coronary artery bypass grafting, 25 (33%) had directed endocardial resection, and 4 (5%) had valve replacement. The hospital mortality rate was 6.7% (5/75). Actuarial survival rates were 86%, 80%, and 64% at 1 year, 2 years, and 5 years, respectively. Mean anginal class improved from 3.49 to 1.24 (p < 0.0001). Mean congestive heart failure class improved from 3.04 to 1.70 (p < 0.0001). By multiple-gated acquisition scan (48 patients), mean ejection fraction improved from 0.25 preoperatively to 0.33 postoperatively (p < 0.0001). Intraoperative transesophageal echocardiography (28 patients) revealed no cases of distortion and demonstrated normalization of left ventricular contour in 69% of patients. Mean wall motion score improved from 16.4 to 18.8 (p < 0.001). Mean cross-sectional area of the left ventricle decreased from 18.7 cm2 to 12.8 cm2 (p < 0.006). Magnetic resonance imaging confirmed normalization of left ventricular contour without distortion. We conclude that linear LVA is clinically effective and objectively improves left ventricular morphology and function. On this basis, we have extended application of LVA to include patients with at least moderate-sized aneurysms undergoing coronary artery bypass grafting, despite the absence of traditional indications of arrhythmia, embolism, and frank congestive heart failure.

Hemodynamic changes due to intraoperative testing of the automatic implantable cardioverter defibrillator: implications for anesthesia management

During the insertion of an automatic implantable cardioverter defibrillator, repeated induction of ventricular tachycardia or ventricular fibrillation and subsequent defibrillation is performed to determine the defibrillation threshold. In this study, the influence of these testing episodes on myocardial function was investigated in 13 patients under general anesthesia. Preoperative ejection fraction (EF) was 41 (14 to 84) % (median and range). Testing was performed 3 (2-5) times. During these testing episodes the patients received a total of 4 (2-8) countershocks. Patients with a preoperative EF < 30% (N = 5) showed a significant reduction of cardiac index (CI) from 2.2 (1.5-3.3) L/min/m2 before testing to 1.5 (1.3-2.3) L/min/m2 after the last testing episode, and of left ventricular stroke work index (LVSWI) from 32 (14-53) g.m/m2 before testing to 22 (7-43) after the last testing episode. These changes were not related to the total fibrillation time or the cumulative defibrillation energy. Patients with a preoperative EF > 30% (N = 8) showed no significant changes of CI (2.15 [1.8-3.0] L/min/m2 v 2.15 [1.7-3.0] L/min/m2) or LVSWI (35 [28-48] g.m/m2 v 33.5 [27-52] g.m/m2). Comparison of the two patient groups revealed similar hemodynamic baseline values, but significant differences in LVSWI after the last testing episode. Defibrillation testing may produce a further reduction in myocardial performance in patients with preexisting poor cardiac function.

Late results of operation for ventricular tachycardia

We have analyzed results in 54 consecutive patients with recurrent ventricular tachycardia and coronary artery disease in whom we used an aggressive surgical approach involving map-directed ventricular tachycardia ablation, scar excision and left ventricular remodeling, and coronary artery bypass grafting, as well as staged mitral valve replacement when necessary. We have previously shown age greater than 65 years to be an independent predictor of mortality and have excluded such patients from this series. Average age was 56 +/- 7 years. All patients had a previous myocardial infarction; 24% of the infarctions (13/54) were posterior in location. Symptoms included syncope or presyncope in 83% of the patients (45/54), angina in 54% (29/54), and congestive heart failure in 52% (28/54). Extensive coronary artery disease was found in 78% (42/54), and 89% (48/54) had serious compromise of left ventricular function (ejection fraction < 0.40; average ejection fraction, 0.28 +/- 0.12). Only 63% (34/54) appeared to have a resectable left ventricular aneurysm on the preoperative angiogram. Ablation techniques included endocardial excision in 82% (44/54), with the addition of cryoablation in 60% (32/54), and balloon electric shock ablation in 22% (12/54); coronary artery bypass grafting was performed in 85% (46/54). There were four hospital deaths (7%). The surgical cure rate (no inducible VT at postoperative electrophysiologic study was 72% (39/54). During follow-up (mean, 50 +/- 31 months) there have been six late deaths (1 sudden death, 1 stroke, 4 congestive heart failures with or without mitral regurgitation). Four patients with progressive congestive heart failure and serious mitral regurgitation have undergone repeat operation for mitral valve replacement.(ABSTRACT TRUNCATED AT 250 WORDS)

Percutaneous endoscopic implantation of Automatic Implantable Cardioverter/Defibrillator (AICD): an animal study of a new nonthoracotomy technique

The Automatic Implantable Cardioverter/Defibrillator (AICD) prevents death due to malignant ventricular arrhythmias but requires thoracotomy for the implantation of the preferred two-patch lead system. The purpose of this study was to develop and test a new percutaneous endoscopic method of the AICD lead implantation without the need for open chest surgery. A high resolution video endoscopy system and currently available endoscopic instrumentation were used to develop pleural-pericardial dissection technique in 7 pigs and to endoscopically implant custom-made AICD patches in 20 pigs. An examining 10 mm rigid endoscope inserted in the 6th intercostal space in the anterior axillary line provided direct visual control for endoscopic dissection of the parietal pleura from the pericardium, delivery, and implantation of the AICD patches. This was successfully carried out through two trocars (10 and 11 mm) inserted into the pleural-pericardial space via the subxyphoid approach in 18 of 20 pigs. Effective patch positioning was confirmed by attaining a defibrillation threshold of 20J or less in 13 pigs. Of those, three required lead polarity reversal, and three others required lead repositioning to lower defibrillation thresholds to 20J or less. In three pigs, defibrillation thresholds of 30J or higher were required. Defibrillation was unsuccessful in two pigs due to patch malfunction. The authors conclude that percutaneous endoscopy is a feasible method of AICD lead implantation.

Strategies in the surgical treatment of malignant ventricular arrhythmias. An 8-year experience

Introduction of the automatic implantable cardioverter defibrillator (AICD) has dramatically affected the surgical treatment of malignant ventricular tachyarrhythmias. The authors continue to perform electrophysiologically directed subendocardial resection (SER) of left ventricular (LV) scars in selected patients, and we revascularize (CABG) those patients undergoing AICD implantation who have significant myocardial ischemia. In an attempt to define the optimal role of each procedure, this report analyzes our 8-year experience with 348 consecutive patients treated surgically for these arrhythmias (SER since 1983 and AICD since 1986). All patients undergoing SER had organized ventricular tachycardia (VT) as a result of myocardial infarction, and most had LV aneurysms; of those undergoing AICD or AICD/CABG, 60% had VT, 15% had ventricular fibrillation, and 25% had both or were noninducible. The thirty-day mortality rate was 1.5% (3/197) for AICD, 5.4% (5/93) for AICD/CABG, and 8.6% (5/58) for SER; these mortality figures are not significant different. Late deaths in all groups were predominantly due to congestive heart failure, and actuarial survival as well as freedom from sudden death was similar between the groups at 4 years. Recurrent VT occurred in 167 of 282 (59%) of long-term survivors of AICD or AICD/CABG during follow-up and in nine of 53 (17%) of those with SER. Forty-eight per cent of survivors of AICD or AICD/CABG required antiarrhythmic medications, whereas only 11% of those with SER required antiarrhythmics. Long-term survival in each group is much higher than that reported for comparable patients with severe LV dysfunction treated medically. In those patients with organized VT and LV aneurysm who are judged able to survive the procedure, SER offers a high likelihood of cure rather than simple prevention of sudden death.

Cosmetic approach for placement of the automatic implantable cardioverter-defibrillator in young women

A surgical approach is described for a more cosmetically acceptable placement of the automatic implantable cardioverter-defibrillator in young women. The transvenous sensing lead and the vena caval spring electrode are placed through a small subclavicular incision. The left ventricular patch electrode is placed through an anterior minithoracotomy in the crease under the left breast. A small transverse incision in the left lower quadrant is used to place the generator under the external oblique fascia in the low abdominal wall. Minimal cosmetic impairment from incisions and hardware results.

The automatic implantable cardioverter-defibrillator. Implications for anaesthetists

This paper describes the anaesthetic management of a patient who had an automatic implantable cardioverter-defibrillator. The working principles of the device, the indications for its insertion and the postoperative complications, are discussed. An increasing number of cardioverter-defibrillators are being implanted in the UK. At least two general anaesthetics are required for each patient; one for implantation of the device and a second for testing its efficiency in terminating ventricular tachycardia and ventricular fibrillation. In future, the number of patients presenting for noncardiac surgical procedures is likely to increase, therefore every anaesthetist should be aware of the problems involved in management.

Retrospective analysis of patients undergoing one- or two-stage strategies for myocardial revascularization and implantable cardioverter defibrillator implantation

Internal defibrillation leads were placed at time of coronary revascularization in 79 patients. In 34, an implantable cardioverter defibrillator (ICD) was placed simultaneously (group I). A two-stage strategy (selective implantation of the ICD in patients with postoperative spontaneous or inducible ventricular tachycardia [VT]) was followed in 45 patients (group II). Group I patients had failed more antiarrhythmic drug trials (2.9 +/- 1.6 vs 1.5 +/- 1.6; P = 0.02), including amiodarone (62% vs 20%; P less than 0.001). There were four operative deaths in each group. Postoperatively, VT was present in 27 group II patients (60%), 25 of whom received an ICD (two refused device implantation). Patients with postoperative VT had a lower left ventricular ejection fraction than those without VT (33 +/- 9 vs 47 +/- 16; P = 0.01). Actuarial survival at 1, 2, and 3 years was 88 +/- 6, 88 +/- 7, and 88 +/- 10 in group I; and 83 +/- 6, 76 +/- 7, and 76 +/- 11 in group II (NS). No patient without an ICD (based on the postoperative electrophysiological study [EPS]) died suddenly. Five patients (6%) had ICD system infection. Sudden death was largely prevented by either strategy, but relatively high rates of operative mortality and ICD system infection were observed. Prospective studies should identify patients more likely to benefit from one or another strategy.