Treatment of life-threatening ventricular arrhythmias with nonguided surgery supported by electrophysiologic testing and drug therapy

Prognostic value of plasma N-terminal pro-brain natriuretic peptide in patients with severe sepsis

BACKGROUND

Increased plasma levels of atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) have been identified as predictors of cardiac dysfunction and prognosis in congestive heart failure and ischemic heart disease. In severe sepsis patients, however, no information is available yet about the prognostic value of natriuretic peptides. Therefore, the aim of the present study was to determine the role of the N-terminal prohormone forms of ANP (NT-proANP) and BNP (NT-proBNP) in the context of outcome of septic patients. Furthermore, the effect of treatment with recombinant human activated protein C [drotrecogin alfa (activated)] on plasma levels of natriuretic peptides in severe sepsis was evaluated.

METHODS AND RESULTS

Fifty-seven patients with severe sepsis were included. Levels of NT-proANP and NT-proBNP were measured on the second day of sepsis by ELISA. Septic patients with NT-proBNP levels >1400 pmol/L were 3.9 times more likely (relative risk [RR], 3.9; 95% CI, 1.6 to 9.7) to die from sepsis than patients with lower NT-proBNP values (P<0.01). NT-proANP levels, however, were not predictive of survival in our patient population. A highly significant correlation was found between troponin I levels and plasma concentrations of NT-proBNP in septic patients (r=0.68, P<0.0001). In addition, troponin I significantly accounted for the variation in NT-proBNP levels (P<0.0001), suggesting an important role for NT-proBNP in the context of cardiac injury and dysfunction in septic patients. Twenty-three septic patients who received treatment with drotrecogin alfa (activated) presented with significantly lower concentrations of NT-proANP, NT-proBNP, and troponin I compared with patients not receiving drotrecogin alfa (activated).

CONCLUSIONS

NT-proBNP may serve as useful laboratory marker to predict survival in patients presenting with severe sepsis.

Long-Term Outcomes After Cryoablation for Ventricular Tachycardia During Surgical Treatment of Anterior Ventricular Aneurysms

Intraoperative map-guided procedures have been widely advocated as the best surgical strategy for the treatment of ventricular tachycardia (VT), though favorable results have been reported with subendocardial resection without mapping. This study examined the very long-term results of encircling cryoablation without mapping during surgery for anterior left ventricular aneurysm complicated by VT. Between 1985 and 2003, this procedure was performed in 52 patients, 7 of whom (13.7%) were operated within 1 month of anterior myocardial infarction. Their mean age was 64.4 +/- 8.3 years and mean left ventricular ejection fraction was 31.7%+/- 9.5%. The overall hospital mortality was 1.9%. At 14 years, 86% of patients (95% CI: 75.4-96.6) were free from VT or sudden death. An implantable defibrillator was implanted in five patients (9.6%) during follow-up. The 14-year overall survival was 51.4% (95% CI: 33.8-72.4), and two patients (3.8%) underwent cardiac transplantation during follow-up. The main cause of late death was congestive heart failure in eight patients (40.0%). Favorable long-term results can be achieved with encircling cryoablation without mapping in patients undergoing surgery for anterior left ventricular aneurysm complicated by VT.

Can catheter ablation in cardiac arrest survivors prevent ventricular fibrillation recurrence?

Ventricular tachyarrhythmias are the most common cause for sudden cardiac death. The success of catheter ablation for supraventricular tachycardias led to the supposition that ablation could also be used in the treatment of ventricular tachycardias. Despite the promising results in bundle branch reentry and some forms of idiopathic ventricular tachycardia, the success rate in patients with coronary artery disease is still low. There is hope that new approaches to reliably localize the critical region of the tachycardia and new ablation techniques to create larger areas of injury may lead to a wider application of ablation therapy in the treatment of ventricular tachycardia. Survivors of cardiac arrest typically have more rapid and unstable arrhythmias than patients with sustained ventricular tachycardia, and these rapid arrhythmias frequently degenerate into ventricular fibrillation. The instability of the arrhythmia makes it impossible to localize the arrhythmia origin with current mapping techniques. Experimental and clinical data, however, suggest that these arrhythmias also frequently start from a localized area of electrical activation. With developments in mapping techniques and energy delivery, catheter ablation may soon become a feasible therapeutic approach in some patients with unstable arrhythmias. The article discusses the prerequisites for this approach and suggests the patients who may be appropriate candidates for this technique.

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.

Ventricular tachycardia after myocardial infarction: from arrhythmia surgery to catheter ablation

Ventricular tachycardia due to prior myocardial infarction is caused by reentry. Intraoperative mapping at the time of arrhythmia surgery has shown that the reentry circuits are diverse in size and location. Many circuits are large, extending over several square centimeters. Endocardial excision guided by activation sequence mapping, fractionated sinus rhythm electrograms, or visual identification of scarred subendocardium renders 69% to 95% of patients free from inducible ventricular tachycardia, but with an operative mortality that exceeds 8% at most centers. Catheter ablation is difficult due to limitations of catheter mapping, relatively small size of lesions produced with current techniques, and limited access to intramural and epicardial portions of the reentry circuits. Many problems need to be overcome for catheter ablation to achieve success comparable to that of surgery. At present, only hemodynamically tolerated ventricular tachycardias can be mapped. Progress is being made, and it is likely that catheter ablation will become a viable therapy for subgroups of patients with postmyocardial infarction ventricular tachycardia.

Why is catheter ablation less successful than surgery for treating ventricular tachycardia that results from coronary artery disease?

Nearly 80% of patients with coronary artery disease who have map-directed surgery for control of ventricular tachycardias require no drug therapy to prevent recurrences, while fewer than 50% of patients undergoing catheter ablation have similar outcomes. Catheter ablation will fail if arrhythmogenic sites are incompletely ablated by lesions that are too small or too far away from the reentrant pathway or if all arrhythmogenic sites are not identified. The underlying assumptions used to guide site selection are that: (a) ventricular tachycardias arise from reentrant mechanisms; (b) monomorphic ventricular tachycardias with similar QRS morphologies arise from the same pathway; (c) the ventricular tachycardia initiated during the procedure represents the patient's spontaneous arrhythmia; (d) the endocardial site that should be ablated can be identified from cardiac activation maps produced during induced ventricular tachycardia or from ancillary techniques; and (e) the patient has only one or two reentrant pathways. Relying on incorrect assumptions may account for the difference in success rates. Patients may have similar appearing ventricular tachycardias that arise from different pathways, and the entire thin layer of viable tissue between the infarct and the endocardium may contain many reentrant pathways. Some ventricular tachycardias may arise from the myocardium away from the endocardium, while others may arise from the epicardium. Small lesions may not be large enough to eliminate all possible reentrant pathways. Catheter ablation may be less successful because the lesions are inadequate, the assumptions guiding the selection of arrhythmogenic tissue are incorrect, or all arrhythmogenic sites are not identified. The primary reason catheter ablation is less successful than surgery in the treatment of ventricular tachycardias is that catheter ablation does not ablate as much tissue as is removed by surgery. The success rate of catheter ablation probably can be improved if the amount of tissue ablated is increased.

The long-term outcome of visually directed subendocardial resection in patients without inducible or mappable ventricular tachycardia at the time of surgery

INTRODUCTION

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.

METHODS AND RESULTS

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).

CONCLUSION

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.

Drugs, surgery, cardioverter defibrillator: a decision based on the clinical problem

These three therapeutic options are the basis of sudden cardiac death prevention: antiarrhythmic drugs, surgery, and automatic implantable cardioverter defibrillator. Each of these treatments has specific favorable and unfavorable indications. Antiarrhythmic drugs are mainly limited by the low therapeutic profile, proarrhythmic effects, complex pharmacokinetics and pharmacodynamics, possible negative inotropic effects, and the possible change of the organic substratum. Arrhythmia surgery may be limited by the need of a highly trained center, by a relatively high perioperative mortality (up to 15%), and by limited electrophysiological and clinical indications. The implantable cardioverter defibrillator is an expensive tool with a theoretically wide range of clinical indications, with already proven efficacy in converting ventricular fibrillation to sinus rhythm but with unproven efficacy on prolonging survival because of a lack of controlled trials (which, we must admit, is also true for drugs and surgery). The results of the ongoing multicenter trials on this item will clarify this clinical point. The choice among these different therapeutic options is mainly based on hemodynamic status (ejection fraction), feasibility of a surgical treatment, and the electrophysiological characteristics of the ventricular arrhythmia.

An overview of the patency and stroke rates following thrombolysis with streptokinase, alteplase, and anistreplase used to treat an acute myocardial infarction

The results of an overview of early (90-240 min) and late (24 hours or more) patency and of stroke rates for each of the three commercially available thrombolytic agents, streptokinase, alteplase, and anistreplase are presented. Studies included in this analysis are all those published between 1985 and March 1992 and focus on the licensed dosage regimens of each agent. The rates of early and late patency for streptokinase were 64.7% and 80.8%; for alteplase, 66.6% and 73.7%; and for anistreplase, 72.1% and 84.5%. The rates of total and hemorrhagic stroke for streptokinase were 0.69% and 0.17%; for alteplase, 1.27% and 0.50%; and for anistreplase 0.91% and 0.38%. These results provided evidence that the rates of early and late patency appeared to be greatest for anistreplase and that the rates of stroke are within "acceptable" ranges for all three thrombolytic agents with streptokinase affording the lowest rate.

Outcome of endocardial resection in 33 patients with coronary artery disease: correlation with ventricular tachycardia morphology

The results in 33 patients with ventricular tachycardia (VT) treated by endocardial resection were reviewed, with special emphasis on the presence of single or multiple morphologies preoperatively and intraoperatively. Multiple VT morphologies were induced in 16 patients and a single VT morphology was induced in the remaining 17. Intraoperative programmed stimulation failed to induce VT in eight patients and visually-directed endocardial resection was performed. The remaining patients underwent map-guided resection. The surgical success rate did not correlate with any morphologic characteristics of the VT, such as bundle branch block pattern or axis. In addition, concordance of VT morphologies preoperatively and intraoperatively before resection did not correlate with the surgical success rate. However, patients in whom multiple morphologies of VT were induced intraoperatively had a significantly higher success rate (100%) compared with those patients in whom only a single morphology was induced intraoperatively (50%, p < 0.05). Long-term follow-up was maintained in 26 patients. Ventricular tachycardia recurred in two patients and VF recurred in two others who did not have inducible VT 1 week after endocardial resection. In conclusion, neither the preoperative morphologic characteristics of VT nor discordance between the morphologies of VT induced preoperatively and in the operating room influenced the outcome of endocardial resection. However, the surgical success rate is higher when multiple morphologies of VT are inducible in the operating room than when only one VT morphology is inducible.

Predictors of surgical mortality and long-term results of endocardial resection for drug-refractory ventricular tachycardia

The results of surgical therapy performed in 51 consecutive patients with ventricular tachycardia were reviewed to determine short- and long-term predictors of success of such therapy in preventing recurrences of life-threatening ventricular arrhythmias. Of 41 patients (80%) who survived surgery, 40 had postoperative programmed stimulation and, of these patients, 78% (n = 31) had no inducible ventricular tachycardia on no antiarrhythmic therapy. This group had a very low incidence of arrhythmia recurrence, with only one nonfatal episode of ventricular tachycardia after a mean follow-up of 41 +/- 30 months. In contrast, two of the nine patients (22%) who had inducible arrhythmias postoperatively had cardiac arrest (p = 0.12). Multivariate analysis identified two significant predictors of perioperative mortality in our patients: increased duration of cardiopulmonary bypass time and increased baseline pulmonary capillary wedge pressure. It is concluded that (1) patients who do not have inducible ventricular tachycardia after arrhythmia surgery have a very low incidence of recurrent arrhythmia and (2) prolonged time of cardiopulmonary bypass and increased pulmonary capillary wedge pressure are predictive of perioperative mortality.

Severe acute myocardial infarction during a staphylococcal septicemia with meningoencephalitis. A possible contraindication to thrombolytic treatment

We report the first case of lethal intracranial haemorrhage complicating a treatment by rt-PA in a patient presenting with a simultaneous staphylococcal septicemia with meningoencephalitis and an acute myocardial infarction with cardiogenic shock. The presence of microvascular lesions in the central nervous system seems to be important risk factor for intracranial haemorrhage and we recommend extreme caution in the use of thrombolytic treatment in septicemic patients with acute myocardial infarction, particularly when neurological symptoms are present.