Effect of coronary revascularization on long-term clinical outcomes in patients with ischemic cardiomyopathy and recurrent ventricular arrhythmia.

BACKGROUND: Patients with ventricular tachycardia (VT) postmyocardial infarction (MI) are a higher risk group with significant morbidity and mortality. We examined the impact of prior coronary revascularization on clinical outcomes in patients with ischemic cardiomyopathy and VT. METHODS: The VANISH trial randomized 259 patients with prior MI and antiarrhythmic drug-refractory VT to receive escalated medical therapy or catheter ablation. Clinical outcomes were compared according to whether patients have undergone prior revascularization procedures. The primary outcome was a composite of death, appropriate implantable cardiac defibrillator (ICD) shock, or VT storm. The secondary outcomes included elements of the primary outcome, hospitalization, and any ventricular arrhythmia. RESULTS: 190 patients (73%) had prior coronary revascularization. Revascularization group had more men (97% vs 83%; P  =  0.0003) and patients in that group were older (mean age 69.3 ± 7.6 vs 66.7 ± 9.2; P  =  0.04), had more renal insufficiency (22.6% vs 8.7%; P  =  0.01), and were more likely to have an implanted cardiac resynchronization device (23% vs 10%, P  =  0.03) as compared with the nonrevascularized patients. There were no significant differences in baseline medication use. There was a trend toward fewer hospitalizations in the revascularization group (64% vs 77%; P  =  0.07); there were no differences in the individual outcomes of mortality, VT storm, ICD shocks, recurrent MI, or cardiac failure. CONCLUSIONS: In this cohort of patients with an ischemic cause for VT, a history of prior coronary revascularization was not associated with a reduction in ventricular arrhythmia or mortality.

Ventricular Tachycardia Burden and Mortality: Association or Causality?

Ventricular tachycardia (VT) is a potentially fatal cardiac rhythm disorder. Implantable cardioverter defibrillators (ICDs) are the primary management strategy for VT and have been shown to reduce the incidence of death but, ICDs do not reduce VT recurrences. Further, mounting evidence indicates that high VT burden, defined as the cumulative number of recurrent VTs or ICD shocks, is associated with an elevated risk of death; however, it is unclear if high VT burden is a cause of death or a marker of severe heart disease. Proposed mechanisms for a causal pathway suggest that multiple VT episodes or potential deleterious effects from ICDs might alter the myocardium of the ventricles to induce worsening heart disease, which might translate to an increased risk of mortality. In this review, we present the evidence to support association and causation hypotheses for the relationship between VT burden and risk of mortality and indicate potential gaps in evidence. Overall, there is insufficient evidence to prove causal hypotheses for the relationship between VT burden and mortality. Consistent definitions for VT burden, randomized controlled trials that assess the relationship between VT burden and mortality, and observational studies that capture VT burden are warranted to investigate if a potential causal relationship exists.

Recent Insights Into Mechanisms and Clinical Approaches to Electrical Storm.

Electrical storm, characterized by repetitive ventricular tachycardia/ventricular fibrillation over a short period, is becoming more common with widespread use of implantable cardioverter defibrillator (ICD) therapy. Electrical storm, sometimes called "arrhythmic storm" or "ventricular tachycardia storm," is usually a medical emergency requiring hospitalization and expert management, and significantly affects short- and long-term outcomes. This syndrome typically occurs in patients with underlying structural heart disease (ischemic or nonischemic cardiomyopathy) or inherited channelopathies. Triggers for electrical storm should be sought but are often unidentifiable. Initial management is dictated by the hemodynamic status, whereas subsequent management typically involves ICD interrogation and reprogramming to reduce recurrent shocks, identification and management of triggers like electrolyte abnormalities, myocardial ischemia, or decompensated heart failure, and antiarrhythmic drug therapy or catheter ablation. Sympathetic nervous system activation is central to the initiation and maintenance of arrhythmic storm, so autonomic modulation is a cornerstone of management. Sympathetic inhibition can be achieved with medications (particularly ß-adrenoreceptor blockers), deep sedation, or cardiac sympathetic denervation. More definitive management targets the underlying ventricular arrhythmia substrate to terminate and prevent recurrent arrhythmia. Arrhythmia targeting can be achieved with antiarrhythmic medications, catheter ablation, or more novel therapies, such as stereotactic radiation therapy, that target the arrhythmic substrate. Mechanistic studies point to adrenergic activation and other direct consequences of ICD shocks in promoting further arrhythmogenesis and hypocontractility. In this report, we review the pathophysiologic mechanisms, clinical features, prognosis, and therapeutic options for electrical storm. We also outline a clinical approach to this challenging and complex condition, along with its mechanistic basis.

Primary transitional cell carcinoma of the fallopian tube.

The fallopian tube is the least common site for origin of malignancy in the female genital tract. Most primary fallopian tube malignancies are adenocarcinomas. Primary transitional cell carcinoma (TCC) of the fallopian tube is an extremely rare tumor with a small number of cases reported in the literature. We present a 67-year-old woman who was found incidentally to have a left adnexal mass on a screening pelvic ultrasound. Subsequently the patient underwent laparoscopic left salpingo-oophorectomy and the specimen was submitted for intraoperative frozen section, which revealed a high-grade carcinoma; therefore, she underwent a laparotomy and total abdominal hysterectomy, right salpingo-oophorectomy and omentectomy. Histopathology revealed high-grade transitional cell carcinoma in the left fallopian tube. Post-surgery she was treated with four cycles of adjuvant chemotherapy with carboplatin and paclitaxel with no complications. Our patient had a family history of malignancy, so genetic testing for BRCA1 and BRCA2 mutations was undertaken and did not reveal any mutation or unclassified variants. Multiplex ligation-dependent probe amplification (MLPA) was normal.

Electrical storm: Prognosis and management.

Electrical storm is present when a cluster of ventricular arrhythmias (VAs) occurs within a short time frame. The most widely accepted definition is 3 or more episodes of VA within a 24-h period, although prognostic risk begins to rise when 2 or more events occur within 3months. Electrical storm often presents as a medical emergency in the form of recurrent implantable cardiac defibrillator (ICD) shocks, recurrent syncope in patients with no ICD or low cardiac output symptoms. Management often requires a multimodality approach including ICD management, pharmacologic therapy, catheter ablation and modulations of the autonomic nervous system. In this article, we review the definition, prognosis and management of electrical storm.

Mortality Risk Increases With Clustered Ventricular Arrhythmias in Patients With Implantable Cardioverter-Defibrillators.

OBJECTIVES: This study sought to examine the adverse prognosis associated with ventricular arrhythmia clusters that falls outside the current electrical storm definition. BACKGROUND: Electrical storm is most frequently defined as a cluster of ≥3 episodes of ventricular arrhythmia (VA) in a 24-h period. This definition has been associated with adverse cardiovascular outcomes and mortality, but the effect of lesser and greater clustering of arrhythmias has not been described. METHODS: Among all patients in the Resynchronization in Ambulatory Heart Failure trial, 14,515 implantable cardioverter-defibrillator-detected events with data available were rigorously adjudicated in blinded fashion. Arrhythmia incidence was examined for clustering, defined as 2 or more VA events occurring within 3 months. The prognostic importance of clustering was analyzed by varying the cluster length and number of events used to define a cluster. Mortality rates of groups with clustered arrhythmias were compared to patients with no arrhythmia or with unclustered arrhythmia. RESULTS: The trial included 1,764 patients, among whom 465 patients had two or more VA episodes within 3 months, whereas 406 had unclustered arrhythmias. Compared to patients with no arrhythmia, patients experiencing unclustered VA had increased risk of death (hazard ratio [HR]: 1.45; 95% confidence interval [CI]: 1.09 to 1.93; p = 0.011), whereas the risk was even higher in patients with clustered arrhythmia (HR: 2.68; 95% CI: 2.13 to 3.36; p < 0.0001). Mortality risk increased with higher VA burden (number of VAs in a cluster) and shorter cluster length. This was observed in all groups tested, including the cluster with the least VA burden in the longest cluster length tested (2 VA episodes occurring within 3 months) (mortality HR: 2.85; 95% CI: 1.95 to 4.17; p < 0.0001). Although clustered arrhythmias terminated with antitachycardia pacing were associated with increased mortality, clusters terminated with implantable cardioverter-defibrillator shocks were associated with still higher mortality risk. CONCLUSIONS: Significant adverse prognostic association of clustered VAs is observable with even 2 VA events within 3 months and increases with higher cluster density.

Automated intraprocedural localization of origin of ventricular activation using patient-specific computed tomographic imaging.

BACKGROUND: To facilitate catheter ablation of ventricular tachycardia (VT), we previously developed an automated method to identify sources of left ventricular (LV) activation in real time using 12-lead electrocardiography (ECG), the accuracy of which depends on acquisition of a complete electroanatomic (EA) map. OBJECTIVE: The purpose of this study was to assess the feasibility of using a registered cardiac computed tomogram (CT) rather than an EA map to permit real-time localization and avoid errors introduced by incomplete maps. METHODS: Before LV VT ablation, 10 patients underwent CT imaging and 3-dimensional reconstruction of the cardiac surface to create a triangle mesh surface, which was registered to the EA map during the procedure and imported into custom localization software. The software uses QRS integrals from leads III, V2, and V6; derives personalized regression coefficients from pacing at ≥5 sites with known locations; and estimates the location of unknown activation sites on the 3-dimensional patient-specific LV endocardial surface. Localization accuracy was quantified for VT exit sites in millimeters by comparing the calculated against the known locations. RESULTS: The VT exit site was identified for 20 VTs using activation and entrainment mapping, supplemented by pace-mapping at the scar margin. The automated localization software achieved incremental accuracy with additional pacing sites and had a mean localization error of 6.9 ± 5.7 mm for the 20 VTs. CONCLUSION: Patient-specific CT geometry is feasible for use in real-time automated localization of ventricular activation and may avoid reliance on a complete EA map.

Prospective Assessment of an Automated Intraprocedural 12-Lead ECG-Based System for Localization of Early Left Ventricular Activation.

BACKGROUND: To facilitate ablation of ventricular tachycardia (VT), an automated localization system to identify the site of origin of left ventricular activation in real time using the 12-lead ECG was developed. The objective of this study was to prospectively assess its accuracy. METHODS: The automated site of origin localization system consists of 3 steps: (1) localization of ventricular segment based on population templates, (2) population-based localization within a segment, and (3) patient-specific site localization. Localization error was assessed by the distance between the known reference site and the estimated site. RESULTS: In 19 patients undergoing 21 catheter ablation procedures of scar-related VT, site of origin localization accuracy was estimated using 552 left ventricular endocardial pacing sites pooled together and 25 VT-exit sites identified by contact mapping. For the 25 VT-exit sites, localization error of the population-based localization steps was within 10 mm. Patient-specific site localization achieved accuracy of within 3.5 mm after including up to 11 pacing (training) sites. Using 3 remotes (67.8±17.0 mm from the reference VT-exit site), and then 5 close pacing sites, resulted in localization error of 7.2±4.1 mm for the 25 identified VT-exit sites. In 2 emulated clinical procedure with 2 induced VTs, the site of origin localization system achieved accuracy within 4 mm. CONCLUSIONS: In this prospective validation study, the automated localization system achieved estimated accuracy within 10 mm and could thus provide clinical utility.

Infusion Needle Radiofrequency Ablation for Treatment of Refractory Ventricular Arrhythmias.

BACKGROUND: Catheter ablation is effective for eliminating most drug-refractory ventricular arrhythmias (VA). However, a major reason for procedural failure is arrhythmia originating deep within the myocardium where it is inaccessible to conventional endocardial or epicardial approaches. Affected patients have limited therapeutic options. OBJECTIVES: The objective of this study was to assess the safety and outcome of a novel radiofrequency ablation catheter that used an extendable/retractable 27-g needle capable of targeting deep arrhythmia (intramural) substrate. METHODS: Patients who failed at least one prior catheter ablation procedure for sustained ventricular tachycardia (VT) or nonsustained VA with associated left ventricular dysfunction were enrolled at 3 centers. The target was sustained monomorphic VT in 26 patients, including 8 with recent VT storm or VT requiring intravenous medication, and 5 with incessant VA associated with ventricular dysfunction. RESULTS: Needle ablation was performed in 31 patients (median of 2 failed prior ablation procedures; 71% nonischemic heart disease). After a median of 15 needle lesions/patient, ablation abolished at least 1 inducible VT in 19 of 26 VT patients (73%), and suppressed ambient arrhythmia in 4 of 5 nonsustained arrhythmia patients. At the 6-month follow-up, 48% of patients were free of recurrent arrhythmia and another 19% were improved. Procedure-related complications included a single pericardial effusion treated with percutaneous drainage and a left ventricular pacing lead dislodgement with no deaths. CONCLUSIONS: In patients with recurrent ventricular arrhythmias refractory to medications and conventional catheter ablation, intramural needle radiofrequency ablation offers significant arrhythmia control with an acceptable procedural risk.

Role of contact force in ischemic scar-related ventricular tachycardia ablation; optimal force required and impact of left ventricular access route.

BACKGROUND: Contact force-sensing technology has become a widely used addition to catheter ablation procedures. Neither the optimal contact force required to achieve adequate lesion formation in the ventricle, nor the impact of left ventricular access route on contact force has been fully clarified. PATIENTS AND METHODS: Consecutive patients (n = 24) with ischemic cardiomyopathy who underwent ablation for scar-related ventricular tachycardia were included in the study. All ablations (n = 25) were performed using irrigated contact force-sensing catheters (Smart Touch, Biosense Webster). Effective lesion formation was defined as electrical unexcitability post ablation at sites which were electrically excitable prior to ablation (unipolar pacing at 10 mA, 2 ms pulse width). We explored the contact force which achieved effective lesion formation and the impact of left ventricular access route (retrograde aortic or transseptal) on the contact force achieved in various segments of the left ventricle. Scar zone was defined as bipolar signal amplitude < 0.5 mV. RESULTS: Among 427 ablation points, effective lesion formation was achieved at 201 points (47.1%). Contact force did not predict effective lesion formation in the overall group. However, within the scar zone, mean contact force ≥ 10 g was significantly associated with effective lesion formation [OR 3.21 (1.43, 7.19) P = 0.005]. In the 12-segment model of the left ventricle, the retrograde approach was associated with higher median contact force in the apical anterior segment (31 vs 19 g; P = 0.045) while transseptal approach had higher median force in the basal inferior segment (25 vs 15 g; P = 0.021). In the 4-segment model, the retrograde approach had higher force in the anterior wall (28 vs 16 g; P = 0.004) while the transseptal approach had higher force in the lateral wall (21 vs 18 g; P = 0.032). There was a trend towards higher force in the inferior wall with the transseptal approach, but this was not statistically significant (20 vs 15 g; P = 0.063). CONCLUSIONS: In patients with ischemic cardiomyopathy, a mean contact force of 10 g or more within the scar zone had the best correlation with electrical unexcitability post ablation in our study. The retrograde aortic approach was associated with better contact force over the anterior wall while use of a transseptal approach had better contact force over the lateral wall.