Clustering of ventricular tachyarrhythmias in heart failure patients implanted with a biventricular cardioverter defibrillator.

BACKGROUND: Temporal patterns of ventricular tachyarrhythmia (VT/VF) have been studied only in patients who have received implantable cardioverter defibrillators (ICD) for secondary prevention of sudden death, and mainly in ischemic patients. The aim of this study was to evaluate VT/VF recurrence patterns in heart failure (HF) patients with biventricular ICD and to stratify results according to HF etiology and ICD indication. METHODS AND RESULTS: We studied 421 patients (91% male, 66 +/- 9 years). HF etiology was ischemic in 292 patients and nonischemic in 129. ICD indication was for primary prevention in 227 patients and secondary prevention in 194. Baseline left ventricular ejection fraction (LVEF) was 26 +/- 7%, QRS duration 168 +/- 32 msec, and NYHA class 2.9 +/- 0.6. In a follow-up of 19 +/- 11 months, 1,838 VT/VF in 110 patients were appropriately detected. In 59 patients who had > or = 4 episodes, we tried to determine whether VT/VF occurred randomly or rather tended to cluster by fitting the frequency distribution of tachycardia interdetection intervals with exponential functions: VT/VF clusters were observed in 46 patients (78% of the subgroup of patients with > or = 4 episodes and 11% of the overall population). On multivariate logistic analysis, VT/VF clusters were significantly (P < 0.01) associated with ICD indication for secondary prevention (odds ratio [OR] = 3.12; confidence interval [CI] = 1.56-6.92), nonischemic HF etiology (OR = 4.34; CI = 2.02-9.32), monomorphic VT (OR = 4.96; CI = 2.28-10.8), and LVEF < 25% (OR = 3.34; CI = 1.54-7.23). Cardiovascular hospitalizations and deaths occurred more frequently in cluster (21/46 [46%]) than in noncluster patients (63/375 (17%), P < 0.0001). CONCLUSIONS: In HF patients with biventricular ICDs, VT/VF clusters may be regarded as the epiphenomenon of HF deterioration or as a marker of suboptimal response to cardiac resynchronization therapy.

Surgical ablation of arrhythmias.

The surgical approach was the earliest therapeutic ablation of hyperkinetic arrhythmias. Following the progressive improvements in electrophysiological mapping and operative techniques, new surgical approaches have been developed for the treatment of those arrhythmias related to ectopic phenomena or reentry mechanisms. These procedures have been proven to be highly effective but the associated morbidity and mortality were unacceptably high. More recent and advanced techniques of transcatheter ablation have revolutionized the treatment of these arrhythmias and now represent the treatment of choice in the majority of cases. However, the significant reduction in the operative risk and the improvement in patient outcome with respect to the past, thanks to a better patient selection and to advances in the surgical and myocardial protection techniques, make do that the surgical approach to some forms of arrhythmias is still valid, especially in those cases requiring associated surgery: atrial tachyarrhythmias in patients with congenital heart disease, post-ischemic ventricular tachycardias in patients who necessitate myocardial revascularization, and/or ventricular remodeling and chronic or paroxysmal atrial fibrillation in patients who require cardiac surgery. New techniques such as radiofrequency, microwaves and cryoablation guarantee the creation of linear and transmural lesions with minimum damage to the cardiac structures and appear very interesting as they are surgically simple and associated with shorter procedure times and less complications. The possibility of performing the ablative procedure completely on the epicardial surface may open the way for atrial fibrillation surgery on a totally beating heart and for procedures that are ever less invasive thus enabling treatment of patients without associated surgical indications.

Clinical Relevance Of Systematic CRT Device Optimization.

Cardiac Resynchronization Therapy (CRT) is known as a highly effective therapy in advanced heart failure patients with cardiac dyssynchrony. However, still one third of patients do not respond (or sub-optimally respond) to CRT. Among the many contributors for the high rate of non-responders, the lack of procedures dedicated to CRT device settings optimization (parameters to regulate AV synchrony and VV synchrony) is known as one of the most frequent. The most recent HF/CRT Guidelines do not recommend to carry-out optimization procedures in every CRT patient; they simply state those procedures "could be useful in selected patients", even though their role in improving response has not been proven. Echocardiography techniques still remain the gold-standard reference method to the purpose of CRT settings optimization. However, due to its severe limitations in the routine of CRT patients management (time and resource consuming, scarce reproducibility, inter and intra-operator dependency), echocardiography optimization is widely under-utilized in the real-world of CRT follow-up visits. As a consequence, device-based techniques have been developed to by-pass the need for repeated echo examinations to optimize CRT settings. In this report the available device-based optimization techniques onboard on CRT devices are shortly reviewed, with a specific focus on clinical outcomes observed in trials comparing these methods vs. clinical practice or echo-guided optimization methods. Particular emphasis is dedicated to hemodynamic methods and automaticity of optimization algorithms (making real the concept of "ambulatory CRT optimization"). In fact a hemodynamic-based approach combined with a concept of frequent re-optimization has been associated - although retrospectively - with a better clinical outcome on the long-term follow-up of CRT patients. Large randomized trials are ongoing to prospectively clarify the impact of automatic optimization procedures.

Left ventricular ejection fraction overcrossing 35% after one year of cardiac resynchronization therapy predicts long term survival and freedom from sudden cardiac death: single center observational experience.

BACKGROUND: Reverse remodeling and increased LVEF after CRT correlate with survival and heart failure hospitalizations, but their relationship with the risk of SCD is unclear. We aimed to evaluate whether exceeding a threshold value of 35% for left ventricular ejection fraction (LVEF) 1 year after cardiac resynchronization therapy (CRT) predicts survival and freedom from sudden cardiac death (SCD). METHODS: 330 patients who survived ≥ 6 months after CRT (males 80%, age 62 ± 11 years) were grouped according to 1-year LVEF ≤ 35% (Group 1, n=187, 57%) or >35% (Group 2, n=143, 43%). According to changes vs. baseline (reduction of left end-systolic volume [LVESV] ≥ 10% or increase of LVEF% > 10 units), patients were also classified as echocardiographic (Echo) non-responders (Group A, n=152, 46%) or responders (Group B, n=178, 54%). RESULTS: At baseline, LVESV volume was larger and LVEF was lower in Group 1 vs. Group 2 (p<0.001). After 1 year, echocardiographic improvement was greater in Group 2 vs. Group 1 (p<0.001 for changes in both LVESV and LVEF). Over a median follow-up of 49 months, 47 patients (14%) died, 36 in Group 1 vs. 11 in Group 2 (19% vs. 8%, p=0.004). A significantly higher rate of freedom from all-cause mortality (p=0.002), cardiovascular mortality (p<0.001) and SCD (p<0.001) was observed in Group 2. Multivariate analysis demonstrated that only 1-year LVEF >35% was associated with freedom from SCD/VF. CONCLUSIONS: LVEF >35% after 1 year of CRT characterizes a favorable long-term outcome, with a very low risk for SCD.

A caval homograft for Budd-Chiari syndrome due to inferior vena cava obstruction.

Transjugular intrahepatic portosystemic shunt (TIPS) is the standard treatment of Budd-Chiari syndrome (BCS) non responsive to medical therapy. However, patients with inferior vena cava (IVC) obstruction proximal to the atrium do not benefit from TIPS and a surgical approach is mandatory. We report the case of BCS due to intrapericardial IVC obstruction. We describe a novel surgical approach using a fresh caval homograft. An attempt to balloon dilatation of the IVC obstruction was complicated by right atrial disruption with tamponade and ventricular fibrillation. Lately, the patient successfully underwent a reconstruction of the cavo-atrial continuity by the interposition of a fresh caval homograft, a novel surgical approach never described before for BCS. Further follow-up revealed progressive reduction and resolution of ascites, and overall clinical improvement. IVC obstruction near to the atrium can be surgically approached with a new technique consisting in inferior vena cava resection and replacement with a caval homograft.

[Risk stratification for sudden cardiac death: should we juist consider ejection fraction?]. / La stratificazione del rischio di morte improvvisa: dobbiamo considerare solo la frazione di eiezione?

Sudden cardiac arrest is a leading cause of death in industrialized countries. There is solid clinical evidence for implantable cardioverter-defibrillators as the only effective means of preventing sudden cardiac arrest and reducing mortality in high-risk patients. The therapeutic strategy has definitively been validated, but we have not yet identified with the same effectiveness the patients who most likely will benefit from such therapy. Risk stratification of sudden death is therefore one of the major unresolved issues of modern cardiology. Current guidelines identify ejection fraction as the only instrumental parameter for risk stratification of sudden cardiac death. It is strongly consolidated from "old and new" clinical trials that ejection fraction reduction is the real powerful predictor of total mortality and sudden death regardless of its etiology; however it cannot be considered as an indisputable gold standard predictor of risk because it lacks of sensitivity and specificity in the prediction of sudden death. It is reasonable that many factors besides ejection fraction influence patient prognosis; there are different aspects suggesting that a reduction in ejection fraction is a risk factor only in combination with other risk factors. The implantable cardioverter-defibrillator therapy is expensive and associated with possible complications. We therefore need better methods for risk stratification of our patients in order to increase the real cost-effectiveness of current and future treatment options.

Patient selection for biventricular pacing.

INTRODUCTION: Biventricular pacing improves functional status in the majority of patients with drug-refractory heart failure, dilated cardiomyopathy, and interventricular conduction delay. The aim of this study was to analyze the baseline clinical and functional data of a cohort of patients implanted with a biventricular stimulation system in a single-center experience, to verify if the pathophysiologic characteristics of patients affect outcome, and to determine if preliminary identification of the right candidates for the new therapy is possible with noninvasive parameters. METHODS AND RESULTS: Since March 1999, 52 patients with advanced heart failure (idiopathic cardiomyopathy 50%, ischemic cardiomyopathy 35%, other etiology 15%) and left bundle branch block underwent cardiac resynchronization and were followed prospectively. Paired analysis over mean (+/- SD) follow-up of 348 +/- 154 days showed an overall significant decrease of QRS width (baseline 194 +/- 33.2 msec vs follow-up 159.6 +/- 20.1 msec), New York Heart Association (NYHA) functional class (baseline 3.2 +/- 0.5 vs follow-up 2.3 +/- 0.5), quality-of-life score (baseline 54 +/- 25 vs follow-up 25 +/- 16), and increase of maximal VO2 (baseline 12.6 +/- 2.5 mL/kg/min vs follow-up 15.0 +/- 3.3 mL/kg/min). There were 80% responders (documented, persistent decrease > or = 1 NYHA class) and 20% nonresponders (same NYHA class or decline of status; need for heart transplant; death due to progressive pump failure). No significant differences in baseline clinical and functional variables between the two subgroups were observed. In responders, there was a highly significant global improvement of all variables; in nonresponders, no parameters changed between baseline and follow-up. CONCLUSION: These data confirm the role of biventricular pacing in improving the functional status of the great majority of a selected patient population having advanced heart failure and left bundle branch block with wide QRS complex. Basal demographic, clinical, and functional characteristics are not helpful in preliminary selection of responders. Simple evaluation of NYHA class confirms favorable outcome (improvement of functional and hemodynamic status).