The Fluoroless Future in Electrophysiology: A State-of-the-Art Review.

Fluoroscopy has always been the cornerstone imaging method of interventional cardiology procedures. However, radiation exposure is linked to an increased risk of malignancies and multiorgan diseases. The medical team is even more exposed to X-rays, and a higher incidence of malignancies was reported in this professional group. In the last years, X-ray exposure has increased rapidly, involving, above all, the medical team and young patients and forcing alternative fluoroless imaging methods. In cardiac electrophysiology (EP) and pacing, the advent of 3D electroanatomic mapping systems with dedicated catheters has allowed real-time, high-density reconstruction of both heart anatomy and electrical activity, significantly reducing the use of fluoroscopy. In addition, the diffusion of intracardiac echocardiography has provided high anatomical resolution of moving cardiac structures, providing intraprocedural guidance for more complex catheter ablation procedures. These methods have largely demonstrated safety and effectiveness, allowing for a dramatic reduction in X-ray delivery in most arrhythmias' ablations. However, some technical concerns, as well as higher costs, currently do not allow their spread out in EP labs and limit their use to only procedures that are considered highly complex and time-consuming and in young patients. In this review, we aim to update the current employment of fluoroless imaging in different EP procedures, focusing on its strengths and weaknesses.

Arrhythmogenic Cardiomyopathy: Definition, Classification and Arrhythmic Risk Stratification.

Arrhythmogenic cardiomyopathy (ACM) is a heart disease characterized by a fibrotic replacement of myocardial tissue and a consequent predisposition to ventricular arrhythmic events, especially in the young. Post-mortem studies and the subsequent diffusion of cardiac MRI have shown that left ventricular involvement in arrhythmogenic cardiomyopathy is common and often develops early. Regarding the arrhythmic risk stratification, the current scores underestimate the arrhythmic risk of patients with arrhythmogenic cardiomyopathy with left involvement. Indeed, the data on arrhythmic risk stratification in this group of patients are contradictory and not exhaustive, with the consequence of not correctly identifying patients at a high arrhythmic risk who deserve protection from arrhythmic death. We propose a literature review on arrhythmic risk stratification in patients with ACM and left involvement to identify the main features associated with an increased arrhythmic risk in this group of patients.

Uric acid significantly correlates with the presence of low-voltage areas at the endocardial mapping in patients with non-valvular atrial fibrillation.

BACKGROUND AND AIMS: Interest in the role of atrial substrate in maintaining Atrial Fibrillation (AF) is growing. Fibrosis is the culprit in the electrical derangement of the myocytes. Many cardiovascular risk factors are known to be linked to atrial scarring; among them Uric Acid (UA) is emerging. The purpose of our study is to find whether UA is associated with Left Atrium (LA) with pathological substrate. METHODS AND RESULTS: 81 patients who underwent radiofrequency transcatheter ablation for nonvalvular AF at the cardiological department of the Niguarda Hospital were enrolled in an observational, cross-sectional, single-center study. UA levels were analysed before the procedure. High density electroanatomic mapping of the LA was performed and patients were divided according to the presence or not of areas of pathological substrate (bipolar voltage <0.5 mV in sinus rhythm). 19 patients showed a LA with pathological substrate. These subjects showed a significant higher prevalence of persistent phenotype of AF (84.2 vs. 25.8%, p < 0.001). UA levels were significantly higher in the group of patients with LA with pathological substrate (6.8 ± 1.9 vs 5.3 ± 1.4 mg/dL, p < 0.001) as well as the prevalence of hyperuricemia (26.5 vs. 6.5%, p = 0.021). The association between uric acid LA with pathological substrate remains significant even after correction for confounding factors (age, left ventricular dysfunction, valvular disease, arrythmia phenotype and furosemide use) and also when the ratio UA/creatinine was evaluated. CONCLUSIONS: In a population of patients who underwent AF ablation, higher UA levels were significantly associated with pathological LA substrate at electro-anatomical mapping.

Subcutaneous ICD implantation in a patient with hypertrophic cardiomyopathy after transvenous ICD failure: A case report.

We describe the case of a patient with hypertrophic cardiomyopathy who experienced the failure of a transvenous implantable cardioverter defibrillator (T-ICD) lead and the following inability of a second T-ICD to convert a ventricular fibrillation. A subcutaneous ICD (S-ICD) was finally implanted and was effective at defibrillation test.

A case of premature ventricular contractions, ventricular tachycardia, and arrhythmic storm induced by right ventricular pacing during cardiac resynchronization therapy: Electrophysiological mechanism and catheter ablation.

A 77-year-old man with ischemic cardiomyopathy and a cardiac resynchronization therapy-defibrillator (CRT-D) device came to our attention due to incessant ventricular tachycardia and multiple implantable cardioverter defibrillator (ICD) shocks. An electrocardiogram showed non-sustained monomorphic ventricular tachycardias (NSVTs) constantly occurring after each biventricular stimulation. During an electrophysiological study, NSVTs reproducibly recurred only after right ventricular (RV) pacing; LV pacing did not induce any NSVTs. The activation map was consistent with a localized reentry at the interventricular septum, and a double exit; at the LV exit site, a single radiofrequency energy application immediately interrupted the occurrence of the NSVTs. Current evidence supports LV pacing to be pro-arrhythmogenic in few CRT patients. This unusual case shows that RV pacing during CRT could produce frequent ventricular arrhythmias and arrhythmic storm. Catheter ablation can be considered an effective therapeutic option, especially when CRT maintenance is highly advisable.

Evaluation of remote monitoring of parturition in dairy cattle as a new tool for calving management.

BACKGROUND: Proper calving management of dairy herds is a crucial aspect of the bovine life cycle, as it has profound effects on calf viability and on the post-partum course of the dam. The objectives of this study were to monitor the calving process through the use of a remote alarm system and to determine the impact of prompt emergency obstetric procedures in case of dystocia for the prevention of stillbirths and post-partum reproductive pathologies, and for improving herd fertility. Six groups of experimental animals were studied: monitored heifers (n = 60) and multiparous cows (n = 60) were compared with non-observed animals (n = 60 heifers and n = 60 multiparous) giving birth during the same time period and housed in the calving barn, and with unmonitored animals placed in a dry zone (n = 240 heifers and n = 112 multiparous cows). RESULTS: The incidence of dystocia ranged from a minimum of 23.4% (monitored multiparous cows) to a maximum of 33.3% (monitored heifers), and there were no differences compared with control groups. However, the rate of stillbirth was higher in control groups than in the monitored groups (P < 0.01). Among both heifers and multiparous cows, the incidence of post-partum uterine infections was higher in the unmonitored animals both in the calving barn (P < 0.01) and in the dry zone (P < 0.05) compared with monitored animals. Among both heifers and multiparous cows, the control groups showed higher rates of foetal membrane retention than did the monitored groups (P < 0.001). The calving-to-conception interval was shorter; in particular, observed heifers showed a significant advantage of approximately 46 days compared with the unmonitored group (P < 0.001) and 32 days compared with the group in the calving barn (P < 0.05). Multiparous cows also had a reduction in the number of days open. CONCLUSIONS: The remote alarm system used to monitor the calving process assured the prompt presence of personnel, improving both the cow's reproductive efficiency and neonatal viability.

[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.

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.

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).