Usefulness of nonlinear analysis of ECG signals for prediction of inducibility of sustained ventricular tachycardia by programmed ventricular stimulation in patients with complex spontaneous ventricular arrhythmias.

INTRODUCTION: The aim of our study was to assess the effectiveness of the nonlinear analysis (NLA) of ECG in predicting the results of invasive electrophysiologic study (EPS) in patients with ventricular arrhythmias. METHODS: We evaluated 25 patients with history of cardiac arrest, syncope, sustained, or nonsustained ventricular tachycardia (VT). All patients underwent electrophysiologic study (EPS) and nonlinear analysis (NLA) of ECG. The study group was compared with a control group of 25 healthy subjects, in order to define the normal range of NLA. ECG was processed in order to obtain numerical values, which were analyzed by nonlinear mathematical functions. Patients were classified through the application of a clustering procedure to the whole set of functions, and the correlation between the results of nonlinear analysis of ECG and EPS was tested. RESULTS: NLA assigned all patients with negative EPS to the same class of healthy subjects, whereas the patients in whom VT was inducible had been correctly and clearly isolated into a separate cluster. In our study, the result of NLA with application of the clustering technique was significantly correlated to that of EPS (P < 0.001), and was able to predict the result of EPS, with a negative predictive value of 100% and a positive predictive value of 100%. CONCLUSIONS: NLA can predict the results of EPS with good negative and positive predictive value. However, further studies are needed in order to verify the usefulness of this noninvasive tool for sudden death risk stratification in patients with ventricular arrhythmias.

Efficacy and safety of radiofrequency catheter ablation in the elderly.

INTRODUCTION: Radiofrequency (RF) catheter ablation has not been widely undertaken in elderly patients. The aim of our study was to compare the success rate of radiofrequency ablation and the incidence of severe procedural complications in young-adult and elderly patients. METHODS: We enrolled all patients undergoing radiofrequency catheter ablation procedures for supraventricular and ventricular arrhythmias at our Cardiology Department from January 2000 to December 2005. The patients were divided into two groups according to age: patients aged <70 years (group A) and those aged >or=70 years (group B). Group B was then divided into two subgroups: B1 (age 70-79 years) and B2 (age >or=80 years). We recorded the incidence of procedural complications and the long-term efficacy (mean follow-up 46 +/- 20 months). RESULTS: We studied 605 patients, 69% in group A and 31% in group B (24% in subgroup B1 and 7% in B2). The prevalence of structural heart disease was higher in elderly patients than in young adults (83 vs 37%, p < 0.01). The rate of procedural complications was 1.3%; no differences emerged between groups A and B (1.2 vs 1.5%, p = NS) or among groups A, B1 and B2 (1.2 vs 1.4 vs 2%, p = NS). The success rate of catheter ablation was 91%, with no differences between the age-groups (92 vs 88%, p = NS) or among groups A, B1 and B2 (92 vs 88 vs 88%, p = NS). CONCLUSION: Catheter ablation in elderly and very elderly patients is as effective and safe as in young-adult subjects, at least in cases which do not require left heart catheterization.

[Competitive sports and leisure-time physical activity in patients with coronary heart disease]. / Il cardiopatico ischemico: approccio all'attività fisica e sportiva.

During recent years, the central role of exercise in the prevention of cardiovascular disease has gradually been demonstrated, and in 2003 the consensus document of the Council on Clinical Cardiology and Council on Nutrition, Physical Activity and Metabolism on the role of physical exercise in the prevention and treatment of coronary artery disease defined sedentary lifestyle as a modifiable independent cardiovascular risk factor, responsible for 12% of total mortality in the United States and for a 1.9-fold increase in the risk of ischemic heart disease. The reduction in cardiovascular mortality and cardiac ischemic events in subjects who perform regular physical activity is mainly due to the action that exercise plays on the control of cardiovascular risk factors. In particular, physical training has proved capable of improving lipid profile, reducing blood pressure and body weight, and improving glycemic control in diabetic subjects. In patients with coronary artery disease, combined exercise training, including both aerobic activities and strength training, is currently recommended. However, physical training in patients suffering from ischemic heart disease should be carefully prescribed, in order to maximize the positive effects and minimize the risks. It is also important that physical training programs are conducted in suitable facilities, with appropriately trained staff and with technical equipment suitable to deal with any emergency situations.

[Antithrombotic prevention in atrial fibrillation: the new anticoagulant drugs]. / I nuovi anticoagulanti nella profilassi antitrombotica della fibrillazione atriale.

Thromboembolic events are the most dangerous complications in patients with atrial fibrillation, affecting the central nervous system in 93% of cases. Vitamin K antagonists have been in clinical use since the '50s for the prevention of thromboembolism. Although effective, vitamin K antagonists have several limitations that render them difficult to administer, which have prompted the need for new antithrombotic strategies. The new class of oral anti-IIa and anti-Xa agents appears to be a promising alternative to overcome these limitations.

[Provocative tests and electrophysiological study in athletes]. / Test provocativi e studio elettrofisiologico nello sportivo.

Provocative tests can be divided into three main categories: first-level or screening tests, consisting basically of step test, which all athletes undergo during pre-participation screening; second-level tests, which include exercise test (simple or cardiopulmonary), performed on the basis of specific clinical indications or for the assessment of functional capacity; and third-level tests, consisting of complex methods such as myocardial scintigraphy and stress echo (or exercise echo), which are performed in subjects adequately selected according to clinical characteristics or to the results of first- and second-level tests. The electrophysiological endocavitary study has specific indications in sustained or frequent ventricular arrhythmias, while it is not useful in diagnostic evaluation of athletes with supraventricular arrhythmias, where it has been replaced in most cases by transesophageal electrophysiological study.

Focus on renin-angiotensin system modulation and atrial fibrillation control after GISSI AF results.

Atrial fibrillation is the most frequently encountered arrhythmia in clinical practice. Given that atrial fibrillation is steadily increasing and that the medium to long-term efficacy of antiarrhythmic drugs has proved poor, it is essential to seek new therapies to prevent its onset and to effectively control recurrences. The study of nonantiarrhythmic drugs that act on the atrial remodeling that constitutes the substrate of the arrhythmia is a new and very interesting field of research. In this regard, several molecules that interact with the renin-angiotensin system at the level of the enzymatic or receptor cascade have been investigated in the past 10 years; some results have been very promising, whereas others have been extremely disappointing. In particular, the publication in 2008 of the results of GISSI AF, a rigorously designed Italian prospective study conducted on a large number of patients, revealed no statistically significant differences between the active drug and a placebo in preventing arrhythmia recurrences. In this study, we reassess the rationale behind the use of this class of drugs for 'antiarrhythmic' purposes, re-examine the most significant results reported in the clinical literature since 1999 and discuss the results of the GISSI AF study in this light.

[Epidemiology, classification and prognosis of palpitations]. / II cardiopalmo: epidemiologia, classificazione e prognosi.

Palpitations can be defined as an unpleasant feeling of heart beat, which is perceived as particularly fast, irregular or intense. This feeling is usually associated with perception of movements and hits in the chest. From the pathophysiological point of view, current knowledge of the neural pathways responsible for the perception of heart beat remains to be clearly elucidated. It has been hypothesized that these pathways include different structures located both at the intracardiac and extracardiac level. Palpitations are a widely diffused complaint in the general population, and particularly in subjects affected by structural heart disease. Clinical presentation makes it possible to divide palpitations into four groups: extrasystolic, tachycardic, anxiety-related, and intense. From the etiological point of view, palpitations may be divided into the following groups: palpitations caused by arrhythmias, by structural heart disease (non-arrhythmic), by psychiatric disease, by systemic noncardiac disease, and by drug or illicit substance assumption. The prompt detection of the causes of palpitations allows to identify clinical conditions potentially at high risk and to choose the most appropriate therapeutic approach.

[Idiopathic ventricular tachycardia: clinical characteristics and management]. / La tachicardia ventricolare idiopatica: significato clinico e terapia.

Outflow tract ventricular tachycardia (VT) is the most common form of idiopathic VT in clinical practice. The correct differential diagnosis with VTs caused by structural heart diseases (particularly arrhythmogenic right ventricular cardiomyopathy) is extremely challenging for the cardiologist. When correctly diagnosed, outflow tract VTs have a favorable prognosis in the majority of patients. At present, technical advancements and improved clinical experience in transcatheter ablation procedures may offer a definite therapy to an increasing number of patients with an acceptable complication rate.

[Atrial fibrillation and flutter in athletes]. / La fibrillazione e il flutter atriale nell'atleta.

Atrial fibrillation (AF) is one of the most frequent findings in the general population, with an incidence of about 0.1% per year and a mean prevalence of 0.95%. However, prevalence values are known to vary with age, being very low (0.1-0.2%) in subjects less than 55 years old, the age group comprising the greatest number of individuals who practice sport at various levels. Long-term, regular, intense physical training determines an increase in vagal tone, leading to bradycardia, and during physical activity, particularly competitive sport, a marked release of catecholamines occurs as a result of both the intense physical effort and the emotional stress involved in competition. Both these adaptive phenomena on the part of the autonomous nervous system may promote the development of AF. Heart diseases with a certain degree of severity are not generally compatible with sport, unless the activity undertaken involves a low expenditure of energy and is noncompetitive. In any case, in the presence of AF, the arrhythmia must be well controlled and well tolerated during performance of the activity.

'Orphan drugs' in cardiology: nadolol and quinidine.

The recent withdrawal from the market of nadolol (Corgard; Bristol-Myers Squibb, Sermoneta, Italy) and quinidine polygalacturonate (Ritmocor; Malesci, Bagno A Ripoli, Italy) has been causing clinical problems to many cardiologists and patients, frequently leading to discontinuance of an effective and well-tolerated pharmacological treatment. Nadolol is useful in the treatment of severe and refractory arrhythmias, particularly in some genetically determined ion-channel diseases, such as long-QT syndrome and catecholaminergic polymorphic ventricular tachycardia.Quinidine is still used in refractory atrial fibrillation recurrences. Recent studies have demonstrated the clinical efficacy of quinidine in the treatment of rare genetically determined ion-channel diseases at high risk of sudden death, such as Brugada syndrome and short-QT syndrome.We hope that scientific societies can influence healthcare and pharmaceutical institutions, in order to restore the availability of two cardiovascular drugs that are extremely important in the care of arrhythmic patients.

[Non-antiarrhythmic pharmacological treatment of atrial fibrillation: focus on drugs acting on the renin-angiotensin system]. / Trattamento farmacologico non antiaritmico della fibrillazione atriale: il punto sui farmaci ad azione sul sistema renina-angiotensina.

Atrial fibrillation is the most frequent arrhythmia in clinical practice. It is necessary to look for new therapeutic solutions because of the unsatisfactory efficacy of antiarrhythmic drugs in controlling relapses and the continuous growth of this phenomenon. The study of non-antiarrhythmic drugs that act specifically on atrial remodeling, which is the arrhythmia substrate, is a novel and very interesting field of investigation. Namely, we have been evaluating drugs that act on the renin-angiotensin system for the last few years with very promising, although not univocal, results. In this paper we discuss the rationale of their employment and review the most important data of the literature since 1999.

[Non-linear analysis of electrocardiographic signals as a non-invasive predictive tool for major ventricular arrhythmias]. / L'analisi non lineare di tracciati elettrocardiografici come strumento predittivo non invasive di aritmie ventricolari maggiori.

The aim of this study was to assess the effectiveness of different methods of non-linear analysis of the ECG in the risk stratification of patients with ventricular arrhythmias. These non-invasive parameters were correlated with the results of the electrophysiological study (EPS). We evaluated 25 patients with a history of cardiac arrest, syncope, sustained or non-sustained ventricular tachycardia. The study group was compared with a control group of 25 healthy subjects. All patients underwent both EPS and non-linear analysis procedures applied to their ECG recording. A comparison between the results of non-linear analysis of the ECG and EPS was performed. Results are presented and discussed.

Implantation of a permanent pacemaker in a pregnant woman under the guidance of electrophysiologic signals and transthoracic echocardiography.

We describe the case of a 30-year-old pregnant woman who underwent pacemaker implantation for recurrent syncope caused by sinus arrest. In order to minimize radiation exposure, which may potentially have teratogenic effects, we decided to perform pacemaker implantation by means of a hybrid technique involving the evaluation of electrophysiologic signals and transthoracic echocardiographic imaging to guide lead positioning within the right ventricle. After the procedure, the patient was always asymptomatic and had no recurrences of syncope. Six months later, she experienced uncomplicated natural labor, and the newborn was absolutely healthy. On a 10-month follow-up examination, the lead position was still optimal, and ventricular sensing and pacing thresholds were good. Our case demonstrates that pacemaker implantation under the guidance of electrophysiologic signals and transthoracic echocardiographic imaging, with only a short view by pulsed fluoroscopy in order to verify the correct lead position, is an effective and well-tolerated procedure in pregnant women.

Microvolt T-wave alternans for risk stratification in athletes with ventricular arrhythmias: correlation with programmed ventricular stimulation.

BACKGROUND: Aim of our study is to evaluate the role of T-wave alternans (TWA) to stratify the risk of sudden cardiac death in athletes (Ath) with complex ventricular arrhythmias (VA), and to document a possible correlation between TWA and electrophysiological testing (EPS) results. METHODS: We studied 85 Ath with VA (61 M, mean age 32 +/- 11 years). In all cases a cardiological evaluation was performed, including TWA and EPS. The patients were evaluated during a follow-up of 30 +/- 21 months. The end point was the occurrence of sudden death (SD) or malignant ventricular tachyarrhythmias (VT). RESULTS: TWA was negative in 57 Ath (68%), positive in 15 (18%) and indeterminate in 13 (14%). All subjects with negative TWA did not show induction of VT at EPS, with significant correlation between negative TWA and negative EPS (P < 0.001). All Ath with positive TWA also had VT induced by a EPS, with significant correlation (P < 0.001). By contrast, our data did not show significant correlation between indeterminate TWA and positive or negative EPS. However, there was significant correlation between abnormal TWA test (positive + indeterminate) and inducibility of VT at EPS (P < 0.001). During follow-up we observed a significant difference in end point occurrence (VT or SD) between Ath with negative or abnormal TWA and between Ath with negative or positive EPS. CONCLUSION: TWA confirm its role as a simple and noninvasive test, and it seems useful for prognostic stratification of Ath with VA.

[Usefulness of home monitoring in patients with implantable cardioverter-defibrillators]. / L'home monitoring nel follow-up del paziente con defibrillatore impiantabile.

During the last years several remote monitoring systems have been introduced in everyday clinical practice, because of the development of new computer and information technologies. Therefore, clinical and technical data of implanted devices can be transmitted by patients directly to the cardiology department through a transtelephonic web-based connection, without undergoing traditional outpatient evaluation. Home monitoring systems are effective in identifying device malfunctioning and clinical instability in patients with implantable cardioverter-defibrillators. Their efficacy does not significantly differ from that of traditional outpatient device interrogation, but with significant advantages in terms of quality of life and reduction in clinic visits for device follow-up.

[Current limitations and new perspectives in the diagnosis of arrhythmogenic right ventricular cardiomyopathy/dysplasia]. / L'iter diagnostico della cardiomiopatia aritmogena del ventricolo destro: limiti attuali e nuove prospettive.

Arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D) is a genetic cardiomyopathy characterized by ventricular arrhythmias and structural abnormalities of the right ventricle. In ARVC/D there is a progressive replacement of right ventricular myocardium with fatty and fibrous tissue and ventricular arrhythmias of right ventricular origin. The precise prevalence of ARVC/D has been estimated to vary between 1 in 1000 to 1 in 5000 of the general population. ARVC accounts for approximately 3-10% of sudden deaths in young people under the age of 65 years. The purpose of this paper is to review the current knowledge of ARVC/D and its management. Particular attention will be focused on some of the recent advances in the understanding of the genetic basis of ARVC/D. Increasing evidence suggests that ARVC/D is a disease of desmosomal dysfunction. Attention will also be focused on the new and somewhat controversial concept that ARVC/D may present primarily as a left ventricular disease. In our experience ARVC/D typically presents as a right ventricular disease, unless a patient has advanced disease. Diagnosis of ARVC/D is challenging and requires a comprehensive evaluation with both non-invasive and invasive testing.

[Outsourced service management of the catheterization laboratory in the cardiology department: lights and shadows]. / La gestione in service del laboratorio di elettrofisiologia ed emodinamica: luci ed ombre.

BACKGROUND: The aim of this study was to compare the economic impact and results achieved by recourse to outsourced management of the procedures carried out in the electrophysiology and catheterization laboratory of the Department of Cardiology of the Crema Hospital with the in-house setting up and operation of the same activities. METHODS: The comparison between the two possible options, "make" or "buy in", was made using the methodology of advanced direct costing, which provides for the allocation of only direct fixed and variable costs to clinical procedures, the subject of calculation. In addition to the financial evaluation, the quality variables showing the advantages and limitations of outsourcing in terms of organizational improvements, streamlining of the organizational structure, operational efficiency and improvement of the quality of service, were examined. RESULTS: The financial evaluation from 2002 to 2006 came out in favor of "make" as opposed to "buy in". Income derived from diagnosis-related-group payments for the more than 4000 procedures carried out was Euro26.239.034,96. On the basis of the economical evaluation the second contribution margin was slightly inferior with the "buy in" than with the "make" hypothesis. Specifically, it is Euro16.397.669,96 in the "buy in" and Euro16.753.579,16 in the "make" hypothesis, with a difference of Euro355.909,20 (-2%). CONCLUSIONS: The economic advantage lies with the "make" alternative compared with "buy in", nevertheless, outsourcing offers greater operational efficiency, better cost control, setting up of the laboratory within a very short time, simplified administration (single point of contact) and an opportunity to concentrate on core business. However, there are limitations due to greater dependence on the supplier, not all the equipment provided for under the contract was used, and loss of management know-how in non-core business areas.

Ventricular arrhythmias in competitive athletes: risk stratification with T-wave alternans.

INTRODUCTION: Aim of our study is to evaluate the role of TWA to stratify the risk of sudden cardiac death in athletes (Ath) with complex ventricular arrhythmias (VA), and to document a possible correlation between TWA and electrophysiological testing (EES) results. METHODS: We studied 43 Ath with VA (31 M, mean age 34 ± 12 years). In all cases a cardiological evaluation was performed, including TWA and EES. The patients were evaluated during a follow-up of 25 ± 22 months. The end-point was the occurrence of sudden death or malignant ventricular tachyarrhythmias (VT). RESULTS: TWA was negative in 28 Ath (65%), positive in 8 (19%) and indeterminate in 7 (16%). All subjects with negative TWA did not show induction of VT at EES, with significant correlation between negative TWA and negative EES (p<0.001). All Ath with positive TWA also had VT induced by a EES, but without significant correlation between positive TWA and positive EES. In 2 Ath with undetermined TWA (29%) VT were induced at EES. Our data did not show significant correlation between indeterminate TWA and positive or negative EES. However, logistic regression analysis showed significant correlation between abnormal TWA test (positive or indeterminate) and inducibility of VT at EES (p<0.001). During follow-up we observed a significant difference in end-point occurrence between Ath with negative or positive TWA and between Ath with negative or positive EES. CONCLUSION: TWA confirm its role as a simple and non-invasive test, and it seems useful for prognostic stratification of Ath with VA.

Atrial flutter: from ECG to electroanatomical 3D mapping.

Atrial flutter is a common arrhythmia that may cause significant symptoms, including palpitations, dyspnea, chest pain and even syncope. Frequently it's possible to diagnose atrial flutter with a 12-lead surface ECG, looking for distinctive waves in leads II, III, aVF, aVL, V1,V2. Puech and Waldo developed the first classification of atrial flutter in the 1970s. These authors divided the arrhythmia into type I and type II. Therefore, in 2001 the European Society of Cardiology and the North American Society of Pacing and Electrophysiology developed a new classification of atrial flutter, based not only on the ECG, but also on the electrophysiological mechanism. New developments in endocardial mapping, including the electroanatomical 3D mapping system, have greatly expanded our understanding of the mechanism of arrhythmias. More recently, Scheinman et al, provided an updated classification and nomenclature. The terms like common, uncommon, typical, reverse typical or atypical flutter are abandoned because they may generate confusion. The authors worked out a new terminology, which differentiates atrial flutter only on the basis of electrophysiological mechanism.