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Massimo Santini

Publications and source records attributed to Massimo Santini.

71 records · Page 4Linked to original sources
PubMed2003

Electropharmacological effects of antiarrhythmic drugs on atrial fibrillation termination. Part II: New insights into the electrophysiological mechanisms of atrial fibrillation termination.

Antiarrhythmic drugs have been largely used to convert atrial fibrillation to sinus rhythm. Classes Ia, Ic and III antiarrhythmic agents are all known to be effective. Nevertheless, the electrophysiological properties of such agents even of the same class are very different. The mechanisms of the pharmacological termination of atrial fibrillation is an interesting issue that has not been so extensively studied yet. In this review we try to summarize the principal concepts about the electrophysiological substrate of atrial fibrillation and to give a unified and modern overview of the issue of the mechanisms of the pharmacological termination of the arrhythmia.

Anti-Arrhythmia Agents↗
PubMed2003

Risk stratification for arrhythmic events in patients with idiopathic dilated cardiomyopathy: a review of the literature and current perspectives.

The prognosis for patients with idiopathic dilated cardiomyopathy (DCM) has markedly improved during the last decade, mainly because of advancements in therapeutic strategies. However, sudden death still accounts for a significant part of the total mortality in patients with moderate disease. Recent primary prophylactic trials failed to demonstrate any benefit of cardioverter-defibrillator implantation in an unselected group of idiopathic DCM patients and thus the identification of the subgroup of patients at high arrhythmic risk is crucial. Although different risk stratification methods have been evaluated in risk assessment, the reported clinical value differs in studies, mainly because of differences in either methodology and/or patient selection. The present review focuses on arrhythmic events in idiopathic DCM and on the value of noninvasive methods and electrophysiological study in the risk stratification of this group of patients.

Arrhythmias, Cardiac↗
PubMed2003

[The SEOT-Urbe project:an observational study on the cardiovascular profile of a young population living in the Roman suburb].

BACKGROUND: Although several observational studies regarding clinical aspects of different populations have been performed, information about the cardiovascular profile and the lifestyle of young Italian people is poor. METHODS: A group of physicians working in the Roman area visited a population of outpatients aging between 20 and 50 years, with a medical history characterized by the absence of cardiovascular events. They collected information about the prevalence of cardiovascular risk factors, lifestyle, and the number of medical and instrumental controls performed by each patient. RESULTS: 5581 consecutive patients (2795 males, 2786 females, mean age 36 +/- 8 years) were included in this study. They were living in three different areas of the Roman suburb: civic zone, rural area, and seaside. At least one cardiovascular risk factor was observed in 4825 people (86.5%). Moreover 549 people (9.8%) reported more than three risk factors. Physical inactivity resulted the most frequently found risk factor; indeed its prevalence is high in every subgroup of patients, regardless of gender or geographical distribution. Regular medical controls are performed by 2774 people (49.7%), most of them being visited by general practitioners; 288 people (5.2%) complain of symptoms like dyspnea or palpitations. Cardiovascular therapy is taken more frequently than non-cardiovascular one (13.3 vs 3.7%). Very few instrumental exams (electrocardiogram, echocardiogram, physical stress test) show alterations. The analysis of the lifestyle and cardiovascular risk profile of people living in the different areas failed to show any significant differences. CONCLUSIONS: Despite the young age of the population, a great number of people show an increased cardiovascular risk profile and report a potentially dangerous lifestyle. The need for a primary prevention policy turns up in order to avoid the occurrence of as more expected cardiovascular events as possible.

Adult↗
PubMed2002

Long-term clinical significance of frequent and complex ventricular tachyarrhythmias in trained athletes.

OBJECTIVES: The aim of this study was to clarify the clinical relevance of ventricular tachyarrhythmias assessed by 24-h ambulatory electrocardiograms (ECG) in a large, unique, and prospectively evaluated athletic population. BACKGROUND: For athletes with ventricular tachyarrhythmias, the risk of sudden cardiac death associated with participation in competitive sports is unresolved. METHODS; We assessed 355 competitive athletes with ventricular arrhythmias (VAs) on a 24-h ambulatory (Holter) ECG that was obtained because of either palpitations, the presence of > or = 3 premature ventricular depolarizations (PVDs) on resting 12-lead ECG, or both. RESULTS: Athletes were segregated into three groups: Group A with > or = 2,000 PVDs/24 h (n = 71); Group B with > or = 100 <2,000 PVDs/24 h (n = 153); and Group C with only <100 PVDs/24 h (n = 131). Cardiac abnormalities were detected in 26 of the 355 study subjects (7%) and were significantly more common in Group A (21/71, 30%) than in Group B (5/153, 3%) or Group C athletes (0/131, 0% p < 0.001). Only the 71 athletes in Group A were excluded from competition. During follow-up (mean, 8 years), 70 of 71 athletes in Group A and each of the 284 athletes in Groups B and C have survived without cardiovascular events. The remaining Group A athlete died suddenly of arrhythmogenic right ventricular cardiomyopathy while participating in a field hockey game against medical advice. Frequent and complex ventricular tachyarrhythmias are common in trained athletes and are usually unassociated with underlying cardiovascular abnormalities. Such VAs (when unassociated with cardiovascular abnormalities) do not convey adverse clinical significance, appear to be an expression of "athlete's heart syndrome," and probably do not per se justify a disqualification from competitive sports.

Adolescent↗
PubMed2002

Early protection against sudden death by n-3 polyunsaturated fatty acids after myocardial infarction: time-course analysis of the results of the Gruppo Italiano per lo Studio della Sopravvivenza nell'Infarto Miocardico (GISSI)-Prevenzione.

BACKGROUND: Our purpose was to assess the time course of the benefit of n-3 polyunsaturated fatty acids (PUFAs) on mortality documented by the GISSI-Prevenzione trial in patients surviving a recent (<3 months) myocardial infarction. METHODS AND RESULTS: In this study, 11 323 patients were randomly assigned to supplements of n-3 PUFAs, vitamin E (300 mg/d), both, or no treatment (control) on top of optimal pharmacological treatment and lifestyle advice. Intention-to-treat analysis adjusted for interaction between treatments was carried out. Early efficacy of n-3 PUFA treatment for total, cardiovascular, cardiac, coronary, and sudden death; nonfatal myocardial infarction; total coronary heart disease; and cerebrovascular events was assessed by right-censoring follow-up data 12 times from the first month after randomization up to 12 months. Survival curves for n-3 PUFA treatment diverged early after randomization, and total mortality was significantly lowered after 3 months of treatment (relative risk [RR] 0.59; 95% CI 0.36 to 0.97; P=0.037). The reduction in risk of sudden death was specifically relevant and statistically significant already at 4 months (RR 0.47; 95% CI 0.219 to 0.995; P=0.048). A similarly significant, although delayed, pattern after 6 to 8 months of treatment was observed for cardiovascular, cardiac, and coronary deaths. CONCLUSIONS: The early effect of low-dose (1 g/d) n-3 PUFAs on total mortality and sudden death supports the hypothesis of an antiarrhythmic effect of this drug. Such a result is consistent with the wealth of evidence coming from laboratory experiments on isolated myocytes, animal models, and epidemiological and clinical studies.

Anti-Arrhythmia Agents↗
PubMed2002

Doppler myocardial imaging to evaluate the effectiveness of pacing sites in patients receiving biventricular pacing.

OBJECTIVES: The goal of this study was to compare the efficacy of biventricular pacing (BIV) at the most delayed wall of the left ventricle (LV) and at other LV walls. BACKGROUND: Biventricular pacing could provide additional benefit when it is applied at the most delayed site. METHODS: In 31 patients with advanced nonischemic heart failure, the activation delay was defined, in blind before BIV, by regional noninvasive Tissue Doppler Imaging as the time interval between the end of the A-wave (C point) and the beginning of the E-wave (O point) from the basal level of each wall. The left pacing site was considered concordant with the most delayed site when the lead was inserted at the wall with the greatest regional interval between C and O points (CO(R)). After BIV, patients were divided into group A (13/31) (i.e., paced at the most delayed site) and group B (18/31) (i.e., paced at any other site). RESULTS: After BIV, in all patients LV end-diastolic (LVEDV) and end-systolic (LVESV) volumes decreased (p = 0.025 and 0.001), LV ejection fraction (LVEF) increased (p = 0.002), QRS narrowed (p = 0.000), New York Heart Association class decreased (p = 0.006), 6-min walked distance (WD) increased (p = 0.046), the interval between closure and opening of mitral valve (CO) and isovolumic contraction time (ICT) decreased (p = 0.001 and 0.000), diastolic time (EA) and Q-P(2) interval increased (p = 0.003 and 0.000), while Q-A(2) interval and mean performance index (MPI) did not change. Group A showed greater improvement over group B in LVESV (p = 0.04), LVEF (p = 0.04), bicycle stress testing work (p = 0.03) and time (p = 0.08) capacity, CO (p = 0.04) and ICT (p = 0.02). CONCLUSIONS: After BIV, LV performance improved significantly in all patients; however, the greatest improvement was found in patients paced at the most delayed site.

Bundle-Branch Block↗
PubMed2002

Transseptal activation during left atrial pacing in humans: electroanatomic mapping using a noncontact catheter and the intracardiac echocardiography.

BACKGROUND: A better understanding of transseptal activation may be important for the treatment of atrial fibrillation, but little is known about preferential routes of conduction from the left atrium (LA) to the right atrium (RA) in humans. METHODS AND RESULTS: Twelve patients were studied. A noncontact mapping system was used to map the RA during pacing from several sites of LA at different cycle lengths. The location of the Bachmann's bundle (BB), the fossa ovalis (FO) and the coronary sinus (CS) ostium were determined using intracardiac echocardiography. The BB was the earliest area of right atrial activation during pacing from the atrial appendage, roof and postero-superior wall in 94% of cases. The FO was the area of earliest activation during pacing from the septum and the right superior pulmonary veins (PV) in 95% of cases. The CS ostium (alone or associated with the FO) was the region of transseptal breakthrough in all patients during pacing from the right inferior PV, postero-inferior wall and distal CS. Various patterns of activation with 2 or 3 distinct areas of transseptal breakthrough were observed during pacing from the lateral wall and the left superior PV. The pacing cycle length did not influence the modality of transseptal activation. CONCLUSIONS: Different patterns of transseptal activation were found during pacing from LA. The preferential routes of conduction from the LA to the RA were related to the sites of stimulation and were not influenced by the pacing cycle length.

Adult↗
PubMed2002

Early and late QRS morphology and width in biventricular pacing: relationship to lead site and electrical remodeling.

UNLABELLED: 48 patients (40 Male), mean age 68 +/- 8 years, in III-IV class, with intraventricular conduction delay, received a biventricular pacemaker. Heart failure aetiology was non-ischemic in 60%. Left ventricular lead positioning was inferior in 5 patients (10%), posterior in 12 (25%), lateral in 18 (37%) and anterior in 13 (27%). QRS duration and axis were evaluated in sinus rhythm, and during right ventricular pacing, left ventricular pacing and biventricular pacing, the last early after implant and late after 8.8 +/- 4.3 months. QRS duration (ms) was 154 +/- 29 in sinus rhythm, 175 +/- 28 during right ventricular pacing, 196 +/- 31 during left ventricular pacing, 122 +/- 23 during biventricular pacing "early" and 120 +/- 18 during biventricular pacing "late." All the differences were statistically significant, but not between "early" and "late" biventricular pacing. Mean QRS axis ( degrees ) was -27 +/- 32 in sinus rhythm, -75 +/- 4 during right ventricular pacing, 112 +/- 41 during left ventricular pacing, -82 +/- 51 during biventricular pacing "early" and -80 +/- 42 during biventricular pacing "late." Only the difference between left ventricular pacing and all the other groups was statistically significant. QRS axis did not significantly differ according to left ventricular lead site during left and biventricular pacing. "Late" compared with "early" biventricular pacing axis showed variation >30 degrees in 35% of patients, in spite of no significant changes in QRS duration and x-ray positioning. CONCLUSION: Biventricular pacing significantly reduced QRS width, which persisted long-term. Left and biventricular pacing axis was poorly related to left ventricular lead positioning. Biventricular pacing axis variability over time may suggest a role of electrical remodeling.

Aged↗
PubMed2002

Diagnostic performance of a dual-chamber cardioverter defibrillator programmed with nominal settings: a European prospective study.

INTRODUCTION: Despite technologic developments, accurate discrimination of ventricular tachyarrhythmia from rapid rhythms of nonventricular origin remains a challenge. We sought to examine the sensitivity and specificity of a dual-chamber arrhythmia detection algorithm, the PARAD algorithm, incorporated in a dual-chamber implantable cardioverter defibrillator, the Defender (ELA Medical). METHODS AND RESULTS: All detailed tachycardia episodes (i.e., with stored atrial and ventricular channel markers and electrograms) retrieved from the Holter memory of the device were analyzed from 95 patients (86 men and 9 women; age 62 +/- 12 years) implanted with the Defender with the algorithm programmed at nominal settings. Over a follow-up of 15 +/- 8 months, 559 detailed sustained tachycardia episodes detected in the tachycardia zone were gathered in 62 patients. Of the 300 ventricular tachycardia (VT) episodes, 298 were appropriately classified as VT by the algorithm. Of the 259 supraventricular tachycardia (SVT) episodes, 231 were appropriately classified as SVT. In 8 patients, 28 episodes of SVT were misclassified as VT: 25 atrial fibrillation episodes (6 patients), 2 sinus tachycardia (1 patient), and 1 atrial tachycardia. Calculated sensitivity and specificity were 99.3% and 89.2% on a per episode basis and 99.8% (95% confidence interval: 97.8 to 100) and 91.6% (95% confidence interval: 86.0 to 97.3) on a per patient basis, respectively. CONCLUSION: In this selected population of patients, the PARAD algorithm was safe and reliable for detection of a wide spectrum of tachyarrhythmias. Its specificity was high, particularly with respect to sinus tachycardia detection, but it must be improved with respect to detection of atrial fibrillation.

Adult↗
PubMed2002

Atrioventricular nodal reentrant tachycardia with ventriculoatrial block and unsuccessful ablation of the slow pathway.

We report the case of failed slow pathway ablation in a woman with typical AV nodal reentrant tachycardia (AVNRT) and periods of Wenckebach-like second-degree VA block and 2:1 VA block. The occurrence of VA block during AVNRT suggests the upper turnaround point of the circuit is confined to the AV node. This supports the notion that, at least in some cases, the location of the reentrant circuit for AVNRT is completely in the compact AV node.

Catheter Ablation↗
PubMed2002

Intracardiac echocardiography: from electroanatomic correlation to clinical application in interventional electrophysiology.

Intracardiac echocardiography (ICE), using an ultrasound transducer at the tip of a percutaneously placed catheter, has recently been introduced for the visualization of the intracardiac anatomy and in order to reduce the fluoroscopy time. This review focuses predominantly on the current use of ICE in interventional electrophysiology. ICE has been shown to facilitate the targeting of specific anatomic landmarks, such as the crista terminalis, the Eustachian ridge, the tricuspid annulus, the coronary sinus ostium, and the pulmonary veins that cannot be adequately visualized at fluoroscopy. Direct imaging of these sites can be advantageous in that it facilitates the accurate guidance of the ablative procedure and shortens the fluoroscopy time. ICE has been demonstrated to be useful in the positioning and stabilization of the imaging ablation catheter, the evaluation of the lesion size and continuity and in the immediate identification of complications. Furthermore, in the last few years there has been a revival in the use of transseptal catheterization due to a larger development of radiofrequency catheter ablation in the left atrium. ICE, providing excellent views of the fossa ovalis and of the transseptal apparatus, can be safely used to prevent life-threatening complications following inadvertent puncture of anatomic structures such as the lateral wall of the left atrium or the aortic root. Moreover, ICE appears to be very useful in combining true anatomical features with electrical activation in an attempt to construct realistic electrical-anatomical maps. Finally, the three-dimensional tomographic reconstruction of intracardiac images and the phased array ICE catheter with Doppler capabilities seem to be promising tools both for the guidance of ablation procedures as well as in leading experimental studies.

Arrhythmias, Cardiac↗
PubMed2002

Hybrid therapy of atrial fibrillation.

Antiarrhythmic drugs have shown a poor long-term efficacy in the management of atrial fibrillation. It has been suggested that the association of antiarrhythmic drugs and non-pharmacological treatments may be superior to the prescription of a single treatment only. Electrical cardioversion of atrial fibrillation can be ineffective in several cases (long-lasting atrial fibrillation, large atria, advanced age, underlying diseases, high transthoracic impedance): the prescription of antiarrhythmic drugs prior to electrical shock has been demonstrated to be able to increase the success rate and to reduce the energy requirement. Ibutilide, amiodarone and sotalol are the most effective, while the efficacy of class IC drugs is controversial. The use of conventional atrial stimulation in case of the brady-tachy syndrome is related to the need of sustaining the atrial rhythm during bradycardia which can be exacerbated by the use of antiarrhythmic drugs. New overdrive algorithms, such as consistent atrial pacing and atrial rate stabilization, can increase the efficacy of physiological pacing. Painless electrical therapies, such as ramp and burst, have been implemented in specific devices, in order to combine the prevention and treatment of atrial arrhythmias. Multisite atrial stimulation has been introduced to improve the activation sequence and to reduce atrial asynchrony in case of slow conduction in the right atrium and of retrograde activation of the left atrium. Two methods are available for multisite atrial pacing: 1) simultaneous biatrial stimulation with the leads placed in the right appendage and in the left atrium through the coronary sinus; 2) dual site right atrial pacing with the leads positioned in the roof of the right atrium and proximal to the ostium of the coronary sinus. Single site non-conventional atrial pacing with the lead placed at the level of the interatrial septum, in the triangle of Koch, has been proposed in order to modulate the anisotropic conduction of this zone, responsible for the onset of atrial fibrillation. Non-conventional stimulation in association with drug therapy has been demonstrated to be more effective than conventional pacing in reducing the incidence of paroxysmal atrial fibrillation. The use of a dual-chamber defibrillator equipped with painless antitachy pacing therapies and atrial cardioversion can be considered the next step in the evolution of implantable devices. Atrioventricular nodal ablation and pacemaker implantation (ablate and pace) has been the first radiofrequency ablation procedure used to control the atrial fibrillation rate. Recently, it has been demonstrated that the survival rate in these patients was similar to that observed in subjects who received antiarrhythmic therapy. In patients in whom the administration of antiarrhythmic drugs (mainly class IC or amiodarone) modified atrial fibrillation in atrial flutter, linear lesions on the isthmus have been demonstrated to be effective in inhibiting the recurrence of arrhythmia. The first approach attempted in order to directly treat atrial fibrillation was the creation of linear lesions in the right atrium by means of radiofrequency current in patients refractory to drug therapy. This procedure was found to be feasible and safe, while lesions on the left atrium were associated with a high rate of side effects. The aim of the lesions was to create block lines in intra-atrial conduction, in order to electrically compartmentalize the atria and to avoid the propagation of reentry waves. More recently the ablation of the automatic activity originating from the posterior wall of the left atrium or within the pulmonary veins, which can trigger the onset of atrial fibrillation, has been performed.

Amiodarone↗
PubMed2002

[Psychological stress and sudden death].

Recent studies provide relevant evidence that psychological stress significantly influences the pathogenesis of sudden cardiac death. Psychological stress expresses a situation of imbalance, derived from a real or perceived disparity between environmental demands and the individual's ability to cope with these demands. A situation of psychological stress may include different components: personality factors and character traits, anxiety and depression, social isolation and acute or chronic adverse life events. In particular, it has been documented that a sudden extremely hard event, such as an earthquake or a war strike, can significantly increase the incidence of sudden death. Nevertheless, each one of these factors, if not present, can balance a partially unfavorable situation; this overview suggests a multifactorial situation where almost all elements are present and in which the relative influence of each one varies according to the individual examined. Sudden death occurs when a transient disruption (such as acute myocardial ischemia, platelet activation or neuroendocrine variations), occurring in a patient with a diseased myocardium (such as one with a post-necrotic scar or hypertrophy), triggers a malignant arrhythmia. Psychological stress acts at both levels: by means of a "chronic" action it contributes to create the myocardial background, while by means of an acute action it can create the transient trigger precipitating sudden death. In the chronic action two possible mechanisms can be detected: the first is a direct interaction, which contributes to cause a hypertension status or to exacerbate coronary atherosclerosis consequent to endothelial dysfunction; the second one acts through adverse health behaviors, such as a poor diet, alcohol consumption or smoking. In case of acute psychological stress, the mechanisms involved are mainly the ability to trigger myocardial ischemia, to promote arrhythmogenesis, to stimulate platelet function, and to increase blood viscosity. Finally, some individuals have a sympathetic nervous system hyper-responsitivity, manifesting as exaggerated heart rate and blood pressure responses which result in accelerated atherosclerosis.

Arrhythmias, Cardiac↗
PubMed2002

Ginkgo biloba-induced frequent ventricular arrhythmia.

The use of herbal medications is becoming ever more widespread, but data for them are not yet as robust as for conventional drugs. The available safety information indicates that potential side effects of such use can be due to allergic reactions and bleeding. In this report, a case of frequent ventricular arrhythmias probably due to Ginkgo biloba is presented. The patient complained of palpitations twice in a month and on both occasions symptoms and electrocardiographic evidence of ventricular arrhythmias resolved with discontinuation of Ginkgo biloba. This case underlines that continuing research is needed to elucidate the pharmacological activities of the many herbal remedies now being used.

Cognition Disorders↗