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Biomedical subjects

M Santini

Publications and source records attributed to M Santini.

At least 19 recordsLinked to original sources
PubMed2000

Heart rate variability patterns before ventricular tachycardia onset in patients with an implantable cardioverter defibrillator. Participating Investigators of ICD-HRV Italian Study Group.

Time- and frequency-domain analysis of heart rate variability (HRV) has been proven effective in describing alteration of autonomic control mechanisms and in identifying patients with increased cardiac and arrhythmic mortality. Patients with implantable cardioverter defibrillators offer the opportunity to evaluate HRV patterns before ventricular tachycardia (VT) and under control conditions. We therefore analyzed time- and frequency-domain parameters of short-term HRV and power-law behavior of RR interval time series at rest, at 15 to 30 minutes, and immediately before VT. In comparison to control conditions, lower values of mean cycle length duration and total power were observed before VT. Spectral analysis indicated that the low- to high-frequency ratio was significantly higher (5.5 +/- 0.6 vs 2.8 +/- 0.3) immediately before VT than during rest. Both findings were consistent with the shift of sympathovagal balance toward sympathetic predominance and reduced vagal tone. Before VT, a more negative value of the scaling exponent beta of the power-frequency relation (-1.57 +/- 0.04 vs -1.33 +/- 0.04) also confirmed the presence of an altered HRV pattern in comparison to controls. Thus, both abnormal autonomic modulation and dynamic patterns of HRV seem to characterize the minutes before arrhythmia onset in these patients.

Aged↗
PubMed2000

Combining antiarrhythmic drugs and implantable devices therapy: benefits and outcome.

At least 50% of patients who received an ICD have been treated with antiarrhythmic drugs (AAD). The potential indications for combining antiarrhythmic drugs and ICD are generally the following: reduction of the number of episodes of ventricular tachycardia or ventricular fibrillation and therefore of the number of shocks, improving patient's quality of life and extending the battery life of the ICD, prevention of supraventricular arrhythmias and/or control of their rate, lengthening of the tachycardia cycle length to allow ventricular tachycardia conversion by antitachycardia pacing and reduction of the number of episodes of syncope. Although previous papers reported conflicting results about pharmacologic therapy in reducing the frequency of iCD shocks, some recent randomized prospective studies showed the efficacy of pharmacologic therapy in reducing the frequency of ICD shocks. The use of antiarrhythmic drugs can have also adverse effect: an increase in the defibrillation threshold, an increase in the pacing threshold and an increase in the VT cycle length leading to detection failure. We have also to consider that some advantages derived from antiarrhythmic drugs can be reached by the new devices with atrial sensing and pacing and/or the possibility of atrial defibrillation or by using catheter ablation as adjunctive therapy to ICD. For these reasons, the concomitant use of antiarrhythmic drugs and ICD should be evaluated in each patient in relation to specific clinical and electrophysiologic features including: the frequency, the rate and the clinical presentation of the ventricular arrhythmia, the effect of the selected drug on the defibrillation threshold, the defibrillation threshold at the implant, the effect of the selected drug on the ventricular function and the likelihood of proarrhythmic events.

Anti-Arrhythmia Agents↗
PubMed2000

Prevalence, awareness, treatment and control of hypertension in the elderly: results from a population survey.

Prevalence, awareness, treatment and control of hypertension were assessed in 1032 (90%) of 1147 elderly (> or = 65 years) inhabitants of three Italian villages. Blood pressure (BP) was measured at home on two separate occasions following a standardised protocol. Persons taking antihypertensive drugs or with BP values > or = 140/90 mm Hg were considered as affected by hypertension. Prevalence of hypertension was 64.8%, with higher rates in women than men, and in those aged 75-84 than in those aged 65-74. Diabetes, strokes and hypercholesterolaemia were more frequent in hypertensive than normotensive people, whereas cardiac diseases, overweight and smoking did not differ significantly between hypertensive and normotensive people. Of the 669 hypertensive patients, 439 (65.6%) were aware of their hypertension, 398 (59.5%) were being treated, and 70 (10.5%) had their hypertension controlled. Of the 230 unaware patients, 201 (87.4%) had had their BP measured in the previous year. Of these, 174 (86.6%) had stage 1 hypertension, while 27 had stage 2 hypertension with SBP values <170 mm Hg. Overall, the patients with stage 1 hypertension accounted for 68.3% of the untreated and 50.5% of the treated patients. The use of a single drug was more frequent in patients with controlled (97.1%) or stage 1 (97.0%) than with stages 2-3 (18.9%) hypertension. The drugs prescribed most were angiotensin-converting enzyme (ACE) inhibitors (45%), followed by diuretics (43%). As our findings suggest that BP values can be effectively reduced by treating or increasing drug treatment in stage 1 hypertensive patients, data on safety and effectiveness of this policy are urgently needed. Journal of Human Hypertension (2000) 14, 825-830

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PubMed2000

Transoesophageal low-energy cardioversion of atrial fibrillation. Results with the oesophageal-right atrial lead configuration.

BACKGROUND: Low energy internal cardioversion is a safe and effective procedure to restore sinus rhythm in patients with atrial fibrillation refractory to external cardioversion. However the procedure is invasive and fluoroscopy is mandatory. Aim of the study To assess the efficacy, safety and tolerability of a new simplified procedure of low energy internal cardioversion. METHODS: Twenty-five consecutive patients (19 males and 6 females) with persistent atrial fibrillation were submitted to low energy internal cardioversion using a step-up protocol (in steps of 50 V, starting from 300 V). A large surface area lead (cathode) was positioned in the oesophagus, 45 cm from the nasal orifice. A second large surface area lead (anode) was positioned in the right atrium. A quadripolar lead was positioned at the right ventricular apex to achieve ventricular synchronization and back-up pacing. Oesophageal endoscopy was performed within 24 h of the end of the procedure and repeated after 48 h, if injury to the oesophageal mucosa had occurred. RESULTS: Sinus rhythm was restored in 23 patients (92%) with a mean delivered energy of 15.74 J (range 5-27) and a mean impedance of 48 Omega. In two patients, endoscopy revealed that small burns had occurred in the oesophageal mucosa. Such lesions spontaneously healed after 48 h. CONCLUSIONS: This new technique of performing low energy internal cardioversion is effective and safe and avoids the positioning of a lead in the coronary sinus or in the left pulmonary artery, thereby simplifying the procedure.

Aged↗
PubMed2000

Diagnosing syncope in clinical practice. Implementation of a simplified diagnostic algorithm in a multicentre prospective trial - the OESIL 2 study (Osservatorio Epidemiologico della Sincope nel Lazio)

BACKGROUND: In some patients with syncope health care is inappropriate and ineffective. In a recent observational investigation in community hospitals of the Lazio region of Italy (the OESIL study) 54.4% of patients admitted with syncope from the emergency room were discharged without a conclusive diagnosis. AIM OF THE STUDY: A simplified two-step diagnostic algorithm was developed and prospectively implemented in nine community hospitals of the Lazio region of Italy in order to improve the diagnostic performance of clinicians, thereby reducing the number of undiagnosed patients. STUDY POPULATION: The study population included 195 consecutive patients (85 males and 110 females, mean age 62.5 years, range 13-95 years) presenting with a syncopal spell at the emergency room of one of the nine participating hospitals in a 2-month period. RESULTS: The systematic implementation of the proposed diagnostic algorithm resulted in a striking reduction of undiagnosed cases. The percentage of patients discharged without a conclusive diagnosis decreased from 54.4% to 17.5%. Neurally mediated syncope was diagnosed in 35.2% of cases, cardiac syncope in 20.9% and neurological syncope in 13.8%. CONCLUSIONS: The use of specific, simplified diagnostic guidelines and algorithms results in an improvement of overall clinical performance. However, the development of such decision-making aids should carefully consider the local circumstances of daily clinical practice.

Adolescent↗
PubMed2000

Comparison of intravenously administered dofetilide versus amiodarone in the acute termination of atrial fibrillation and flutter. A multicentre, randomized, double-blind, placebo-controlled study.

AIMS: This study compared the efficacy and safety of intravenous dofetilide with amiodarone and placebo in converting atrial fibrillation or flutter to sinus rhythm. METHODS AND RESULTS: One hundred and fifty patients with atrial fibrillation or flutter (duration range 2 h-6 months) were given 15-min intravenous infusions of 8 microg. kg(-1)of dofetilide (n=48), 5 mg. kg(-1)of amiodarone (n=50), or placebo (n=52) and monitored continuously for 3 h. Sinus rhythm was restored in 35%, 4%, and 4% of patients, respectively (P<0.001, dofetilide vs placebo;P=ns, amiodarone versus placebo). Dofetilide was more effective in atrial flutter than in atrial fibrillation (cardioversion rates 75% and 22%, respectively;P=0.004). The mean time to conversion with dofetilide was 55+/-15 min. Dofetilide prolonged the QTc interval (+16% at 20 min). Amiodarone substantially decreased the ventricular rate in non-converters (-18 beats. min(-1)at 30 min). Two patients given dofetilide (4%) had non-sustained ventricular tachycardias, and four (8%) had torsade de pointes, in one case requiring electrical cardioversion. CONCLUSION: Intravenous dofetilide is significantly more effective than amiodarone or placebo in restoring sinus rhythm in patients with atrial fibrillation or flutter. However, when infused intravenously at this dose and rate, dofetilide causes a significant incidence of torsade de pointes.

Acute Disease↗
PubMed2000

[Epidural spinal stimulation in the treatment of refractory angina pectoris. Its clinical efficacy, complications and long-term mortality. An Italian multicenter retrospective study].

BACKGROUND: Spinal cord stimulation has been used for many years in the treatment of refractory angina pectoris. Its anti-anginal and anti-ischemic effect has been well documented in several studies, but the long-term efficacy, safety and survival rate are not well known. The aim of this study was to carry out a retrospective analysis of a series of patients from the Italian Multicenter Registry, the data of which were collected in five centers, by means of a questionnaire. METHODS: One hundred and thirty patients (83 males, 47 females, mean age 74.8 +/- 9.8 years) were submitted to spinal cord stimulator implantation for refractory angina pectoris in the period 1988-1995 and controlled during a mean follow-up of 31.4 +/- 25.9 months. A previous myocardial infarction had already occurred in 69.3% of patients, whereas in 67.6% multivessel coronary artery disease was documented. A left ventricular dysfunction (ejection fraction < 0.40) was present in 34% of patients; bypass surgery and coronary angioplasty were performed in 49.6% and in 27% of patients respectively. In 96.3% of cases revascularization procedures were not advisable. RESULTS: A complete follow-up of 116 patients (89.2%) was available. The spinal cord stimulator induced a significant reduction in NYHA functional class from 2.5 +/- 1.2 to 1.5 +/- 0.9 (p < 0.01). During the follow-up 41 patients (35.3%) died, and in 14.2% a new acute myocardial infarction developed. The total percentage of minor spinal cord stimulation-related complications was 6.8%. No major complications occurred. The annual total mortality rate was 6.5%, whereas the cardiac mortality rate was 5%. Compared to the survivors, patients who died showed a higher incidence of left ventricular dysfunction, previous myocardial infarction and bypass surgery at implantation. CONCLUSIONS: In our experience, spinal cord stimulation is an effective therapy in patients affected by refractory angina pectoris and who cannot undergo revascularization procedure. The complication rate is low, with the total and cardiac mortality showing a trend as that reported for patients with similar coronary disease.

Aged↗
PubMed2000

Electrophysiology of atrial fibrillation: evolving insights.

In the last few years many studies have been performed to better understand the pathophysiological nature of atrial fibrillation (AF). These recent observations provide new insights into the initiation and perpetuation of AF, underlying the importance of the pulmonary veins as major sources of atrial triggers and introducing new concepts such as atrial electrical remodeling and spatial heterogeneity of the electrophysiologic characteristics of this arrhythmia. The purpose of this review was to provide current knowledge about AF electrophysiology in an effort to unite old models and new concepts.

Animals↗
PubMed1999

Single shock endocavitary low energy intracardiac cardioversion of chronic atrial fibrillation.

BACKGROUND: Discomfort related to low-energy internal cardioversion (LEIC) represents a real problem in patients (pts) with atrial fibrillation (AF). The aim of our study was to verify if a single shock could restore sinus rhythm (SR) with a lower discomfort for the pt. METHODS: Thirty pts with chronic AF were randomized to receive a single 350 V shock (15 pts) or multiple shocks of increasing energy (15 pts). Three leads were positioned, respectively, in the coronary sinus and in the lateral right wall for shock delivery, and in the right ventricular apex for R wave synchronization. Truncated, biphasic shocks were used. In the first group a single 350 V shock was directly delivered and a second 400 V shock was given only if SR has not been restored. In the second group, beginning at 50 volts the voltage was increased in steps of 50 volts until SR restoration. No patient was sedated. After each shock the pts were asked to rate their discomfort on a scale of 1 to 5 (1 = not perceived, 5 = severe discomfort). RESULTS: SR was restored in all the subjects. In group 1 SR was obtained in 12/15 (80%) pts with the first 350 V (8.1 +/- 0.8 joules) shock, while the remaining 3 patients required the second 400 V (10.2 +/- 0.3 joules) shock. In group 2 the mean atrial defibrillation threshold was 346.7 +/- 1029.7 volts (8.0 +/- 101.5 joules). Then discomfort score was 2.5 +/- 0.6 in group 1 and 3.3 +/- 10.6 in group 2 (p < 0.01). CONCLUSIONS: A single shock of 350 V restores SR in the majority of pts with chronic AF; by use this new approach, LEIC is tolerated better than the multiple shocks step-up protocol.

Aged↗
PubMed1999

Botulism: a case associated with pyramidal signs.

Botulism is a widespread neuroparalytic disease that may be confused with other neurological disorders. As it is potentially lethal, clinicians are required to be aware of its diagnosis and management. We report a case of botulism complicated by pyramidal signs in a 35-year-old woman. Clinical aspects, differential diagnoses and therapeutic problems are discussed.

Adult↗
PubMed1999

The effect of atropine in vasovagal syncope induced by head-up tilt testing.

AIMS: This single-blinded, randomized, placebo-controlled study was designed and undertaken to assess the efficacy of intravenous atropine administration on haemodynamic impairment induced by head-up tilt testing in patients with vasovagal syncope. METHODS AND RESULTS: One hundred and thirteen consecutive patients (62 male and 51 female, mean age 46.3 years) with recurrent syncope, no evidence of cardiac, neurological or metabolic disease and a positive head-up tilt test were included in the study. Within 2 weeks of the first head-up tilt test all patients underwent a second tilt test. During this second test, all patients were randomized to receive a bolus of either atropine (0.02 mg. kg(-1)) or placebo (isotonic saline solution). The administration of atropine or placebo was performed at the onset of the haemodynamic modifications (heart rate and/or blood pressure fall) in conjunction with typical vasovagal prodromal symptoms. Treatment was taken as effective when symptoms aborted and the test was completed. In 29 of 113 patients the second tilt test was negative and these patients were excluded from final data analysis. Forty-one patients received placebo, which was effective in nine cases (21.9%). Atropine was administered to 43 patients and was effective in 30 cases (69.7%, P<0.01 vs placebo). The effects of treatment were analysed further to consider the haemodynamic patterns of tilt-induced vasovagal reflex. In the cardio-inhibitory form, placebo was never effective (15 cases), while atropine was effective in 15 of 18 cases (83.3%, P<0.001 vs placebo). In the vasodepressor form, placebo was effective in nine of 26 patients (34.6%), while atropine was effective in 15 of 25 cases (60.0%, no significant difference vs placebo). CONCLUSIONS: Atropine is fully effective in the cardio-inhibitory form of tilt-induced vasovagal reflex, but is limited in the vasodepressor form.

Atropine↗
PubMed1999

Lack of correlation between ventricular late potentials and left ventricular mass in top-level male athletes.

PURPOSE: The aim of this study was to establish: 1) the prevalence of abnormal signal-averaged electrocardiogram (SAECG) in a large population of top-level athletes and 2) the relationship between SAECG parameters and left ventricular mass. One-hundred and fifty-three elite male athletes without apparent heart disease, symptoms, or arrhythmias were studied. METHODS: Fifty-six athletes (37%) had increased left ventricular mass (> 134 g.m(-2)). All athletes underwent time-domain SAECG on 300-400 heart beats recorded at rest from three bipolar orthogonal tests with a filter setting of 40-250 Hz. Criteria for abnormality were 1) filtered QRS duration > 114 ms, 2) duration of low-amplitude signals > 38 ms, or 3) root mean square voltage of the last 40 ms of the filtered QRS < 20 microV. RESULTS: The prevalence of abnormal SAECG was 7.2% (abnormality of one parameter), 6.5% (abnormality of two parameters), and 5.8%(abnormality of three parameters). The prevalence of abnormal SAECG was similar in athletes with or without increased left ventricular mass. CONCLUSIONS: In conclusion, this study showed: 1) the low rate of positive results of SAECG parameters in top-level male athletes, similar to that found in healthy sedentary subjects; and 2) the lack of correlation between left ventricular mass and overall SAECG parameters.

Action Potentials↗
PubMed1999

Spinal cord stimulation for the treatment of refractory angina pectoris: a two-year follow-up.

Twenty-three patients affected by severe, refractory angina were submitted to permanent spinal cord stimulation (SCS) and then followed in our outpatient clinic for 24 months. During the follow-up period, the number of weekly angina episodes drastically dropped from 9.2 (preimplant) to 1.8 in the 3rd, 2.5 in the 6th, 4.5 in the 12th, and 4.2 in the 24th month, with a statistically significant difference (P < 0.01) between the first and last values. A significant increase in the average exercise time from 320 +/- 120 seconds (in baseline condition) to 410 +/- 115 seconds (during SCS) was observed at the treadmill stress test (P < 0.01). SCS was well tolerated by all the patients. However, 7 patients died during follow-up (3 myocardial infarctions, 2 noncardiac deaths, and 2 sudden deaths). Three generators were replaced because of battery depletion after 15, 17, and 21 months. No serious complication was observed. In conclusion, in patients with otherwise intractable angina or already submitted to myocardial revascularization, SCS is very effective in reducing the number of angina episodes. The time of the work during exercise stress test is also significantly prolonged.

Adult↗
PubMed1999

Spatial extension of local pacing capture in the lateral free wall of the right atrium during clinical chronic atrial fibrillation.

OBJECTIVES: The aims of our study were to define the spatial extension of local atrial pacing capture (LAPC) in the right lateral atrial wall and to verify the effects of antiarrhythmic drugs on capture extension. BACKGROUND: Recently, LAPC during spontaneous chronic atrial fibrillation (AF) has been demonstrated directly in humans, but no systematic attempt has been made to evaluate its spatial extension. METHODS: The study was conducted in 14 consecutive patients with chronic AF, nine of whom were taking antiarrhythmic drugs. A Franz catheter for pacing and monophasic action potential recording was positioned in the lateral right atrial wall. An octopolar recording lead was positioned about 10 mm apart. The presence of atrial capture and its extension (number of captured bipolar pairs) were evaluated during decremental pacing. RESULTS: Forty-eight atrial capture attempts were made. LAPC was achieved in all the performed attempts. The AF types immediately before capture were type 1 in 35 (73%) and type 2 in 13 (27%) episodes. In 32 episodes, the capture was lost within 15 seconds and in the remaining 16 pacing was stopped after 15 seconds of stable capture. In 26 episodes, capture extended radially up to 4 cm from the pacing site, in 18 up to 3 cm, in 3 up 1 cm and in 1 up 1 cm. The mean extension in patients being treated with antiarrhythmic drugs was significantly greater than what was seen in untreated patients (3.8 +/- 0.4 vs 2.9 +/- 0.7 cm, p < 0.00001). Capture loss was less frequently observed when all four of the bipolar recording sites had been captured (13/25, 52% vs 19/23, 82%, respectively, p = 0.05). CONCLUSIONS: LAPC in the lateral right atrial wall extends over a radius of 30-40 mm in the majority of capture episodes and is greater in patients treated with antiarrhythmic drugs. Our results suggest that, at least theoretically, simultaneous multisite pacing could be used to terminate AF. Moreover, a reduction in the atrial defibrillation threshold could be expected performing low-energy internal cardioversion during LPC.

Aged↗