RESUMEN

This report describes the late potentials obtained by signal averaged electrocardiography (ECG) in 19 patients (13 male, 6 female, mean age 31 +/- 17 years) with acute myocarditis and their evolution. Five patients (26%) had positive signal averaged ECG in time domain analysis and two had technically inadequate signal averaged ECG. All five patients with positive signal averaged ECG, and 6 of the 12 patients with negative, developed heart failure (100%). One patient died. Signal averaged ECG was repeated at 3 months in all 18 surviving patients. Two patients had a good clinical evolution, normalized left ventricular function, and changed from positive to negative signal averaged ECG. All patients with heart failure on admission with negative signal averaged ECG had clinical improvement. Late potentials in patients with acute myocarditis are associated with a worse prognosis and greater extent of myocardial damage.

Asunto(s)

RESUMEN

Sinus tachycardia has been reported after radiofrequency catheter ablation of supraventricular tachycardia. Frequently, these patients require beta-blocking agents for symptomatic control. The purpose of this study was to evaluate prospectively the incidence of inappropriate sinus tachycardia and heart rate variability after ablation of atrioventricular nodal reentrant tachycardia and accessory pathways. Patients undergoing ablation had 24-h ambulatory monitoring ECG (Holter) performed before the procedure, on the day of the ablation, and 3 months afterwards. There were 170 patients, mean age 48 +/- 23 years; 93 were female. A complete study of the 24-h Holter with analysis of heart rate variability: SD, rMSSD, pNN50, high and low frequency was obtained. There was a low prevalence of inappropriate sinus tachycardia after the ablation procedure (10 of 170 patients: five with four atrioventricular nodal reentry, with posteroseptal accessory pathways and one of the latter following ablation of the left accessory pathway). There was no modification of time and frequency domain parameters of heart rate variability in the remaining patients who underwent radiofrequency ablation. Holter monitoring 3 months after ablation showed that parameters of heart rate and heart rate variability had normalized in patients who had developed inappropriate sinus tachycardia. Inappropriate sinus tachycardia may be initiated by both radiofrequency ablation of atrioventricular nodal reentrant tachycardia and radiofrequency ablation of posteroseptal accessory pathways. Specific damage to the posteroseptal region is responsible for these changes, which usually recover spontaneously after 3 months.

Asunto(s)

RESUMEN

We have performed 2 implantations of transvenous automatic cardioverter defibrillator in a cardiac laboratory devoted to electrophysiology and pacemaker implantation. This is a preliminary experience with a novel implant strategy. Cardiologists were the primary operators. The automatic cardioverter defibrillator were placed in a subcutaneous pectoral region, with a non-thoracotomy lead system. The automatic cardioverter defibrillator were two Medtronic 7219D PCD Jewel, with a Transvene system. There were no perioperative complications. Acceptable defibrillation threshold were obtained in both patients, 12 and 20 J, respectively. Leads were inserted percutaneously through the left subclavian vein. After 8 months of follow-up the patients continue to tolerate the device satisfactorily. Implantation of automatic cardioverter defibrillator systems by trained cardiologists in an electrophysiology laboratory is safe and feasible. Moreover, its cost-effectiveness is superior, the saving includes the surgeons, and the reduction of stay in unit of intensive care and hospitalization.

Asunto(s)

RESUMEN

UNLABELLED: INTRODUCTION AND PURPOSES: Autonomic nervous system plays an important role in the pathogenesis of vasovagal/vasodepressor syncope and may also be assessed by the RR variability analysis. Head up tilt test (HUT) is a currently established tool to evaluate patients with neuromediated syncope. However, the relationship between heart rate variability and tilt induced syncope is not established. The purpose of this study was to assess the differences in heart rate variability among patients with syncope and negative or positive tilt test. METHODS: Fifty patients (mean age 33 +/- 17 years, 24 female, 26 male) with syncope underwent tilt test (20 min, 80 degrees tilt and 20 min more under isoproterenol infusion). Twenty-three patients have a negative tilt, the rest had a positive test. There were not significant differences in age or sex. Immediately after the HUT a 24-hour ambulatory electrocardiogram was performed (Marquette system 8000, 002A program). The parameters measured during Holter monitoring were: SDANN, SD, rMSSD, pNN50 and frequency analysis of heart rate spectrum (low frequency 0.04-0.15 Hz, high frequency 0.15-0.4 Hz and the relation low/high). No significant differences were detected in age and sex in patients with and without positive HUT. RESULTS: pNN50 and rMSSD were the best predictors of the results of tilt (p = 0.006). SDANN and SDNN were not useful parameter. The finding of a value of pNN50 > 25% (value significantly different between patients with HUT--and +) have a specificity for predicting a positive HUT of 82.6%, with a sensibility of 51.8%. Positive predictive value was 77%. As can be easily understood, if the cut value of pNN50 is lowered, its sensibility increased and the specificity. decreased. In the frequency analysis only the relation low/high (L/H) was significantly different between both populations. CONCLUSIONS: Heart rate variability is a useful tool in the evaluation of patients with vasovagal syncope, that may identify patients with chronically elevated vagal tone and thus may predict tilt test results.

Asunto(s)

Asunto(s)

RESUMEN

UNLABELLED: INTRODUCTION AND PURPOSES: Propafenone is an antiarrhythmic drug with well known electrophysiological effects. We performed this prospective non comparative study, in order to evaluate its efficacy and safety to terminate spontaneous episodes of monomorphic sustained ventricular tachycardia. METHODS: Thirty-two episodes of sustained monomorphic ventricular tachycardia in 32 consecutive patients were treated with intravenous propafenone. Twenty-five were male and 7 female, mean age of 62 +/- 12 years; 23 suffered chronic ischemic heart disease, 2 dilated cardiomyopathy, 1 arrhythmogenic dysplasia of the right ventricle and 6 no organic heart disease. Patients with overt heart failure, acute myocardial infarction or a systolic blood pressure less than 90 mmHg were excluded. The ventricular origin of the tachycardia was assessed by clinical and electrocardiographic criteria and by the presence of AV dissociation in intraesophageal recording. The dose of propafenone was 0.2 mg/kg/min until interruption of ventricular tachycardia, or maximal dose of 2.5 mg/kg in 10 min. RESULTS: In 23 episodes (72%) sinus rhythm was restored in less than 10 minutes (mean time and dose, 398 +/- 97 s and 95 +/- 42 mg, respectively). Two patients developed proarrhythmia with acceleration of the ventricular tachycardia. A significant decrease in blood pressure was noted in 6 patients. Presence of organic heart disease, advanced age and poor functional class were the best predictors of inefficacy to convert to sinus rhythm and of the presence of acute adverse effects (p < 0.05). CONCLUSIONS: Propafenone is an effective drug for the acute conversion of spontaneous monomorphic sustained ventricular tachycardia, especially in patients without organic heart disease. Age, functional class and presence of organic heart disease could predict the response to propafenone and the incidence of complications.

Asunto(s)

RESUMEN

PURPOSE: To assess the relationship between late potentials and spontaneous ventricular arrhythmias, organic heart disease, inducibility of arrhythmias at electrophysiological study and ejection fraction. METHODS: The population is comprised by 52 patients (41 men, 11 women with mean age 50 +/- 16 years) with spontaneous clinically documented ventricular tachycardia or ventricular fibrillation. An electrophysiological study was performed with conventional programmed stimulation. Within a week of the test a study of late potentials was also performed. RESULTS: Late potentials were documented in 73% of the patients with ventricular tachycardia and only in 17% of the patients with ventricular fibrillation. Sixty-eight percent of the patients with ischemic cardiopathy presented late potentials and in these, ventricular tachycardia was inducible in 93%. Only one from a group of 7 patients with ventricular arrhythmias and no organic heart disease, presented late potentials. In patients with late potentials, 84% have inducible ventricular tachycardia, but only 26% of patients without late potentials have inducible ventricular tachycardia. The incidence of late potentials was inversely correlated with left ventricular ejection fraction. CONCLUSION: The presence of late potentials was more frequent in patients with ventricular tachycardia than in patients with ventricular fibrillation. The presence of late potentials has a sensibility of 81.5% and a specificity of 78% to detect patients with inducible ventricular tachycardia.

Asunto(s)

RESUMEN

In this prospective, controlled and randomized cross-over study we tried to establish the efficiency and safety of flecainide vs procainamide for the treatment of acute atrial fibrillation. Eighty patients (30 females, 50 males, mean age: 55 +/- 14 years) were included. Patients entered into the study if they had atrial fibrillation of recent onset (< 24 h) with a ventricular rate > 100 beats.min-1 at rest and were < 75 years of age. Exclusion criteria were any sign of heart failure, conduction disturbances, sick sinus syndrome or acute ischaemic events. Randomly 40 patients received flecainide and 40 procainamide as the first treatment. There were no significant clinical difference between the two groups. Procainamide ws given at a dose of 1 g infused over 30 min, and followed by an infusion of 2 mg.min-1 over 1 h. Flecainide was given at a dose of 1.5 mg.kg-1 over 15 min followed by an infusion of 1.5 mg.kg-1 over 1 h. Drug infusion was continued until maximal dose, intolerance or reversion to sinus rhythm. After 1 h of wash out, patients remaining in atrial fibrillation were started on the second drug. Left atrial size was measured by echo. Serum levels of drug and atrial size did not differ between patients who returned to sinus rhythm and those who remained in atrial fibrillation. Conversion to sinus rhythm was achieved in 37 (92%) of the 40 patients treated with flecainide and 25 (65%) of those treated with procainamide (P < 0.001). The time required for reversion to sinus rhythm was similar between the two groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Asunto(s)

RESUMEN

We comment the results with non pharmacological treatment in 23 patients (mean age 11 +/- 4 years) with multiple episodes of palpitations, most of them required intravenous drugs for interrupting it. Twenty-eight procedures were performed, 17 catheter ablation and 11 surgical interventions. The energy source employed for fulguration until 1990 was DC and since 1991 radiofrequency. The best results with catheter ablation were obtained with accessory pathways. Interruption was achieved in all patients after a mean of 1.2 sessions per patient, but it was definitive in only 72%. Most of the patients (81%) remained asymptomatic without antiarrhythmic drugs. Nine patients with accessory pathways underwent surgery interruption, it was achieved in all; only one patient had arrhythmia recurrence, due to a second pathway in a different localization. We could not ablate a ectopic atrial tachycardia, that underwent surgery. There was only one indication for surgery in a patient with ventricular tachycardia. Catheter ablation does not present technical problem in children and teenagers, different from adults. The presented results lead us to suppose that the indications for non pharmacological treatment in the young will become more common.

Asunto(s)

RESUMEN

Sotalol has Class II and III antiarrhythmic effects. Its efficacy and safety as a treatment of atrial fibrillation in patients with the Wolff-Parkinson-White (WPW) syndrome is controversial. We evaluated the effects of isoproterenol and IV sotalol (1.5 mg/kg in 10 minutes) given together versus isoproterenol alone on anterograde conduction through the AV node and accessory pathway. Atrial fibrillation was induced in 22 patients with WPW (13 men, 9 women, 36 +/- 16 years old). AV node and accessory pathway conduction were both enhanced by isoproterenol, although the effect was greater on the AV node. The minimum interval between preexcited QRS complexes shortened in all patients. Conversely, sotalol caused a significant prolongation of the shortest preexcited QRS interval as well as of the shortest interval between narrow QRS complexes. In addition, sotalol reversed all the effects of isoproterenol during atrial fibrillation. The percent of preexcited QRS complexes was not significantly modified because variations in ventricular preexcitation results from a balance between the relative effects on refractoriness of the accessory pathway versus of the AV node and in the amount of respective anterograde and retrograde concealed conduction. There were no serious adverse effects. Reversion to sinus rhythm was documented in 12 patients (60%). These short-term observations suggest that sotalol may be safe and effective in the treatment of patients with WPW and atrial fibrillation.

Asunto(s)

Asunto(s)