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Syncope is a syndrome caused by a reversible reduction of blood to the brain. Three hemodynamic abnormalities can cause syncope: an acute decrease in cardiac output, an acute increase in cerebrovascular resistance and a fall in systemic blood pressure due to ineffective control of peripheral vascular resistance. We made a retrospective study of 121 patients with syncope history, 67 males, and 57 females, with mean age 48 +/- 14 years, and at least six months of clinical follow-up. Twelve patients had valvular disease, two patients had hypertrophic cardiomyopathy, eight patients had dilated cardiomyopathy, 14 patients had ischemic disease, three patients had congenital disease; 82 patients did not have cardiac disease. Syncope etiology was arrhythmic in 69 patients: 47 patients had tachyarrhythmia (supraventricular--in 27 patients and ventricular in 20 patients) and 15 patients had bradyarrhythmia (seven patients had sinus node disease and eight patients had atrioventricular block). Non arrhythmic etiology of syncope was identified in 29 patients (neurologic disease--ten patients, metabolic disease--one patient and iatrogenic--two patients; vasodepressor syncope--14 patients, and hypertrophic cardiomyopathy--two patients). It was not possible to determine the syncope etiology in 30 patients. The assessment of patients who present syncope depends on establishing the basis for the symptoms. The initial step is differentiating patients with normal cardiovascular systems from those with heart disease. In the former, tilt-table testing proved to be the most productive from a diagnostic perspective; in the latter group, electrophysiologic evaluation was the most elucidative from a diagnostic perspective. The ultimate goal is to obtain a sufficiently strong correlation between syncopal symptoms and detected abnormalities to permit an accurate assessment of prognosis and to develop an effective treatment plan.It is very important to establish the etiology of syncope for optimal management of patients and it is therefore possible to control the symptoms in the majority of them. The patients who present syncope require a complete history and a physical examination for an appropriate workup to be initiated. Tilt-table testing was the most accurate for the diagnosis of vasodepressor syncope while electrophysiologic testing provides an accurate method for assessing the etiology of tachyarrhythmic syncope.

The aim of this study was to evaluate our results of radiofrequency catheter ablation (RFCA) of concealed accessory atrioventricular pathways (CP).We treated with RFCA 19 patients, with 21 CP, 10 men and 9 women, mean age 37 +/- 16 years, with supraventricular tachycardia (SVT) and absence of ventricular pre-excitation in the electrocardiogram (ECG). These patients comprised 50% of the patients who underwent RFCA for SVT and had no ventricular pre-excitation in the ECG. The diagnosis of CP was made by electrophysiologic study, based on the demonstration of a pathway capable of retrograde conduction only.The RFCA was performed without antiarrhythmic drugs in the same session of the electrophysiologic diagnosis. The location of the CP site was obtained by catheter mapping, looking for the earliest atrial retrograde activation during tachycardia or ventricular pacing.The CP had a right-sided location in only 2 patients who had an incessant form of SVT, the CP in these patients exhibit decremental conduction--permanent junctional reciprocating tachycardia. In the other patients the CP was left-sided, lateral in 11 patients, posterior in 3, postero-septal in 3 and medial septal in one patient. In 9 patients there was a simultaneous ventricular activation in the his bundle electrogram and in the electrogram of the ablation site, suggesting partial anterograde penetration of the stimuli on the accessory pathway. Success criteria were achieved in 18 patients (95%) corresponding to 20 CP.The prevalence of CP in the presence of SVT without ventricular pre-excitation is high, almost all left-sided. The CP displays eccentric atrial activation during SVT. It is possible that CP are capable of partial anterograde conduction as well. The success rate of RFCA is high.

First results of tachyarrhythmia's direct current (DC) and radiofrequency (RF) catheter ablation in Portugal (St. Cruz Hospital, Carnaxide).Retrospective analysis of the first 20 patients (P) submitted to catheter ablation in our Center: 11 males and 9 females, aging 36 years (SD 14), with drug-refractory symptomatic tachyarrhythmias. DC ablation was used in the first case and RF current in the nineteen subsequent P.Accessory pathway RF ablation: 92% successful rate (12/13 P); AV nodal modification: fast pathway--1 P (DC ablation), slow pathway--3 P (RF ablation) with one case of late clinical recurrence; two successful His bundle ablation (in paroxysmal atrial flutter/fibrillation) one standard right side and other from left ventricle outflow; one successful RF ablation of a verapamil-sensitive ventricular tachycardia. The mean follow-up was 3.5 months (1 to 7 months for RF and 20 months for DC ablation).Catheter ablation (mainly RF current) is highly effective in tachyarrhythmia's suppression, with 90% global success in our experience without morbidity.

To compare clinical and electrocardiographic characteristics of Nonsustained Ventricular Tachycardia (NSVT) and Idioventricular Accelerated Rhythm (IVAR).We studied 155 patients, 113 men and 42 women, with mean age 54 +/- 14 retrospectively, of these, 108 had NSVT and 47 IVAR. The arrhythmias were defined as follows: NSVT-more than 3 ventricular consecutive beats with an heart rate superior to 110 b/m and lasting less than 30 s.; IVAR-3 or more ventricular consecutive beats with an heart rate equal or superior to 50 and lower than 110 b/m, lasting less than 30 s. We evaluated clinical data (symptoms, functional class and anti-arrhythmic therapy), electrocardiographic data (rhythm, changes in conduction and repolarization) and ventricular function (with ECO, Radionuclide Angiography or Ventriculography). In the Holter recording (ECG-H), we analysed the presence of associated ventricular arrhythmias, their electrocardiographic characteristics (number of episodes, number of beats per episode, previous arrhythmia rate, morfology, regularity) and the relations of the arrhythmia with symptoms.Analysis of underlying pathology showed in both groups, the importance of coronary artery disease (44.5% vs 40%) followed by valvular heart disease (24% vs 27.6%) and cardiomyopathy (22.2% vs 17%) respectively to NSVT and IVAR. Only in the NSVT group there were patients without cardiac pathology (3.6%). Comparing with one control group of our department, this distribution was substantially different (p less than 0.0001). All IVAR episodes were assympthomatic compared with 90% of NSVT. Ventricular premature beats were found in all NSVT patients and in 90% of IVAR patients, and were frequent (greater than 10/h) in 79% and 60%, couplets in 84% and 53% respectively (ns). The previous rate of the arrhythmia was 85.3 +/- 20 b/m in NSVT against 68.7 +/- 14 in IVAR (p less than 0.0001). We found left ventricular disfunction in 60% of NSVT patients and in 63.7% in IVAR patients, being serious in 35% and 39% respectively. The follow-up was of 18.5 months (1-72) and posterior evolution showed 14.8% and 17% of deaths with no relation to the arrhythmia, although in NSVT the number of complexes and episodes were related with the ventricular disfunction (p = 0.02 and p = 0.05).Both arrhythmias appeared in patients with similar clinical and arrhythmic setting and identified a population with structural cardiopathy, bad function and poor outcome.

Evaluation of a WPW Syndrome population by non invasive methods; identification of the sudden death risk; results of treatment and patient selection for Electrophysiologic Studies (EPS).Retrospective study.Arrhythmology Outpatients Clinic from a Cardiac Department.Successive patients older than 12 years with a WPW pattern on the ECG and history of paroxysmal tachycardia followed-up for a period of 46 +/- 29 months.The clinical, ECG, Holter, stress test and echocardiographic data from 32 patients, were analysed. A study evaluating clinical follow up and the results of treatment was done.The group of patients was very symptomatic. The main complaint was a feeling of tachycardia (84.4%). Orthodromic tachycardia was documented in 7 cases and atrial fibrillation with rapid ventricular rate in five. Intermittent delta wave pattern was found in 21 patients, with 11 cases identified by Holter and 4 by stress test. A predominant left accessory pathway was found (47%), but the anteroseptal location was frequent too (25%). The echocardiogram was not useful in any case. Eighty per cent of the patients became asymptomatic with medical treatment. Beta blockers and amiodarone (the last chance) were the most useful drugs. No mortality was found in the study group. EPS was considered for the 5 patients with paroxysmal atrial fibrillation and the 7 cases resistant to medical treatment.The difficulty to define the risk of a population with WPW Syndrome by non invasive methods was demonstrated. Eighteen one cases were included in a low risk group, due to the intermittent WPW pattern in the ECG. A high risk group was considered for the 5 patients with atrial fibrillation with fast ventricular rate. The risk was not established in 9 cases. Most of the patients became asymptomatic by medical treatment.

The cases of two young patients with repetitive syncopal attacks due to idiopathic long QT syndrome (ILQTS) are reported. Both had been primarily misdiagnosed for seizures. In one of the cases the QT interval in the ECG at rest was normal. The same patient had a previous episode of cardiac arrest with ventricular fibrillation. The treadmill stress test was of great value, revealing polymorphic ventricular tachycardia induced by exercise, and evaluating the efficacy of beta-blocking therapy in the follow-up. The ILQTS should be considered a possible etiology in any patient presenting with new onset seizures, especially in the young. The treatments were different in both cases. In the first one, the treatment with nadolol (100 mg od) revealed to be very effective with total remission of symptoms. The treadmill stress test performed 15 days after the beginning of treatment did not show any ventricular arrhythmias, and it was assumed that the patient was effectively protected against ventricular arrhythmias. After 4.5 months of follow up, no syncopal episodes occurred. In the second case due to young age, the frequency, and the severity of the attacks (cardiac arrest with ventricular fibrillation), and the inefficacy of beta-adrenergic-blocking agents, the implantable cardioversor-defibrillator was the treatment chosen, although the beta blocking therapy was maintained to reduce the number of arrhythmic events. The ILQTS is a rare anomaly related to sudden cardiac death. The ILQTS is characterised by the association of several distinctive electrocardiographic features, among which prolongation of the QT interval is the best known. Life-threatening arrhythmia occurs usually under conditions of physical or psychological stress. Relatively effective therapies do exist and are represented by antiadrenergic interventions: beta-adrenergic-blocking agents are the treatment of choice. When they fail, left sympathetic denervation or the automatic implantable cardioversor-defibrillator have also proved to be effective.

To determine the value of the Cardiac Event Recorder (CER) in the diagnosis and treatment orientation of bradydysrhythmias, tachydysrhythmias and ischaemic events, based on our experience at the Santa Cruz Hospital.We retrospectively analysed 100 consecutive patients tested with a CER between January 1990 and December 1996 (mean follow-up, 272 +/- 202 days); the mean age of the patients (66 women and 34 men) was 45 +/- 18 years (range: 7 to 83); structural cardiac disease was present in 34% of the patients. CER was indicated for the investigation of symptoms suggestive of bradydysrhythmias (pre-syncope and/or syncope)--Group B--in 24 patients, tachydysrhythmias (palpitations and/or tachycardia sensation)--Group T--in 72 patients and ischaemic events--Group I--in the remaining four patients. We compared these groups with respect to demographic characteristics, prevalence of structural cardiac disease and efficacy of the test in the investigation of symptoms; periodicity of symptoms and duration of CER testing were analysed. In patients that experienced typical symptoms during the test, we analysed the electrocardiogram recorded at the time of the event and we investigated whether abnormal ECG findings influenced the therapeutic approach and whether this led to better symptomatic outcome.Patients in groups B and T were mainly women (54 percent vs 74 percent, NS). Group B patients were older than group T patients (mean age, 56.4 +/- 17.8 vs 40.0 +/- 16.0 yrs, P0.001). In group B, structural cardiac disease was less prevalent (37.5% vs 78.0%, P0.001) and symptom periodicity was greater (weekly: 12.5% vs 78.0%, monthly: 87.5% vs 15.2%, P0.001) than in group T. Duration of CER testing and number of events recorded were similar in the two groups. In both, CER testing was an important aid for therapeutic approach. Twenty two patients (eight B, 13 T and one I) had no typical symptomatic episodes during the CER test; in the remaining 78 patients (16 B, 59 T and three I), an electrocardiogram recording during such episodes was available for analysis. The ECG was abnormal in 44 of these patients, 12 (75%) being of group B and 32 (54%) of group T. Symptom periodicity was a few weeks in 65% of all patients (6 B, 57 T and two I). Duration of CER testing wasor = two weeks in 91 percent of the patients (22 B, 65 T and four I). CER testing guided the therapeutic approach in 78% of all patients. Changes of treatment strategy were more frequent in patients with CER documented typical symptomatic episodes than in those without (46% vs 9%, P0.02). When changes of treatment occurred, symptomatic outcome was better (97% vs 55%, P0.001).The CER is an important guide for the diagnostic and therapeutic approach for patients with intermittent arrhythmia suggesting, symptoms (78% of patients). A recording of normal ECG during typical symptoms reassures the patient and excludes potentially toxic treatments. Our selection of patients for CER testing seemed adequate since most typical symptomatic events occurred during the first two weeks of the test; longer duration of CER testing seems unnecessary.

To study the exercise blood pressure response in patients with hypertrophic cardiomyopathy (HC) and its relationship with sudden death.Retrospective study.We studied 51 patients (P) with HC: 18 women and 33 men. Their average age was 45 +/- 14 years, with a mean follow-up of 55 +/- 37 months.Every patient had been subjected to a treadmill stress-test, a 24-hour Holter monitoring and an echocardiographic examination. Particular emphasis was given to blood pressure increments (BPI) during stress-test, the existence of premature ventricular contractions with a frequency of 10 or more per hour (PVCor = 10), the occurrence of couplets (C) and/or non-sustained ventricular tachycardia (NSVT) on a 24-hour Holter. Finally, the finding of systolic anterior motion (SAM) of the mitral valve, in the routine echocardiogram, was valued.Four patterns of BPI were identified: "1": normal evolution (27 P); "2": plateau type increment (16 P); "3": fall in blood pressure during exercise (6 P); "4": abnormal BPI during recovery (2 P). Two groups were considered: group N-normal BPI, group A-patients with abnormal blood pressure responses. There were no significant differences among therapeutic agents, between the two groups, when the stress-test was performed. SAM was found in 21 P. Only 8 P registered ventricular arrhythmias, half of them with NSVT. No statistical relations were found between BPI and P age, the presence of SAM, PVCor = 10, C, or NSVT. We found 78% of P in group N in NYHA class I. In contrast, in group A only 46% were in class I (p = 0.04). Only one death, of non cardiac cause, occurred (group A).There is a large number of patients with HC and abnormal BPI. This is, seemingly, not influenced either by a dynamic left ventricular gradient or by ventricular ectopic beat occurrence. However, a relation appears to exist between the abnormal response and functional class, not explained by the usual (noninvasive) clinical tests.

To review the results of our experience with oral dl-sotalol for preventive treatment of supraventricular tachyarrhythmias (atrial fibrillation and paroxysmal supraventricular tachycardia).51 patients, 28 female and 23 male, mean age 46.2 +/- 14.4 years, from outpatient arrhythmology clinics of our institution, with recurrent supraventricular tachyarrhythmias (atrial fibrillation in 24 patients and paroxysmal supraventricular tachycardia in 27). All the patients, but one, had normal left ventricular function. Dl-sotalol was first choice medication in only three patients. Previously 2 +/- 1.3 antiarrhythmic drugs had been used.Retrospective evaluation of therapeutic response (number of clinical recurrences according to a semi-quantitative scale) and secondary effects of dl-sotalol during a minimum follow-up of 18 months. The mean daily dose was 205 +/- 90 mg (80 to 400 mg).In 37% of the patients there were no clinical recurrences of arrhythmia during follow-up. In 37% of the patients there was a significant reduction in recurrences. In 26% there was no change in the number of recurrences. There were no significant differences in response between patients with atrial fibrillation and those with paroxysmal supraventricular tachycardia. Secondary effects occurred in 16% of the patients: symptomatic bradycardia, asthma or sexual dysfunction. No patient had heart failure, torsades de pointes, syncope or death.From our experience, DL-sotalol seems to be a good therapeutic alternative for the preventive treatment of supraventricular tachyarrhythmias, with a low risk in patients with good ventricular function.

A case report of a patient with syncope and family history of sudden death is presented. The precordial recordings in the standard 12-lead ECG showed a right bundle-branch block pattern with persistent ST elevation in V1 and V2-V3. After a thorough evaluation, we found no underlying organic cardiomyopathy. The diagnosis of symptomatic Brugada syndrome was made. A cardioverter-defibrillator was implanted.

The introduction of the implantable cardioverter-defibrillator was a very important advance in the treatment of malignant ventricular arrhythmias. However, its use is associated with some possible adverse events, which should be taken into consideration when a patient is proposed for implantation. These complications may occur early after implantation and be associated with the procedure itself, or they may be late complications, usually associated with the device or the arrhythmia. It was our objective to assess the incidence of these complications in our population of patients.We describe the complications found in 98 patients (55.9 +/- 13.9 years, 89% male) with an implantable cardioverter-defibrillator and compare our results with the incidence of complications described by other authors.We found complications associated with the presence of the implantable cardioverter-defibrillator in 32% of patients. The most frequent complication was inappropriate shocks in 13%. The presence of infection was detected in 4%, lead insulation faults in 5%, need for lead extraction in 2%, repositioning in 1% and re-establishment of the connection with the generator in 2%. In 5% of patients, there was inefficacy of the device, 3% due to non-detected ventricular tachycardias (slow tachycardias) and 2% due to electrical storms. There was syncope in 2% of patients. The total mortality in a 2.9 +/- 1.9 year follow-up was 13% (sudden death in 3%).Major complications associated with implantable cardioverter-defibrillators were in our experience relatively rare, our results agreeing with those of other centers.

We describe a clinical case of a patient with Ebstein's anomaly and syncope in Wolff-Parkinson-White's syndrome. After a radiofrequency ablation of an accessory atrioventricular pathway there was a different arrhythmia of ventricular origin. Although we have some doubts about their clinical relevance, we discuss the complex arrhythmic background, the medical management difficulties and the prognostic issues. There is an evaluation about ablation usefulness in this context regarding future attitudes in relation to other kinds of rhythm disorder.

Evaluation of the diagnostic value of continuous electrocardiographic recording (Holter monitoring) in Paediatric Cardiology.Retrospective study based on the data records of the Arrhythmia Department regarding patients with less than 20 years of age with Holter monitoring performed between January 1983 and February 1995 (374 recordings).277 patients were studied, 163 were male and 114 female with a mean age of 12 +/- 5 years. Heart organic anomalies were present in 155 patients and 92 patients had previous cardiac surgery with cardiopulmonary bypass. Clinical indications for Holter recording were the evaluation of symptoms related to arrhythmias (38%), documented dysrhythmia (23%), arrhythmia detected on physical examination (18%) and evaluation of risk in patients without symptoms of arrhythmia (17%).Holter recordings were performed during 24 hours with two channels (modified V1 and V5).Significant rhythm and conduction disturbances were found in 122 patients. These were ventricular premature complexesor = 10/hour (27 patients), AV block (25 patients) and supraventricular premature complexesor = 10/hour (22 patients). Holter recording revealed significant dysrhythmias in 52% of patients with previously documented dysrhythmia, in 43% of patients referred for assessment of risk without symptoms of arrhythmia, provided insight in 48% of requests due to arrhythmia detected on physical examination and 24% of requests for symptoms related to arrhythmias. In 13 patients the results of Holter recording led to therapeutic or diagnostic measures.Holter recording showed an overall sensitivity of 44% in the detection of significant arrhythmias and led to therapeutic and additional diagnostic measures in 11% of these patients. Holter recording seems to provide important information in the evaluation of arrhythmias in the paediatric age group.

The aim of this paper was to evaluate our results of radiofrequency catheter ablation (RFCA) of accessory pathways in patients with WPW syndrome.We studied 100 consecutive patients with WPW syndrome, 52 men and 48 women, mean age 37 +/- 15 years who underwent RFCA. All patients were symptomatic, with documented episodes of supraventricular tachycardia and 9% of patients had underlying cardiac disease.The RFCA was performed without antiarrhythmic drugs in the same session of the electrophysiologic diagnosis. The location of the accessory pathway site was obtained by catheter mapping, based on the premature and/or the presence of Kent potentials. According to the location of the accessory pathway, the ablation catheter was introduced either by the femoral vein or artery with mapping of the tricuspid or mitral ring. In the first cases performed energy application was manually controlled and thereafter was temperature guided with an upper temperature limit of 70 degrees C. We considered primary success criteria the disappearance of the delta wave in the surface ECG and the absence of ventricular preexcitation under atrial pacing and after adenosine injection. Clinical success was defined as the absence of clinical recurrence of tachycardia during the follow-up period.The primary success rate achieved was 88%; 91% in the left free wall pathways, 100% in the right free wall and 85% in the septal pathways (antero-septal-83%; right postero-septal-76.5%; left postero-septal-92%). A second ablation procedure was performed in seven of the twelve patients with primary unsuccess obtaining a final success rate of 93% (left free wall-94.5%; septal pathways-91.6%). After a mean follow-up period of 8 +/- 7 months clinical recurrence occurred in 9% (eight patients), five of which are under anti-arrhythmic therapy (62.5%). Clinical success rate at the end of the follow-up period was 88%.In our experience RFCA has shown to be safe and with a high success rate in patients with symptomatic pre-excitation. In this group of patients it was an effective therapy.

The aim of this study was to evaluate the results of our experience with implantable cardioverter-defibrillator therapy.We treated with implantable cardioverter-defibrillator (ICD) 18 patients, 15 male and 3 female, mean age 51 years, ranging from 12 to 76 years, with life threatening ventricular arrhythmias. Eleven patients were resuscitated from cardiac arrest and seven had refractory ventricular tachycardia. The underlying condition was coronary artery disease in 12 patients, dilated cardiomyopathy in two, congenital long QT syndrome in one, mitral regurgitation in one and idiopathic in two patients.All patients underwent cardiac catheterization and electrophysiological study before ICD implantation. In the first patient epicardial leads were used, but a transvenous approach was used in the remaining 17 patients. The device was implanted in an abdominal position in all patients. Defibrillation and pacing threshold tests were performed during the implantation procedure and whenever necessary. After implantation, patients were followed up in an outpatient basis, with evaluation of therapy efficacy and reprogramming of the device if required. The mean follow-up time was 16 months, ranging from 1 to 40 months.The implantation was successful and without complications in all patients. Defibrillation threshold was considered within normal range, with an electrode impedance ranging from 40 to 65 Ohms. During the follow-up period no deaths occurred, 8 patients (44%) had episodes of VT or VF that were successfully treated, with shock in six patients, with antitachycardia pacing in one and with both modalities in another patient. Inappropriate shocks were observed in three patients (16%). The device was reprogrammed in five patients.Our experience with implantable ICD in patients who survived cardiac arrest or with refractory VT has shown a low surgical risk with no mortality. The incidence of ICD discharges was high, with a satisfactory efficacy rate and the number of inappropriate shocks was acceptable. The careful patient selection made possible a good cost/benefit relation.

The prognostic value of late potentials (LP) in the subacute phase of myocardial infarction (MI) is well known, but its prognostic value in long-standing coronary disease (LSCD) has not yet been established. In a population with LSCD we searched for a relation between the presence of LP in signal-averaged ECG (SAECG) performed before cardiac catheterization, and the incidence of cardiac events.Based on our department's casuistics, we selected 50 consecutive patients with coronary disease confirmed by an angiogram and LP, and a control group without LP, in SAECG. We selected 91 men and nine women with an average age of 59 +/- 8 years. None of the patients had had ischemic events or revascularization procedures, in the 3 month period before catheterization. The follow-up was made between the time of the SAECG and the last medical visit. The events recorded were: ventricular arrhythmia, cardiac death, coronary angioplasty, coronary artery by-pass graft, MI or unstable angina.During a follow-up period of 20.1 +/- 8 months, we found no statistically significant difference between the two groups, regarding the incidence of such events. However, there was a higher incidence of ventricular arrhythmic events in the group with LP (four patients with ventricular tachycardia against none in the control group). All patients with ventricular tachycardia had had a previous MI.In this study, the presence of LP in SAECG did not have the same prognostic value found in the subacute phase of MI, but a higher incidence of arrhythmic events was observed in the group with LP and a previous MI.

The aim of this study was to evaluate our results of radiofrequency catheter ablation (RFCA) of ventricular tachycardia.We treated with RFCA nine patients, six male and three female, mean age 36 +/- 12 years with ventricular tachycardia (VT), who fulfilled the following criteria; 1) recurrent VT; 2) resistant fo medical therapy despite the use of more than one antiarrhythmic drug; 3) inducible by programmed ventricular stimulation; 4) hemodynamically well tolerated. The VT etiology was coronary artery disease (CAD) in three patients, dilated cardiomyopathy in one, right ventricular dysplasia in one and it was idiopathic in four (being fascicular in three and catecholaminergic right ventricular outflow tract VT in one).The RFCA was performed under antiarrhythmic medication. The adequate ablation site was obtained by mapping of the VT, looking for the earliest ventricular activation, identification of isolated mid-diastolic potentials during sinus rhythm or presystolic during VT, good pace mapping (at least 10 of the 12 standard ECG leads), and high frequency short duration spikes, the so called P potentials in fascicular VT. Primary success achieved when occurred termination of VT during application of RF energy and/or VT was no longer inducible by programmed stimulation with the same stimulation protocol.Global primary success rate was 89%, being 100% in idiopathic VT, and 80% in VT associated with structural heart disease. In a follow-up period of 12 +/- 14 months all patients were alive, 75% free of VT in the idiopathic VT group; and 50% in patients with structural heart disease. One of these patients underwent cardioverter defibrillator implantation to treat a fast VT with a new morphology not treated by ablation, and the other two had VT modification with a significant reduction in the number of episodes.Radiofrequency catheter ablation of VT has shown a good success rate, and it is a valuable alternative in patients with hemodynamically tolerable VT, refractory to drug treatment, highly symptomatic and without surgical indication. In cases of idiopathic VT we had a high rate success and we think that RFCA will probably become the primary indication in symptomatic patients.