Endocardial and epicardial radiofrequency ablation in the treatment of atrial fibrillation with a new intra-operative device.

OBJECTIVE: Atrial fibrillation has been a difficult problem to solve in many surgical patients, especially in those with mitral valve pathology. This study evaluates the results of endocardial and epicardial radiofrequency ablation with a new intra-operative device in the treatment of atrial fibrillation. METHODS: We operated on 65 patients with atrial fibrillation, 58 of which had concomitant mitral surgery. Atrial fibrillation was chronic (over 1 year) in 46 patients (group A) and paroxysmal or recent onset in 12 (group B). Group C had lone atrial fibrillation (two), concomitant coronary artery disease (four) or a sarcoma (one). Bilateral pulmonary vein isolation with a new intra-operative device was performed through multiple dry lesions in all patients. Groups A and B had endocardial applications at 70 degrees C during 60 s and group C had epicardial applications at 75 degrees C. Three group C patients had epicardial applications off pump. Atrial wall biopsies were performed in nine patients from groups A and B. RESULTS: There were no serious post-operative complications. At 1 month follow-up 54% of all patients were out of atrial fibrillation and 34% were in normal sinus rhythm with bilateral atrial contraction (Santa Crus Score 4). At 6 months follow-up, in spite of some crossover of patients among groups, similar results were obtained. The success of the procedure was 69% (Santa Crus scores 3 and 4) in mitral patients with a left atrial volume smaller than 200 cm(3). Preliminary data on the transmurality of the lesions is presented. The patients submitted to epicardial radiofrequency ablation (group C) have satisfactory results at 1 month (six out of seven were out of AF). CONCLUSIONS: Both endocardial and epicardial RF applications are simple and quick to perform and do not pose an additional risk for most patients. Furthermore we believe that it is possible to perform bilateral epicardial radiofrequency ablation of the pulmonary veins without cardiopulmonary bypass. Further refinements of the technique are needed to assure transmurality of all lesions and better results.

When and how to report results of surgery on atrial fibrillation.

OBJECTIVE: Several medical, interventional and surgical techniques are used to treat atrial fibrillation, aimed at different goals and having variable success rates. To be able to assess and compare all these techniques a methodology of study and a classification is proposed. METHODS: We developed a five grade score, named the Santa Crus Score, based upon the post-operative atrial rhythm and the effective atrial contraction. Score 0 corresponds to a persistence of atrial fibrillation, the presence of a regular rhythm is grade 1, 2 or 3 if there is no atrial contraction; right atrial contraction; or bilateral atrial contraction, respectively. Score 4 corresponds to sinus rhythm and bilateral atrial contraction. Surgery for atrial fibrillation was performed on 51 patients since 1992. All patients but two had associated mitrial surgery. Three different maze techniques were performed on 17 patients and the pulmonary veins isolation procedure on 34 patients. Patients were reassessed at 1, 6, 12, 24 and 36 months. RESULTS: After the maze I procedure atrial fibrillation eradication was achieved in 88% of patients but none scored 4. Three patients changed score during the first year. All maze III patients scored 0 initially and one changed to score 3 in the first year. Sixty percent of the maze IIIA patients scored 4, but one evolved to score 0 at 6 months. The pulmonary veins isolation technique eliminated atrial fibrillation in 71% of the patients initially, and in 60% after 1 year, and achieved a score of 4 in a third of the patients. CONCLUSION: This classification considers the intermediate grades of success that can occur with absence of atrial fibrillation and is applicable to all forms of therapy.

Surgery for atrial fibrillation using radiofrequency catheter ablation: assessment of results at one year.

OBJECTIVE: The results obtained in 43 patients using direct intraoperative radiofrequency catheter ablation, as an alternative to surgical incisions, to perform atrial fibrillation surgery, are presented. METHODS: Forty-three patients with ages ranging from 43 to 74 years (x = 59), with chronic atrial fibrillation with an average duration 6+/-5 years were operated. Eleven patients suffered from clinically relevant tachyarrythmia and eight had previous thromboembolic events. All but one patient had concomitant mitral valve surgery. Direct intraoperative radiofrequency catheter ablation was used to perform endocardial bilateral isolation of the pulmonary veins from the left atrium. RESULTS: There were no local or general complications, namely bleeding or thromboembolic events. Of the 33 patients with more than 3 months of follow-up, 36% remained in atrial fibrillation (Santa Cruz score 0); 30% had Score 4; 18% had Score 3; 6% had Score 2; 9% had Score 1. CONCLUSIONS: We conclude that the use of intraoperative radiofrequency catheter ablation is fast and safe. Presently, this is our method of choice for surgical treatment of atrial fibrillation in mitral patients.

[Portuguese Association of Arrhythmology, Pacing and Electrophysiology (APAPE). National Registry of Interventional Electrophysiology for 1999]. / Associação Portuguesa de Arritmologia, Pacing e Electrofisiologia (APAPE). Registo Nacional de Electrofisiologia de Intervenção para 1999.

Based on data supplied by the centres that execute Interventional Electrophysiology in Portugal, the authors performed a survey of the electrophysiological studies, with or without associated catheter ablation. This report quantifies the experience of all centres, as well as with different classes of ablation techniques. Furthermore, the authors performed a survey of implanted cardiovertor defibrillators, distinguishing their distribution among the different centres. They conclude that the number of centres that practice Interventional Arrhythmias in Portugal is continuously increasing, as well as the number of catheter ablations performed, although these rates have somewhat stabilised in the last year. The number of implanted cardiovertor defibrillators has also grown yearly since 1992, with a 24% increase last year, but is not yet close to the European average of implants per million of inhabitants.

Clinical implications of the "Multicenter Automatic Defibrillator Implantation Trial" (MADIT)

Efficacious therapy for chronic coronary patients, known to be at high risk of sudden arrhythmic death, has been a long-lasting challenge for cardiologists. The "Multicenter Automatic Defibrillator Implantation Trial" (MADIT) has demonstrated in a prospective, randomized trial that such patients achieve 54% better survival (p < or = 0.009) when treated with implantable defibrillators (ICDs) compared to conventional pharmaceutical therapy-primarily amiodarone. The identification of these patients is well-defined, and patients with previous myocardial infarction fitting the appropriate risk profile as defined by MADIT (ejection.fraction < or = 0.35), non-sustained ventricular tachycardia should seriously be considered for prophylactic ICD implantation.

[Diagnostic value of the submaximal treadmill exercise test in the subacute phase of myocardial infarct]. / Valor diagnóstico da prova de esforço submáxima em tapete rolante na fase subaguda do enfarte do miocárdio.

OBJECTIVES: To assess the diagnostic value of treadmill submaximal exercise testing (TSET), early after myocardial infarction (MI) under medical treatment, evaluating the ST changes predominantly. MATERIALS AND METHODS: 65 patients, 62 males and 3 females, mean age 52 years with demonstrated MI under clinical, electrocardiographic and enzymatic criteria were evaluated with TSET before hospital discharge. Thrombolytic therapy in acute phase of MI was done in 45 of the patients. All patients underwent angiographic studies with left ventriculography and selective coronariography. RESULTS: Of all TSET variables considered (Treadmill time, ST segment, presence of chest pain, systolic pressure, double product and presence of ventricular arrythmias) the single most important predictor for high-risk groups like left main disease and three vessels disease, was ST changes alone or associated with exercise precordial pain, with a sensitivity of 100% to left main and 83% to three vessels disease. In the thrombolytic group we did not find any differences related with reperfusion. IN CONCLUSION: TSET is a useful, noninvasive, and safe method for risk stratification after MI mainly when ST segment changes are considered alone or with stress precordial pain, predicting high risk groups, namely left main or three vessels disease patients.

[Amiodarone and propafenone: evaluation using serial Holter recordings in patients with ventricular arrhythmia]. / Amiodarona e propafenona: avaliação por registos de Holter seriados em doentes com arritmias ventriculares.

OBJECTIVE: To review the experience of the Arrhythmology Department in evaluating antiarrhythmic therapy for ventricular arrhythmias with serial Holter electrocardiographic recordings (ECG-H). To compare the results obtained with the most used drugs in this Department: amiodarone and propafenone (groups AMIO and PROP). DESIGN: Retrospective study. No statistically significant differences between the two groups were found in respect to age, sex, underlying disease, functional class, left ventricular function and associated therapy. SETTING: Arrythmology Department at a Cardiology Service. PATIENTS: 105 sequential patients with ventricular arrhythmias in a basal ECG-H recording, that were evaluated within 1 year with a new recording on amiodarone or propafenone, without major clinical events or therapeutic changes between the two recordings. INTERVENTIONS (daily oral doses): Amiodarone 200-600 (mean 270) mg or propafenone 300-900 (mean 602) mg. RESULTS: No statistically significant differences were found between the two groups, in either the basal ECG-H or that recorded on therapy. The two drugs were similar in the degree of suppression of ventricular premature complexes per hour (VPCH): equal or superior to 75% in 64.3% of the patients on amiodarone and in 63.9% of those on propafenone. The following reductions on therapy were statistically significant (p less than 0.001 if not specified): VPCH, from 346 +/- 480 to 86 +/- 158 on amiodarone and from 418 +/- 524 to 110 +/- 215 on propafenone; most complex arrhythmia recorded, on both drugs; number of patients with pairs, from 72.1 to 34.9% on amiodarone and from 69.4 to 33.9% on propafenone; number of patients with runs of nonsustained ventricular tachycardia (VT), from 27.9 to 2.3% on amiodarone (p less than 0.01); number of runs of VT per recording, from 3 +/- 5 to 1 on amiodarone (p less than 0.06); and maximum number of complexes per run of VT, from 8 +/- 8 to 4 on amiodarone and from 7 +/- 4 to 5 +/- 1 on propafenone (both with p less than 0.06). CONCLUSIONS: Holter recordings were useful in evaluating antiarrhythmic therapy. The effectiveness of amiodarone and propafenone in treating ventricular arrhythmias was not significantly different. The choice between one of these drugs must rely on their collateral effects profile.

[Non-invasive evaluation of a population with WPW syndrome]. / Avaliação não invasiva de uma população com o síndroma de WPW.

OBJECTIVE: 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). DESIGN: Retrospective study. SETTING: Arrhythmology Outpatients Clinic from a Cardiac Department. PATIENTS: 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. MATERIAL AND METHODS: 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. RESULTS: 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. CONCLUSIONS: 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 catheter ablation of tachyarrhythmias. The experience of the Hospital de Santa Cruz]. / Ablação por cateter de taquiarritmias. Experiência do Hospital de Santa Cruz.

BACKGROUND: First results of tachyarrhythmia's direct current (DC) and radiofrequency (RF) catheter ablation in Portugal (St. Cruz Hospital, Carnaxide). POPULATION AND METHODS: 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. RESULTS: 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). CONCLUSIONS: Catheter ablation (mainly RF current) is highly effective in tachyarrhythmia's suppression, with 90% global success in our experience without morbidity.

[Unsustained ventricular tachycardia and accelerated idioventricular rhythm--clinical and electrocardiographic features]. / Taquicardia ventricular não mantida e ritmo idioventricular acelerado--contexto clínico e electrocardiográfico.

OBJECTIVE: To compare clinical and electrocardiographic characteristics of Nonsustained Ventricular Tachycardia (NSVT) and Idioventricular Accelerated Rhythm (IVAR). MATERIAL AND METHODS: 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. RESULTS: 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). CONCLUSION: Both arrhythmias appeared in patients with similar clinical and arrhythmic setting and identified a population with structural cardiopathy, bad function and poor outcome.

[Catheter ablation with radiofrequency energy in 100 patients with Wolff-Parkinson-White syndrome]. / Ablação por cateter com energia de radiofrequência de 100 doentes com síndrome de Wolff-Parkinson-White.

OBJECTIVE: The aim of this paper was to evaluate our results of radiofrequency catheter ablation (RFCA) of accessory pathways in patients with WPW syndrome. STUDY PATIENTS: 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. METHODS: 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. RESULTS: 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%. CONCLUSIONS: 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 Brugada syndrome--a clinical case]. / Síndrome de Brugada--caso clínico.

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.

[Syncope in a patient with Ebstein's anomaly and Wolff-Parkinson-White syndrome]. / Síncope em doente com anomalia de Ebstein e síndrome de Wolff-Parkinson-White.

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.

[Effects of coronary surgery on silent ischemia]. / Influência da cirurgia coronária na isquémia silenciosa.

In order to assess the effects of coronary artery bypass surgery on silent myocardial ischemia, we studied a group of 39 consecutive patients, 38 male and 1 female with a mean age of 56 + 7 years, with stable chronic angina pectoris, by 48 hours-Holter monitoring and maximal treadmill exercise test before and after operation. The reduction of angina was 92% (p less than 0.0001) and of ischemia 57% (p less than 0.0001) after operation. Silent myocardial ischemia was detected in 21 patients (54%) before operation, 13 by Holter, 4 by exercise test and 4 by the two methods. After operation 13 patients (36%) continue to have silent ischemia depicted in 7 by Holter and in 7 by exercise test. No new patient developed silent ischemia after operation. The group of patients with silent ischemia preoperatively was not significantly different from the group without silent ischemia based on clinical and angiographic characteristics, results of surgery and exercise test parameters with exception of ST segment depression. In conclusion, silent myocardial ischemia may persist after successful coronary artery bypass surgery for the relief of angina pectoris, and should be monitored by serial Holter recordings and treated medically, if its prognosis and consequences proved to be similar to manifest symptomatic ischemia.

Implantable cardioverter-defibrillator: beyond efficacy.

OBJECTIVES: 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. POPULATION AND METHODS: 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. RESULTS: 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%). CONCLUSIONS: Major complications associated with implantable cardioverter-defibrillators were in our experience relatively rare, our results agreeing with those of other centers.

[Echo-Doppler in patients undergoing mitral commissurotomy. Comparison of open and closed commissurotomy]. / Avaliação com ECO-Doppler de doentes submetidos a comissurotomia mitral-comparação entre comissurotomia a céu aberto e céu fechado.

OBJECTIVE: 1. To evaluate with Echo-Doppler the medium/long term results of mitral commissurotomy. 2. To compare the results of open mitral commissurotomy to those of closed commissurotomy. PATIENTS AND METHODS: The Echo 2D-Doppler study has been performed in 117 patients (104 females and 13 males), randomly selected among patients previously submitted to open (62 d.) or closed (55 d.) mitral commissurotomy, with greater than or equal to 12 months follow-up. Pulsed and continuous Doppler recordings were obtained in all 117 patients, and the following parameters were evaluated: Maximum Mitral Gradient (MG); mitral valvular area calculated by half-pressure time (MVA); presence of mitral regurgitation greater than or equal to grade 2 (MR); evaluation of systolic Pulmonary Artery pressure (PAP) by the gradient RV/RA + 14mmHg, in the patients with tricuspid insufficiency; acceleration time (ACT), ejection time (EJT) and the relation ACT/EJT in pulmonary artery. To compare the results of open commissurotomy, to those of closed commissurotomy, and in order to minimize the pre-operative differences between the patients submitted to each of these interventions, only the patients in the same NYHA functional class before surgery (class III), and in sinus rhythm have been selected. In this way two groups were compared: group A-24 patients with open commissurotomy and group F-37 patients with closed commissurotomy. RESULTS: in the total of patients the results were: MG-9.8 +/- 4.2 mmHg; MVA-2.3 +/- 0.95 cm2; MR 16 pts. (13.7%); PAP obtained in 30 pts. (25.6%) -27.47 +/- 1.18 mmHg; the ACT, the EJT and the relation ACT/EJT in PA were respectively 115.63 +/- 34 ms, 309.9 +/- 38.5 ms, 0.37 +/- 0.1. The Doppler parameters obtained respectively in group A and in group F were: MG 8.96 +/- 4.5 mmHg and 10.38 +/- 3.82 mmHg (ns); MVA 2.62 +/- 1.01 cm2 and 2.08 +/- 0.84 cm2 (ns); MR 8.3% and 15.6% (ns) (Fig.3); the PAP have been calculated on 5(20.8%) patients in group A and on 10(27%) patients in group F and their respective values were 30.78 +/- 0.48 mmHg and 28.26 +/- 1.11 mmHg (ns); ACT 109.09 +/- 41.55 ms and 116.67 +/- 33.22 ms (ns); EJT 297.27 +/- 72.94 ms and 308.7 +/- 41.58 ms; ACT/EJT 0.35 +/- 0.12 and 0.38 +/- 0.10 (ns). CONCLUSION: Both open and closed commissurotomy revealed to be good therapeutic alternatives to mitral stenosis with identical long term results as evaluated by Echo-Doppler. The results of percutaneous mitral valvuloplasty should be compared with these in the future.

[Surgery of atrial fibrillation with intraoperative radiofrequency]. / Cirurgia da fibrilhação auricular utilizando radiofrequência intra-operatório.

Radiofrequency ablation is successful in most supraventricular tachyarrhythmias and the first results in percutaneous applications in atrial fibrillation have been published. At present, all the surgical techniques for the treatment of atrial fibrillation use extensive atrial incisions. A case report is presented of a 67 year old woman with chronic atrial fibrillation and rheumatic mitral and tricuspid valve disease. At surgery, pulmonary vein isolation was performed using a continuous linear ablation around the pulmonary veins, instead of using extensive atrial incisions. Concomitantly, a mitral valve replacement and tricuspid valve annuloplasty were performed. Five months after surgery the patient remains with a stable sinus rhythm surgery and in functional class I (NYHA).

[The prognostic significance of late potentials in patients with chronic coronary disease]. / Significado prognóstico dos potenciais tardios em doentes com doença coronária crónica.

OBJECTIVE: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.

[Experience with dl-sotalol in the treatment of supraventricular arrhythmia]. / Experiência com dl-sotalol na terapêutica de arritmias supraventriculares.

OBJECTIVES: To review the results of our experience with oral dl-sotalol for preventive treatment of supraventricular tachyarrhythmias (atrial fibrillation and paroxysmal supraventricular tachycardia). POPULATION: 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. METHODS: 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). RESULTS: 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. CONCLUSIONS: 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.