Effectiveness of the maze procedure using cooled-tip radiofrequency ablation in patients with permanent atrial fibrillation and rheumatic mitral valve disease.

BACKGROUND: Although the Cox-Maze III procedure is effective for treating permanent atrial fibrillation (AF), its high complexity limits its use. The Saline-Irrigated Cooled-tip Radiofrequency Ablation (SICTRA) System is an alternative source of energy used to ablate AF. The aim of this study was to evaluate the effectiveness of the SICTRA for the treatment of permanent AF in patients with rheumatic mitral valve (MV) disease. METHODS AND RESULTS: Between February 2002 and April 2003, 70 patients with permanent AF and rheumatic MV disease were randomly assigned to undergo a modified Maze III procedure using SICTRA associated with MV surgery (group A) or MV surgery alone (group B). Groups A and B were similar in terms of baseline characteristics. The in-hospital mortality rate was 2.3% (1 death) in group A versus 0% (no deaths) in group B (P>0.99). The additional time required for the left-sided radiofrequency ablation in group A was 14.2+/-5.1 minutes and for right-sided ablation was 12.3+/-4.2 minutes. The mean postoperative follow-up periods were 13.8+/-3.4 and 11.5+/-7.3 months, respectively, in groups A and B. The overall mid-term survival rate was 95.1% in group A and 92.8% in group B (P>0.99). The cumulative rates of sinus rhythm were 79.4% in group A and 26.9% in group B (P=0.001). Doppler echocardiography documented biatrial transport function in 90.3% of group A patients in sinus rhythm. CONCLUSIONS: The SICTRA is effective for treating permanent AF associated with rheumatic MV disease.

Accessory atrioventricular pathways refractory to catheter ablation: role of percutaneous epicardial approach.

BACKGROUND: Epicardial mapping and ablation of accessory pathways through a subxiphoid approach can be an alternative when endocardial or epicardial transvenous mapping has failed. METHODS AND RESULTS: We reviewed acute and long-term follow-up of 21 patients (14 males) referred for percutaneous epicardial accessory pathway ablation. There was a median of 2 previous failed procedures. All patients were highly symptomatic, 8 had atrial fibrillation (3 with cardiac arrest) and 13 had frequent symptomatic episodes of atrioventricular reentrant tachycardia. Six patients (28.5%) had a successful epicardial ablation. Five patients (23.8%) underwent a successful repeated endocardial mapping, and ablation after epicardial mapping yielded no early activation site. Epicardial mapping was helpful in guiding endocardial ablation in 2 patients (9.5%), showing that the earliest activation was simultaneous at the epicardium and endocardium. Four patients (19%) underwent successful open-chest surgery after failing epicardial/endocardial ablation. Two patients (9.5%) remained controlled under antiarrhythmic drugs after unsuccessful endocardial/epicardial ablation. Two patients had a coronary sinus diverticulum and one a right atrium to right ventricle diverticulum. Three patients acquired postablation coronary sinus stenosis. There was no major complication related to pericardial access. CONCLUSIONS: Percutaneous epicardial approach is an alternative when conventional endocardial or transvenous epicardial ablation fails in the elimination of the accessory pathway. A new attempt by endocardial approach was successful in a significant number of patients. Open-chest surgery may be required in symptomatic cases refractory to endocardial-epicardial approach.

Electrocardiogram during tachycardia in patients with anterograde conduction over a Mahaim fiber: old criteria revisited.

OBJECTIVES: The aim of this study was to prospectively evaluate the sensitivity, specificity, and positive and negative predictive values of previously described ECG criteria to identify preexcited tachycardia due to decrementally conducting accessory pathways (QRS axis between 0 and -75 degrees , QRS width < or = 0.15 seconds, an R wave in lead I, an rS pattern in lead V(1), RS > 1 QRS transition > V(4), and cycle length between 220 and 450 ms). BACKGROUND: Preexcited tachycardia associated with decrementally conducting right-sided accessory pathways usually shows a rather "narrow" QRS complex and can be difficult to differentiate from supraventricular tachycardia (SVT) with left bundle branch block (LBBB) aberrant conduction. METHODS: We analyzed three groups of patients: 32 patients with an atriofascicular pathway (group I); 8 patients with long (n = 3) or short (n = 5) decrementally conducting right-sided AV pathway (group II); and a control group that consisted of 35 patients with SVT and LBBB (group III). RESULTS: Presence of all six criteria had 87.5% sensitivity in group I and a 0% sensitivity in group II. There were four false negatives in group I. The negative predictive value was 82.5%, with six false positives in group III (five patients with an aberrant LBBB-shaped tachycardia with ventriculoatrial conduction over an accessory AV pathway). The criterion cycle length was not helpful. CONCLUSIONS: Criteria for identifying a tachycardia with anterograde conduction over a Mahaim fiber are helpful only in atriofascicular pathways, with a sensitivity of 87.5% and a negative predictive value of 82.5%. The major cause of false positives was a tachycardia with aberrant LBBB conduction and ventriculoatrial conduction over an accessory AV pathway.

Unusual complications of percutaneous epicardial access and epicardial mapping and ablation of cardiac arrhythmias.

BACKGROUND: Percutaneous epicardial access and mapping/ablation of cardiac arrhythmias are being increasingly performed. Although complications such as pericardial effusion are relatively common, other unusual complications may occur due to the complex anatomic architecture of the heart and surrounding tissues. In this report, we report a series of rare and unusual complications related to percutaneous epicardial procedures. METHODS AND RESULTS: Between 2006 and 2011, 334 patients underwent attempts at percutaneous, subxiphoid access for epicardial mapping/ablation at 5 experienced centers. Seven selected complications are highlighted in this case series. Patient 1 had a 1-cm right ventricular pseudoaneurysm after several unsuccessful attempts at epicardial access. This was successfully managed conservatively. Patient 2 had intra-abdominal bleeding related to puncture of the left lobe of the liver during access that required surgical repair. Patient 3 had a subcapsular hepatic hematoma that was probably related to percutaneous access and was successfully managed conservatively. Patient 4 had severe pericardial bleeding followed by ventricular fibrillation, immediately after obtaining percutaneous epicardial access. A lacerated middle cardiac vein was repaired surgically. However, the patient ultimately died of complications. Patient 5 had a history of cardiothoracic surgery and developed a right ventricle-abdominal fistula after multiple attempts at percutaneous access. This was surgically repaired without major sequelae. Patient 6 had cardiac tamponade caused by a lacerated coronary sinus branch during epicardial catheter ablation and required surgical repair. Patient 7 had severe left coronary vasospasm and ventricular fibrillation during catheter manipulation in the pericardium. This complication was successfully managed with intracoronary nitrates. CONCLUSIONS: Though generally safe, percutaneous epicardial access and mapping/ablation can result in uncommon complications. Awareness of these rare complications may facilitate early detection and successful management.

Left atrial function after ablation for paroxysmal atrial fibrillation.

Radiofrequency ablation of the pulmonary veins has been used to treat patients with paroxysmal atrial fibrillation (AF), and atrial damage after ablation is an issue of concern. To evaluate left atrial function shortly and midterm after ablation, 33 consecutive patients with paroxysmal AF were studied at baseline, 24 hours, and > or =6 months after ablation. Patients in sinus rhythm with normal ventricular function were included in the study. Echocardiographic measurements of left atrial volumes (Simpson's rule) and transmitral and tissue Doppler myocardial (A') velocities at the septal and lateral mitral annulus were undertaken at each time. Left atrial emptying fraction (EF; maximal - minimal left atrial volume/maximal left atrial volume) was used to express left atrial function. After 8 +/- 2 months, 30 of 33 patients returned (23 men, age 53 +/- 13 years), and all except 2 were in sinus rhythm. Shortly after ablation, left atrial minimal volumes increased (from 30 +/- 15 to 35 +/- 15 ml; p = 0.02), with maximal volumes unchanged, resulting in decreased left atrial EF (from 47 +/- 8 to 40 +/- 7 ml; p <0.05). Tissue Doppler septal A' velocities also decreased (from 8.2 +/- 1.8 to 6.9 +/- 2.0 cm/s; p <0.05). However, after midterm follow-up, both left atrial EF and septal A' velocities had slightly increased compared with shortly after ablation, although left atrial volumes remained similar to baseline. Septal A' velocity changes paralleled left atrial EF both shortly (r = 0.46, p = 0.02) and at midterm after ablation (r = 0.47, p = 0.01). In conclusion, after radiofrequency ablation, patients with paroxysmal AF experienced an initial impairment in atrial function, with improvement at longer term follow-up.

Effect of local anesthetics with and without vasoconstrictor agent in patients with ventricular arrhythmias.

BACKGROUND: The routine use of local anesthetics associated to vasoconstrictors for the dental treatment of patients with cardiopathies is still controversial, due to the risk of adverse cardiovascular effects. OBJECTIVE: To evaluate and compare the hemodynamic effects of the use of local anesthetics with a non-adrenergic vasoconstrictor in patients with ventricular arrhythmia, when compared to the use of anesthetics without vasoconstrictor. METHODS: A prospective randomized study evaluated 33 patients with positive serology for Chagas' disease and 32 patients with coronary artery disease that presented complex ventricular arrhythmia at Holter monitoring (>10 EV/h and NSVT), of which 21 were females, aged 54.73 + 7.94 years, submitted to routine dental treatment with pterygomandibular anesthesia. These patients were divided in two groups: group I received prilocaine 3% associated with felypressin 0.03 IU/ml and group II received lidocaine 2% without vasoconstrictor. The number and complexity of extrasystoles were analyzed, as well as the heart rate and systemic arterial pressure of the patients on the day before, one hour before, during the procedure and one hour after the dental procedure. RESULTS: No hemodynamic alterations or increase in the number and complexity of the ventricular arrhythmia related to the anesthetic used in the dental procedure were observed in either group. CONCLUSION: The results suggest that prilocaine 3% associated to a felypressin 0.03 IU/ml can be safely used in patients with Chagas' disease or coronariopathy with complex ventricular arrhythmia.

Ablation of typical atrial flutter: a prospective randomized study of cooled-tip versus 8-mm-tip catheters.

OBJECTIVES: Both ablation catheters with closed irrigated system and 8mm tip-catheters have been shown to be more effective for typical atrial flutter radiofrequency (RF) ablation when compared to conventional 4 mm tip catheter. Considering the differences in complexity and costs of both systems, a prospective study was designed to compare the efficacy and safety of cooled-tip and 8mm-tip catheters for atrial flutter ablation. METHODS: Fifty-two consecutive patients underwent RF ablation of cavotricupsid isthmus (CTI) for the treatment of typical atrial flutter, using catheter with closed irrigation system (n=26) or 8 mm-tip catheter (n=26). The RF pulses were applied point-by-point for 60 seconds, with power limited at 50 w for the irrigated catheter and by temperature control (60 degrees/70 w) for the 8 mm catheter. RESULTS: The CTI block was successfully performed in 98.1%. Four patients in the irrigated group needed to switch to the other group. There was no significant difference with regard to ablation parameters, such as total time of RF ablation (591.1+/-309.0 s vs 486.2+/-250.8 s), total procedure duration (86.4+/-23.6 vs 78.1+/-22.5 min) and time of fluoroscopy (17.0+/-6.7 vs 15.4+/-4.6 min). During follow-up of 10.6 months in average, one patient in the irrigated group had recurrence of typical atrial flutter. CONCLUSION: Efficacy and safety of CTI ablation was comparable between both techniques (irrigated catheter and 8 mm-tip catheter). The complexity of irrigated catheter makes it less competitive.

Radiofrequency catheter ablation of premature ventricular contractions originating in the right ventricular outflow tract.

OBJECTIVES: To evaluate if radiofrequency catheter ablation is an effective procedure for the treatment of right ventricular outflow tract premature ventricular contractions (RVOT-PVC) and ascertain if it results in an improvement of symptoms. METHODS: A prospective study with 30 consecutive patients (mean age 40 +/- 13 years, 25 females), with no apparent structural cardiopathy, with very frequent (mean density of 1,263 +/- 593/h) RVOT-PVC, symptomatic for more than one year (mean = 74 months) and resistant to antiarrhythmic drugs (3 +/- 1.7, including beta-blockers), who underwent radiofrequency catheter ablation. RESULTS: After the first procedure, there were 23 initial successful cases (76.6%) and 7 initial failures (23.4%). Four patients experienced relapses, two of whom did not undergo the second procedure. The second procedure was carried out in 9 patients (7 initial failures and 2 relapses), and there was success in 5 additional patients, one of them by epicardial access. The final success rate was 80% (24/30), and there were no major complications. After a mean follow-up of 14 +/- 6 months, in the successful group there was a reduction greater than 90% in density of premature ventricular contractions (PVC) (24/24; p<0.0001) and a resulting absence of symptoms in the majority of patients (23/24; p<0.001). CONCLUSION: Radiofrequency catheter ablation is a safe and effective treatment for patients with persistent and symptomatic PVC with RVOT morphology.

Short atrioventricular Mahaim fibers: observations on their clinical, electrocardiographic, and electrophysiologic profile.

UNLABELLED: Short A-V manheim fiber. INTRODUCTION: A short atrioventricular decrementally conducting accessory pathway is an uncommon variant of preexcitation. Available data from small series suggest that their decremental properties might not be caused by A-V nodal-like tissue. METHODS: We compared clinical, electrocardiographic and electrophysiologic parameters in two groups of patients: 8 patients with a short A-V Mahaim pathway (Group A), and 33 patients with atriofascicular pathways (Group B). Radiofrequency catheter ablation was carried out guided by activation mapping at the annulus in Group A patients and targeting the "M" potential in Group B patients. RESULTS: After ablation of all associated rapidly conducting bypass tracts, 7 of the 8 Group A patients showed clear preexcitation. In only 1 of 8 patients the short A-V Mahaim fiber was actively engaged in a reentrant tachycardia circuit. During radiofrequency catheter ablation an automatic rhythm occurred in 4 of 8 patients. Intravenous adenosine caused conduction a block in the Mahaim fiber in 3 of the 5 patients tested. In group B, no patient showed clear preexcitation (P<00001) while 72% had a minimal preexcitation pattern. Twenty-nine of the 33 patients had a circus movement tachycardia with AV conduction over the atriofascicular fiber. During radiofrequency catheter ablation 30 of 33 patients showed accessory pathway automaticity. Adenosine caused transient block at the atriofascicular pathway in 11 (92%) of the 12 patients tested. CONCLUSIONS: While short decrementally conducting right-sided accessory pathways show a typical ECG pattern different from atriofascicular pathways, their electrophysiologic properties do not seem to be uniform. Those pathways can be successfully interrupted by catheter ablation.

Dual conduction in a Mahaim fiber.

The case of an 8-year-old girl with incessant nonsustained left bundle branch block-like tachycardia refractory to antiarrhythmic drug therapy is reported. Electrophysiologic study revealed the presence of a right-sided accessory atriofascicular pathway. Episodes of nonsustained tachycardia were found to be based upon a dual response in AV conduction over the Mahaim fiber to one P wave. No reentrant tachycardia could be induced. The arrhythmia was cured by catheter ablation targeting a Mahaim potential at the right lateral tricuspid annulus. The findings can be explained by longitudinal dissociation in a single Mahaim fiber, a fiber distally diverging into two fibers with different conduction times, or (less likely) two closely located Mahaim fibers with different conduction times.

Automaticity in Mahaim fibers.

INTRODUCTION: Automatic rhythms associated with Mahaim fibers usually occur during radiofrequency catheter ablation. The incidence and significance of spontaneous automaticity in Mahaim fibers are unknown. METHODS AND RESULTS: Spontaneous automatic rhythms were observed in 5 (12.5%) of 40 patients with Mahaim fibers referred for nonpharmacologic therapy because of recurrent episodes of symptomatic tachyarrhythmias, usually antidromic circus movement tachycardia (33/40 patients). Three were female and two were male. Their mean age was 15 +/- 7 years compared to 26 +/- 13 years of the patients without automaticity (P = 0.09). Three patients had both antidromic tachycardia and asymptomatic spontaneous automatic rhythms recorded during ambulatory ECG (1 patient) or electrophysiologic study (2 patients). In 2 patients, the automatic rhythm triggered antidromic tachycardia. Two other patients had nonsustained repetitive episodes of wide QRS tachycardia due to automaticity arising in the Mahaim fiber, without antidromic tachycardia. All automatic rhythms were abolished by successful catheter ablation of the Mahaim fibers. CONCLUSION: Spontaneous automaticity occurred in 12.5% of our Mahaim patients and may trigger antidromic tachycardia. Spontaneous automaticity, which is not seen in rapidly conducting accessory pathways, is another argument for the presence of an AV nodal-like structure in Mahaim fibers.

Efeito de anestésicos locais com e sem vasoconstritor em pacientes com arritmias ventriculares / Effect of local anesthetics with and without vasoconstrictor agent in patients with ventricular arrhythmias

FUNDAMENTO: A utilização de anestésicos locais associados a vasoconstritores para tratamento odontológico de rotina de pacientes cardiopatas ainda gera controvérsia, em razão do risco de efeitos cardiovasculares adversos. OBJETIVO: Avaliar e comparar os efeitos hemodinâmicos do uso de anestésico local com vasoconstritor não-adrenérgico em pacientes portadores de arritmias ventriculares, em relação ao uso de anestésico sem vasoconstritor. MÉTODOS: Um estudo prospectivo randomizado avaliou 33 pacientes com sorologia positiva para doença de Chagas' e 32 pacientes com doença arterial coronariana, portadores de arritmia ventricular complexa ao Holter (>10 EV/h e TVNS), 21 do sexo feminino, idade de 54,73 + 7,94 anos, submetidos a tratamento odontológico de rotina com anestesia pterigomandibular. Esses pacientes foram divididos em dois grupos: no grupo I, utilizou-se prilocaína a 3 por cento associada a felipressina 0,03 UI/ml, e no grupo II, lidocaína a 2 por cento sem vasoconstritor. Avaliaram-se o número e a complexidade de extra-sístoles, a freqüência cardíaca e a pressão arterial sistêmica dos pacientes no dia anterior, uma hora antes, durante o procedimento odontológico e uma hora após. RESULTADOS: Não foram observadas alterações hemodinâmicas, nem aumento do número e da complexidade da arritmia ventricular, relacionados ao anestésico utilizado, em ambos os grupos. CONCLUSÃO: Os resultados sugerem que prilocaína a 3 por cento associada a felipressina 0,03 UI/ml pode ser utilizada com segurança em pacientes chagásicos e coronarianos, com arritmia ventricular complexa.

BACKGROUND: The routine use of local anesthetics associated to vasoconstrictors for the dental treatment of patients with cardiopathies is still controversial, due to the risk of adverse cardiovascular effects. OBJECTIVE: To evaluate and compare the hemodynamic effects of the use of local anesthetics with a non-adrenergic vasoconstrictor in patients with ventricular arrhythmia, when compared to the use of anesthetics without vasoconstrictor. METHODS: A prospective randomized study evaluated 33 patients with positive serology for Chagas' disease and 32 patients with coronary artery disease that presented complex ventricular arrhythmia at Holter monitoring (>10 EV/h and NSVT), of which 21 were females, aged 54.73 + 7.94 years, submitted to routine dental treatment with pterygomandibular anesthesia. These patients were divided in two groups: group I received prilocaine 3 percent associated with felypressin 0.03 IU/ml and group II received lidocaine 2 percent without vasoconstrictor. The number and complexity of extrasystoles were analyzed, as well as the heart rate and systemic arterial pressure of the patients on the day before, one hour before, during the procedure and one hour after the dental procedure. RESULTS: No hemodynamic alterations or increase in the number and complexity of the ventricular arrhythmia related to the anesthetic used in the dental procedure were observed in either group. CONCLUSION: The results suggest that prilocaine 3 percent associated to a felypressin 0.03 IU/ml can be safely used in patients with Chagas' disease or coronariopathy with complex ventricular arrhythmia.

Ablação do flutter atrial típico: estudo prospectivo e randomizado do cateter irrigado fechado versus cateter com eletrodo distal de 8 mm / Ablation of typical atrial flutter: a prospective randomized study of cooled-tip versus 8-mm-tip catheters

OBJETIVOS: Trabalho prospectivo, randomizado para comparar a eficácia e a segurança do cateter irrigado em relação ao cateter com eletrodo distal de 8 mm para ablação com radiofreqüência (RF) do flutter atrial. MÉTODOS: Em 52 pacientes consecutivos referidos para tratamento do flutter atrial típico, a ablação do istmo cavotricuspídeo (Ist-CT) foi realizada com cateter de irrigação fechada (n=26) ou com cateter de eletrodo distal de 8 mm (n=26). Os pulsos de RF foram aplicados ponto a ponto por 60 segundos com potência limitada a 50 w com o cateter irrigado e por controle de temperatura (60°C, 70 w) com cateter de 8 mm. O critério de fim do procedimento foi a obtenção de bloqueio bidirecional do Ist-CT. RESULTADOS: O bloqueio Ist-CT foi obtido em 98,1 por cento dos pacientes. O "crossover" ocorreu em quatro pacientes do grupo com cateter irrigado. Não se encontrou diferença estatística significante em relação aos parâmetros da ablação, tais como tempo total de aplicação de RF (591,1±309,0s vs 486,2±250,8s), duração do procedimento (86,4 ± 23,6 vs 78,1±22,5min) e tempo de fluoroscopia (17,0±6,7 vs 15,4±4,6min) entre os dois grupos. Durante seguimento médio de 10,6 meses, um paciente do grupo irrigado apresentou recorrência do flutter atrial típico. CONCLUSÃO: A ablação do Ist-CT resultou ser efetiva e segura para o controle do flutter atrial com ambas as técnicas empregadas (cateter com eletrodo distal de 8 mm e cateter irrigado). A complexidade técnica do cateter irrigado proporciona menor competitividade.

OBJECTIVES: Both ablation catheters with closed irrigated system and 8mm tip-catheters have been shown to be more effective for typical atrial flutter radiofrequency (RF) ablation when compared to conventional 4 mm tip catheter. Considering the differences in complexity and costs of both systems, a prospective study was designed to compare the efficacy and safety of cooled-tip and 8mm-tip catheters for atrial flutter ablation. METHODS: Fifty-two consecutive patients underwent RF ablation of cavotricupsid isthmus (CTI) for the treatment of typical atrial flutter, using catheter with closed irrigation system (n=26) or 8 mm-tip catheter (n=26). The RF pulses were applied point-by-point for 60 seconds, with power limited at 50 w for the irrigated catheter and by temperature control (60°C / 70 w) for the 8mm catheter. RESULTS: The CTI block was successfully performed in 98.1 percent. Four patients in the irrigated group needed to switch to the other group. There was no significant difference with regard to ablation parameters, such as total time of RF ablation (591.1±309.0s vs 486.2±250.8s), total procedure duration (86.4±23.6 vs 78.1±22.5min) and time of fluoroscopy (17.0±6.7 vs 15.4±4.6min). During follow-up of 10.6 months in average, one patient in the irrigated group had recurrence of typical atrial flutter. CONCLUSION: Efficacy and safety of CTI ablation was comparable between both techniques (irrigated catheter and 8mm-tip catheter). The complexity of irrigated catheter makes it less competitive.

Ablação com radiofreqüência de extra-sístoles da via de saída do ventrículo direito / Radiofrequency catheter ablation of premature ventricular contractions originating in the right ventricular outflow tract

OBJETIVOS: Avaliar se a ablação com radiofreqüência é um procedimento eficiente para o tratamento das extra-sístoles da via de saída do ventrículo direito (EVSVD), e se resulta em melhora dos sintomas. MÉTODOS: Estudo prospectivo, com 30 pacientes consecutivos (idade média de 40±13 anos, 25 do sexo feminino), sem cardiopatia estrutural aparente, com EVSVD, muito freqüentes (densidade média de 1.263±593/h), sintomáticos por mais de 1 ano (média =74 meses) e refratários aos fármacos antiarrítmicos (3±1,7, incluindo os beta-bloqueadores), que foram submetidos à ablação com radiofreqüência. RESULTADOS: Após o primeiro procedimento, houve 23 sucessos iniciais (76,6 por cento) e 7 iniciais insucessos (23,4 por cento). Quatro pacientes tiveram recorrências, sendo que dois desses não se submeteram ao segundo procedimento. O segundo procedimento foi realizado em 9 pacientes (7 insucessos iniciais e 2 recorrências), e o sucesso ocorreu em 5 pacientes adicionais, sendo 1 caso por acesso epicárdico. A taxa de sucesso final foi de 80 por cento (24/30), e nenhuma complicação maior ocorreu. Após um seguimento médio de 14±6 meses, no grupo de sucesso final houve uma redução de mais de 90 por cento na densidade das extra-sístoles(24/24; p<0,0001) e resultante ausência de sintomas na maioria dos pacientes (23/24; p<0,001). CONCLUSÃO: A ablação com radiofreqüência é um tratamento seguro e eficaz para os pacientes com extra-sístoles persistentes e sintomáticas com morfologia do trato de saída do ventrículo direito.

OBJECTIVES: To evaluate if radiofrequency catheter ablation is an effective procedure for the treatment of right ventricular outflow tract premature ventricular contractions (RVOT-PVC) and ascertain if it results in an improvement of symptoms. METHODS: A prospective study with 30 consecutive patients (mean age 40 ± 13 years, 25 females), with no apparent structural cardiopathy, with very frequent (mean density of 1,263 ± 593/h) RVOT-PVC, symptomatic for more than one year (mean = 74 months) and resistant to antiarrhythmic drugs (3 ± 1.7, including beta-blockers), who underwent radiofrequency catheter ablation. RESULTS: After the first procedure, there were 23 initial successful cases (76.6 percent) and 7 initial failures (23.4 percent). Four patients experienced relapses, two of whom did not undergo the second procedure. The second procedure was carried out in 9 patients (7 initial failures and 2 relapses), and there was success in 5 additional patients, one of them by epicardial access. The final success rate was 80 percent (24/30), and there were no major complications. After a mean follow-up of 14 ± 6 months, in the successful group there was a reduction greater than 90 percent in density of premature ventricular contractions (PVC) (24/24; p<0.0001) and a resulting absence of symptoms in the majority of patients (23/24; p<0.001). CONCLUSION: Radiofrequency catheter ablation is a safe and effective treatment for patients with persistent and symptomatic PVC with RVOT morphology.

Disfunçäo miocárdica secundária à taquicardia persistente / Myocardial dysfunction secondary to persistent tachycardia

Este estudo demonstra a reversibilidade de graus variáveis de disfunçäo ventricular em cinco portadores de taquicardias atrioventriculares incessantes (TAVI) submetidos à ressecçäo cirúrgica da via anômala. Três pacientes eram do sexo feminino e as idades variaram entre 4 e 39 anos. Três apresentavam palpitaçöes taquicárdicas, dois em classe funcional II (NYHA) e um em classe IV e os outros dois eram assintomáticos. O ECG pré-operatório apresentava taquicardia persistente com QRS estreito e relaçäo RP > PR. A onda P era negativa em D2, D3 e AVF e de V2 a V6. O Holter demonstrava ritmo de TAVI com raros batimentos sinusais nas 24 horas. A FC variou entre 140 e 190 (média de 158) bpm. Ao ecocardiograma, a fraçäo de ejeçäo ventricular esquerda variou de 33% a 59% (média de 49,6%) e o diâmetro diastólico do ventrículo esquerdo de 47 a 66 (média de 53,8) mm. A radiografia torácica, dois pacientes apresentavam aumento moderado da área cardíaca e um, aumento discreto. Todos pacientes foram refratários à terapêutica com antiarritmicos isolados ou em associaçäo. O estudo eletrofisiológico registrou a presença de via anômala AV póstero-septal com conduçäo retrógrada lenta. Após oblaçäo cirúrgica da via anômala, todos os pacientes apresentavam-se assintomáticos sem emdicaçäo e em ritmo sinusal permanente entre quatro e 24 meses de seguimento com FC variando entre 62 e 100 (média de 78,4) bpm. A fraçäo de ejeçäo ao ecocardio-grama modificou-se para 63 a 81% (média de 71,6%) e o diâmetro...

Anomalia de Ebstein com coarctaçäo de aorta: uma associaçäo rara / Ebstein's anomaly with coarctation of the aorta: an unusual association

Ebstein's anomaly with coarctation of the aorta is an extremely unusual condition. In this report, the clinical and surgical features of 3 male patients, aged 7 months, 4 years and 14 years, are discussed. All patients were in situs solittus. The first 2 patients had atrioventricular and ventriculoarterial discordance and progressed to heart failure in the neonatal period. The third had atrioventricular and ventriculoarterial concordance, as well as Wolf-Parkinson-White syndrome, with frequent episodes of paroxysmal tachycardia. The 3 patients underwent surgery for correction of the coarctation of the aorta. The patient with atrioventricular and ventriculoarterial concordance underwent tricuspid valvuloplasty using a De Vega-like technique. In addition, ablation of 2 anomalous pathways (Kent bundle), which were detected by the electrophysiologic study, was also subsequently performed. The 3 patients showed a good postoperative outcome for 2 years, although, in those with discordance, the surgical procedure did not influence the dysplasia of the tricuspid valve, because this valve showed light to moderate dysfunction.

Terapêutica empírica com amiodarona em portadores de miocardiopatia chagásica crônica e taquicardia ventricular sustentada / Long term results of empiric amiodarone therapy in patients with sustained ventricular tachycardia and chronic chagasic myocarditis

Objetivo: Avaliar eficácia e tolerância do uso empírico de amiodarona, a longo prazo, em portadores d e Miocardiopatia Chagásica Crônica (MCC) e Taquicardia Ventricular Sustentada (TVS). Casuística e Métodos: Trinta e cinco portadores de MCC e TVS, 18 (51% ) dos quais, refratários a outras drogas antiarritmicas. A dose de impregnação variou de 600 a 1200 (média de 883 ± 239) mg/dia, por período de uma a quatro semanas. A dose de manutenção foi reduzida progressivamente à média de 356 ± 125 mg/dia ao final de seis a 80 (média de 27 ± 20) meses. Foram construídas curvas de estimativa de recorrência clínica, morte súbida e morte cardíaca, segundo o método de Kaplan e Meier e comparadas variáveis clínicas na avaliação de risco de recorrências e morte súbita, através dos testes do Qui-quadrado de Pearson e t de Student.

Purpose: To evaluate the efficacy and safety of long-term empiric amiodarone therapy in patients with recurrent Sustained Ventricular Tachycardia (SVT) and Chronic Chagasic Myocarditis (CCM). Patiens and Methods: Thirty-five patients with CCM and SVT, eighteen (51%) of them were refratary to other antiarrhythmic drugs. The Amiodarone loading dose was between 600 and 1200 mg/day, mean of 883 ± 239 mg/day, from a period of one to four weeks. The maintenance dose was decreasing in the follow-up period, it fell down to 356 ± 125 mg/day at the end of six to 80 (mean = 27 ± 20) months. Cumulative, event-free interval curves were generated by the Kaplan-Meier method. Clinicals variables were compared with the use of the Student t-test or by means of chi-square tests.

Variabilidade espontânea da extra-sistolia ventricular na cardiopatia chagásica crônica / Spontaneous variabitity of ventricular extrasystole in chronic Chagas cardiopathy

Purpose - To study the spontaneous variability of single (VPCs) and coupled (CVPCs) in patients with chronic Chagas' disease (CCD). Patients and Methods - Twenty patients with CCD, 14 male, in class I and III NYHA, with frequent VPCs and VCPCs, free of drug therapy were studied.21 hour Holter monitoring was done for 4 subsequent days. The data analysis assessed the variation in the frequency of VPCs and CVPCs between patients, seven hour periods one hour periods in a hierarchical model by a Poisson process. Results - a) the frequency of VPCs follows a circadian rhythm, closely related to the hourly variations of the mean heart rate; b) disregarding the heart rate influence on the variability of the ventricular arrhythmia, its behavior was at random and unpredictable; c) the minimal percentual reduction in VPCs/h that discriminated between antiarrhythmic effect and spontaneous between antiarrhythmic effect and spontaneous variability was 121.86% for sevenhour, 58.42% for 21-hour and 38.45% for 42-hour electrocardiographic monitoring periods; d) the same approch for the VCPCs revealed values of 133,8%, 63.21% and 41.3% respectively

Valor diagnóstico do teste de inclinçäo na avaliaçäo da síncope de origem indeterminada: resultados preliminares / Diagnostic value of the tilt test in the evaluation of syncope of unknown origin: preliminary results

PURPOSE--In order to identify neurally mediated syncope, head-up tilt testing was performed in patients with recurrent unexplained syncope. METHODS--The tests were performed in 125 patients in the fasting state, between 8:30 and 11:30 a.m. The blood pressure and heart rate were continuously monitored during 20 minutes in the resting state, and then, positioned at 60 degrees angle, for up to 40 minutes. A group of 20 patients with first negative test was submitted to intravenous isoproterenol in bolus of 2 micrograms every 2 minutes until symptoms occur or at a total dose of 8 micrograms. The test was considered positive when systolic blood pressure decreased at least 30 mmHg and the patient experimented syncope or pre-syncope. RESULTS--In 52 patients the test was positive (41.6 per cent ), 63.5 per cent of which had hypotension exclusively; 7.7 per cent asystole; and 28.8 per cent had hypotension and bradycardia. Nine of the 20 patients submitted to isoproterenol test were positive (45 per cent ). All patients recovered spontaneously after returning to supine position. CONCLUSION--Head-up tilt testing is a safe and effective method for the identification of neurally mediated syncope

Objetivo - Identificar a possível etiologia neuralmente mediada, em portadores de síncope de origem indeterminada (SOI) submetidos ao teste de inclinação. Métodos - Cento e vinte e cinco portadores de SOI foram submetidos, entre abril de 1991 a outubro de 1992, ao teste de inclinação, realizado pela manhã, em jejum, com período de repouso de 20min em decúbito horizontal e 40min a 60o, com monitorização contínua da pressão arterial (PA) e da freqüência cardíaca (FC). O teste sensibilizado consistiu na administração de isoproterenol em doses de 2µg a cada 2min a 60o , até a dose máxima de 8µg ou até o aparecimento de sintomas présincopais ou síncope e foi aplicado em um grupo de 20 pacientes nos quais o 1º teste havia sido negativo. O critério de positividade foi a queda sintomática da pressão arterial sistólica maior que 30mmHg. Resultados - Cinqüenta e dois (41,6%) indivíduos apresentaram testes positivos, dos quais 63,5% apresentaram resposta exclusivamente vasodepressora (queda da PA sem modificação da FC), 7,7% cardio-inibitória (assistolia) e 28,8% resposta mista. Dos 20 pacientes submetidos ao teste sensibilizado, 9 (45%) apresentaram resultados positivos. Todos recuperaram-se espontaneamente com o retorno para o decúbito horizontal. Conclusão - O teste de inclinação é um método eficiente e seguro na identificação da etiologia neurocardiogênica das síncopes até então de origem indeterminada

Relaçäo entre a persistência da conduçäo / Relation between the persistence of AV conduction over the slow pathway after AVRNT radiofrequency ablation and its recurrences

Objetivo - Verificar se a persistência de salto nodal relaciona-se à taxa de recorrência de taquicardia por reentrada nodal (TRN) após ablação com radiofreqüência (RF) da via lenta do nó atrioventricular. Métodos - Num seguimento de 20+12 meses, foi analisada a recorrência de TRN em 126 pacientes consecutivos submetidos a ablação com RF da via lenta nodal. O critério de interrupção do procedimento foi a não reindução da TRN, após estimulação atrial programada, com e sem isoproterenol intravenoso. Ao final do procedimento, 98 pacientes não apresentavam salto nodal, e em 28 persistia o salto nodal e/ou o eco atrial. Resultados - Houve recorrência clínica de TRN em 15 (11 por cento) pacientes: 9 no grupo sem salto nodal e/ou eco atrial e em 6 do grupo que persistiu com salto e/ou eco atrial. A recorrência tendeu a ser maior no 2§ grupo (9 por cento vs 21 por cento), mas não houve significância estatistica entre os resultados (p=0,09). Conclusão - Desde que a TRN não passa ser induzida após a infusão de isoproterenol, a recorrência espontânea da arritmia após a ablação por RF da via lenta nodal não é diferente entre pacientes que persistem ou não com salto nodal e/ou eco atrial.