INTRODUÇÃO: O diabetes é um fator de risco conhecido para eventos adversos precoces e tardios em pacientes submetidos à cirurgia de revascularização miocárdica (CRM); entretanto, poucos estudos investigaram sua influência no grupo de pacientes mais idosos, especialmente nos octogenários. OBJETIVOS: Comparar a mortalidade e a morbidade hospitalar de pacientes com idade > 80 anos diabéticos e não-diabéticos submetidos à CRM. MÉTODOS: Foram estudados 140 casos consecutivos, sendo 37 (26,4%) diabéticos, em um estudo transversal retrospectivo incluindo todos os pacientes com idade > 80 anos submetidos à CRM isolada/associada. A idade média dos pacientes foi de 82,5 ± 2,2 anos e 55,7% eram do sexo masculino. RESULTADOS: A taxa de mortalidade hospitalar não diferiu de maneira significativa na análise multivariada entre os grupos, 16,2% diabéticos x 13,6% não-diabéticos (P=0,554), assim como a morbidade pós-operatória, 43,2 x 37,9%, respectivamente (P=0,533). Em relação à morbidade, a ocorrência de acidente vascular cerebral foi significativamente maior em pacientes diabéticos na análise univariada (10,8% x 1,9%; P = 0,042). Na análise multivariada, no entanto, a incidência dessa complicação não foi associada com a presença de diabetes (P=0,085), mas com a presença de fibrilação atrial (P=0,044). Não se observou nenhuma diferença significativa em relação às outras complicações. CONCLUSÃO: Nessa pequena série de casos retrospectiva, não houve um aumento significativo da morbimortalidade hospitalar no grupo de pacientes octogenários diabéticos. O impacto dos resultados desta série é limitado pelo tamanho amostral e poderá ser confirmado por futuros ensaios clínicos randomizados.

INTRODUCTION: Diabetes is a well known risk factor for early and late adverse outcomes in patients undergoing coronary artery bypass graft surgery (CABG); however, few studies have investigated the impact of this risk factor in the group of older patients, especially octogenarians. OBJECTIVES: To compare in-hospital mortality and morbidity of diabetic and nondiabetic patients aged > 80 years submitted to CABG. METHODS: A total of 140 consecutive cases were studied, of whom 37 (26.4%) were diabetics, in a retrospective cross-sectional study, that included all patients aged > 80 years submitted to isolated/associated CABG. The patients' mean age was 82.5 ± 2.2 years and 55.7% were males. RESULTS: The hospital mortality rate did not significantly differ in multivariate analysis: 16.2% diabetic x 13.6% nondiabetic (P = 0.554), as well as morbidity: 43.2% x 37.9%, respectively (P = 0.533). Regarding to operative morbidity, the occurrence of stroke was significantly higher in diabetic patients in the univariate analysis (10.8% x 1.9%, P = 0.042). In multivariate analysis, however, the incidence of stroke was not associated with the presence of diabetes (P = 0.085), but it was associated with atrial fibrillation (P = 0.044). There was no significant difference related to other complications. CONCLUSION: In this small consecutive retrospectively analyzed series, there was no significant increase in hospital mortality and morbidity related to diabetes for CABG in octogenarian patients. The impact of the results of this study is limited by the sample size and might be confirmed by future randomized clinical trials.

OBJETIVO: Analisar a eficácia do isolamento cirúrgico das veias pulmonares para restabelecer ritmo sinusal em pacientes com fibrilação atrial secundária à doença mitral. MÉTODOS: 33 pacientes com indicação de correção cirúrgica da valva mitral e com fibrilação atrial permanente, foram submetidos ao isolamento cirúrgico das veias pulmonares, sendo 67% mulheres. Média de idade de 56,3±10 anos, classe funcional NYHA pré-operatória de 3,2±0,6, tamanho de átrio esquerdo de 5,5± 0,9 cm, fração de ejeção de 61,3±13%. A técnica cirúrgica consistiu de incisão circunferencial ao redor das 4 veias pulmonares, excisão do apêndice atrial esquerdo e de incisão perpendicular desde a borda inferior da incisão, isolando as veias pulmonares, até o ânulo da valva mitral. Arritmias precoces foram tratadas, agressivamente, com cardioversão. RESULTADOS: O seguimento médio foi de 23,9±17 meses e ocorreram 3 óbitos no pós-operatório. Dez pacientes necessitaram de cardioversão elétrica no pós-operatório; 87% apresentavam ritmo sinusal na última consulta e 33% estavam em uso de amiodarona. CONCLUSÃO: Isolamento das veias pulmonares associado à cirurgia da valva mitral é uma técnica efetiva e segura na manutenção de ritmo sinusal em pacientes com fribilação atrial permanente.

OBJECTIVE: To assess the efficacy of surgical isolation of the pulmonary veins for re-establishing sinus rhythm in patients with atrial fibrillation secondary to mitral valve disease. METHODS: Thirty-three (67% were women) patients with permanent atrial fibrillation and indication for surgical correction of the mitral valve underwent surgical isolation of the pulmonary veins. Their mean age was 56.3±10 years, preoperative NYHA functional class was 3.2±0.6, left atrial size was 5.5±0.9 cm, and ejection fraction was 61.3±13%. The surgical technique consisted of a circumferential incision surrounding the 4 pulmonary veins, excision of the left atrial appendage, and a perpendicular incision originating in the inferior margin of the circumferential incision isolating the pulmonary veins down to the mitral valve. Early arrhythmias were aggressively treated with cardioversion. RESULTS: The mean follow-up was 23.9±17 months, and 3 patients died in the postoperative period. Ten patients required electrical cardioversion in the postoperative period; 87% had sinus rhythm in the last medical visit, and 33% were using amiodarone. CONCLUSION: Isolation of the pulmonary veins associated with mitral valve surgery is an effective and safe technique for maintaining sinus rhythm in patients with permanent atrial fibrillation.

OBJECTIVE - To assess the surgical results of endoventricular patch plasty repair in akinetic and dyskinetic left ventricular areas. METHODS - We studied 52 patients who had undergone endoventricular patch plasty repair associated with myocardial revascularization. The preoperative functional class distribution was as follows: class I in 1 (1.9%) patient; class II in 2 (3.8%) patients; class III in 23 (44.2%) patients; and class IV in 26 (50%) patients. RESULTS - The immediate mortality rate was 7.6% (4 patients). The clinical outcome of 44 patients followed up within a mean postoperative time of 29±25 months was as follows: class I in 33 (75%) patients; class II in 7 (15.9%) patients; class III in 2 (4.5%) patients; and class IV in 2 (4.5%) patients. Comparison between pre- and postoperative catheterization in 21 patients showed that the ejection fraction increased from 46.3% to 51.3% (p=0. 17); the left ventricular systolic volume decreased from 76.4 mL to 57.5 mL, (p=0.078); and the left ventricular diastolic volume decreased from 141.2 mL to 105.8 mL (p=0.0 73). These findings showed the tendency toward improvement, but with nonsignificant results. CONCLUSION - The technique proved to be effective, to have a low mortality rate, to cause significant clinical improvement, an increase in ejection fraction, and a reduction in left ventricular volumes.

OBJECTIVE: Evaluation of the long-term clinical results of the Fontan operation in patients with tricuspid atresia. METHODS: A retrospective analysis was made at the Instituto de Cardiologia do Rio Grande do Sul (Institute of Cardiology of Rio Grande do Sul), from August 1980 through January 2000, of 25 patients with a long-term follow-up, out of a series of 36 patients who underwent the Fontan operation or one of its variants due to tricuspid atresia. Their mean age at surgery was 5.4±3.1 years, and their mean weight was 15.8±6.1 kg, the majority of them (63.9%) being males. Four patients underwent the classical Fontan operation, 12 the Kreutzer variant, 6 the Björk variant, 9 total cavopulmonary shunt with a fenestrated tube, and 5 total cavopulmonary shunt with a nonfenestrated tube. RESULTS: The patients were followed-up on an outpatient basis, with a mean long-term survival time of 5.5±4.2 years (50 days to 17.8 years) and a late mortality rate of 8%. Arterial saturation increased from 77.2±18.8% in the preoperative period to 91±6.7% upon the last outpatient visit (p>0.05). At the final check, most (67%) patients were asymptomatic and 87% could tolerate exercise. Ten (40%) patients experienced some kind of complication during the long-term follow-up, such as cardiac arrhythmia, cyanosis, protein-losing enteropathy, neurological events, right heart failure, intolerance to exercise and reoperation. CONCLUSION: The results indicate that, once the immediate postoperative period is over, during which the adaptations to the new circulatory physiology occur, the evolution of patients with tricuspid atresia who underwent the Fontan operation is satisfactory, in spite of a low, yet significant, morbidity.

OBJECTIVE: To assess the occurrence of late thromboembolism after surgical repair of chronic atrial fibrillation (AF) simultaneously with repair of mitral valve using the Cox-Maze procedure. METHODS: 69 patients underwent Cox 3 procedure, with no cryoablation simultaneously with mitral valvuloplasty or prosthesis. Mean age was 49.9±13.2 years. Mean follow-up was of 31.7±19 months. Types of lesion were as follows: 33 (48%) stenoses, 23 (33%) insufficiencies, and 13 (19%) double lesions. Procedures were: 64 (93%) valvuloplasties, 3 (4%) biological and 2 (3%) mechanical prosthesis placement. There were 9 (13%) patients with previous systemic embolism and 2 (3%) had left atrial thrombi. RESULTS: Early mortality was 7% and late 1%. 2 patients (3%) were reoperated for mitral placement. At last evaluation, 10 patients (15%), were in AF. The remaining 59 (85%) were either in sinus / atrial rythm (74%) or under pacing (12%). There were no occurrence of early or late, systemic or pulmonary embolism. Permanent anticoagulation was employed in 16 cases, 10 in regular rythm and 6 in AF. The remaining 47 (75%), 2 in AF and 45 in regular rythm, did not receive anticoagulants. CONCLUSIONS: These results are in accordance with others series, where the occurrence of embolism was rare after maze procedure. Permanent systemic anticoagulation seems to be unnecessary in those cases.

OBJETIVO: Nos anos recentes, a ressincronização ventricular tem sido proposta como adjuvante no tratamento da insuficiência cardíaca congestiva. O objetivo deste estudo é comparar as alterações eletrocardiográficas e o efeito hemodinâmico imediato das estimulações ventricular direita (EVD) e biventricular (EBV), no pós-operatório de operação de revascularização miocárdica (CRM) com circulação extracorpórea (CEC). CASUÍSTICA E MÉTODOS: Em um ensaio clínico cruzado, 13 pacientes com doença coronária multiarterial, e fração de ejeção inferior a 50%, foram submetidos a estimulação epicárdica temporária univentricular direita e biventricular, no 5° dia de pós-operatório. As variáveis analisadas foram duração do complexo QRS, dimensões do átrio esquerdo (AE) e ventrículo esquerdo (VE), fração de encurtamento do VE (delta D) e fração de ejeção do VE. Os grupos foram comparados através do teste de t de Student para amostras pareadas, considerando-se nível de significância de 0,05. RESULTADOS: A duração média do complexo QRS foi de 185±26 ms durante a EVD, e de 126±37 ms com a EBV (p<0,001). O diâmetro médio do AE com a EVD foi de 40±4 mm, e de 35±4 mm na EBV (p<0,001). As médias dos diâmetros diastólico e sistólico finais do VE foram, respectivamente, de 49±13 mm e 59±11 mm com a EVD, e de 42±12 mm e 52±10 mm durante a EBV (p<0,001). A delta D média do VE determinada pela EVD foi de 18±7%, e de 22±8% com a EBV (p=0,017). A fração de ejeção média do VE com a EVD foi de 33±14%, e de 46±17% durante a EBV (p<0,001). CONCLUSÃO: No modelo estudado, a estimulação biventricular temporária determinou melhora significativa do desempenho hemodinâmico, em comparação à estimulação ventricular direita, e um complexo QRS com duração próxima à fisiológica.

OBJECTIVE: In recent years, the ventricular resynchronization has been proposed as an assisting therapy in congestive heart failure. This study objective is to compare the electrocardiographic changing and the acute hemodynamics effects of right ventricular (RVS) and biventricular stimulation (BVS), in post-operative of myocardial revascularization with cardiopulmonary bypass. MATERIAL AND METHODS: In a cross-over trial, thirteen patients with multiarterial coronary disease and ejection fraction lower than 50%, were submitted to right ventricular and biventricular epicardial temporary stimulation, in 5th post-operative day. The variables researched were lenght of time of the QRS complex, diameter of left atrium (LA) and left ventricle (LV), the LV shortening fraction and LV ejection fraction. The results from two groups were compared through the Student's t test for paired observations and the value p<0.05 was considered significant. RESULTS: The duration of QRS complex was 185±26 ms during RVS, and 126±37 ms with BVS (p<0.001). The left atrium diameter with RVS was 40±4 mm, and 35±4 mm during BVS (p<0.001). The end systolic and dyastolic LV diameters were respectivelly 49±13 mm and 59±11 mm during RVS, and 42±12 mm and 52±10 mm with BVS (p<0.001). The LV shortening fraction established by RVS was 18±7 %, and with BVS was 22±8 % (p=0.017). The LV ejection fraction during RVS was 33±14 %, and with BVS was 46±17 % (p<0.001). CONCLUSION: In the studied pattern, biventricular artificial stimulation determined a significant improvement of the hemodynamic performance in comparison to the right ventricular stimulation, and a QRS complex with duration close to the physiological.

OBJECTIVE: To analyze late clinical evolution after surgical treatment of children, with reparative and reconstructive techniques without annular support. METHODS: We evaluated 21 patients operated upon between 1975 and 1998. Age 4.67±3.44 years; 47.6% girls; mitral insufficiency 57.1% (12 cases), stenosis 28.6% (6 cases), and double lesion 14.3% (3 cases). The perfusion 43.10±9.50min, and ischemia time were 29.40±10.50min. The average clinical follow-up in mitral insufficiency was 41.52±53.61 months. In the stenosis group (4 patients) was 46.39±32.02 months, and in the double lesion group (3 patients), 39.41±37.5 months. The echocardiographic follow-up was in mitral insufficiency 37.17±39.51 months, stenosis 42.61±30.59 months, and in the double lesion 39.41±37.51 months. RESULTS: Operative mortality was 9.5% (2 cases). No late deaths occurred. In the group with mitral insufficiency, 10 (83.3%) patients were asymptomatic (p=0.04). The majorit y with mild reflux (p=0.002). In the follow-up of the stenosis group, all were in functional class I (NYHA); and the mean transvalve gradient varied between 8 and 12mmHg, average of 10.7mmHg. In the double lesion group, 1 patient was reoperated at 43 months. No endocarditis or thromboembolism were reported. CONCLUSION: Mitral stenosis repair has worse late results, related to the valve abnormalities and associated lesions. The correction of mitral insufficiency without annular support showed good long-term results.

OBJECTIVE: Report clinical experience in surgical treatment of atrial fibrillation (AF) by Cox-maze procedure. METHODS: 61 patients underwent surgical treatment for AF. Two had primary AF and 59 AF secondary to heart disease (2 atrial septal defects, 57 mitral). Ages ranged from 20 to 74 years (mean = 49). There were 44 females (72%). The surgical technique employed was Cox 3 without cryoablation. The patients were follow-up in specific at patient clinics and underwent periodical ECG, exercise tests, echocardiogram and Holter monitoring. RESULTS: In-hospital mortality was 4.9% and late mortality 1.6%. A temporary pacemaker was used in 28 (46%) and a definitive in 7 patients (11.4%). On hospital discharge, AF remained in 17%; 63.9% had sinus rhythm, 6.9% atrial rhythm, 1.7% junctional rhythm, and 10.3% had pacemaker rhythm. In the last evaluation, AF was present in 19.5%; (70.5% sinus rhythm, 4% atrial rhythm, 2% atrial tachycardia, and 4% pacemaker rhythm). There was no report of thromboembolic episodes. Chronotropic response was considered adequate in 19%, intermediate in 29%, and inadequate in 42%. In Holter monitoring, the mean heart rate was 82±8 bpm, with a minimum of 57±7 bpm and maximum of 126±23 bpm, with supraventricular extrasystoles in 2.3±5.5% of the total heartbeats and ventricular extrasystoles in 0.8±0.5%. In the echocardiogram, the A wave was present in the left atrium in 87.5%. CONCLUSION: Maze procedure is effective and has acceptable surgical risk. Atrial or sinus rhythms remain stable with a small but remarkable frequency of atrial and ventricular arrhythmias. Left atrial contraction is present, although attenuated, as well as the chronotropic response to exercise.

OBJETIVO: Comparar resultados da correção de Fibrilação Atrial (FA) Crônica em Doença Mitral Reumática (R) ou Degenerativa (D) a curto e médio prazos. CASUÍSTICA E MÉTODOS: De 1994 a 1997, 57 pacientes foram submetidos à Cirurgia do Labirinto e correção mitral. Oito (20%) reumáticos eram do sexo masculino; 32 (80%) feminino. Dos degenerativos 8 (47%) eram do sexo masculino; 9 (53%) femininos, (NS). Idade 47 ± 11 anos R; 54 ± 17 D (p < 0,05). Diâmetro do AE: 6,1 ± 1,1 cm R e 5,9 ± 1,2 D, (NS). RESULTADOS: Óbitos: 1 (2,5%) imediato em R; 2 (12%) hospitalares e 1 (7%) tardio em D (NS). Implante de marcapasso (MP) em 4 (10%) R e 2 (17%) D (NS). Tempos de isquemia: 63 ± 16 min R; 63 ± 15 min D, (NS). Circulação extracorpórea: 92 ± 19 min R e 96 ± 23 min D, (NS). Na alta hospitalar: 3 (10%) R e nenhum D recebiam medicação antiarrítmica, (NS); 9 (23%) R e 3 (20%) D recebiam anticoagulantes (NS). Conversão a ritmo sinusal (RS) em 31 (80%) do grupo R e em 12 (80%) do D, (NS). Ritmo de MP em 4 (10%) R, NS. FA incidiu em 4 (10%) R e em 2 (13%) D, (NS). Ritmo juncional em 1 (7%) D, (NS). Na última avaliação: RS em 27 (71%) R e 9 (75%) D (NS). Ritmo de MP em 4 (10%) R e 2 (17%) D, (NS). FA em 6 (16%) R e nenhum D, (NS). Taquicardia atrial paroxística em 1 (3%) R e 1 (8%) do grupo D, (NS). À ergometria, realizada em média de 16,2 ± 11,1 meses PO por 24 (60%) pacientes R e a 16,4 ± 10,0 meses PO para 10 (59%) degenerativos, 6 (25%) R e 1 (10%) D apresentaram RC adequada (NS). Em 3 (12,5%) R e 6 (60%) D foi considerada intermediária (p = 0,009). RC inadequada foi detectada em 15 (62,5%) pacientes R e 3 (30%) D- (p = 0,09). CONCLUSÃO: A etiologia R ou D não afeta a morbimortalidade e os benefícios aos pacientes com valvopatia mitral submetidos à Cirurgia do Labirinto e correção valvar. A recuperação do RS e a presença de arritmias no PO foi semelhante nos grupos. A resposta cronotrópica ao exercício tende a ser menor no grupo degenerativo.

The results of maze procedure in rheumatic mitral valve disease are subject to debate. This paper reports medium term results in rheumatic and degenerative mitral valve surgery associated with maze procedure. From 1994 to 1997, 57 patients were operated on. They were divided into two Groups; R (rheumatic) 40 patients and D (degenerative) 17. Group R included 8 (20%) males and 32 (80%) females. Group D: 8 (47%) males and 9 (53%) females (NS). Age in R = 47 ± 11 and D 54 ± 17 years (p < 0.05). Left atrial size was 6.1 ± 1.1 cm in R and 5.9 ± 1.2 in D (NS). There were 3 hospital deaths, 1 (2.5%) in R and 2 (12%) in D. One D patient (7%) died late. Pacemakers were implanted in 4 (10%) R and 2 (17%) in D (NS). There were no significant differences regarding surgical duration of perfusion or myocardial ischemia, antiarrhythmic medications, immediate or late cardiac rythms and occurrence of arrythmias. Ergometric evaluation for measuring chronotropic response revealed a normal response in 6 (25%) R and 1 (10%) in D at a mean of 16.6 months PO. In the lower response group, 3 (12.5%) R and 6 (60%) D had intermediate values (p = 0.009) and 15 (62.5%) R versus 3 (30%) D had values below 75% of expected heart rate (p = 0.09). Rheumatic or degenerative ethiology of mitral valve disease does not influence the results of maze procedure in this patient population. Mean chronotropic response to exercise tends to be lower in degenerative patients.

OBJETIVO: Avaliar, morfologicamente, por tomografia computadorizada espiral, enxertos de pericárdio bovino liso empregados como substitutos aórticos. MÉTODOS: Dez pacientes foram submetidos a exame por tomografia computadorizada espiral para reconstituição da imagem dos enxertos. Os critérios de seleção foram tempo de seguimento superior a 2 anos, enxertos de pericárdio liso não revestido, implantados na aorta ascendente ou descendente. RESULTADOS: Os exames demonstraram bom resultado cirúrgico em todos os casos, persistindo em alguns, a imagem de dissecção aórtica distal à anastomose. Um caso apresentava hematoma entre o enxerto e a parede aórtica, em 5 não foram encontradas alterações estruturais no pericárdio e, nos demais, foi detectada dilatação de grau leve, em relação ao diâmetro descrito do enxerto implantado. Não foram vistos sinais de calcificação ou pseudoaneurismas. CONCLUSÃO: Os enxertos tubulares de pericárdio bovino liso, não revestido, apresentam resultados satisfatórios quando empregados como substitutos aórticos. A médio prazo, não foram detectadas anormalidades estruturais relacionadas ao material empregado, pela tomografia computadorizada espiral, exceto dilatação em alguns casos.

PURPOSE: To evaluate morphologically by spiral computed tomography (SCT) bovine pericardial grafts as aortic substitutes. METHODS: Ten patients were submitted to aortic graft evaluation with SCT. There were 8 ascending and 2 descending grafts. Examination was done after 2 to 7 years post operative. Ages ranged from 49 to 67 years, with 6 male and 4 female patients. All had implanted smooth surface naked pericardial grafts. RESULTS: Surgical result was good in all. Distal dissection persisted in some cases. One had a peri-graft hematoma, 5 had no structural changes and 4 presented mild graft dilatation. There were no graft calcification or pseudoaneurysm. CONCLUSION: Glutaraldehyde preserved naked smooth surface bovine pericardial aortic grafts present satisfactory structural aspect, as seen by SCT, at medium term follow-up. Mild dilatation may be seen in some cases.

Quarenta e oito pacientes com marcapasso unicameral de ajuste automático de freqüência de pulso mediado por movimentação corporal (AAI-R/VVI-R) foram avaliados através da eletrocardiografia dinâmica, para correlacionar a atividade física com a variação da freqüência de estímulos e teste ergométrico em esteira (pareados e randomizados em modo AAI/VVI e modo AAI-R/VVI-R), para quantificar a capacidade de realizar esforço físico, um mês após o implante do gerador de pulso Activitrax 8400. A idade média dos pacientes era de 46 anos e a etiologia predominante da arritmia que motivou o implante era a miocardiopatia chagásica. O eletrocardiograma ambulatorial mostrou modificações apropriadas na freqüência cardíaca (exceto em 1 paciente, que permaneceu em ritmo sinusal). Teste ergométrico no modo AAI-R/VVI-R mostrou elevação significativa na freqüência cardíaca com relação ao valor médio controle: de 66,9+0,8 ppm para 84,6+2,1 ppm aos 14 minutos 90,5*2,8 ppm aos 6 minutos e 95,7+2,9 ppm aos 8 minutos (P < 0,05). O modo AAI-R/VVI-R possibilitou um aumento no tempo de exercício de 20,2% quando comparado ao modo AAI/VVI (P < 0,05). Em 12 pacientes, arritmias ventriculares foram detectadas durante o exercício em modo AAI/VVI, mas não no modo AAI-R/VVI-R. No curto período avaliado (1 mês), os pacientes referiram melhora clínica e puderam reassumir vida mais ativa. O gerador de pulsos Activitrax 8400 mostrou-se efetivo e seguro. A estimulação unicameral com variação da freqüência de pulso melhorou a capacidade de realizar exercícios físicos, quando comparada com a estimulação em freqüência pré-determinada.

To evaluate the physiologic benefits of the rate response estimulation, 48 patients were submited to a 24 hours Holter recording and paired tolerance treadmill test (AAI VVI and AAI-R/VVI-R modes, selected in random order) one month after implantation of an activity sensing pacemaker Activitrax 8400. Mean age of the patients was 46 years and indications for pacing included atrial arrhythmias (16 patients) or A-V conduction disturbances (32 patients, including 25 with complete A-V block). The underlying disease was Chagas cardiomiopathy, in 32 patients. Initial pacemaker setting was: basic rate: 60 or 70 ppm; maximum activity rate: 125 ppm; activity threshold: medium, rate response: 5. The 24 hours Holter recording documented appropriate changes in heart during daily activities. Oversensing, which resulted in pacing interval fluctuations, was diagnosed in two patients and required pacemaker reprograming. Treadmill test showed a significant increase in heart rate during exercise: mean control value: 66.9 ppm; 4 min.: 84.6 ppm; 6 min.: 90.5 ppm (P < 0.05). In the paired test, the AAI/VVI-Activity mode enabled the patients to increase heart rate (12.5%) and exercise time (20.2%; P < 0.05). None of the patients presented exercise induced ventricular arrhythmias in mode AAI/VVI-Activity; on the other hand, 12 patients showed ventricular arrhythmia during exercise in mode AAI/VVI. Clinical improvement and more active life was referred by all patients in this short follow-up period. The Activitrax 8400 was effective in improving patients exercise capacity.