OBJECTIVES: Perfusion abnormalities are frequently seen in Single Photon Emission Computed Tomography (SPECT) when a left bundle branch block is present. A few studies have shown decreased coronary flow reserve in the left anterior descending territory, regardless of the presence of coronary artery disease. OBJECTIVE: We sought to investigate rubidium-82 (82Rb) positron emission tomography imaging in the assessment of myocardial blood flow and coronary flow reserve in patients with left bundle branch block. METHODS: Thirty-eight patients with left bundle branch block (GI), median age 63.5 years, 22 (58%) female, 12 with coronary artery disease (≥70%; GI-A) and 26 with no evidence of significant coronary artery disease (GI-B), underwent rest-dipyridamole stress 82Rb-positron emission tomography with absolute quantitative flow measurements using Cedars-Sinai software (mL/min/g). The relative myocardial perfusion and left ventricular ejection fraction were assessed in 17 segments. These parameters were compared with those obtained from 30 patients with normal 82Rb-positron emission tomography studies and without left bundle branch block (GII). RESULTS: Stress myocardial blood flow and coronary flow reserve were significantly lower in GI than in GII (p<0.05). The comparison of coronary flow reserve between GI-A and GI-B showed that it was different from the global coronary flow reserve (p<0.05) and the stress flow was significantly lower in the anterior than in the septal wall for both groups. Perfusion abnormalities were more prevalent in GI-A (p=0.06) and the left ventricular ejection fraction was not different between GI-A and GI-B, whereas it was lower in GI than in GII (p<0.001). CONCLUSION: The data confirm that patients with left bundle branch block had decreased myocardial blood flow and coronary flow reserve and coronary flow reserve assessed by 82Rb-positron emission tomography imaging may be useful in identifying coronary artery disease in patients with left bundle branch block.

OBJETIVO: Avaliar estratégia de titulação para prescrever uma dose de propranolol que seria eficiente em reduzir isquemia do miocárdio em idosos. MÉTODOS: Foram estudados 14 homens idosos (73,6 ± 5,3 anos), portadores de doença coronariana estável, documentada pela cinecoronariografia, com resposta isquêmica ao teste ergométrico e função ventricular esquerda preservada. O propranolol foi titulado a fim de atingir redução de 15% na freqüência cardíaca, ao final da carga de 50 W (correspondente às atividades diárias normais de idosos), em testes ergométricos semanais e feito estudo cintilográfico sincronizado das câmaras cardíacas, em repouso e durante exercício, antes e após seu uso. RESULTADOS: As reduções da freqüência cardíaca na carga de 50 W e em repouso foram semelhantes (21% vs 20%; p=0,5100). O propranolol melhorou a duração do exercício (12,2 ± 2,0 min vs 13,1 ± 1,8 min; p=0,0313) e aboliu as alterações do segmento ST induzidas pelo exercício em 8 (57%) pacientes. Em repouso, a fração de ejeção não foi modificada pelo betabloqueador. Durante o exercício máximo, o propranolol reduziu o índice de volume sistólico final e aumentou a fração de ejeção. CONCLUSÃO: A estratégia de empregar betabloqueadores para reduzir a freqüência cardíaca em 15% na carga de 50 W é segura e benéfica nos idosos com isquemia miocárdica e função ventricular preservada. A dose utilizada reduziu a isquemia miocárdica e melhorou a tolerância ao exercício, sem prejudicar o desempenho ventricular durante exercício máximo.

OBJECTIVE: To assess the strategy of titration for prescribing an efficient dosage of propranolol to reduce myocardial ischemia in the elderly. METHODS: The study comprised 14 elderly men (73.6 ± 5.3 years) with stable coronary heart disease documented on coronary cineangiography, ischemic response to exercise testing, and preserved left ventricular function. Titration was performed to identify the dosage of propranolol that would cause a 15% reduction in heart rate at the end of a 50 W load (corresponding to normal daily activities in the elderly) in weekly exercise tests. Synchronous scintigraphic study of the cardiac chambers was performed at rest and during exercise prior to and after propranolol use. RESULTS: The reductions in heart rate with the 50 W load and at rest were similar (21% vs 20%; P=0.5100). Propranolol improved the duration of exercise (12.2 ± 2.0 min vs 13.1 ± 1.8 min; P=0.0313) and abolished the changes in the ST segment induced by exercise in 8 (57%) patients. At rest, the ejection fraction was not modified by the beta-blocker. During maximum exercise, propranolol reduced the end-systolic volume index and increased ejection fraction. CONCLUSION: The strategy of using beta-blockers to reduce heart rate by 15% with a 50 W load is safe and beneficial in the elderly patient with myocardial ischemia and preserved ventricular function. The dose of beta-blocker used reduced myocardial ischemia and improved tolerance to exercise without hampering ventricular performance during maximum exercise.

OBJECTIVE: To compare single-photon-emission computed tomography (SPECT) imaging scans using 201Tl and 99mTc-MIBI in detection of viable myocardium, in regions compromised by infarction. METHODS: Thirty-two (59.3±9.8 years old and 87% male) myocardial infarction patients were studied. All had Q waves on the ECG and left ventricle ejection fraction of <50%. They underwent coronary and left ventricle angiographies and SPECT before (including 201Tl reinjection) and after coronary artery bypass surgery (CABG). Improvement in perfusion observed after surgery was considered the gold standard for myocardial viability. RESULTS: Among 102 studied regions of the heart, there were 40 (39.2%) areas of transient perfusion defects in the conventional protocol with 201Tl and 52 (51.0%) after reinjection. Therefore, 12/62 (19.4%) more viable regions were identified by reinjection. Using 99mTc-MIBI, only 14 (13.7%) regions with transient defects were identified, all of which were seen also in 201Tl protocols. After surgery, 49 of a total of 93 regions analyzed (52.7%) were viable. Sensitivity, specificity, accuracy, positive and negative prediction values were, respectively, 201Tl SPECT scans - 65.3%, 90.9%, 77.4%, 88.9% and 70.2%, reinjection protocol with 201Tl scans - 81.6%, 81.8%, 81.7%, 83.3% and 80.0%; 99mTc-MIBI SPECT scans - 20.4%, 90.9%, 53.8%, 71.4% and 50.6%. Logistic regression demonstrated that the reinjection protocol with 201Tl was the best predictor of viability (P<0.001). CONCLUSION: Our data suggest the election of 201Tl for viability studies, especially when using the reinjection protocol.

A cardiomioplastia tem sido proposta, como uma alternativa ao transplante cardíaco, no tratamento de pacientes com insuficiência miocárdica em fase avançada. O objetivo deste trabalho é estudar a evolução clínica e o comportamento da função ventricular no pós-operatório tardio desse procedimento em 34 pacientes portadores de cardiomiopatia dilatada, que foram operados no período de maio de 1988 a setembro de 1994. Vinte e sete pacientes estavam em classe funcional III e 7 pacientes em classe IV no preoperatorio, apesar do uso de terapêutica clínica otimizada. A mortalidade hospitalar foi de 2,9% e 1 paciente que evoluiu em choque cardiogênico foi submetido a transplante cardíaco 42 dias após a cardiomioplastia. O tempo de seguimento pós-operatório variou entre 2 e 73 meses, com média de 27,4 meses. Aos 6 meses de pós-operatório, 12 pacientes estavam em classe funcional 1,15 pacientes em classe 11 e 3 pacientes em classe III (p=0,001) em relação ao pré-operatório. Quatorze pacientes faleceram até 5 anos de pós-operatório e os índices de sobrevida foram 84,7% em 1 ano, 67,7% em 2 anos e 39,6% aos 5 anos de seguimento, sendo que, em 9 pacientes, os óbitos ocorreram por progressão da insuficiência cardíaca, e 5 pacientes faleceram subitamente. A análise de regressão de Gox mostrou que a mortalidade nos pacientes operados em classe funcional IV foi 5,5 vezes maior do que nos pacientes operados em classe III (p=0,006), cuja sobrevida foi de 52,7% aos 5 anos de pós-operatório. O estudo sistemático da função ventricular através da angiografia com radioisótopos, da ecocardiografia com Doppler e do cateterismo cardíaco direito documentou a melhora da fração de ejeção do ventrículo esquerdo (V E) de 19,8 ± 3 para 23,9 ± 7,2% (p<0,01), associada a modificações significativas do encurtamento segmentar do V E, do volume e do índice sistólico, da pressão arterial média, das pressões pulmonares e do índice de trabalho sistólico do V E, aos 6 meses de seguimento. No período pós-operatório tardio, a fração de ejeção e o encurtamento segmentar do V E tenderam a cair e retornaram a valores semelhantes aos do pré-operatório em 5 anos, sendo observada no mesmo período a manutenção dos benefícios hemodinâmicos demonstrados após o procedimento. A eletrocardiografia dinâmica mostrou que a incidência de arritmias ventriculares e de fibrilação atrial não se modificou após a cardiomioplastia. Finalmente, dos 5 pacientes que completaram 5 anos de seguimento, 3 faleceram por progressão de insuficiência cardíaca e 1 por morte súbita até os 73 meses de pós-operatório. Além disso, o estudo anatomopatológico mostrou a existência de infiltração gordurosa no enxerto muscular em 9 pacientes que faleceram entre 20 e 73 meses de pós-operatório, sendo observadas alterações mais intensas do enxerto em pacientes com maior tempo de seguimento. Em conclusão, a cardiomioplastia melhora a condição clínica e a função ventricular esquerda de pacientes com cardiomiopatia dilatada. A sobrevida no pós-operatório tardio do procedimento é limitada, no entanto, em pacientes operados em classe funcional IV. Além disso, os benefícios da cardiomioplastia sobre a função sistólica do VE podem estar restritos a poucos anos de pósoperatório, fato que parece estar associado à degeneração tardia do enxerto muscular.

Dynamic cardiomyoplasty has been proposed as an alternative to heart transplantation in the treatment of severe cardiomyopathies. In this investigation, its results were investigated in 34 patients with idiopathic dilated cardiomyopathy submitted to this procedure from May 1988 to September 1994. Twenty seven patients were in New York Heart Association functional class III and 7 were in class IV before the operation, despite the use of maximal medical therapy. Hospital mortality was 2.9% and 1 patient presenting heart failure progression was submitted to urgent heart transplantation 42 days after cardiomyoplasty. The other patients were followed-up from 2 to 73 months (mean, 27.4 months). At 6 months of follow-up, 12 patients were in functional class 1,15 patients in class II and 3 patients in class III (p=0.001, in relation to preoperative data). Similar findings were observed from one to four years of follow-up. On the other hand, 14 patients died up to 5 years after the operation and the survival rates were 84.7% at 1 year, 67.7% at 2 years and 39.9% at 5 years of follow-up. The cause of death was progression of heart failure in 9 patients and 5 patients died suddenly. By stepwise Cox regression method, patients operated in functional class IV had relative risk of death 5.5 times higher than class III patients (p=0.006), whose survival rate was 52.7% at 5 years of followup. Regarding cardiomyoplasty influence on ventricular function, radioisotopic left ventricular (LV) ejection fraction improved from 19.8 + 3.1% to 23.6 + 6.2%, at 6 months of follow-up. Doppler-echocardiography documented similar changes in LV wall shortening. Also, right heart catheterization showed significant increases in mean arterial pressure, stroke index and LV stroke work index, which were associated with the decrease of mean pulmonary wedge pressure. On the other hand, it was not found any significant postoperative change in ventricular arrhythmia and atrial fibrillation incidence. At the late postoperative period, the hemodynamic improvement was maintained up to 5 years of follow-up, while LV ejection fraction and wall shortening tended to decrease after the second postoperative year returned to the preoperative levels. Finally, 3 of the 5 patients who completed 5 years of follow-up died due to heart failure progression and other died suddenly up to 73 months after the operation. Furthermore, histological examinations showed important fat tissue infiltration in the skeletal muscle flap of 9 patients submitted to necropsy studies from 20 to 73 months of follow-up. These histological changes were more severe in patients with longer follow-up. In conclusion, dynamic cardiomyoplasty improves congestive heart failure and LV function in patients with idiopathic dilated cardiomyopathy. However, long-term survival after this procedure is limited in patients operated upon in functional class IV. Furthermore, the cardiomyoplasty benefits on left ventricular function appear to be limited to a midterm period and this fact may be associated with late muscle flap degeneration.

A cardiomioplastia tem sido proposta como uma alternativa ao transplante cardíaco no tratamento das cardiomiopatias isquémicas ou dilatadas. No período de maio de 1988 a outubro de 1990, 16 pacientes portadores de cardiomiopatia dilatada foram submetidos à cardiomioplastia no Instituto do Coração. Dez pacientes estavam em classe funcional III e seis em classe IV. Não houve óbitos no período de pós-operatório imediato. O tempo médio de seguimento foi de 16,9 ± 2,5 meses e a sobrevida atuarial foi 74% no 1º ano e 64,8% no 2º ano após a cardiomioplastia, sendo influenciada pela má evolução dos pacientes operados com diâmetro de ventrículo esquerdo maior do que 80 mm. Esses valores foram superiores, contudo, à sobrevida de um e dois anos de 39,5 e 29,6%, respectivamente, apresentada pelo grupo controle de 20 pacientes mantidos clinicamente (p = 0,06). Cinco dos 11 pacientes em seguimento após a cardiomioplastia, retornaram à classe funcional I e seis estão em classe II. Aos seis meses de pós-operatório, foi documentada a elevação da fração de ejeção do ventrículo esquerdo de 20,1 ± 3,8 para 26 ± 7,8% pelo estudo radioisotópico (p < 0,01), sendo que esse parâmetro se alterou principalmente em pacientes com menor dilatação da câmara ventricular esquerda. A Doppler-ecocardiografia mostrou que o encurtamento segmentar do ventrículo esquerdo se elevou de 12 ± 3,1 para 17,8 ± 2,3% (p < 0,01), enquanto que o volume sistólico aumentou de 23,6 ± 5,2 para 32,3 ± 7,9 ml (p < 0,01). Elevações semelhantes do índice sistólico, associados à queda da pressão em território pulmonar, foram também observadas pelo cateterismo cardíaco. O estudo ergoespirométrico documentou o aumento do consumo máximo de oxigênio de 14,9 ± 3,9 para 18,2 ± 3,4 ml/kg/min (p < 0,05). Um ano e aos 18 meses após a operação, as alterações decorrentes da cardiomioplastia permaneceram essencialmente as mesmas. Em conclusão, a cardiomioplastia melhora a função ventricular esquerda, reverte o quadro congestivo e melhora a sobrevida de pacientes portadores de cardiomiopatia dilatada. Fatores como a existência de grande cardiomegalia podem, contudo, influenciar a evolução tardia dos pacientes submetidos a este procedimento.

Dynamic cardiomyplasty has been proposed as an alternative surgical treatment for severe cardiomyopathies. From May 1988 to October 1990, dynamic cardiomyoplasty was performed in 16 patients with dilated or chagasic cardiomyopathy at the Heart Institute. Ten patients were in New York Heart Association (NYHA) Class III and six in Class IV. There were no operative deaths. During a men follow-up of 16.9 ± 2.5 months, the actuarial survival was 74% at 1 year and 64.8% at 2 years of follow-up. This survival was influenced by the worse evolution of patients with left ventricular internal diameter more than 80 mm. These results were, however, better than the survival of 39.5 and 29.6%, presented at the same periods, respectively, by 20 patients maintained under medical therapy. Five of the 11 surviving patients in cardiomyoplasty group are in NYHA Class I and six in Class II. At 6 months of follow-up, radioisotopic left ventricular (LV) ejection fraction increased from 20.1 ± 3.8 to 26 ± 7.8% (p < 0.01). Doppler-echocardiography demonstrated that LV segmental wall shortening improved from 12 ± 3.1 to 17.8 ± 2.3% (p < 0.01), while LV stroke volume increased from 23.6 ± 5.2 to 32.3 ± 7.9 ml (p < 0.01). Similar increases in cardiac index, associated with decreases in pulmonary artery and wedge pressures, were also demonstrated by cardiac catheterization. Cardiopulmonary exercise test showed the improvement of maximal oxygen consumption from 14,9 ± 3.9 to 18.2 ± 3.4 ml/kg/min (p < 0.05). One year and 18 months after the cardiomyoplasty, these data remained essentially unchanged. In conclusion, dynamic cardiomyoplasty improves left ventricular function, reverses congestive heart failure and may improve survival of patiens with dilated cardiomyopathies. Factors as the existence of severe left ventricular dilation may, however, limited the late results of this procedure.