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: no estudo de perfusão miocárdica, apesar dos avanços tecnológicos, continuamos utilizando o desconfortável e às vezes impraticável posicionamento em decúbito dorsal com braços acima da cabeça (U). O objetivo do estudo foi investigar se os resultados da perfusão e da função cardíacas obtidos com a aquisição U são equivalentes ao de outra modalidade de posição: com braços para baixo nas laterais do tronco (D). Métodos e resultados: adquirida a aquisição U, na sequência foi realizada a aquisição D em 120 pacientes (pts) em um único dia (repouso e estresse sincronizado ao ECG), com 99mTc-sestamibi (370 MBq e 1110 MBq). As imagens foram processadas usando reconstrução iterativa (OSEM). Cada estudo foi quantificado usando o modelo de 17-segmentos ao repouso (R) e ao estresse (S). Os parâmetros funcionais (fração de ejeção do ventrículo esquerdo e volumes) foram obtidas automaticamente pelo programa gated SPECT quantitativa (QGS). De acordo com a dimensão da alteração perfusional no estresse na aquisição U, os pacientes foram classificados em dois subgrupos: 80 pts normais (SSS ≤ 3 ou < 5%) e 40 pts anormais (SSS > 3 ou ≥ 5%). Dor no ombro e/ou nas costas ocorreu em 23,3% dos pacientes de U e em 5% de D. Não houve diferenças significativas entre U e D quanto ao SSS (p = 0,82) e SRS (p = 0,74) no grupo normal. No grupo anormal, boa correlação foi encontrada entre U e D para SSS (Rho = 0,95, p = 0,0001) e SRS (Rho = 0,96 p = 0,0001), entretanto a média dos valores de SSS (12,53 ± 7,54) e SRS (10,60 ± 7,08 ) de D foram significativamente menores (p < 0,05) que o SSS (13,43 ± 6,81) e SRS (11,33 ± 6,97) de U. As medidas de função apresentaram boas correlações, exceto para o volume diastólico final (p = 0,0001). Conclusão: embora o modo D pareça ser mais confortável e apresente boa correlação com valores de SSS e SRS do modo U, em pacientes anormais, a extensão e a gravidade dos defeitos podem ser subestimadas. Considerando as implicações clínicas da precisa avaliação da extensão de alterações na perfusão miocárdica, a aquisição com os braços para baixo deve ser evitada.

Objective: despite the technologic advances in myocardial perfusion imaging, we keep using an uncomfortable and sometimes impracticable patient position - supine with arms raised above the head (U). The purpose of this study was to investigate whether perfusion and functional cardiac gated SPECT scan results of acquisition U are equivalent to another position modality: supine with arms down at the sides of the trunk (D). Methods and Results: we performed U acquisition and in sequence D acquisition in 120 patients (pts) using a one-day MPI (rest-gated/stress), with 99mTc-sestamibi (370 MBq and 1110 MBq). Images were processed by the iterative reconstruction method (OSEM). Rest (R) and stress (S) studies were scored using 17-segments model. Functional parameters (left ventricular ejection fraction, and volumes) were automatically obtained by the quantitative gated SPECT (QGS) program. According to the degree of stress defects observed in U study, the patients were categorized in two subgroups: normal (SSS ≤ 3 or < 5%) and abnormal (SSS>3 or ≥ 5%). Shoulder/back pain occurred in 23.3% of U patients and in 5% of D. No significant differences between U and D were found for SSS (p = 0.82) and SRS (p = 0.74) in normal group. In abnormal group, good correlation was found between U and D modes for SSS (Rho = 0.95, p = 0.0001) and SRS (Rho = 0.96 p = 0.0001), but the mean SSS (12.53 ± 7.54) and SRS (10.60 ± 7.08) values of D were significantly lower (p < 0.05) than SSS (13.43 ± 6.81) and SRS (11.33 ± 6.97) of U mode. Function measurements presented good correlations, except for end-diastolic volume (p = 0.0001). Conclusion: although D mode appears to be more comfortable and presented a good correlation with U values of SSS and SRS, in abnormal pts, the extent and severity of defects can be underestimated. Considering clinical implications of an accurate perfusion measurement, the acquisition with the arms down should be avoided.

FUNDAMENTO: O infarto do miocárdio perioperatório (IMPO) é uma complicação da cirurgia de revascularização miocárdica (CRM) com potencial impacto prognóstico. A cintilografia miocárdica (CM) com pirofosfato marcado com tecnécio-99m é utilizada no diagnóstico de IMPO, mas demonstra limitada sensibilidade para lesões subendocárdicas. A ressonância magnética cardiovascular (RMC), por sua vez, detém alta acurácia para a detecção de necrose miocárdica. OBJETIVO: Comparar a RMC e a CM para a detecção de IMPO após CRM. MÉTODOS: Foram estudados 24 pacientes portadores de doença arterial coronária crônica, com a técnica de realce tardio pela RMC e com a CM, antes e depois da CRM, analisando-se o surgimento de áreas de necrose miocárdica perioperatória (IMPO). Mensuraram-se também marcadores bioquímicos de lesão miocárdica (CKMB e troponina I), antes e depois da cirurgia. RESULTADOS: Dezenove pacientes completaram o estudo. Desses, 6 (32%) apresentaram IMPO à RMC, e 4 (21%) à CM (p = NS). Dos 323 segmentos do ventrículo esquerdo avaliados, 17 (5,3%) exibiram necrose perioperatória à RMC, e 7 (2,2%) à CM (p = 0,013). Observou-se moderada concordância entre os métodos (kappa = 0,46), havendo divergência, quanto ao diagnóstico de IMPO, em 4 (21%) casos, a maioria com pequenas áreas de necrose perioperatória à RMC, não visualizadas à CM. Em todos os casos com IMPO à RMC, houve elevação significativa de CKMB e troponina I. CONCLUSÃO: Houve moderada concordância diagnóstica entre os métodos para a detecção de IMPO, mas a RMC permitiu a visualização de pequenas áreas de necrose miocárdica perioperatória, não identificadas pela CM e associadas à elevação de marcadores bioquímicos de lesão miocárdica.

BACKGROUND: Perioperative myocardial infarction (POMI) is a complication of coronary artery bypass grafting (CABG) with a potential prognostic impact. Technetium-99m pyrophosphate myocardial scintigraphy (MS) is used in the diagnosis of POMI; however it shows a limited sensitivity for subendocardial lesions. Cardiovascular magnetic resonance imaging (CMRI), in turn, has a high accuracy in the detection of myocardial necrosis. OBJECTIVE: To compare CMRI and MS for the detection of POMI after CABG. METHODS: A total of 24 patients with chronic coronary artery disease were studied using the delayed contrast enhanced CMRI and MS before and after CABG by analyzing the development of areas of perioperative myocardial necrosis (POMI). Biochemical markers of myocardial injury (CKMB and troponin I) were also determined before and after surgery. RESULTS: Nineteen patients completed the study. Of these, 6 (32%) presented POMI on CMRI and 4 (21%) on MS (p = NS). Of the 323 left ventricular segments assessed, 17 (5.3%) showed perioperative necrosis on CMRI and 7 (2.2%) on MS (p = 0.013). Moderate agreement was observed between the methods (kappa = 0.46). There was disagreement regarding the diagnosis of POMI in 4 (21%) cases, most of them with small areas of perioperative necrosis on CMRI which were not visualized on MS. In all cases with POMI on CMRI, significant CKMB and troponin I elevations were observed. CONCLUSION: Moderate diagnostic agreement was observed between the methods for the detection of POMI, but CMRI enabled visualization of small areas of perioperative myocardial necrosis which were not identified on MS and were associated with elevation of biochemical markers of myocardial injury.

OBJETIVO: Estabelecer parâmetros de sincronia intra- e interventricular em indivíduos normais e compará-los aos de pacientes com miocardiopatia dilatada com e sem distúrbios de condução ao eletrocardiograma (ECG). MÉTODOS: Três grupos de pacientes foram incluídos no estudo: 18 indivíduos (G1) sem cardiopatia e com ECG normal (52+/-12 anos, 29% masculinos); 50 portadores de miocardiopatia dilatada e disfunção ventricular esquerda grave, sendo 20 pacientes (G2) com QRS < 120 ms (51+/-10 anos, 75% masculinos) e 30 pacientes (G3) com QRS > 120 ms (57+/-12 anos, 60% masculinos). Todos foram submetidos à ventriculografia radioisotópica (VR). Para avaliar dissincronia intraventricular esquerda foi estudada a largura do histograma de fase e para avaliar dissincronia interventricular foi medida a diferença da média do ângulo de fase entre o ventrículo direito e o esquerdo (DifDE). RESULTADOS: As frações de ejeção do ventrículo esquerdo (FEVE)s foram: 62±6% (G1), 27±6% (G2) e 22±7% (G3) e do VD foram: 46 ± 4% (G1), 38±9%(G2) e 37±9% (G3). A avaliação da largura do histograma de fase foi de: 89±18 ms (G1), 203±54 ms (G2) e 312±130 ms (G3), p<0,0001. A medida da difVDVE foi de: 14±11 ms (G1), 39±40 ms (G2) e 87±49 ms (G3); quando se compararam G1 x G2 e G1 x G3, p<0,0001 e G2 x G3, p=0,0007. CONCLUSÃO: Os parâmetros analisados discriminam os três grupos de pacientes de acordo com o grau de sincronia ventricular. Pacientes com miocardiopatia dilatada e sem bloqueio de ramo ao ECG (QRS < 120 ms) podem apresentar dissincronia, porém em menor grau que os pacientes com QRS alargado.

OBJECTIVE: To establish the parameters of intra- and interventricular synchrony in normal individuals and to compare them with patients with dilated cardiomyopathy with and without conduction disorders shown in the electrocardiogram (ECG) examination. METHODS: Three groups of patients were included in this study: 18 individuals (G1) with no cardiomyopathy and with a normal ECG (52±12 years, 29% male); 50 patients with dilated cardiomyopathy and severe left ventricular dysfunction, with 20 patients (G2) presenting QRS <120ms (51±10 years, 75% male) and 30 patients (G3) with QRS >120ms (57±12 years, 60% male). All patients underwent RV. Evaluation of left intraventricular dyssynchrony was carried out with the measurement of the phase histogram width and interventricular dyssynchrony was evaluated by the difference of the mean phase angle between the right and left ventricles (RLDif). RESULTS: Left ventricle ejection fractions (LVEF)s were: 62 ± 6% (G1), 27 ± 7% (G2) and 22 ± 8% (G3) and right ventricle ejection fractions were: 46 ± 5% (G1), 41 ± 6%(G2) and 38 ± 8% (G3). Evaluation of the phase histogram width was: 89 ± 18 ms (G1), 203 ± 54 ms (G2) and 312 ± 130 ms (G3), p<0.0001. The measurement of RLDif was: 14 ± 11 ms (G1), 39 ± 40 ms (G2) and 87 ± 49 ms (G3); comparing G1 vs. G2 and G1 vs. G3, p<0.0001 and G2 vs. G3, p=0.0007. CONCLUSION: The parameters analyzed discriminate the three groups of patients according to the ventricular synchrony degree. Patients with dilated cardiomyopathy and withno branch block in ECG (QRS <120 ms) may present dyssynchrony, but at a lower degree than patients with widened QRS.