Intraventricular synchronism assessment by gated-SPECT myocardial perfusion imaging in cardiac resynchronization therapy. Does cardiomyopathy type influence results?

PURPOSE: To analyze the evolution post-cardiac resynchronization therapy (CRT) in left ventricular non-compaction (LVNC) cardiomyopathy (CM) patients compared to other types of CM, according to clinical and functional variables, by using gated-SPECT myocardial perfusion imaging (MPI). METHODS: Ninety-three patients (60 ± 11 years, 28% women) referred for pre-CRT assessment were studied and divided into three groups: 1 (non-ischemic CM with LVNC, 11 patients), 2 (ischemic CM, 28 patients), and 3 (non-ischemic CM, 53 patients). All were studied by a 99mTc-MIBI gated-SPECT MPI at rest pre-CRT implantation and 6 ± 1 months after, including intraventricular dyssynchrony assessment by phase analysis. Quality of life was measured by the Minnesota Living with Heart Failure Questionnaire (MLHFQ). RESULTS: No differences in sex, atherosclerotic risk factors other than smoking habit, and MLHFQ results were found among groups. LVNC CM patients were younger, with greater QRS width and lower left ventricular ejection fraction (LVEF) at baseline, but the differences were not significant. No significant differences were found at baseline regarding ventricular function, although end-systolic volume was slightly higher in LVNC CM patients. Mean SRS was significantly higher (p < 0.0001) in ischemic patients (14.9) versus non-ischemic ones (8.7 in group 1 and 9 in group 2). At baseline, LVNC CM patients were significantly more dyssynchronous: Their phase standard deviation (PSD) was higher (89.5° ± 14.2°) versus groups 2 (65.2° ± 23.3°) and 3 (69.7° ± 21.7°), p = 0.007. Although the quality of life significantly improved in all groups, non-ischemic patients (with or without LVNC) showed a higher LVEF increase and volumes reduction at 6 months post-CRT. Dyssynchrony reduced post-CRT in all groups. Nevertheless, those more dyssynchronous at baseline (LVNC CM) exhibited the most significant intraventricular synchronism improvement: PSD was reduced from 89.5° ± 14.2° at baseline to 63.7° ± 20.5° post-CRT (p = 0.028). Six months post-CRT, 89% of patients were responders: 11 (100%) of those with LVNC CM, 25 (86%) of those with ischemic CM, and 47 (89%) of patients with non-ischemic CM. No patient with LVNC CM had adverse events during the follow-up. CONCLUSION: CRT contributes to a marked improvement in non-ischemic CM patients with non-compaction myocardium. Phase analysis in gated-SPECT MPI is a valuable tool to assess the response to CRT.

Could myocardial viability be related to left ventricular dyssynchrony? Simultaneous evaluation by gated SPECT-MPI.

BACKGROUND: Left ventricular contraction dyssynchrony (LVCD) has been related to induced ischemia and transmural scar but the interplay of myocardial viability and dyssynchrony is unknown. The aim of the present study was to establish the role of dyssynchrony in the context of a viability study performed with nitrate augmentation gated single photon emission computed tomography (GSPECT) myocardial perfusion imaging (MPI). METHODS: Fifty-four consecutive patients with ischemic dilated cardiomyopathy (IDC) and depressed left ventricular ejection fraction (LVEF) were included. They underwent a two-day rest/nitroglycerine (NTG) study GSPECT MPI to determine the myocardial viability. Patients with a nitrate-induced uptake increase of > 10% vs baseline, in at least, two consecutive dysfunctional segments were considered viable as well as those who showed no improvement in the uptake but the uptake was > 50% on post NTG study. Patients with no nitrate-induced uptake increase of > 10% and the uptake of < 50% were considered non-viable. Perfusion, function and LVCD were compared in 25 viable patients vs 29 non-viable patients at baseline and after NTG administration. RESULTS: After NTG administration, in the viable group, the LVEF increased (36.44 ± 6.64% vs 39.84 ± 6.39%) and the end-systolic volume decreased significantly (119.28 ± 31.77 mL vs 109.08 ± 33.17 mL) (P < 0.01). These patients also experienced a significant reduction in the LVCD variables: phase standard deviation was reduced in the post NTG study (57.77° ± 19.47° vs 52.02° ± 17.09°) as well as the phase histogram bandwidth (190.20° ± 78.83° vs 178.0° ± 76.14°) (P < 0.05). Functional and LVCD variables remained similar in the non-viable patients (P > 0.05). CONCLUSION: In patients with IDC and depressed LVEF, the myocardial viability detected by rest/ NTG GSPECT MPI, might determine LVCD improvement.

Association between non-perfusion parameters and presence of ischemia in gated-SPECT myocardial perfusion imaging studies.

BACKGROUND: Combined assessment of perfusion and function improves diagnostic and prognostic power of gated-SPECT in patients with coronary artery disease. The aim of this study was to investigate whether the presence of stress-induced ischemia is associated with abnormal resting left ventricular (LV) function and intraventricular dyssynchrony. METHODS AND RESULTS: Gated-SPECT myocardial perfusion imaging (MPI) at rest and 15 min post-stress was performed in 101 patients, who were divided into three groups: those with stress-induced ischemia (Group 1, n = 58), those with normal scans (Group 2, n = 28), and those with scar but no ischemia (Group 3, n = 15). More extensive perfusion defects were found in patients of Groups 1 and 3 [Summed stress score (SSS): 13 ± 8 and 21 ± 9, respectively]. In Group 2, the mean SSS was 1.5. The mean change in LV ejection fraction (LVEF at stress - LVEF at rest) was higher in Group 1 v. Group 2 patients: -5.54% ± 6.24% vs -2.46% ± 5.56%, p = 0.02. Group 3 patients also had higher values, similar to Group 1: -6.47% ± 8.82%. Patients with ischemia had almost 50% higher end-diastolic volumes than patients with normal MPI. Similarly, end-systolic volumes were almost twice as high in this group (p < 0.0001). In addition, the histogram bandwidth, a measure of intraventricular dyssynchrony, was greater in Group 1. CONCLUSIONS: Baseline differences in left ventricular volumes and degree of dyssynchrony are associated with inducible ischemia on stress testing in a gated-SPECT MPI. Stress-induced ischemia increases the degree of intraventricular dyssynchrony.

Cardiac outcomes 3 years after screening for asymptomatic coronary artery disease in patients with type 2 diabetes: value of myocardial perfusion imaging and coronary calcium score.

OBJECTIVE: The aim of the study was to identify the possible association among myocardial perfusion imaging (MPI) variables, coronary calcium score (CCS), and adverse events at medium term in type 2 asymptomatic diabetes mellitus patients. MATERIALS AND METHODS: Patients who participated in a first study that included a stress-rest MPI and a CCS assessment were asked to take part in this study. The present study protocol required a control single-photon emission computerized tomography after 3 years. Forty-one patients gave their informed consent. RESULTS: Of the 41 patients, 13 (32%) showed perfusion defects at the initial MPI. Of them, at 3 years, five continued showing perfusion defects, whereas another two had new defects (incidence of ischemia of 17%). Thus, 61% of the initial positive MPIs were normal at 3 years (P=0.04). In these cases the therapy was modified between the two studies. Left ventricular ejection fraction at stress showed a slight increase at 3 years (P=NS). Ventricular volumes significantly decreased at 3 years (P<0.01). Three patients (7.3%) developed an event during the follow-up (FU): two noncardiac deaths and one non-ST elevation myocardial infarction. The only variables that showed a possible association with the occurrence of events at FU were a CCS higher than 100 and less than 5 metabolic equivalents (METS) reached during the stress test (P=0.01). CONCLUSION: A CCS higher than 100 and a low functional capacity (<5 METS), but not an abnormal MPI, can be associated with cardiac events at 3-year FU in asymptomatic type 2 diabetic patients.

Gated SPECT myocardial perfusion imaging, intraventricular synchronism, and cardiac events in heart failure.

PURPOSE: The purpose of this study was to evaluate the ability of rest gated SPECT myocardial perfusion imaging (MPI) and intraventricular synchronism, to identify heart failure (HF) patients most likely to experience cardiac events. METHODS: We studied 165 patients with left ventricular ejection fraction of less than 40%, who were divided in 2 groups according to the diagnosis of coronary artery disease (group 1: 136 patients) or not (group 2: 29 patients). All underwent a rest gated SPECT MPI. RESULTS: In 160 patients, the MPI was abnormal. Mean summed rest score was 17 ± 6 (group 1) versus 10 ± 6 (group 2), P < 0.0001. Mean volumes showed a marked ventricular dilation, slightly higher among nonischemic. The mean value of the phase-derived SD was 70 ± 19 (group 1) versus 59 ± 21 degrees (group 2), P = 0.016. The histogram bandwidth showed no significant differences. Forty-four (39%) of 114 patients showed some kind of event during the follow-up. The more frequent events were HF progression (13%) and acute coronary syndrome (11%). The highest odds ratios for prediction of events were 1.91 (phase SD), 1.66 (etiology), and 1.55 (summed rest score), although the association was not significant. CONCLUSIONS: A rest gated SPECT is a valid approach to identify HF patients most likely to experience cardiac events.

Prognostic value of gated SPECT after reperfusion for acute myocardial infarction.

INTRODUCTION: Myocardial reperfusion during the course of an acute myocardial infarction improves patients' short- and long-term prognosis; coronary blood flow is successfully re-established while preserving a large amount of at-risk muscle. Clinical evolution, however, varies. Presence of residual ischemia or viable myocardial tissue affects a patient's prognosis. Assessment by noninvasive methods allows better prognostic stratification. Cardiac-gated SPECT provides appropriate parameters to support treatment selection and monitoring of these patients. OBJECTIVES: Assess the prognostic value--ability to predict occurrence of major cardiac events--of perfusion and cardiac function obtained by myocardial perfusion scintigraphy in myocardial infarction patients treated by any myocardial reperfusion method, whether pharmacological or surgical. METHODS: Forty patients were included, mean age 58.8 ± 9 years, diagnosed with myocardial infarction. Participants were divided into two groups: primary percutaneous transluminal coronary angioplasty (15) or thrombolysis (25). All received myocardial perfusion scintigraphy with cardiac-gated SPECT to assess perfusion and left ventricular function, and were followed for six months with telephone interviews and review of clinical records. RESULTS: In the 11 patients who had major cardiac events within six months of followup, a nonsignificant increase in perfusion defect extent was seen post reperfusion. Six (54.5%) of those with major cardiac events had anterior perfusion defects. In functional parameters, a significant increase in end-diastolic and end-systolic volumes and decrease in left ventricular ejection fraction were observed post stress (p = 0.006) and at rest (p = 0.001). Post-stress end-diastolic volume of ≥70 mL had a higher prognostic value for major cardiac events [sensitivity 100%; specificity 89%, area under ROC curve 0.835 (CI 0.702-0.969), p = 0.001]. CONCLUSIONS: Cardiac-gated SPECT is useful to identify variables (including left ventricular systolic dysfunction and dilation of left cavities, particularly left end-systolic volume of >70 mL) predictive of major cardiac events in reperfused patients, independent of treatment modality.

Gated-SPECT myocardial perfusion imaging and coronary calcium score for evaluation of patients with acute chest pain and a normal or nondiagnostic electrocardiogram.

OBJECTIVE: To assess the ability of rest myocardial perfusion imaging (MPI) to rule out an acute coronary syndrome (ACS) in emergency department patients, as well as to investigate whether there exists a concordance between MPI and coronary calcium. MATERIALS AND METHODS: Fifty-five patients with chest pain and a normal or nondiagnostic ECG were included. Clinical follow-up was carried out within 1 year. RESULTS: Sixteen patients (29%) showed an abnormal rest MPI, and in 11 (20%) the MPI was equivocal. There was a weak concordance between MPI and coronary arteries calcium score (CACS) (κ: 0.25). Coronary angiogram driven by a positive MPI was performed in 12 patients (23%), resulting in percutaneous coronary intervention in nine cases (75%). A positive MPI (abnormal or equivocal results) was associated with the occurrence of events in the follow-up (χ(2)=19.961, P<0.0001). For a patient presenting to the emergency department with acute chest pain and a normal or nondiagnostic ECG, with a positive MPI, the relative risk of having events during the first year was 7.5 (95% confidence interval: 2.8-19.2), P<0.05, but with a positive CACS this was 1.77 (95% confidence interval: 0.69-4.56), P=NS. At 1 year 68.6% of patients were free of events. CONCLUSION: Patients presenting with acute chest pain and a low-to-intermediate likelihood of coronary artery disease with a normal rest MPI have a very low probability of cardiac events during the first year. Coronary calcium score was not helpful in risk-stratifying these patients.

Interrelationship between myocardial perfusion imaging, coronary calcium score, and endothelial function in asymptomatic diabetics and controls.

BACKGROUND: Coronary artery disease is a leading cause of death among diabetics, and silent ischemia is a major concern in patients with diabetes mellitus (DM). METHODS: To detect the prevalence of ischemia in diabetics by myocardial perfusion imaging (MPI), and compare it to a control group without DM but with coronary risk factors, as well as to explore the relationship between silent ischemia, endothelial dysfunction, and coronary calcium, 59 patients (Group I) and 42 controls (Group II) were included. All underwent clinical and laboratory evaluations, gated MPI, brachial artery vasodilation measured by ultrasonography, and coronary calcium score (CCS). RESULTS: Twenty diabetics showed perfusion defects, vs seven controls (P = .04). There was no significant difference between both groups regarding the brachial artery vasodilator responsiveness: 4.49% ± 4.26% (diabetics) vs 4.70% ± 4.98% (controls). Mean CCS was 74 in diabetics vs five in controls (P = .01). The only risk factor significantly associated with an abnormal MPI was the presence of diabetes (P = .03). In the whole population of patients and in diabetics, the abnormal endothelium-dependent vasodilation, the CCS >100, and the cholesterol/HDL ratio >4, showed an OR >1. CCS exhibited the higher OR among the whole population: OR 2.15 [95% CI 0.42-10.99]; while for diabetics it was the cholesterol/HDL ratio: OR 3.95 [95% CI 0.71-21.84]. CONCLUSIONS: Reversible perfusion defects and coronary calcium are more frequent in diabetics. CCS, abnormal endothelium-dependent vasodilation, and cholesterol/HDL ratio higher than 4, showed an association with perfusion abnormalities in asymptomatic diabetics.

Left ventricular dysfunction secondary to ischemia in women with angina and normal coronary angiograms.

BACKGROUND: Microvascular disease is proposed as a cause of segmental myocardial blood flow abnormalities and heterogeneous myocardial perfusion in cardiac syndrome X. OBJECTIVE: To assess if myocardial ischemia can be evidenced through both perfusion abnormalities and poststress left ventricular ejection fraction (LVEF) reduction by gated single photon emission tomography (SPECT) myocardial scintigraphy in women with syndrome X in a similar way to those with epicardial coronary lesions. METHODS: Three groups of postmenopausal women were studied: group I, 20 women with angina, perfusion defects, and normal coronary angiography; group II, 20 women with epicardial coronary lesions (> or =50% of coronary lumen reduction); group III, 15 volunteers without signs or symptoms of ischemia (control group). Each underwent technetium-99m ((99m)TC) methoxyisobutylisonitrile gated SPECT myocardial scintigraphy (protocol: exercise-stress-rest), brachial artery endothelial function measured by ultrasonography, and lipidogram. RESULTS: Groups I and III patients had a higher body mass index (BMI). There were more smokers in groups I and II. Very low density lipoprotein cholesterol (VLDL-C) and triglycerides were higher in group II patients. The brachial artery vasodilator responsiveness after 5 minutes of ischemia was similarly lower in patients of groups I and II compared with those of group III (3% vs. 6.5%, respectively; p = 0.03 group III vs. group I and group II). Mean DeltaLVEF (LVEF poststress minus LVEF at rest) was -3.86%, -2.90%, and 4.18% in groups I, II, and III, respectively (p = NS between I and II, p = 0.005 between II and III, and p = 0.003 between I and III). In 43% of group I patients and in 10 of 18 group III patients with perfusion defects, there was a poststress LVEF reduction >5%. CONCLUSIONS: Stress-induced ischemia is associated with poststress LVEF reduction as a probable manifestation of myocardial stunning in postmenopausal women with typical angina and normal coronary angiography.

Ischemia in women with angina and normal coronary angiograms.

BACKGROUND: Coronary artery disease is frequent in postmenopausal women. Myocardial ischemia has been induced with stress testing, and a relationship between endothelial dysfunction and perfusion defects has been reported. OBJECTIVE: To evaluate whether myocardial ischemia can be evidenced both by perfusion and function abnormalities using gated single-photon emission computed-tomography myocardial scintigraphy with technetium-labeled compounds in women with typical angina, normal coronary angiography, and endothelial dysfunction. METHODS AND RESULTS: Fifty-nine postmenopausal patients were studied. Each underwent technetium-99m methoxy-isobutyl-isonitrile myocardial scintigraphy (protocol: exercise stress-rest), brachial artery endothelial function measured by ultrasonography, lipidogram, and 24-h ambulatory ECG recording (Holter). Twenty-one patients (group I) showed perfusion defects in myocardial scintigraphy, whereas the other 38 patients (group II) did not. Group I patients exhibited endothelial dysfunction more frequently (57 vs. 29%) than those of group II. Among group I patients, 12 showed a reversible perfusion defect that, in 75% of the cases, was associated with poststress left ventricular ejection fraction reduction greater than 5% and a regional hypokinesis. Nine patients had fixed defects, which in 56% of the cases were associated with poststress left ventricular ejection fraction reduction greater than 5%. Left ventricular ejection fraction poststress minus left ventricular ejection fraction at rest was -5.2% in group I patients versus -1.8% in group II (P<0.001). Three patients in group I showed evidence of ischemia by Holter compared with four in group II. CONCLUSION: Stress-induced ischemia is associated with poststress left ventricular ejection fraction reduction in postmenopausal women with typical angina, normal coronary angiography, and a trend toward abnormal endothelial-mediated vasodilation.

Mental stress-induced myocardial ischemia in women with angina and normal coronary angiograms.

BACKGROUND: Coronary artery disease is frequent in postmenopausal women. Silent myocardial ischemia has been induced with mental stress testing. METHODS AND RESULTS: To evaluate whether mental stress can induce ischemia in women with typical angina and normal coronary angiography, postmenopausal patients (n = 16) were studied. Each underwent technetium 99m methoxyisobutylisonitrile myocardial scintigraphy (exercise stress/rest/mental stress protocol), brachial artery endothelial function measurement by ultrasonography, and 24-hour ambulatory electrocardiographic recording (Holter). During mental stress testing, 6 patients (group I) had reversible perfusion defects on myocardial scintigraphy whereas the other 10 patients (group II) did not. Group I patients exhibited endothelial dysfunction more frequently than those in group II (83% vs 20%). Myocardial scintigraphy showed anteroapical/septal ischemia in 5 patients and inferoapical ischemia in one other patient, with both types of stress. Among group II patients, none showed a reversible perfusion defect during physical or mental stress. No group I patients had evidence of ischemia by Holter monitoring, whereas 2 of 10 group II patients did. CONCLUSION: In postmenopausal women with typical angina and normal coronary arteries, mental stress may provoke myocardial ischemia, which can be concordant with ischemia induced by exercise stress, and is associated with endothelial dysfunction.

Reparación del miocardio mediante la terapia con células madre / Myocardial repair with bone marrow stem cell therapy

Para evaluar la efectividad del transplante de células madre en pacientes con infarto del miocardio e insuficiencia cardíaca crónica severa mediante técnicas de cardiología nuclear, se estudiaron 15 pacientes revascularizados: nueve (grupo I) recibieron células madre autólogas de médula ósea. Los 6 restantes correspondieron al grupo II (controles). Se les realizó evaluación clínica, ventriculografía radioisotópica y gammagrafía de perfusión con SPECT-gatillado (tecnecio-99m MIBI; protocolo de dos días: dipiridamol – reposo), antes y tres meses después del proceder. A los tres meses hubo mejoría clínica en el 89 por ciento de los pacientes del grupo I. La fracción de eyección de ventrículo izquierdo aumentó: de 32±9 por ciento a 44±13 por ciento (p=0.03; grupo I) y de 38±2 por ciento a 48±14 por ciento (p NS; grupo II). La velocidad máxima de llenado se incrementó de 120±11 a 196±45 VTD/seg (p=0.03; grupo I). El score sumado del dipiridamol disminuyó significativamente sólo en el grupo I (de 35±5 a 23±14; p=0.02). La mejoría de la perfusión estuvo relacionada con el sitio de implante en el 60 por ciento de los casos. Concluimos que el transplante de células madre de médula ósea es efectivo en pacientes con insuficiencia cardíaca crónica severa de etiología isquémica.

Gammagrafía de perfusión miocárdica con Tecnecio 99m- MIBI para predecir al año, la evolución de mujeres referidas para evaluación de dolor precordial / Myocardial perfusion scintigraphy with Technetium 99m-MIBI to predict the evolution at one year of women referred for evaluation of precordial pain

Con el propósito de evaluar la capacidad de tecnecio-99m metoxi-isobutil-isonitrilo (Tc99m -MIBI) para predecir la evolución de mujeres enviadas para evaluación de dolor precordial, se estudiaron las tasas de sucesos cardiovasculares al año en un grupo de pacientes con gammagrafía normal (grupo 1: 17 pacientes) y en otro con defectos de perfusión reversible (grupo 2: 17 pacientes). Se aplicó el protocolo de un día para la gammagrafía con Tc99m -MIBI (reposo/estrés), con estrés combinado (bicicleta ergométrica más 0,28 mg/kg de dipiridamol) en los casos en que fue necesario. Se hizo análisis cualitativo y cuantitativo de la captación regional. Las pacientes del grupo 1 eran más jóvenes que las del grupo 2 (edad promedio: 49 vs 55 años, respectivamente, p=0,04); y también tuvieron menos hipercolesterolemia (12 por ciento vs 59 por ciento, respectivamente, p=0,01). Se calcularon las tasas de aparición de sucesos cardiovasculares al año para las pacientes del grupo 2 usando el método de Kaplan.-Meier. Las tasas de aparición de sucesos clínicos (infarto miocárdico y angina inestable) y de necesidad de procedimientos de revascularización (angioplastia coronaria transluminal percutánea y cirugía de bypass aortocoronario) fueron 0,24 en ambos casos. Solo una paciente del grupo 1 presentó angina variante a los 5 meses. No hubo muertes en ninguno de los grupos. El 94 por ciento de las pacientes con gammagrafía de perfusión normal estuvo libre de eventos al año de seguimiento, mientras que solo el 53 por ciento de aquellas con defectos reversibles de perfusión mostraron igual comportamiento. Concluimos que la gammagrafía de perfusión miocárdica con Tc99m -MIBI es un instrumento útil para predecir la evolución al año de mujeres referidas para evaluación de dolor precordial

El corazón en hibernación ¿isquemia miocárdica asintomática o no? / Heart at hibernation: asymptomatic myocardium ischemia or not?

Con el propósito de determinar si hay manifestaciones de isquemia en el corazón en hibernación, se estudiaron 11 pacientes con antecedentes de infarto del miocardio de más de 6 meses de evolución y fracción de eyección ventricular izquierda (FEVI) en reposo menor del 50 %, obtenida por ventriculografía nuclear. Todos los pacientes habían tenido un aumento mayor del 5 % de la FEVI, así como incremento del segmento con contractilidad afectada una hora después de recibir 60 mg de nicardipina por vía oral. A cada paciente se le realizó un ECG-Holter de 24 ó 48 horas de duración. Todos presentaron al menos un desnivel asintomático del segmento ST > 1 mm con una duración mayor de 1 minuto. El promedio de episodios de desnivel patológico del segmento ST en 24 horas fue de 2,09. La frecuencia cardíaca aumentó al inicio del desnivel un promedio de 27 latidos/min. La duración total de los desniveles del segmento ST en 24 horas fue de 23 ñ 11 minutos y el promedio de máximo desnivel fur de 1,3 mm. Excepto un episodio de angina, todos los demás fueron asintomáticos