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.

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.

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