Alexandre Baldini de Figueiredo

Sustained Ventricular Tachycardia Is Associated with Regional Myocardial Sympathetic Denervation Assessed with 123I-Metaiodobenzylguanidine in Chronic Chagas Cardiomyopathy

Cardiac sympathetic denervation and ventricular arrhythmia are frequently observed in chronic Chagas cardiomyopathy (CCC). This study quantitatively evaluated the association between cardiac sympathetic denervation and sustained ventricular tachycardia (SVT) in patients with CCC. Methods: We prospectively investigated patients with CCC and left ventricular ejection fraction (LVEF) greater than 35% with SVT (SVT group: n = 15; mean age ± SD, 61 ± 8 y; LVEF, 51% ± 8%) and patients without SVT (non-SVT group: n = 11; mean age ± SD, 55 ± 10 y; LVEF, 57% ± 10%). Patients underwent myocardial scintigraphy with 123I-metaiodobenzylguanidine (123I-MIBG) for the evaluation of sympathetic innervation and resting perfusion with 99mTc-methoxyisobutylisonitrile (99mTc-MIBI) for the evaluation of myocardial viability. A visual semiquantitative score was attributed for regional uptake of each radiotracer using a 17-segment left ventricular segmentation model (0, normal; 4, absence of uptake). A mismatch defect was defined as occurring in segments with a 99mTc-MIBI uptake score of 0 or 1 and a 123I-MIBG score of 2 or more. Results: Compared with the non-SVT group, the SVT group had a similar 99mTc-MIBI summed score (6.9 ± 7.5 vs. 4.4 ± 5.2, respectively, P = 0.69) but a higher 123I-MIBG summed score (10.9 ± 7.8 vs. 22.4 ± 9.5, respectively, P = 0.007) and a higher number of mismatch defects per patient (2.0 ± 2.2 vs. 7.1 ± 2.0, respectively, P < 0.0001). The presence of more than 3 mismatch defects was strongly associated with the presence of SVT (93% sensitivity, 82% specificity; P = 0.0002). Conclusion: In CCC, the amount of sympathetically denervated viable myocardium is associated with the occurrence of SVT. Myocardial sympathetic denervation may participate in triggering malignant ventricular arrhythmia in CCC patients with relatively well-preserved ventricular function.

Characterization of the apical aneurysm of chronic chagas' heart disease by scintigraphic image co-registration

.Recent clinical trials have shown that the presence of this cardiac lesion is an independent risk factor for cardioembolic stroke in patients with chronic Chagas’ heart disease 3-5 . Therefore, early detection of the aneurysm using several diagnostic imaging methods is clinically relevant because of its therapeutic implications. ECG-gated SPECT myocardial perfusion imaging has been recently validated for assessing left ventricular function, and is now widely used 6 . Visual analysis of tomographic slices displayed in cine mode allows the identification of dyskinetic areas, including left ventricle aneurysms, associated with ischemic heart disease 7 . Nevertheless, while many Chagasic patients undergo myocardial perfusion imaging due to symptoms suggestive of myocardial ischemia, there is no report on characterization of the apical aneurysm of chronic Chagas’ disease by gated-SPECT. Multi-gated blood pool SPECT (MUGA-SPECT), which produces images of the ventricular cavity, and gated-SPECT (which produces images of the ventricular walls) provide complementary information for better characterization of this form of ventricular lesion in chronic Chagas’ heart disease. Recent computational techniques allow these images to be aligned and co-registered, with simultaneous visualization of these structures. This report describes the anatomical and functional characteristics of apical aneurysms in chronic Chagas’ heart disease patients using different modalities of three-dimensional cardiac image co-registration, most specifically, myocardial perfusion and labeled blood pool images.

Assessment of myocardial perfusion and function in victims of scorpion envenomation using Gated-SPECT

FUNDAMENTO: O choque cardiogenico e o edema agudo de pulmao sao as principais causas de obito em pacientes com escorpionismo, cujo mecanismo fisiopatologico ainda e controverso. OBJETIVOS: Investigar a correlacao entre os disturbios da perfusao miocardica e a funcao contratil do ventriculo esquerdo, em vitimas de escorpionismo. METODOS: Quinze pacientes submeteram-se a cintilografia de perfusao miocardica sincronizada com ECG (Gated SPECT), dentro de 72 horas e 15 dias apos o acidente escorpionico. As imagens foram analisadas visualmente por escore semiquantitativo de perfusao (0 = normal, 4 = ausente) e mobilidade (0 = normal, 4 = acinetico), utilizando modelo de 17 segmentos. Para cada paciente foram calculados escores somados de perfusao (ESP) e mobilidade (ESM). A fracao de ejecao (FEVE) foi calculada por software comercialmente disponivel. RESULTADOS: Na avaliacao inicial, 12 dos 15 pacientes apresentaram alteracoes da contratilidade e da perfusao miocardica. O ESP foi de 12,5 ± 7,3, o ESM de 17,0 ± 12, 8 e a FEVE de 44,6 ± 16,0%. Houve correlacao positiva entre o ESP e o ESM (r = 0,68; p = 0,005) e negativa entre o ESP e a FEVE (r = -0,75; p = 0,0021). Os estudos de seguimento mostraram recuperacao da contratilidade global (FEVE de 68,9 ± 9,5, p = 0,0002), segmentar (ESM 2,6 ± 3,1, p = 0,0009) e da perfusao (ESP 3,7 ± 3,3, p = 0,0003). A melhora da FEVE correlacionou-se positivamente com a melhora do ESP (r = 0,72; p = 0,0035). CONCLUSOES: Alteracoes perfusionais miocardicas sao comuns no envenenamento escorpionico e correlacionam-se topograficamente com a disfuncao contratil. A recuperacao da contratilidade correlaciona-se com a reversibilidade dos defeitos perfusionais. Estes achados sugerem a participacao de alteracoes perfusionais miocardicas na fisiopatologia desta forma de insuficiencia ventricular aguda. (Arq Bras Cardiol 2010;94(4): 444-451)BACKGROUND Cardiogenic shock and acute pulmonary edema are the major causes of death of patients with scorpion envenomation, whose pathophysiological mechanism remains controversial. OBJECTIVE To investigate the correlation between myocardial perfusion abnormalities and left ventricular contractile function in victims of scorpion envenomation. METHODS Fifteen patients underwent ECG-gated myocardial perfusion scintigraphy (gated SPECT) within 72 hours of, and 15 days after scorpion envenomation. Images were analyzed by means of a semi-quantitative visual perfusion score (0 = normal, 4 = absent) and motion score (0 = normal, 4 = akinesia), using the 17-segment model. Summed perfusion (SPS) and summed motion (SMS) scores were calculated for each patient. Ejection fraction (LVEF) was calculated by a commercially available software. RESULTS At baseline, 12 out of the 15 patients presented abnormal myocardial perfusion and contractility. Mean values of SPS, SMS and LVEF were 12.5 A+/- 7.3, 17.0 A+/- 12.8, and 44.6 A+/- 16.0%, respectively. A positive correlation between SPS and SMS (r = 0.68; p = 0.005) and negative correlation between SPS and LVEF (r = -0.75; p = 0.0021) were found. The follow-up studies showed recovery of global contractility (LVEF of 68.9 A+/- 9.5, p = 0.0002), segmental contractility (SMS of 2.6 A+/- 3.1, p = 0.0009) and perfusion (SPS of 3.7 A+/- 3.3, p = 0.0003). Improvement of LVEF correlated positively with improvement of SPS (r = 0.72; p = 0.0035). CONCLUSIONS Myocardial perfusion abnormalities are common in scorpion envenomation and correlate topographically with the contractile dysfunction. Recovery of contractility correlates with reversibility of perfusion defects. These findings suggest the participation of myocardial perfusion abnormalities in the pathophysiology of this form of acute ventricular failure.

Avaliação da perfusão e função miocárdicas em vítimas de escorpionismo utilizando o Gated-SPECT

FUNDAMENTO: O choque cardiogenico e o edema agudo de pulmao sao as principais causas de obito em pacientes com escorpionismo, cujo mecanismo fisiopatologico ainda e controverso. OBJETIVOS: Investigar a correlacao entre os disturbios da perfusao miocardica e a funcao contratil do ventriculo esquerdo, em vitimas de escorpionismo. METODOS: Quinze pacientes submeteram-se a cintilografia de perfusao miocardica sincronizada com ECG (Gated SPECT), dentro de 72 horas e 15 dias apos o acidente escorpionico. As imagens foram analisadas visualmente por escore semiquantitativo de perfusao (0 = normal, 4 = ausente) e mobilidade (0 = normal, 4 = acinetico), utilizando modelo de 17 segmentos. Para cada paciente foram calculados escores somados de perfusao (ESP) e mobilidade (ESM). A fracao de ejecao (FEVE) foi calculada por software comercialmente disponivel. RESULTADOS: Na avaliacao inicial, 12 dos 15 pacientes apresentaram alteracoes da contratilidade e da perfusao miocardica. O ESP foi de 12,5 ± 7,3, o ESM de 17,0 ± 12, 8 e a FEVE de 44,6 ± 16,0%. Houve correlacao positiva entre o ESP e o ESM (r = 0,68; p = 0,005) e negativa entre o ESP e a FEVE (r = -0,75; p = 0,0021). Os estudos de seguimento mostraram recuperacao da contratilidade global (FEVE de 68,9 ± 9,5, p = 0,0002), segmentar (ESM 2,6 ± 3,1, p = 0,0009) e da perfusao (ESP 3,7 ± 3,3, p = 0,0003). A melhora da FEVE correlacionou-se positivamente com a melhora do ESP (r = 0,72; p = 0,0035). CONCLUSOES: Alteracoes perfusionais miocardicas sao comuns no envenenamento escorpionico e correlacionam-se topograficamente com a disfuncao contratil. A recuperacao da contratilidade correlaciona-se com a reversibilidade dos defeitos perfusionais. Estes achados sugerem a participacao de alteracoes perfusionais miocardicas na fisiopatologia desta forma de insuficiencia ventricular aguda. (Arq Bras Cardiol 2010;94(4): 444-451)BACKGROUND Cardiogenic shock and acute pulmonary edema are the major causes of death of patients with scorpion envenomation, whose pathophysiological mechanism remains controversial. OBJECTIVE To investigate the correlation between myocardial perfusion abnormalities and left ventricular contractile function in victims of scorpion envenomation. METHODS Fifteen patients underwent ECG-gated myocardial perfusion scintigraphy (gated SPECT) within 72 hours of, and 15 days after scorpion envenomation. Images were analyzed by means of a semi-quantitative visual perfusion score (0 = normal, 4 = absent) and motion score (0 = normal, 4 = akinesia), using the 17-segment model. Summed perfusion (SPS) and summed motion (SMS) scores were calculated for each patient. Ejection fraction (LVEF) was calculated by a commercially available software. RESULTS At baseline, 12 out of the 15 patients presented abnormal myocardial perfusion and contractility. Mean values of SPS, SMS and LVEF were 12.5 A+/- 7.3, 17.0 A+/- 12.8, and 44.6 A+/- 16.0%, respectively. A positive correlation between SPS and SMS (r = 0.68; p = 0.005) and negative correlation between SPS and LVEF (r = -0.75; p = 0.0021) were found. The follow-up studies showed recovery of global contractility (LVEF of 68.9 A+/- 9.5, p = 0.0002), segmental contractility (SMS of 2.6 A+/- 3.1, p = 0.0009) and perfusion (SPS of 3.7 A+/- 3.3, p = 0.0003). Improvement of LVEF correlated positively with improvement of SPS (r = 0.72; p = 0.0035). CONCLUSIONS Myocardial perfusion abnormalities are common in scorpion envenomation and correlate topographically with the contractile dysfunction. Recovery of contractility correlates with reversibility of perfusion defects. These findings suggest the participation of myocardial perfusion abnormalities in the pathophysiology of this form of acute ventricular failure.

The presence of contractile reserve predicts the left ventricular systolic function improvement after prolonged oral dipyridamole use in patients with non-ischemic dilated cardiomyopathy

Despite current optimized treatment including neurohormonal blockers, inmany cases chronic heart failure (HF) is a progressive disease with high morbidity and mortality [1], indicating that new treatment options are warranted. A promising therapeutic approach is the enhancement of endogenous counter-regulatory mechanisms [2] such as adenosine, a potent endogenous arteriolar vasodilator, that may contribute to alleviate the severity of the HF syndrome [3]. Previous studies reported on the use of oral dipyridamole to promote sustained increase of the circulating levels of adenosine with beneficial effects including improvement of functional capacity and LVEF at rest, mainly in patients with ischemic DCM [4,5]. The present study aimed at investigating the impact of oral dipyridamole in a population constituted exclusively by non-ischemic DCM patients, describing the individual responses of the LV systolic function and investigating the baseline LV contractile reserve as a predictor of a positive response. In this regard, LV contractile reserve has been employed to predict prognosis [6] and the favorable outcome of the ventricular function in other clinical scenarios [7,8,9]. The studywasprospectivelyconductedon31 subjectswith chronicHF due to DCMof non-ischemic etiology being followed at the outpatient HF clinic of our institution. The eligibility criteria included DCM as a cause of HF, with mild to moderate reduction of LVEF measured by echocardiography (LVEF b 50% and≥ 35%), both genders, age between 18 and 75 years. All patients were in stable clinical condition, not requiring changes in treatment within the past 3 months. The exclusion criteria were advanced or decompensated heart failure, cardiac valve disease, asthma or chronic obstructive pulmonary disease with bronchial hyperreactivity, pregnancy or important disorder of heart rhythm that prevents the effective acquisition of ECG-synchronized scintigraphic images. Coronary artery disease was ruled out by the finding of a normal stressrest myocardial perfusion imaging or by coronary artery angiography in patients presenting an abnormal myocardial perfusion study (n= 10). Patients were submitted to a radionuclide ventriculography (RNV) at rest and during graded exercise at baseline evaluation and after a two-month period of treatment with oral dipyridamole, 75 mg TID, in addition to the standard HF pharmacological treatment. The studywas conducted according to the precepts of the Helsinki Declaration and was approved by the Research Ethics Committee of our institution. All patients gave written informed consent to participate. Multigated planar equilibrium RNVwas performed with a medium field-of-view gamma camera (Orbiter Siemens, Erlangen, Germany), with a frame rate of 16 frames/cardiac cycle. An initial rest image was followed by the exercise phase. The effort was limited by symptoms and was performed in the supine position on a cycle-ergometer, with stages of 3 min and increments of 25 W per stage; images were acquired during exercise within the last 2 min of each stage. The presence of significant LV contractile reserve in individual patients was defined as an LVEF increase during exercise≥5%. For this analysis the higher value of the LVEF during exercise was considered. The Shapiro–Wilk test was used to test whether the variables showed normal distribution. For comparison of the normally distributed variable mean values we used the Student paired test, for correlation analysis we used the Pearson correlation test and Fischers exact test was used to test the association between the nominal variables. The level of significance was set at p b 0.05 in all analyses. The software Stata® (StataCorp. 2011; Release 12. College Station, TX: StataCorp LP) was used in all analyses. Demographic and clinical characteristics of the study population at the baseline evaluation are summarized in Table 1.

Evaluación de la perfusión y función miocárdicas en víctimas de escorpionismo utilizando el Gated-SPECT

FUNDAMENTO: O choque cardiogenico e o edema agudo de pulmao sao as principais causas de obito em pacientes com escorpionismo, cujo mecanismo fisiopatologico ainda e controverso. OBJETIVOS: Investigar a correlacao entre os disturbios da perfusao miocardica e a funcao contratil do ventriculo esquerdo, em vitimas de escorpionismo. METODOS: Quinze pacientes submeteram-se a cintilografia de perfusao miocardica sincronizada com ECG (Gated SPECT), dentro de 72 horas e 15 dias apos o acidente escorpionico. As imagens foram analisadas visualmente por escore semiquantitativo de perfusao (0 = normal, 4 = ausente) e mobilidade (0 = normal, 4 = acinetico), utilizando modelo de 17 segmentos. Para cada paciente foram calculados escores somados de perfusao (ESP) e mobilidade (ESM). A fracao de ejecao (FEVE) foi calculada por software comercialmente disponivel. RESULTADOS: Na avaliacao inicial, 12 dos 15 pacientes apresentaram alteracoes da contratilidade e da perfusao miocardica. O ESP foi de 12,5 ± 7,3, o ESM de 17,0 ± 12, 8 e a FEVE de 44,6 ± 16,0%. Houve correlacao positiva entre o ESP e o ESM (r = 0,68; p = 0,005) e negativa entre o ESP e a FEVE (r = -0,75; p = 0,0021). Os estudos de seguimento mostraram recuperacao da contratilidade global (FEVE de 68,9 ± 9,5, p = 0,0002), segmentar (ESM 2,6 ± 3,1, p = 0,0009) e da perfusao (ESP 3,7 ± 3,3, p = 0,0003). A melhora da FEVE correlacionou-se positivamente com a melhora do ESP (r = 0,72; p = 0,0035). CONCLUSOES: Alteracoes perfusionais miocardicas sao comuns no envenenamento escorpionico e correlacionam-se topograficamente com a disfuncao contratil. A recuperacao da contratilidade correlaciona-se com a reversibilidade dos defeitos perfusionais. Estes achados sugerem a participacao de alteracoes perfusionais miocardicas na fisiopatologia desta forma de insuficiencia ventricular aguda. (Arq Bras Cardiol 2010;94(4): 444-451)BACKGROUND Cardiogenic shock and acute pulmonary edema are the major causes of death of patients with scorpion envenomation, whose pathophysiological mechanism remains controversial. OBJECTIVE To investigate the correlation between myocardial perfusion abnormalities and left ventricular contractile function in victims of scorpion envenomation. METHODS Fifteen patients underwent ECG-gated myocardial perfusion scintigraphy (gated SPECT) within 72 hours of, and 15 days after scorpion envenomation. Images were analyzed by means of a semi-quantitative visual perfusion score (0 = normal, 4 = absent) and motion score (0 = normal, 4 = akinesia), using the 17-segment model. Summed perfusion (SPS) and summed motion (SMS) scores were calculated for each patient. Ejection fraction (LVEF) was calculated by a commercially available software. RESULTS At baseline, 12 out of the 15 patients presented abnormal myocardial perfusion and contractility. Mean values of SPS, SMS and LVEF were 12.5 A+/- 7.3, 17.0 A+/- 12.8, and 44.6 A+/- 16.0%, respectively. A positive correlation between SPS and SMS (r = 0.68; p = 0.005) and negative correlation between SPS and LVEF (r = -0.75; p = 0.0021) were found. The follow-up studies showed recovery of global contractility (LVEF of 68.9 A+/- 9.5, p = 0.0002), segmental contractility (SMS of 2.6 A+/- 3.1, p = 0.0009) and perfusion (SPS of 3.7 A+/- 3.3, p = 0.0003). Improvement of LVEF correlated positively with improvement of SPS (r = 0.72; p = 0.0035). CONCLUSIONS Myocardial perfusion abnormalities are common in scorpion envenomation and correlate topographically with the contractile dysfunction. Recovery of contractility correlates with reversibility of perfusion defects. These findings suggest the participation of myocardial perfusion abnormalities in the pathophysiology of this form of acute ventricular failure.