Antonio Osvaldo Pintya

Relation of regional sympathetic denervation and myocardial perfusion disturbance to wall motion impairment in Chagas' cardiomyopathy

Impairment of sinus node autonomic control and myocardial perfusion disturbances have been described in patients with chronic Chagas cardiomyopathy. However, it is not clear how these conditions contribute to myocardial damage. In this investigation, iodine-123 (I-123) meta-iodobenzylguanidine (MIBG) and thallium-201 myocardium segmental uptake were studied in correlation with the severity of left ventricular (LV) dysfunction detected in various phases of Chagas heart disease. Group I consisted of 12 subjects (43 +/- 4 years, 7 men) with no symptoms and no cardiac involvement on electrocardiogram (ECG) or echocardiography; group II consisted of 13 patients (48 +/- 3 years, 9 men) with abnormal resting ECG and/or echocardiographic segmental abnormalities, and LV ejection fraction of > or = 0.5; group III was comprised of 12 patients (59 +/- 3 years, 10 men) with more severe heart disease, LV dilation, and LV ejection fraction of < 0.5. Eighteen control volunteers (38 +/- 3 years, 9 men) were also included in the study. I-123 MIBG single-photon emission computed tomographic (SPECT) segmental uptake defects were observed in group I (33%), group II (77%), and group III (92%). Quantitative analysis showed mean areas of reduced LV I-123-MIBG uptake: group I was 3.7 +/- 2.1%; group II was 8.3 +/- 2.3%; and group III was 19.0 +/- 3.3%. The differences between group I and both groups II and III were statistically significant (p < 0.001, analysis of variance test). Myocardial perfusion defects (reversible, fixed, and paradox) were observed in group I (83%), group II (69%), and group III (83%). A marked topographic association between perfusion, innervation, and wall motion abnormalities (assessed by gated-SPECT perfusion studies) was observed in all the groups. Defects predominated in the inferior, posterior lateral, and apical LV regions. Thus, extensive impairment of cardiac sympathetic function at the ventricular level occured early in the course of Chagas cardiomyopathy and was related to regional myocardial perfusion disturbances, before wall motion abnormalities. Both conditions are associated with progression of ventricular dysfunction.

Abnormal baroreflex control of heart rate in decompensated congestive heart failure and reversal after compensation

Congestive heart failure (CHF) causes impairment of baroreflex control of heart rate (HR). To determine if this derangement is reversible, the cardiac chronotropic control was assessed in 10 patients with class IV chronic CHF of various etiologies before and after compensation achieved by bed rest, salt restriction, diuretics and vasodilators. Mean time between the 2 studies was 15 +/- 3 days. The management was modified 3 days before the second autonomic evaluation, so as to reestablish the same diet and pharmacologic conditions of the previous study. Compensation led to significant reduction in symptom-based class, body weight, and pulmonary and systemic congestion. Mean +/- standard error of the mean HR responses (beats/min) before and after compensation were, respectively: (1) to atropine (0.04 mg/kg): 10 +/- 2 and 27 +/- 2 (p less than 0.01); (2) to handgrip (30% maximum capacity, 1 minute): 9 +/- 2 and 19 +/- 3 (p less than 0.005); (3) to headup tilt (5 minutes): 4 +/- 3 and 20 +/- 4 (p less than 0.005). Mean +/- standard error of the mean baroreflex sensitivity (ms/mm Hg) of RR responses to phenylephrine and amyl nitrate-induced changes in systolic pressure was, respectively, in each condition: phenylephrine, 0.9 +/- 0.2 and 8 +/- 2.3 (p less than 0.05); amyl nitrate, 0.3 +/- 0.2 and 4.1 +/- 1.1 (p less than 0.05). A significant correlation between improvement in HR responses to atropine and tilt and changes in body weight was obtained. These findings show a reversible component of impaired baroreflex control of HR in severe CHF, possibly due to its congestive effects.

Evaluation of the Autonomic Nervous System of the Heart in Male Patients with Mitral Valve Prolapse Syndrome Using Respiratory Sinus Arrhythmia and Dynamic Exercise

The autonomic nervous system of the heart was evaluated in two male groups composed of 11 patients with mitral valve prolapse and of 10 normal subjects, using the heart rate response in two types of tests: respiratory sinus arrhythmia at rest and dynamic exercise. Sinus arrhythmia was of higher magnitude in patients with mitral valve prolapse when compared to the control group; however, the differences reached statistical significance only at a respiratory frequency of 7 cycles/min. With respect to dynamic exercise (25, 50, 100, 150 W during 4 min), the heart rate response, either in terms of the early, vagus-dependent fast tachycardia (first 10 s), or the late, sympathetic-dependent tachycardia (1-4 min) was normal in both groups studied, the same occurring with aerobic exercise capacity evaluated by measurement of the anaerobic threshold. Thus, our results show that in the group of male patients with mitral valve prolapse studied here, the parasympathetic abnormalities, if present, are of questionable physiological significance and do not affect the sympathetic and parasympathetic control of heart rate during dynamic exercise.

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.

The severity of ventricular arrhythmia correlates with the extent of myocardial sympathetic denervation, but not with myocardial fibrosis extent in chronic Chagas cardiomyopathy : Chagas disease, denervation and arrhythmia.

BackgroundTo investigate the correlation between the extent of myocardial sympathetic denervation and fibrosis and the presence of degrees of severity of ventricular arrhythmias in chronic Chagas cardiomyopathy (CCC).MethodsForty-three CCC patients with left ventricular ejection fraction (LVEF) ≥ 35% were divided into three groups: SVT group—presenting Sustained Ventricular Tachycardia (SVT) (nxa0=xa015), NSVT group—exhibiting episodes of non-SVT (NSVT) on 24-h Holter monitoring (nxa0=xa011), and Control group—exhibiting neither SVT nor episodes of NSVT (nxa0=xa017). The patients underwent SPECT imaging for myocardial sympathetic innervation with 123Iodine-MIBG (MIBG) and myocardial perfusion with 99mTc-Sestamibi (MIBI) for the evaluation of regional myocardial fibrosis.ResultsThe summed rest perfusion scores were similar in the three groups. The summed difference score between MIBG and MPI images, which evaluated the extent of denervated but viable myocardium, was significantly higher in SVT group (20.0xa0±xa08.0) as compared with the control group (2.0xa0±xa05.0, Pxa0<xa0.0001) and with the NSVT group (11.0xa0±xa08.0, Pxa0<xa0.05).ConclusionsThe occurrence of ventricular arrhythmias of different degrees of severity correlates quantitatively with the extent of cardiac sympathetic denervation, but not with the extent of fibrosis, suggesting that myocardial sympathetic denervation plays a major role in triggering ventricular arrhythmia in CCC.

Pilot study testing the effect of physical training over the myocardial perfusion and quality of life in patients with primary microvascular angina

BackgroundPrimary microvascular angina (PMA) is a common clinical condition associated to negative impact on quality of life (QOL) and reduced physical capacity. This study aimed at evaluating the effects of aerobic physical training (APT) on myocardial perfusion, physical capacity, and QOL in patients with PMA.MethodsWe investigated 12 patients (53.8xa0±xa09.7xa0years old; 7 women) with PMA, characterized by angina, angiographycally normal coronary arteries, and reversible perfusion defects (RPDs) detected on 99mTc-sestamibi-SPECT myocardial perfusion scintigraphy (MPS). At baseline and after 4xa0month of APT, the patients underwent MPS, cardiopulmonary test, and QOL questionnaire. Stress-rest MPS images were visually analyzed by attributing semi-quantitative scores (0xa0=xa0normal; 4xa0=xa0absent uptake), using a 17-segment left ventricular model. Summed stress, rest, and difference scores (SDS) were calculated.ResultsIn comparison to the baseline, in the post-training we observed a significant increase in peak-VO2 (19.4xa0±xa04.8 and 22.1xa0±xa06.2xa0mL·kg−1·minute−1, respectively, Pxa0=xa0.01), reduction of SDS (10.1xa0±xa08.8 and 2.8xa0±xa04.9, Pxa0=xa0.008), and improvement in QOL scores.ConclusionsPhysical training in patients with PMA is associated with reduction of myocardial perfusion abnormalities, increasing of physical capacity, and improvement in QOL. The findings of this hypothesis-generating study suggest that APT can be a valid therapeutic option for patients with PMA.

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)BACKGROUNDnCardiogenic shock and acute pulmonary edema are the major causes of death of patients with scorpion envenomation, whose pathophysiological mechanism remains controversial.nnnOBJECTIVEnTo investigate the correlation between myocardial perfusion abnormalities and left ventricular contractile function in victims of scorpion envenomation.nnnMETHODSnFifteen 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.nnnRESULTSnAt 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).nnnCONCLUSIONSnMyocardial 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)BACKGROUNDnCardiogenic shock and acute pulmonary edema are the major causes of death of patients with scorpion envenomation, whose pathophysiological mechanism remains controversial.nnnOBJECTIVEnTo investigate the correlation between myocardial perfusion abnormalities and left ventricular contractile function in victims of scorpion envenomation.nnnMETHODSnFifteen 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.nnnRESULTSnAt 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).nnnCONCLUSIONSnMyocardial 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.

Replacement of carvedilol for propranolol in patients with heart failure

BACKGROUNDnLarge clinical trials using the betablockers carvedilol, metoprolol, bisoprolol and nebivolol have demonstrated improvement of survival and symptoms in patients with heart failure. Despite the lack of scientific evidence, it is plausible that their beneficial effects are extensible to other betablockers.nnnOBJECTIVEnTo evaluate the impact of the replacement of carvedilol for propranolol on left ventricular function, functional capacity, quality of life, pressure levels, and cardiac autonomic control in patients with heart failure.nnnMETHODSnTwenty nine patients receiving optimized drug therapy including maximum tolerated doses of carvedilol were divided into two groups: replacement of carvedilol for propranolol (n = 15) and continued carvedilol (n = 14). At baseline and 6 months later, clinical and laboratorial assessments were carried out with radionuclide ventriculography, echocardiography, Minnesota questionnaire, walk test, APBM and Holter monitoring.nnnRESULTSnThe clinical and demographic characteristics were similar in the two groups at baseline. Individualized propranolol dose adjustment ensured a similar degree of beta-blockade, as assessed by resting heart rate and chronotropic reserve. The mean propranolol dose used was 109 +/- 43 mg/day. Only one patient presented with intolerance to propranolol, thus carvedilol was reintroduced. One death was recorded in group propranolol. Ejection fraction significantly increased in the propranolol group. No significant change was observed in the other cardiovascular variables after betablocker replacement.nnnCONCLUSIONnOur results indicate that replacement of carvedilol for propranolol in patients with heart failure is not associated with deterioration of the ejection fraction, functional capacity, quality of life, and other cardiovascular variables related to autonomic and blood pressure control., PP.0-0).FUNDAMENTO: Grandes estudos clinicos empregando os betabloqueadores carvedilol, metoprolol, bisoprolol e nebivolol, demonstraram melhora da sobrevida e dos sintomas em pacientes com insuficiencia cardiaca. Apesar da falta de evidencias cientificas, e plausivel que o efeito benefico seja extensivel a outros betabloqueadores. OBJETIVO: Avaliar em pacientes com insuficiencia cardiaca o impacto da substituicao do carvedilol por propranolol sobre a funcao ventricular esquerda, capacidade funcional, qualidade de vida, niveis pressoricos e controle autonomico cardiaco. METODOS: Vinte e nove pacientes com terapeutica medicamentosa otimizada incluindo doses maximas toleradas de carvedilol foram divididos em dois grupos: substituicao de carvedilol por propranolol (n = 15) e manutencao de carvedilol (n = 14). Na condicao basal, e apos 6 meses, foram realizadas avaliacoes clinica e laboratorial com: ventriculografia nuclear, ecocardiografia, questionario de Minnesota, teste de caminhada, MAPA e Holter. RESULTADOS: As caracteristicas laboratoriais e demograficas foram similares nos dois grupos na avaliacao inicial. Ajuste individualizado da dose do propranolol garantiu grau semelhante de betabloqueio avaliado pela frequencia cardiaca em repouso e reserva cronotropica. A dose media de propranolol usada foi 109 ± 43 mg/dia. Apenas um paciente apresentou intolerância ao propranolol com retorno do carvedilol. Foi registrado um obito no grupo propranolol. A fracao de ejecao apresentou aumento significativo no grupo propranolol. As demais variaveis cardiovasculares nao sofreram modificacoes significativas apos troca do betabloqueador. CONCLUSAO: Nossos resultados indicam que a substituicao do carvedilol por propranolol em pacientes com insuficiencia cardiaca nao esta associada a deterioracao da fracao de ejecao, da capacidade funcional, da qualidade de vida e das variaveis cardiovasculares de controle pressorico e autonomico.

Persistência de distúrbios perfusionais miocárdicos após intervenção coronária percutânea com êxito: dependência de fatores microcirculatórios

INTRODUCTION: The transitory persistence of perfusion defects immediately after successful percutaneous coronary interventions to correct coronary stenosis is well known METHODS: To test the hypothesis that such perfusion abnormalities are associated with microcirculatory disorders caused by coronary microembolization we compared the intensity and extent of these perfusion defects detected using myocardial scintigraphy in groups of patients randomly assigned to coronary balloon angioplasty (BA) or to rotational atherectomy plus balloon angioplasty (RA + B). The clinical and angiography characteristics were comparable in both groups, as well as the success of the coronary angioplasty procedure. RESULTS: Before the percutaneous coronary intervention the myocardium defect index, related to the extent and severity of hypoperfusion, was comparable for the two groups, both under stress (AB = 7.72±1.91 vs. RA + B = 8.61±3.38) and at rest (AB = 3.11±1.22 vs. RA + B = 2.40±1.63). After the procedure, the perfusion defect index decreased for both groups during stress, but with statistical significance only in the AB Group = 3.96±1.40 vs. RA + B = 3.71±1.89. The difference between the two groups was greater at rest after the coronary intervention procedure: the defect index decreased with marginal significance for the AB Group to 1.46±0.66 and increased, though without statistical significance, for the RA + B Group to 3.47±1.92. CONCLUSION: These results are compatible with the notion that transitory persistence of perfusion defects after successful coronary angioplasty are dependent on microcirculatory disorders associated to microembolization during the procedure.