Persistência de distúrbios perfusionais miocárdicos após intervenção coronária percutânea com êxito: dependência de fatores microcirculatórios / Myocardial perfusion disturbances persisting after successful percutaneous coronary angioplasty: relationship to microcirculatory derangements

Introdução: A persistência transitória de defeitos perfusionais imediatamente após intervenção coronária percutânea bem sucedida para correção de estenoses coronárias é bem documentada. Método: Para testar a hipótese de que tais anormalidades perfusionais sejam associadas a distúrbios microcirculatórios causados por microembolização coronária, comparou-se a intensidade e extensão desses defeitos perfusionais detectados com cintilografia miocárdica em grupos randomicamente constituídos de pacientes tratados com angioplastia coronária por balão (AB) ou submetidos a aterectomia rotacional complementada por balão (AR + B). As características clínicas e angiográficas foram comparáveis nos dois grupos, assim como o sucesso do procedimento de angioplastia coronária. Resultados: Antes da intervenção coronária percutânea, o índice de defeito miocárdico, englobando a extensão e a gravidade da hipoperfusão, foi comparável nos dois grupos, na condição de estresse (AB = 7,72±1,91 vs AR + B = 8,61±3,38) e de repouso (AB = 3,11±1,22 vs AR + B = 2,40±1,63). Após o procedimento, o índice de defeito perfusional decresceu em ambos os grupos durante o estresse, mas com significância estatística apenas no grupo AB = 3,96±1,40 vs AR + B = 3,71 ±1,89. O contraste entre os dois grupos se acentuou na condição de repouso após a intervenção coronária: o índice de defeito decresceu de forma marginalmente significante no grupo AB para 1,46±0,66 e aumentou, embora sem significância estatística, no grupo AR + B, para 3,47±1,92. Conclusão: Esses resultados são compatíveis com o conceito de que a persistência transitória de defeitos perfusionais após angioplastia coronária bem sucedida seja dependente de distúrbios microcirculatórios associados à microembolização durante o procedimento.

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 successof 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±1.22vs. 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

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.

[Detection of myocardial ischemia in chronic Chagas disease patients with atypic precordial pain by exercise and Holter tests]. / Detecção de isquemia miocárdica em chagásicos crônicos com precordialgia atípica pelos testes de esforço e Holter.

PURPOSE: To determine the incidence and characteristics of myocardial ischemia, as detected by stress electrocardiography and Holter monitoring in Chagas' patients whose main complaint was precordial pain. METHODS: Thirty-one consecutive patients with Chagas' disease diagnosed on the basis of clinical and serological tests, and precordial pain severe enough to warrant cardiac catheterization were studied. Mean age was 54.4 +/- 9.6 years, and 51% were males. EKG changes indicative of myocardial ischemia were sought during maximal exercise and also during 24-hour Holter monitoring. The detection of myocardial ischemia by each one of these tests was compared by Fischer exact test, and also correlated to anatomical and functional results of coronary angiography at rest and after standardized hyperventilation for detecting coronary vasospasm. RESULTS: Baseline EKG changes mainly associated with ventricular conduction defects precluded the analysis of the ST segment in 11 patients. Among the other 20 patients, 7(35%) had angina during the exercise test, of whom only 2(10%) showed concomitant ischemic ST changes: one had 90% stenosis in the circumflex branch and the other 50% reduction of luminal diameter in a intramyocardial segment of the left anterior descending coronary artery, undergoing further 30% constriction after hyperventilation, with pain and ST-elevation that responded to nitrate administration. Thus, a positive correlation between a positive EKG exercise test with accompanying symptoms, and organic/functional coronary artery disease was found (p = 0.03). Holter tracings of good quality were obtained in 16 patients. Angina-like symptoms occurred in 25% of these patients, without concomitant ischemic or dysrhythmic EKG changes. Conversely, silent ischemia was detected in 1 (5%) patient during exercise and in 3 (18%) patients during the Holter monitoring. None of these patients had any evidence of organic or functional alterations in the coronary arteries. The absence of significant (> 50%) narrowing of the coronary arteries, at baseline and after hyperventilation, was also documented in the 11 patients in whom no valid EKG tracings were obtained for analysis. CONCLUSION: EKG-based methods for detecting myocardial ischemia are of limited value in the general population with Chagas' disease presenting with precordial pain, due to the high prevalence of baseline ST changes. The overall incidence of significant coronary artery disease, as detected by angiography, was low but not negligible in this population of Chagas' patients with precordial pain (4%). Nevertheless, a positive EKG test based on ST changes and accompanying pain has a 100% positive predictive accuracy for the presence of organic or functional coronary abnormalities. No additional yield was obtained with Holter monitoring, for the elucidation of the pathophysiology of the precordial pain in Chagas' patients with atypical angina. The significance of episodes of silent ischemia in some of these patients, with angiographically normal coronary arteries, remains to be determined.

Detecção de isquemia miocárdica em chagásicos crônicos com precordialgia atípica pelos testes de esforço e Holter / Detection of Myocardial Ischemia in Chagas' Disease Patients with Angina-Like Symptoms by the Effort Test and Holter Monitoring

Objetivo - Investigar a freqüência e as características de alteraçöes isquêmicas miocárdicas detectadas pela eletrocardiografia de esforço e monitorizaçäo eletrocardiográfica contínua (Holter) em pacientes chagásicos com dor precordial. Métodos - Trinta e um pacientes com diagnósticos clínicos e sorológico de doença de Chagas (54,4 ñ 9,6 anos, 51// homens) foram investigados para esclarecimento causal de angina de peito intensa e preocupante a ponto de afetar o padräo de vida e exigir exploraçäo agressiva. A detecçäo de isquemia miocárdica consistiu de 1 teste de esforço máximo e 2) Holter de 24h. Todos os pacientes foram submetidos a cinecoronariografia, ocasiäo em que se executava manobra de hiperventilaçäo controlada para constataçäo de espasmo arterial coronário. Os resultados obtidos com os dois testes (esforço e Holter) foram correlacionados e confrontados com os obtidos durante a cinecoronariografia. Resultados - alteraçöes basais do eletrocardiograma (ECG) impediram a análise do segmento ST em 11 pacientes. Dos restantes, 7(35//) apresentaram angina no teste de esforço. Dois deles (10//) tiveram isquemia miocárdica concomitante, detectando-se coronariopatia orgânica/funcional em ambos (associaçäo positiva, p=0,03): lesöes de 90// na artéria circunflexa e de 50// no trajeto intramiocárdico da descendente anterior esquerda. Nesta última, após hiperventilaçäo, ocorreu espasmo que reduziu em mais de 30// o diâmetro luminal do segmento estenótico, com dor precordial e elevaçäo de ST, que reverteram com nitrato. Durante o Holter (16 pacientes com traçados aproveitáveis), 25// dos indivíduos apresentaram angina do peito, sem qualquer distúrbio arrítmico ou isquêmico concomitante. Isquemia silente ocorreu em 1 paciente (5//) durante o esforço e, em outros (18//), durante o Holter. Sua presença näo foi preditiva de alteraçöes coronárias orgânicas ou funcionais. Näo foram documentadas lesöes significativas nos 11 pacientes cujo ECG näo era passível de análise. Conclusäo - Observou-se importante limitaçäo da aplicabilidade geral dos métodos eletrocardiográficos para detecçäo de isquemia miocárdica nos pacientes chagásicos em decorrência das alteraçöes basais do ECG. Contudo, quando o ECG basal é adequado, o teste de esforço positivo (ST isquêmico, acompanhado de dor precordial) apresentou 100// de valor preditivo para doença arterial coronária orgânica/funcional. Isto ocorreu em pequena, porém näo desprezivel proporçäo desta populaçäo chagásica específica (10//). O teste de Holter näo contribuiu para elucidaçäo da origem da angina do peito em qualquer um dos doentes estudados. Ante a inconsistência dos resultados, o significado o significado clínico e fisiopatológico da isquemia silente na cardiopatia chágasica demanda investigaçäo ulterior

Purpose - To determine the incidence and characteristics of myocardial ischemia, as detected by stress electrocardiography and Holter monitoring in Chagus' patients whose main complaint was precordial pain. Methods - Thirty-one consecutive patients with Chagas' disease diagnosed on the basis of clinical and serological tests, and precordial pain severe enough to warrant cardiac catheterization were studied. Mean age was 54.4 ± 9.6 years, and 51% were males. EKG changes indicative of myocardial ischemia were sought during maximul exercise and also during 24-hour Holter monitoring. The detection of myocardial ischemia by each one of these tests was compared by Fischer exact test, and also correlated to anatomical and functional results of coronary angiography at rest and after standardized hyperventilation for detecting coronary vasospasm. Results - Baseline EKG changes mainly associated with ventricular conduction defects precluded the analysis of the ST segment in 11 patients. Among the other 20 patients, 7(35%) had angina during the exercice test, of whom only 2(10%) showed concomitant ischemic ST changes: one had 90% stenosis in the circumflex branch and the other 50% reduction of luminal diameter in a intramyocardial segment of the leit anterior descending coronary artery, undergoing further 30% constriction after hyperventilation, with pain and ST-elevation that responded to nitrate administration. Thus, a positive correlation between a positive EKG exercise test with accompanying symptoms, and organic/functional coronary artery disease was found (p = 0.03). Holter tracings of good quality were obtained in 16 patients. Angina-like symptoms occurred in 25% of these patients, without concomitant ischemic or dysrhythmic EKG changes. Conversely, silent ischemia was detected in 1 (5%) patient during exercice and in 3 (18%) patients during the Holter monitoring None of these patients had any evidence of organic or functional alterations in the coronary arteries. The absence of significant (> 50%) narrowing of the coronary arteries, t baseline and after hyperventilation, was also documented in the 11 patients in whom no valid EKG tracings were obtained for analysis. Conclusion - EKG-based methods for detecting myocardial eschemia are of limited value in the general population with Chagas' disease presenting with precordial pain, due to the high prevalence of baseline ST changes. The overall incidence of significant coronary artery disease, as detected by angiography, was low but not negligible in this population of Chagas' patients with precordial pain (4%). Nevertheless, a positive EKG test based on ST changes and accompanying pain has a 100% positive predictive accuracy for the presence of organic or functional coronary abnormalities. No additional yield was obtained with Holter monitoring, for the elucidution of the pathophysiology of the precordial pain in Chagas' patients with atypical angina. The significance of episodes of silent ischemia in some of these patients, with angiographically normal coronary arteries, remains to be determined

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.