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Biomedical subjects

J A Marin-Neto

Publications and source records attributed to J A Marin-Neto.

At least 37 records · Page 2Linked to original sources
PubMed1998

Cardiac autonomic impairment and early myocardial damage involving the right ventricle are independent phenomena in Chagas' disease.

Cardiac autonomic impairment and right side heart failure are prominent features in patients with Chagas' disease, but no causal relationship between these phenomena has been disclosed and the pathophysiology of such manifestations is unclear. Aim of study was to assess the cardiac autonomic control and biventricular function in chagasic patients in early stages of the disease, using radionuclide angiography, Valsalva manoeuvre, head-up tilt and baroreflex sensitivity evaluation. Thirty-one chagasic patients with no clinical signs of Chagas' heart disease-16 in the indeterminate phase and 15 with sole organic digestive involvement-were studied, and results compared with those obtained in 14 normal volunteers. No significant differences were observed among the three groups, in regard to any systolic or diastolic parameter of LV function, including ejection fraction, peak ejection and filling rates and correspondent times, time to end-systole, and the standard deviation of phase values. The indeterminate and digestive groups of chagasics had significantly lower right ventricular ejection fraction (45.7 +/- 6.3 and 46.2 +/- 10.1 respectively) and peak ejection rate (respectively 2.8 +/- 0.6 and 2.9 +/- 0.6) and higher right ventricular phase standard deviation (22.4 +/- 5.9 and 20.1 +/- 5.6 degrees, respectively), as compared with the control group (53.6 +/- 4.3, 3.5 +/- 0.5, and 15.8 +/- 3.8 respectively for right ventricular ejection fraction, peak ejection rate and phase standard deviation). No significant differences were found between the results of autonomic evaluation in the control and indeterminate groups of chagasic patients. The group of digestive disease patients showed abnormally lower Valsalva ratio (1.5 +/- 0.15), baroreflex sensitivity (8.85 +/- 2.05 ms/mmHg) and parasympathetically-dependent heart rate response to tilt (8.85 +/- 8.42 beats/mm) and higher Valsalva delay (15.67 +/- 1.35 s) values, compared with the control group (respectively 1.85 +/- 0.49, 20.23 +/- 12.66 ms/mmHg, 21.61 +/- 5.77 beats/mm and 10.1 +/- 2.5 s). Thus, cardiac autonomic impairment is a prominent feature in chagasic patients with the digestive but not the indeterminate form of Chagas' disease. It bears no causative relationship to the early myocardial damage that is apparent only regarding right ventricular function, in both groups of patients. Early right ventricular dysfunction is a likely mechanism for the marked predominance of systemic over pulmonary congestion when heart failure supervenes in patients with Chagas' disease.

Adult↗
PubMed1998

[Hypertrophic cardiomyopathy treated by interventional technique of septal reduction].

A 75-year old woman with obstructive hypertrophic cardiomyopathy and class IV dyspnea refractory to medical management had relative contraindications for both pacemaker implantation and surgical approach. Percutaneous intervention was devised to perform the selective injection of absolute alcohol in the first septal branch of the left anterior descending coronary artery. This led to a limited septal infarction documented by ST elevation, enzymatic elevation and the appearance of complete right bundle branch block on the electrocardiogram. A baseline left ventricular outflow tract pressure gradient of 66mmHg was immediately abolished and no unexpected complications supervened. Currently, two months after the procedure, marked symptomatic relief is present and associated with the absence of obstructive outflow gradient, as documented by echocardiography.

Aged↗
PubMed1997

Reversible segmental left-ventricular dysfunction caused by accidental administration of sympathomimetic drug in human.

A inadvertently administrated high dose of sympathomimetic drug induced cardiogenic shock manifestations in a previously healthy woman. This state was characterized by EKG subendocardial injury, serum cardiac enzymes elevation, extensive regional left ventricular wall motion abnormalities on echocardiogram. Therapeutics included oxygen, systemic vasodilators and diuretics. Clinical recovery occurred over a four days period and parallels the normalization of echocardiogram and EKG alterations.

Adult↗
PubMed1997

[Risk stratification in acute myocardial infarction survivors. Exercise stress test versus coronary angiography].

PURPOSE: To compare the predictive accuracy for future ischemic events of heart rate limited treadmill exercise test (HET) and coronary angiography (CA) applied to survivors of an uncomplicated myocardial infarction. METHODS: 142 consecutive patients (55 +/- 11 years, 80% males), presenting a non complicated acute myocardial infarction (AMI) were included. HET was performed 10 +/- 3 days after AMI, and CA during hospital stay or within 4-6 weeks. HET positivity criteria were: 1) horizontal or down-sloping ST segment displacement > or = 1 mm; 2) angina; 3) arterial pressure drop during exercise; 4) low workload (< 6 METS); 5) complex ventricular arrhythmia. At CA lesions causing > or = 50% of luminal reduction were considered significant. HET and CA results were correlated to ischemic events occurring during the follow-up (unstable angina in 20%, cardiac death 6%, and reinfarction 6%). RESULTS: HET was positive in 69 (49%) patients, exhibiting a positive predictive value for ischemic events (PV+) of 26% and a negative predictive value (PV-) of 77%. The mean event-free time was 43 +/- 3 months for positive HET and 46 +/- 3 months for a negative one (p = 0.48). CA showed 0-1 vessel involvement in 93 (66%) patients and > or = 2 vessels in 49 (34%) patients. The presence of multivascular disease at CA presented a PV+ of 37% and PV- of 82%; the mean event-free time was 37 +/- 4 months for patients with multivascular involvement and 48 +/- 2 months for patients without this pattern (p = 0.007). CONCLUSION: The predictive accuracy of HET for future ischemic events in the thrombolytic era is markedly reduced. This population of AMI survivors presents an overall good prognosis that seems to justify the poor predictive accuracy of this test.

Adult↗
PubMed1995

Severe myocarditis and esophagitis during reversible long standing Chagas' disease recrudescence in immunocompromised host.

An unusual form of reagudization of Chagas' disease, from its indeterminate phase, was documented in an immunocompromised patient. Long-standing progressive visceral aggression due to extensive intracellular proliferation of T. cruzi manifested by severe isolated right ventricular failure and esophageal ulcerations. Antiparasite chemotherapy was effective in the control of the disease.

Adult↗
PubMed1995

[Esophageal origin of precordial pain in chagasic patients with normal subepicardial coronary arteries].

PURPOSE: To study the chest pain of esophageal origin in chagasic patients (CH) and non-chagasic subjects (NCH) with normal coronary arteries. METHODS: The study comprised 48 patients: 33 CH (age 56 years, 50% male) and 15 NCH (age 47 years, 25 male), with precordial chest pain and normal subepicardial coronary arteries. They were assigned to upper digestive tract radiologic and endoscopic study, esophageal manometric evaluation at baseline and after provocative tests (Bernstein and intravenous edrophonium). RESULTS: Radiologic study: 14 (42%) CH and 4 (27%) NCH had esophageal dilation (p > 0.05). Hiatal hernia was documented in 7 (21%) CH and 6 (40%) NCH (p > 0.05). 2) Digestive endoscopy: In 15 (45%) CH and 6 (40%) NCH distal esophagitis were seen. In the NCH, esophagitis occurred with hiatal hernia; however only 30% of CH with esophagitis had also hiatal hernia while another 30% had esophageal dilation. 3) Esophageal motility disorders (EMD): 11 (33%) CH showed EMD: 8 with inferior esophageal sphincter achalasia (IESA) and 3 with diffuse esophageal spasm. Among NCH, 2 (13%) had IESA (p > 0.05). 4) Bernstein test--a positive test was seen in 5 (15%) CH and 3 (20%) NCH-p > 0.05. CH with esophageal dilation had 14% of positive results, while CH without esophageal dilation had 16%-p > 0.05. 5) Intravenous edrophonium-esophageal contraction amplitude enhancement provoked by the drug infusion was clearly attenuated in the chagasic (6.9 +/- 12.7 mmHg) when compared with the NCH group (18.8 +/- 21.4 mmHg). A positive test (i.e. chest pain) was obtained in only one patient who was NCH. CONCLUSION: Esophageal pain could be elicited at a relatively low and comparable rate in both groups of patients.

Adult↗
PubMed1994

Clinical significance of reduced regional myocardial glucose uptake in regions with normal blood flow in patients with chronic coronary artery disease.

OBJECTIVES: The objective of this study was to assess the clinical significance of reduced regional fluorine-18 (18F) fluorodeoxyglucose uptake with normal flow in patients with chronic coronary artery disease. BACKGROUND: In patients with ischemic left ventricular dysfunction, 18F-fluorodeoxyglucose uptake may be reduced in some myocardial regions despite normal flow. The significance of this finding is unclear and has not been investigated systematically. METHODS: Twenty-three patients with coronary artery disease and impaired ventricular function (mean ejection fraction [+/- 1 SD] 28 +/- 10%) underwent positron emission tomography with 18F-fluorodeoxyglucose and oxygen-15-labeled water at rest, exercise thallium-201 tomographic imaging with rest reinjection and gated magnetic resonance imaging to measure end-diastolic wall thickness and systolic wall thickening. RESULTS: Of 168 regions with normal flow (> or = 0.7 ml/g per min), 125 (74%) had normal 18F-fluorodeoxyglucose uptake (98 +/- 10%), and the remaining 43 (26%) showed moderately reduced 18F-fluorodeoxyglucose uptake (69 +/- 8%). Systolic wall thickening was absent at rest in 14% of regions with normal 18F-fluorodeoxyglucose uptake compared with 32% of regions with reduced 18F-fluorodeoxyglucose uptake (p < 0.01). Reversible thallium abnormalities were observed in 45 (36%) of 125 regions with normal 18F-fluorodeoxyglucose uptake compared with 27 (63%) of 43 regions with reduced 18F-fluorodeoxyglucose uptake (p < 0.01). This difference was accounted for by a higher proportion of partially reversible defects in regions with reduced 18F-fluorodeoxyglucose uptake compared with regions with normal 18F-fluorodeoxyglucose uptake (42% vs. 18%, respectively, p < 0.01). CONCLUSIONS: Thus, regions with moderately reduced 18F-fluorodeoxyglucose uptake with normal flow occur commonly in patients with ischemic left ventricular dysfunction. The majority of these regions show impaired systolic function at rest and exercise-induced thallium abnormalities that are only partially reversible. These observations suggest that such regions represent an admixture of fibrotic and reversibly ischemic myocardium.

Coronary Circulation↗
PubMed1994

Myocardial viability in patients with chronic coronary artery disease. Comparison of 99mTc-sestamibi with thallium reinjection and [18F]fluorodeoxyglucose.

BACKGROUND: 99mTc-sestamibi and thallium imaging have similar accuracy when used for diagnostic purposes, but whether sestamibi provides accurate information regarding myocardial viability in patients with chronic coronary artery disease has not been established. Since there is minimal redistribution of sestamibi over time, it may overestimate nonviable myocardium in patients with left ventricular dysfunction, in whom blood flow may be reduced at rest. METHODS AND RESULTS: We studied 54 patients with chronic coronary artery disease with a mean ejection fraction of 34 +/- 14%. Patients underwent stress/redistribution/reinjection thallium tomography and, within a mean of 5 days, same-day rest/stress sestamibi imaging using the same exercise protocol and with patients achieving the same exercise duration. Of the 111 reversible thallium defects on either the redistribution or reinjection study, 40 (36%) were determined to be irreversible on the rest/stress sestamibi study, whereas only 3 of 63 irreversible thallium defects despite reinjection (5%) were classified to be reversible by sestamibi imaging. The concordance regarding reversibility of myocardial defects between thallium stress/redistribution/reinjection and same day rest/stress sestamibi studies was 75%. A subgroup of 25 patients also underwent positron emission tomography (PET) studies with 15O-labeled water and [18F]fluorodeoxyglucose (FDG) at rest after an oral glucose load. As in the overall group of 54 patients, there was concordance between thallium and sestamibi imaging regarding defect reversibility in 51 of 73 regions (70%). In the remaining 22 discordant regions (30%), 18 (82%) appeared irreversible by sestamibi imaging but were reversible by thallium imaging. Myocardial viability was confirmed in 17 of 18 regions, as evidenced by normal FDG uptake (10 regions) or FDG/blood flow mismatch (7 regions) on PET. These regions were present in 16 of the 25 patients studied (64%). We then explored methods to improve the sestamibi results. First, when the 18 discordant regions with irreversible sestamibi defects were further analyzed according to the severity of defects, 14 (78%) demonstrated only mild-to-moderate reduction in sestamibi activity (51% to 85% of normal activity), suggestive of predominantly viable myocardium, and the overall concordance between thallium and sestamibi studies increased to 93%. Second, when an additional 4-hour redistribution image was acquired in 18 patients after the injection of sestamibi at rest, 6 of 16 discordant irreversible regions (38%) on the rest/stress sestamibi study became reversible, thereby increasing the concordance between thallium and sestamibi studies to 82%. CONCLUSIONS: These data indicate that same-day rest/stress sestamibi imaging will incorrectly identify 36% of myocardial regions as being irreversibly impaired and nonviable compared with both thallium redistribution/reinjection and PET. However, the identification of reversible and viable myocardium can be greatly enhanced with sestamibi if an additional redistribution image is acquired after the rest sestamibi injection or if the severity of reduction in sestamibi activity within irreversible defects is considered.

Adult↗
PubMed1994

[Reagudization of Chagas myocarditis inducing exclusive right ventricular failure].

Woman, 42 years-old, receiving immunosuppressive therapy for a lymphoma, presented reagudization of Chagas' disease, from its indeterminate phase. Intense inflammatory visceral aggression, due to extensive intracellular proliferation of the Trypanosoma cruzi, was the likely mechanism for acute myocarditis leading to severe right ventricular failure. Antiparasite chemotherapy was effective in the control of visceral involvement and for the remission of cardiac failure. The clinical course in this case is compatible with the hypothesis of early right ventricular damage in Chagas' disease.

Adult↗
PubMed1993

Influence of angiotensin converting enzyme inhibition on exercise performance and clinical symptoms in chronic heart failure: a multicentre, double-blind, placebo-controlled trial.

One hundred and seven patients with chronic heart failure (NYHA class II to IV) stabilized on digitalis and/or diuretics, recruited from 11 centres were randomized into a double-blind, placebo-controlled study to assess the effect of 12 weeks of cilazapril therapy on exercise tolerance and clinical status. Thirty-five patients were randomized to placebo and 72 to cilazapril at a starting dose of 1 mg daily; titration to cilazapril 2.5 mg at week 4 and 5 mg at week 8 (or matching placebo) was carried out in patients who did not improve clinically. Demographic characteristics, including exercise test duration increased from 402 s (+/- 17 SEM) at baseline to 462 s (+/- 19 SEM) at week 12 for the cilazapril group (+15%) and from 405 s (+/- 23 SEM) at baseline to 408 s (+/- 30 SEM) at week 12 in patients on placebo (+1%) (P < 0.001). In the placebo group, patients able to exercise for more than 6 min at baseline showed an increase in exercise duration at week 12 while those able to exercise for up to 6 min at baseline showed a decrease (P = ns). In contrast, cilazapril-treated patients showed an increase in exercise tolerance regardless of baseline exercise test duration; patients with the most impaired exercise tolerance at baseline showed a greater improvement than patients with mildly impaired baseline exercise tolerance (P < 0.05 vs placebo). NYHA class improved by at least one grade in 51% of the cilazapril group vs 32% in the placebo group (P = ns). At the end of the trial, 15% of the patients were non-responders on cilazapril vs 41% on placebo (P < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Thallium reinjection demonstrates viable myocardium in regions with reverse redistribution.

BACKGROUND: The clinical significance and pathophysiological mechanisms of reverse redistribution on stress-redistribution thallium-201 myocardial scintigraphy in patients with chronic coronary artery disease are unclear. Recent studies have shown that thallium-201 reinjection is a useful technique for the detection of myocardial viability in chronic coronary artery disease. In this investigation we determined whether thallium reinjection distinguishes viable from nonviable myocardium in regions with reverse redistribution. METHODS AND RESULTS: We studied 39 patients with chronic stable coronary artery disease (age, 60 +/- 10 years), all of whom demonstrated reverse redistribution on standard exercise-redistribution thallium single-photon emission computed tomography (SPECT). Reverse redistribution was defined as > or = 10% decrease in relative thallium-201 activity between stress and redistribution images and included either the worsening of a perfusion defect apparent on post-stress images or the appearance of a new defect on the redistribution images. Thallium reinjection was performed immediately after the 3- to 4-hour redistribution study. Of 39 regions with reverse redistribution, 32 (82%) showed enhanced thallium-201 activity (> or = 10% increase) after reinjection. In the other 7 regions (18%), the scintigraphic defect persisted after reinjection. Abnormal Q waves were present in only 8 of 32 (25%) regions with enhanced thallium-201 uptake after reinjection compared with 5 of 7 (71%) regions not responding to reinjection (P < .05). Akinetic or dyskinetic wall motion was present in 3 of 32 (9%) regions showing enhanced uptake after reinjection, in contrast with 5 of 7 (71%) regions not responding to reinjection (P < .01). Critically stenosed or totally occluded coronary arteries supplied 24 of 29 (83%) regions with enhanced thallium-201 uptake after reinjection but only 2 of 7 (28%) regions not showing a positive response to reinjection (P < .05). Collateral circulation was detected in 23 of 29 (79%) regions with a positive thallium reinjection effect but in only 1 of the other 7 regions (P < .01). Sixteen of the 39 patients also underwent positron emission tomography using 18F-fluorodeoxyglucose (FDG) to assess glucose utilization and H2(15)O to assess regional blood flow. The 14 regions with reverse redistribution that responded to reinjection with enhanced thallium uptake all showed either normal patterns of FDG uptake and flow or an ischemic pattern with increased FDG uptake relative to flow. Reduced FDG uptake and reduced flow values were seen in the two regions not responding to thallium reinjection. CONCLUSIONS: These observations indicate that reverse redistribution in chronic coronary artery disease usually reflects viable myocardium, critically dependent upon collateral circulation.

Cardiac Catheterization↗
PubMed1993

[Detection of myocardial ischemia in chronic Chagas disease patients with atypic precordial pain by exercise and Holter tests].

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.

Adult↗
PubMed1992

Myocardial perfusion abnormalities in chronic Chagas' disease as detected by thallium-201 scintigraphy.

Most patients with chronic Chagas' heart disease complain of chest pain. The pathophysiology of this symptom is unknown, although myocardial necrosis and fibrosis are frequent necropsy findings and cardiac autonomic impairment is a prominent feature of the disease. To evaluate the possibility of an ischemic cause for these abnormalities in 23 patients (18 men, aged 32 to 60 years, mean 42) with chronic Chagas' disease complaining of chest pain, thallium-201 myocardial scintigraphy was performed after maximal effort and 4-hour redistribution. Regional wall motion was assessed by radionuclide and contrast angiography. Heart rate responses to sinus respiratory arrhythmia, atropine, phenylephrine and Valsalva maneuver were evaluated in all patients and in 22 normal control subjects. Coronary angiography was performed in 16 patients. Only 1 patient had chest pain and no ischemic electrocardiographic changes occurred in any case during the effort test. Scintigraphic analysis of 7 segments per patient showed perfusion defects in at least 1 segment in all patients. Of 161 myocardial segments 16 showed fixed, 10 reversible, and 22 paradox defects (reverse redistribution). The majority (75%) of the fixed perfusion defects occurred in dyssynergic regions, whereas reverse redistribution predominated in regions with normal wall motion (82%). The reversible defects were present in normal or mildly hypokinetic regions. Markedly impaired parasympathetic cardiac control was present but no significant coronary abnormalities were seen in any of the 16 patients undergoing angiography. It is concluded that whereas fixed defects are likely to correspond to fibrotic or necrotic lesions, reversible and paradox perfusion defects may be caused by regional flow or metabolism derangements, possibly related to abnormal parasympathetic control of the coronary microcirculation.

Adult↗
PubMed1992

Metabolic evidence of viable myocardium in regions with reduced wall thickness and absent wall thickening in patients with chronic ischemic left ventricular dysfunction.

Reduced end-diastolic wall thickness with absent systolic wall thickening has been reported to represent nonviable myocardium in patients with chronic coronary artery disease. To assess whether reduced regional end-diastolic wall thickness and absent wall thickening accurately identify nonviable myocardium, 25 patients with ischemic left ventricular dysfunction (ejection fraction at rest 27 +/- 10%) underwent positron emission tomography with oxygen-15-labeled water and 18fluorodeoxyglucose to assess metabolic activity and spin-echo gated nuclear magnetic resonance imaging to measure regional end-diastolic wall thickness and wall thickening. The presence of metabolic activity was defined as 18fluorodeoxyglucose uptake (corrected for partial volume) greater than 50% of that in normal regions. Of 355 myocardial regions evaluated, 266 were hypokinetic or normokinetic at rest and 89 were akinetic (that is, absent wall thickening). 18Fluorodeoxyglucose uptake was observed in 97% of the hypokinetic and normokinetic regions and in 74% of the akinetic regions. End-diastolic wall thickness was greater in akinetic regions with than in those without 18fluorodeoxyglucose uptake (11 +/- 4 vs. 7 +/- 3 mm, p less than 0.01). The highest values for sensitivity and specificity of end-diastolic wall thickness in predicting the absence of metabolic activity in akinetic regions were 74% and 79%, respectively, and corresponded to an end-diastolic threshold of 8 mm. However, the positive predictive accuracy was only 55% and did not improve for other end-diastolic wall thickness values. In all myocardial regions, there was only a weak correlation between 18fluorodeoxyglucose activity and either end-diastolic wall thickness (r = 0.17) or wall thickening (r = 0.32). Thus, metabolic activity is present in many regions with reduced end-diastolic wall thickness and absent wall thickening. These data indicate that assessment of regional anatomy and function may be inaccurate in distinguishing asynergic but viable myocardium from nonviable myocardium.

Adult↗
PubMed1992

Acute myocardial infarction complicating the clinical course of dilated cardiomyopathy in childhood.

An acute myocardial infarction occurred in a 6-year-old child with dilated cardiomyopathy. This caused severe hemodynamic deterioration that led to a fatal outcome. Autopsy revealed diffuse myocardial atrophy without cell infiltrate, normal epicardial coronary arteries, and a massive healed anteroapical infarction. Coronary embolism or spasm could not be ruled out as the cause of the infarction.

Cardiomyopathy, Dilated↗
PubMed1991

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.

Adaptation, Physiological↗