Morteza Amidi

Effect of the Thyroid State on Myocardial Contractility and Ventricular Ejection Rate in Man

Although the circulatory changes in various thyroid states are well known, the alterations of myocardial contractility of hypothyroidism and hyperthyroidism have remained controversial. The changes in the length of the ejection time (ET) and isovolumic contraction time (ICT) are used as indicative of alterations in inotropic state of the myocardium. Isovolumic contraction time, ejection time, and pre-ejection period were measured externally in 10 normal, 13 hyperthyroid, and five hypothyroid subjects. Cardiac outputs, mean rate of left ventricular ejection index, and predicted ejection times were calculated. More shortening of ICT and ET in hyperthyroid and more prolongation of these intervals in hypothyroid subjects than could be attributed to other factors were interpreted as indicative of increased and decreased myocardial contractility, respectively. Catecholamine depletion in hyperthyroid subjects with adequate administration of intramuscular reserpine induced no changes in cardiac output and oxygen consumption and caused no alteration in different phases of ventricular systole; consequently it had no effect on enhancement of hyperthyroid myocardial contractility.

The iron (Fe) and atherosclerosis study (FeAST): A pilot study of reduction of body iron stores in atherosclerotic peripheral vascular disease

BACKGROUND Levels of body iron stores, represented by the serum ferritin concentration, rise with age after adolescence in men and menopause in women. This rise has been implicated mechanistically and epidemiologically in the pathogenesis of atherosclerosis through iron-induced oxygen free radical-mediated lipid oxidation. However, the precise contribution of iron stores to atherosclerosis and its complications are unknown because prospective randomized trials designed to test effects of reduction of iron stores on clinical outcomes in this disease have not been performed. METHODS AND RESULTS In preparation for a prospective randomized trial, a randomized pilot study was conducted to evaluate the feasibility, safety, and methodologic accuracy of calibrated reduction in iron stores by phlebotomy in a cohort of patients with advanced peripheral vascular disease. Phlebotomy resulted in a significant reduction in serum ferritin concentration to near targeted levels. Thus the formula for calculating the volume of blood to be removed to achieve a predetermined decrement in serum ferritin concentration was accurate and phlebotomy was not associated with any adverse laboratory or clinical effects. CONCLUSIONS Reduction of body iron stores to a predetermined level is feasible and can be achieved in a timely manner with excellent patient compliance. Prospective randomized trials of calibrated reduction of body iron stores may be undertaken to define their pathophysiologic significance in atherosclerosis and other diseases in which excessive iron-induced oxidative stress has been implicated.

Left ventricular diastolic filling in patients with left ventricular dysfunction

The pattern of abnormal left ventricular diastolic filling and its specificity in coronary disease patients with severe left ventricular dysfunction has received little attention. We evaluated the left ventricular diastolic filling curve derived from gated blood pool scans in 21 normals, 61 coronary disease patients with ejection fractions less than or equal to 30%, and 51 congestive cardiomyopathy patients with ejection fraction less than or equal to 30%. The peak filling rate (PFR), peak ejection rate (PER), PFR/PER and the % stroke volume filled at 1/3 of diastole (%SV-1/3 DT) and at the end of the rapid filling period (%SV-RFP) were determined for each group. The PFR and PER were reduced in both coronary disease and congestive cardiomyopathy groups. The PFR/PER was increased in the coronary disease group (1.19 +/- 0.28) and congestive cardiomyopathy group (1.21 +/- 0.32) as compared to normals (0.93 +/- 0.20, P less than 0.001). A greater %SV-1/3 DT and %SV-RFP were noted in both coronary disease and congestive cardiomyopathy groups. Coronary disease and congestive cardiomyopathy patients with a mean pulmonary capillary pressure (PCP) greater than or equal to 18 mm Hg had a greater PFR/PER, %SV-1/3 DT, and %SV-RFP than patients with a PCP less than 18 mm Hg. An abnormal and nonspecific pattern of left ventricular diastolic filling is present in both coronary disease and congestive cardiomyopathy patients and is characterized by an increased PFR/PER, a greater %SV-1/3 DT, and a greater %SV-RFP. This pattern may be related to elevated PCPs.

Venous systolic thrill and murmur in the neck: A consequence of severe tricuspid insufficiency

A palpable venous systolic thrill and murmur at the base of the neck are described as new physical findings in five patients with severe tricuspid regurgitation. In two of these patients, the tricuspid valve had been resected as treatment for infective endocarditis related to intravenous drug abuse. The third patient had severe chronic pulmonary disease with right heart failure. The fourth patient had a complex congenital defect in which the mitral valve served as the venous atrioventricular valve and was severely incompetent. The fifth patient suffered from long-standing rheumatic mitral and tricuspid disease with pulmonary hypertension 10 years after placement of a mitral prosthesis. From these observations, it is apparent that pulsatile retrograde flow in the cervical veins resulting from severe right-sided atrioventricular valve incompetence can produce a palpable systolic thrill and murmur at the base of the neck.

Left heart work and temperature responses to cold exposure in man

Abstract Resting normal men respond to various types of cold exposure by somewhat different mechanisms. Cold air breathing evokes an increase in stroke volume without changing heart rate or peripheral resistance. Left ventricular ejection time does not change, and so the principal response may be viewed as an increase in the mean rate of left ventricular ejection. On the other hand, exposure to a cold environment evokes an increase in peripheral resistance without changing cardiac index or heart rate. In both cases cardiac work and pressure-time relations increase, implying an increased myocardial oxygen utilization. These various responses are probably attributable to catecholamine effects; at rest they occur in the absence of cooling of the left heart chambers and of the subsequent coronary perfusate. It is likely that exercise in a cold environment results in reduction of the temperature of the left heart chambers and of the coronary perfusate.

Detectable Troponin Levels Predict Poor Prognosis in Patients With Left Ventricular Dysfunction Undergoing Internal Defibrillator Implantation

Introduction: Troponin levels have been demonstrated to predict mortality in patients with cardiomyopathy. Implantable cardiac defibrillator (ICD) devices have been demonstrated to improve survival. It is not clear if ICDs would mitigate the negative outcome predicted by elevated troponin levels.

Serum creatine phosphokinase, lactic dehydrogenase, and their isoenzymes in the perioperative period

The purpose of the present investigation was to determine the normal perioperative variations in the serum concentration of creatine phosphokinase (CPK) and its isoenzymes MM, MB, and BB, and of lactic dehydrogenase (LDH) and its isoenzymes LDH1 to LDH5 to distinguish operation-induced changes in these enzymes from those due to acute myocardial infarction or malignant hyperthermia. In 30 patients, 52 to 75 years of age undergoing elective orthopedic operations, 10 serial blood samples were obtained in the perioperative period: two samples before skin incision and eight samples after the incision over a time span of 70 hours. The preinduction mean serum CPK level of 141 U/L increased gradually and significantly and reached a maximum mean concentration of 809 U/L 34 hours after incision (p less than 0.01). The CPK-MM percent increased after incision, whereas that of CPK-MB and CPK-BB decreased, although their absolute values in terms of U/L rose. The preinduction mean serum LDH value of 173 U/L increased gradually after incision and achieved peak levels at 34 hours (203 U/L) and 58 hours (210 U/L) after incision (p less than 0.05). The LDH1:LDH2 ratio did not change. The LDH5 percent increased and peaked 10 hours after incision (p less than 0.05). There was a significant correlation between severity of operation-induced tissue damage and the serum CPK concentration (p less than 0.001). The large increase in total CPK (primarily MM fraction) occurring after surgery may minimize the percentile effects caused by an increase in MB level due to myocardial infarction.

Early manifestation of noncalcific aortic stenosis after porcine valve replacement

Symptoms of noncalcific aortic stenosis developed in a 57-year-old man 3 months after implantation of a Carpentier-Edwards porcine heterograft. The glutaraldehyde-processed bioprosthesis was removed 7 months after implantation and replaced with a No. 3 Medtronic Hall valve.

Iatrogenic coronary-cameral fistula after left ventricular radiofrequency ablation

A 52-year-old white woman with normal cardiac andcoronary anatomy, frequent premature ventricular com-plexes (PVCs), and syncope underwent electrophysiologicstudy, which revealed sustained monomorphic ventriculartachycardia (VT). Radiofrequency (RF) ablation was per-formed. VT could not be induced, so noncontact activationmapping of PVCs was performed. Ablation at the earliestsite of endocardial activation of the respective PVC con-firmedbypacemapofthePVCs(Figure1A)wasperformedusing an internally irrigated 4-mm-tip catheter (Boston Sci-entific, Natick, MA, USA). Lesions initially were deliveredcaudal to the lateral mitral annulus. RF ablation was deliv-ered under temperature control not exceeding 40°C, withpower titrated to achieve a drop of 10 .

Natural history of posterobasal left ventricular aneurysm

Abstract The data from 2,500 patients undergoing cardiac catheterization were reviewed to detect the presence of a posterobasal left ventricular (LV) aneurysm. An aneurysm was defined as a localized mural protrusion that extended beyond the LV contour during both systole and diastole. 1,2 In all cases, left ventriculography was performed in the 30 degree right anterior oblique position. The area over the left ventricle exclusively at the aneurysm and the area of the aneurysm were determined planimetrically (Figure 1). The ratio of aneurysm area to total LV area was used as an index of aneurysm size; it was estimated for both systole and diastole. The length of the longitudinal chord at the connection of the aneurysm to the left ventricle was compared with the largest similar cord of the aneurysm, per se. The smallest LV size was considered systole and the largest LV area usually simultaneous with the peak of the R wave on the electrocardiogram over the cine trace was considered diastolic LV area.