Atrial level right to left intracardiac shunt associated with postoperative hypoxemia: demonstration with contrast two-dimensional echocardiography

Transient hypoxemia is not uncommon after major cardiac or thoracic surgery. The differential diagnosis includes atelectasis, pulmonary embolus, pneumonitis, congestive heart failure and several other diverse cardiovascular and pulmonary problems. Less well recognized is transient right to left intracardiac shunting through a patient foramen ovale or previously unsuspected atrial septal defect. Three cases of clinically important hypoxemia associated with right to left shunting after aortocoronary bypass surgery are presented. The right to left shunting was documented with contrast-enhanced echocardiography, which is a simple, inexpensive and accurate means of screening patients for intracardiac right to left shunts and may play a valuable role in the postoperative management of patients.     

Evidence for phosphorylation of pancreatic islet pyruvate kinase

Rabbit pancreatic islet cytosol catalyzes the calcium-activated phosphorylation by [gamma 32P]ATP of a protein with a molecular weight of 57,000 that is precipitated with antipyruvate kinase antibodies. We were unable to demonstrate that phosphorylation in the presence of calcium or cAMP had any immediate effect on rat pancreatic islet pyruvate kinase activity. This finding is consistent with our inability to confirm the finding of others that pancreatic islets contain phosphoenolpyruvate carboxykinase activity (Diabetes, 34:246, 1985). Since the carboxykinase catalyzes phosphoenolpyruvate formation and pyruvate kinase catalyzes essentially the opposite reaction, if the carboxykinase were present in the beta cell, pyruvate kinase would need to be inhibited to prevent recycling of phosphoenolpyruvate.     

Evaluation of dopaminergic tone in hyperprolactinemia. III. Thyroid-stimulating hormone response to metoclopramide in differential diagnosis and postoperative follow-up of prolactinoma patients

Recently, it has been shown that patients with a PRL-secreting pituitary adenoma have a greater thyroid stimulating hormone (TSH) release after dopamine (DA)-receptor blockade than normal subjects. We have compared the TSH and PRL responses to metoclopramide (MCP) in normal and postpartum lactating women with those in 28 patients with hyperprolactinemia of different origin. Patients with a PRL-secreting pituitary adenoma were also tested after transsphenoidal removal of the tumor in order to establish the prognostic value of this test in such patients. Following MCP administration, percent increases in plasma PRL levels were greater in normal female subjects than postpartum lactating women. Plasma TSH levels did not increase in postpartum women and had a modest increment in normal subjects. In patients with hypothalamic tumors and empty sella syndrome plasma PRL and TSH levels showed modest or no increases after MCP administration. In ten patients harboring a microprolactinoma, plasma TSH levels showed an exaggerated increment after DA-receptor blockade. Postoperatively, despite normal or borderline PRL levels in the immediate postoperative period, a TSH response to MCP was present (in five patients one to two weeks after the operation, and in five patients one to three years after the operation), suggesting an increased DA activity even in the absence of hyperprolactinemia. In conclusion, the TSH test can easily detect increased DA-activity in patients with a microprolactinoma both preoperatively and postoperatively. It is possible that some patients with increased DA-activity in presence of normal PRL levels and normal PRL responsiveness to stimulation will experience a recurrence of hyperprolactinemia.(ABSTRACT TRUNCATED AT 250 WORDS)     

Entrainment of circus movement tachycardia utilizing an accessory pathway with long retrograde conduction times during ventricular and atrial stimulation

An unusual case is presented in which a circus movement tachycardia incorporating an accessory pathway with long retrograde conduction time was transiently entrained. Overdrive high right atrial stimulation produced entrainment without atrial fusion since collision of anterograde and retrograde impulses took place within the accessory pathway. Tachycardia termination occurred when, at a faster pacing rate, an atrial impulse that collided in the accessory pathway was blocked at the atrioventricular (AV) node. In contrast, the entrainment seen during right ventricular apical stimulation was characterized by the occurrence of both fusion and collision within the ventricles. The tachycardia was terminated when a pure paced impulse that collided in the normal pathway was blocked in a retrograde direction in the accessory pathway. These data indicate that: 1) transient entrainment of this arrhythmia (circus movement tachycardia) can be identified by the classical criteria used to diagnose it, provided that fusion and collision occur within the ventricles; and 2) the accessory pathway is the weak link for tachycardia termination only during ventricular pacing since the AV node is the weak link during atrial stimulation.     

P-wave changes in obstructive and restrictive lung diseases

To evaluate the P wave changes in the electrocardiogram (ECG) in chronic lung diseases, we examined ECGs from twenty patients with interstitial pulmonary fibrosis (the FLD group) and twenty patients with chronic obstructive lung disease (fifteen with pulmonary emphysema and five with bronchial asthma, the COLD group). In the COLD group, the amplitude of P waves in leads II and III increased and the axis of the P wave shifted rightward. In the FLD group, however, these changes were not observed. Furthermore, the axis of the P wave exceeded +70 degrees in all the patients in the COLD group, and was less than +70 degrees for all the patients in the FLD group. The increased P wave terminal force in lead V1 was found in nine patients (45%) of the FLD group and in ten patients (50%) in the COLD group. We concluded that the rightward shift of the axis of the P wave was a characteristic of obstructive lung disease and that it was mainly caused by the overinflation of the lung. This P wave change was not observed in interstitial pulmonary fibrosis.     

Detection of posterior myocardial infarction by body surface mapping: A comparative study with 12 lead ECG and VCG

To examine the diagnostic ability of body surface mapping in posterior myocardial infarction (PMI), mapping was performed in 11 patients with PMI proven by left ventriculography and T1-201 myocardial perfusion imaging (PMI group) and in 44 normal subjects (N group). Map data was analysed by the following methods: (1) potential departure maps at 10, 20, 30, 40 and 50 msec after the onset of QRS; each map indicates the area of decreased potential out of the normal range at the time. (2) AQRS departure map which indicates the area of decreased time-integral value of QRS out of the normal range. True positive (TP) in the PMI group and false positive (FP) in the N group were calculated for each method, and were compared with those of various criteria for PMI with standard 12-lead electrocardiogram (ECG) and Frank lead vectorcardiogram (VCG). The potential departure maps and the AQRS departure map had high TP (10/11 and 8/11) and low FP (0/44 and 0/44). The diagnostic ability of mapping is considered to be higher than that of ECG and VCG. Mapping, especially the departure map technique, is a sensitive and specific method to detect posterior infarction.     

Diabetic osteopenia and circulating levels of vitamin D metabolites in type 2 (noninsulin-dependent) diabetes

The degree of diabetic osteopenia and serum vitamin D metabolite levels were measured in 168 type 2 (noninsulin-dependent) diabetic patients. Based on six indices obtained by microdensitometry, we found the bone mass in 26.2% of diabetic patients to be clearly decreased and in 11.9% to be severely decreased. Our direct method of analysis of bone mass shows that diabetic osteopenia differs from typical osteoporosis in character. In addition, serum 24,25-dihydroxyvitamin D was significantly decreased (P less than 0.01), but 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D were similar to those of controls.     

Studies of HBV replication during acute hepatitis followed by recovery and acute hepatitis progressing to chronic disease

The serologic and viral profiles of 24 patients who presented with acute hepatitis B virus (HBV) infection were studied. Although in rare cases, HBV-DNA was detectable before hepatitis B surface antigen (HBsAg) and e antigen (HBeAg), in the majority the viral proteins appeared first. In acute hepatitis followed by recovery, as IgM anti-HBc (hepatitis B core antigen) titres rose, the level of HBV replication fell and serum transaminases became elevated. In patients progressing to chronic HBV infection, IgM anti-HBc titres rose early, viral replication was initially low but continued to rise as the serum transaminase levels became elevated. 7S IgM anti-HBc, although present in the phase of established chronic HBV infection, was not found in the early phase of the chronic infection. Thus this antibody appears to be a consequence of, rather than a causative factor in, chronic HBV infection.     

Normalization of low-density lipoprotein levels and disappearance of xanthomas during pregnancy in a woman with heterozygous familial hypercholesterolemia

Serum lipids and lipoproteins were studied prior to conception, during pregnancy, and after delivery in a woman heterozygous for familial hypercholesterolemia. Prior to conception, serum and low-density lipoprotein (LDL) cholesterol levels were 613 and 528 mg/dL, respectively. At 37-week gestation, serum and LDL cholesterols decreased to the normal levels, 226 and 90 mg/dL, respectively. At two-week postpartum serum and LDL cholesterols returned to the preconception levels, 547 and 427 mg/dL, respectively. At delivery her cutaneous xanthomas almost disappeared. The patient was challenged by ethinyl estradiol of 120 micrograms/d for two months, as a result serum cholesterol decreased from 565 to 385 mg/dL, and LDL cholesterol fell from 460 to 208 mg/dL. During her second pregnancy, serum and LDL cholesterol decreased again significantly. Thus, this case, which showed dramatic reductions of serum and LDL cholesterol levels, may be considered a new variant of heterozygous familial hypercholesterolemia, and the reductions were probably brought about by the action of estrogens, which are known to increase LDL degradation through LDL receptors.     

The effect of cost containment on the practice of cardiology: predictions

When health care cost containment is tied to unit pricing, the system may become price-driven rather than care-driven. Although the incentives engendered by unit pricing may not necessarily result in practices detrimental to the young or the patient with relatively pure disease, the potential for adverse effects on the elderly, the poor and the chronically ill is real. Hospitals will soon emphasize quick turnover, efficiency and intensive care. Diagnostic evaluations and chronic disease care will be moved out of hospitals into physician owned-and-operated facilities and out-of-hospital settings, respectively. The health care system will fractionate, and quality control will require restructuring to achieve the present level of quality assurance. Cardiologists, as well as other physicians, will need to alter their teaching style and teaching locations. Better methods for predicting outcomes will need to be developed; we will no longer have the safety net of following a patient closely and altering management plans according to the patient's response. Cost containment may occur under diagnosis related groups, preferred provider organizations, health maintenance organizations and other prepaid or "capped" systems. There are, however, many issues relative to cost versus quality that need to be resolved if severe detrimental effects on care are to be avoided.