The Immediate Effect of Changing Mandibular Position on the EMG Activity of the Masseter, Temporalis, Sternocleidomastoid, and Trapezius Muscles

This study investigated the immediate effect of changing mandibular position on the electromyographic (EMG) activity of the masseter (MS), temporalis (TM), sternocleidomastoid (SCM) and trapezius (TR) muscles. Thirty-three (33) asymptomatic subjects (16 males and 17 females), ages 23 to 52 were selected. Surface EMG recordings were obtained for all muscles bilaterally with the mandible in a relaxed open position (relaxed) and during maximal voluntary clenching (fullbite) for the following: a non-repositioning appliance (NONREPOS) and repositioning appliance (REPOS). REPOS significantly reduced EMG activity of all muscles bilaterally during fullbite. During relaxation, reduction in EMG activity was only found for TR bilaterally. NONREPOS decreased the EMG activity bilaterally for TM and TR and unilaterally (left) for MS and SCM during fullbite. During relaxation, NONREPOS decreased muscle activity bilaterally for TR and SCM. A unilateral reduction was found for TM (right). These findings suggest that immediate alterations in mandibular position affect the cranio-cervical system. Both mandibular positions tested lowered the EMG activity of masticatory and cervical muscles in the relaxed and fullbite positions. The trapezius muscle was the most responsive to alterations in mandibular position.

The Connecticut Cardiovascular Consortium: a unique, state-wide research collaboration to advance clinical outcomes in patients with heart disease

The establishment of "best clinical practices" founded upon evidence-based medicine has become an increasingly important priority. Frequently, management guidelines are derived from published research data and disseminated among practitioners to help optimize patient care. The ultimate clinical impact of these guidelines in the "real world," however, is often clouded by an incomplete assessment of patient outcomes throughout the continuum of health-care delivery models. In order to address this gap in clinical outcome assessment, we propose to establish the Connecticut Cardiovascular Consortium. The Consortium will consist of a collaborative partnership among all 31 Connecticut hospitals working in concert with Connecticut Office of Health Care Access (OHCA). The primary objective of the Consortium will be to assess, compare, and optimize clinical outcomes among Connecticut residents with cardiovascular disease. As an initial goal for the Consortium, we further propose to undertake a prospective, observational study of Connecticut residents who present with ST Segment Elevation Acute Myocardial Infarction (STEMI). Recent advances in pharmacologic and mechanical reperfusion for STEMI have resulted in a need to define the optimal use of these therapies in the community at large. The primary purpose of this study will be to determine the relative merits of different treatment patterns for STEMI with regard to the use of fibrinolytic therapy and percutaneous coronary intervention (PCI). Particular emphasis will be placed on assessing the relative benefits of urgent mechanical revascularization performed at the state's seven tertiary facilities with PCI capability compared to all other treatment modalities. Successful completion of this unique collaborative endeavor is expected to have significant impact on improved patient care and on current health-care policy for medical resource allocation. Moreover, continued collaboration of health-care providers within the Connecticut Cardiovascular Consortium infrastructure should serve as a useful mechanism for ongoing improvements in evidence-based cardiovascular medicine and clinical research in the state of Connecticut.

Accuracy and utility of 3-dimensional computed tomography in evaluating donors for adult living related liver transplants

Three-dimensional (3D) computed tomography (CT) is an imaging technique that renders anatomic detail in 3D images from helical computed tomographic scans. The purpose of this study is to assess 3D CT in the preoperative evaluation of adult living related liver transplant donors. Nine patients underwent right-lobe liver resection for adult living related liver transplants between October 1999 and September 2000. All donors underwent triphasic helical CT of the liver with 3D computed tomographic reconstruction and conventional angiography. The 3D images were correlated with angiography and intraoperative findings. The origin of vessels, relative length of segments, and position of branches were considered for accuracy. The 3D computed tomographic images were compared with angiograms to determine whether angiography could be replaced by 3D CT. 3D CT identified all variations of the hepatic vein confluences and portal vein trifurcations and all hepatic arterial variants. At surgery, the 3D computed tomographic images of hepatic and portal veins were judged to be accurate and helpful in 8 of 9 cases, and images of the hepatic artery, accurate and helpful in 5 of 9 cases. The 3D computed tomographic images of hepatic and portal veins were better than or equivalent to angiograms in nearly all cases. The 3D computed tomographic images of the hepatic artery were better than or equivalent to angiography in 5 of 9 cases. By providing an accurate 3D map of the liver and its vasculature, 3D computed tomographic reconstructions of the hepatic vasculature are a useful adjunct for surgical planning in adult living related liver donors. 3D CT clearly delineates portal and hepatic veins as well as or better than the angiogram and can identify the hepatic artery and its branches well enough to consider replacing angiography, thus reducing cost, inconvenience, and risk to the donor.

Identification of a novel transforming growth factor-beta (TGF-beta 5) mRNA in Xenopus laevis

A novel transforming growth factor-beta (TGF-beta) mRNA of about 3.0 kilobases, which encodes a putative protein of 382 amino acids, has been identified in amphibians by cDNA cloning. This mRNA, which we designate as TGF-beta 5, is developmentally regulated and highly expressed beginning at early neurula (stage 14) and in many adult tissues in Xenopus laevis. Following the first methionine, the putative precursor protein has a hydrophobic region, approximately 22 amino acids long, which probably represents a signal sequence, similar to that found in TGF-beta s 1-3. The precursor also has potential sites for glycosylation, integrin binding (RGD), and a tetrabasic amino acid (RKKR) site for potential cleavage of the precursor peptide to a biologically active protein. The putative mature protein consists of 112 amino acids with 9 cysteines and has 76, 66, 69, and 72% identity to TGF-beta s 1-4, respectively.

Quantitative analysis of stress thallium-201 myocardial scintigrams: a multicenter trial

Previously we validated a method for quantification of 201TI myocardial stress distribution and washout in which the patient's stress and washout circumferential profiles are compared with observed normal limits. The present study reports the results of a multicenter trial in which this method, utilizing normal limits from our institution, was employed to evaluate the presence, location, and extent of coronary artery disease (CAD). The normal limits utilized were generated from 49 patients having a low likelihood of CAD. The study population included 157 patients from four centers in the United States and Canada as well as a comparative prospective population from Cedars-Sinai Medical Center (CSMC) of 51 patients with CAD, 30 patients with normal coronary arteriograms, and 30 additional low-likelihood normals. The results in the combined centers regarding overall detection of CAD revealed a sensitivity of 84% and a frequency of test normality in the patients with low likelihood of CAD of 88%, compared to a sensitivity of 82% and true normalcy rate of 83% obtained in the prospective CSMC population. The sensitivity for detecting disease increased according to the extent of angiographic CAD in both the multicenter sites and the prospective CSMC group. Regarding localization of disease, similar sensitivities and specificities for detecting disease in individual coronary arteries were found in the multicenter sites and the prospective CSMC population. The results indicate that our method for quantifying 201TI stress-redistribution scintigrams utilizing standard normal limits can be applied at other institutions using a variety of scintillation cameras with similar accuracy to that currently obtained at our institution.

Left tension pneumothorax masquerading as anterior myocardial infarction

Spontaneous pneumothorax is an emergency that can present with variable signs and symptoms. Diagnosis of pneumothorax can be difficult, particularly in patients who present with unusual clinical findings. The electrocardiographic changes that develop with left pneumothorax are not widely known and can mimic acute myocardial ischemia. Our patient was admitted to the Cardiovascular Intensive Care Unit because of characteristic changes on the electrocardiogram. An admission chest film revealed left tension pneumothorax.

Gold-195m for serial first pass radionuclide angiocardiography during upright exercise in patients with coronary artery disease

Sequential first pass radionuclide angiocardiography can be performed in rapid succession using gold-195m because of its low radiation dose and short half-life (30.5 seconds). In 25 patients with known or suspected coronary artery disease, first pass studies with gold-195m were obtained using a computerized multicrystal gamma camera at rest (n = 29), at the end of each 3 minute stage of exercise (n = 25) and immediately after exercise (n = 23). In 13 patients, assessment of left ventricular function during exercise with gold-195m was combined with thallium-201 stress scintigraphy. Left ventricular ejection fraction at rest assessed with technetium-99m and gold-195m correlated well (r = 0.93). In addition, repeat left ventricular ejection fractions at rest with gold-195m correlated closely (r = 0.96). Comparing peak exercise left ventricular ejection fraction with ejection fraction at rest, abnormal left ventricular reserve was found in 20 of 25 patients. Various abnormal patterns of left ventricular ejection fraction response were noted, showing the diagnostic potential of serial exercise angiocardiography. Thallium-201 myocardial images, obtained on a single crystal gamma camera after multiple gold-195m injections, were all of good diagnostic quality and were abnormal in 10 of 13 patients. Thus, multiple high count rate first pass studies can be obtained with gold-195m during and after exercise, allowing serial study of physiologic changes in left ventricular function during exercise. Thallium-201 myocardial imaging can be performed using the same exercise test, providing direct comparison of myocardial function and perfusion.

Beat-to-beat left ventricular performance in atrial fibrillation: radionuclide assessment with the computerized nuclear probe

There is wide beat-to-beat variability in cycle length and left ventricular performance in patients with atrial fibrillation. In this study, left ventricular ejection fraction and relative left ventricular volumes were evaluated on a beat-to-beat basis with the computerized nuclear probe, an instrument with sufficiently high sensitivity to allow continuous evaluation of the radionuclide time-activity curve. Of 18 patients with atrial fibrillation, 5 had mitral stenosis, 6 had mitral regurgitation, and 7 had coronary artery disease. Fifty consecutive beats were analyzed in each patient. The mean left ventricular ejection fraction ranged from 17 to 51%. There was substantial beat-to-beat variation in cycle length and left ventricular ejection fraction in all patients, including those with marked left ventricular dysfunction. In 14 patients who also underwent multiple gated cardiac blood pool imaging, there was an excellent correlation between mean ejection fraction derived from the nuclear probe and gated ejection fraction obtained by gamma camera imaging (r = 0.90). Based on beat-to-beat analysis, left ventricular function was dependent on relative end-diastolic volume and multiple preceding cycle lengths, but not preceding end-systolic volumes. This study demonstrates that a single value for left ventricular ejection fraction does not adequately characterize left ventricular function in patients with atrial fibrillation. Furthermore, both the mean beat-to-beat and the gated ejection fraction may underestimate left ventricular performance at rest in such patients.

Progressive heart failure and death associated with Mycoplasma pneumoniae pneumonia

A case of progressive CHF and death associated with serologically confirmed Mycoplasma pneumoniae pneumonia in a previously healthy man is described. The association between the organism and significant cardiac or pericardial dysfunction discussed, the literature reviewed, and speculation made as to the underlying pathophysiologic mechanisms.

Radionuclide angiographic exercise left ventricular performance in chronic aortic regurgitation: relationship to resting echographic ventricular dimensions and systolic wall stress index

Forty-five patients with chronic aortic regurgitation (AR) underwent first-pass radionuclide angiocardiography (RNA) at rest and during upright bicycle exercise, as well as M-mode echocardiography at rest. Abnormal left ventricular (LV) exercise reserve, defined by the absolute change in ejection fraction (EF), was present in 16 of 45 patients (36%). Seven of ten patients with abnormal resting EF (less than 50%) and three of seven symptomatic patients had normal LV exercise responses. Patients with normal LV exercise reserve by RNA had LV dimensions by echo at end diastole (5.9 +/- 0.2 vs 6.5 +/- 0.3 cm, p = NS) and end systole (3.9 +/- 0.2 vs 4.4 +/- 0.3 cm, p = NS) comparable to those in patients wht abnormal LV exercise reserve. However, the mean corrected LV end-diastolic (LVED) radius/wall thickness ratio was significantly greater in AR patients with abnormal LV exercise reserve than in those with normal LV exercise reserve (395 +/- 15 vs 315 +/- 16, p less than 0.01). There data suggest that resting echocardiographic LV dimensions as well as the corrected echo LVED radius/wall thickness ratio have a variable relationship to RNA LV exercise performance in patients with chronic AR.

Exercise left ventricular performance in patients with chest pain, ischemic-appearing exercise electrocardiograms, and angiographically normal coronary arteries

Left ventricular performance was evaluated using first-pass radionuclide angiocardiography in 31 patients with chest pain, an ischemic-appearing exercise electrocardiogram, and angiographically normal coronary arteries at rest and during maximal upright bicycle exercise. Thallium-201 (201 TI) imaging was done in all patients after treadmill exercise and in selected patients after ergonovine provocation. Resting left ventricular performance was normal in all patients. An abnormal ejection fraction response to exercise was detected in 12 of 31 patients. Regional dysfunction was present during exercise in four patients, all of whom also had abnormal global responses. Three of these 12 patients and two additional patients had exercise-induced 201 TI perfusion defects. In all nine patients who underwent ergonovine testing, there was no suggestion of coronary arterial spasm. Thus, left ventricular dysfunction during exercise, in the presence of normal resting performance, was found in a substantial number of patients with chest pain, an ischemic-appearing exercise electrocardiogram, and normal coronary arteries.

Longevity comparisons among lithium anode power cells for cardiac pacemakers

Of over 10,000 lithium-powered pacemakers followed by a commercial transtelephone monitoring service, 148 have been explanted due to rate decline. A breakdown according to the power cell manufactures shows that the longevity is not uniform, indicating that significant differences exist among the power cell designs even though all have lithium anodes. One tenth of all lithium-powered pacemakers in the study were explanted for rate declines within 4 years.

Pericarditis and perimyocarditis associated with active Mycoplasma pneumoniae infection

In 13 patients an association existed from 1970-73 between Mycoplasma pneumoniae infection and acute pericarditis (in eight) or perimyocarditis (in five). In 12 patients the association was moderately probable, with a fourfold rise in complement-fixing antibody titers between acute and convalescent phase sera being noted. In the last patient, a lesser-order association was found using only convalsecent phase serum. The presence of influenza, herpes simplex, Coxsackie B, or adenovirus was excluded by serologic testing. Acute illness was variable, with four patients developing heart failure. Long-term evaluation (mean, 47 months) found eight patients asymptomatic and three symptomatic. Two patients died. Residual effects of the Mycoplasma infection seemed at least partially responsible in one compromised patient and in one who died. Mycoplasma infection should be considered in the presence of acute cardiovascular decompensation, especially when preceded by upper respiratory infection, and added to the possible causes of idiopathic cardiomyopathy.

Pseudomalfunction of a Beall mitral valve prosthesis in the presence of paravalvular aortic regurgitation

Premature closure of a Beall mitral valve prosthesis is described in a patient with aortic prosthetic paravalvular regurgitation. Differentiation from valvular malfunction and diagnostic confirmation by means of cinefluoroscopy and simultaneous electrocardiography are discussed.

The evaluation of left ventricular function in man. A comparison of methods

Comparisons of the sensitivities of parameters for assessing left ventricular performance in man were made in 38 patients. The parameters compared were the ejection fraction, ventriculographic contraction patterns, the left ventricular end-diastolic pressure, and the contractile indices including the contractile element velocity at 10 mm Hg (Vce 10) and maximal contractile element velocity (Vmax). The contractile indices were obtained by catheter tip manometry, utilizing developed pressure (DP) to calculate the velocity of contractile element shortening (Vce) from the formula: dp/dt divided by 32 DP. Vce 10 was measured directly and Vmax was derived by linear manual extrapolation of the pressure-velocity plot to 0 mm Hg. Vmax values derived from linear manual extrapolation were compared with values obtained by computer least squares fitting of the Vce and developed pressure data points to single and double exponential equations. The Vce and developed pressure data points fit the single exponential equation better than the double exponential equation but the use of either equation resulted in slightly higher values for Vmax than obtained with linear manual extrapolation. The effect of heart rate on myocardial contractility was eliminated by making comparisons at both a basal and atrial paced rate of 100. Utilizing all methods, 24 patients were identified to have ventricular dysfunction. The contractile indices were significantly less sensitive than any other parameter (P smaller than 0.05) and identified seven patients while the left ventricular end-diastolic pressure, ejection fraction, and presence of asynergy identified 15, 15, and 12 patients, respectively. The use of a common atrial paced rate of 100 did not increase the sensitivity of the contractile indices. Since there was only partial overlapping between parameters in the identification of left ventricular dysfunction, the combination of different parameters was more sensitive than any single parameter alone. It is concluded that several methods are required to identify all patients with left ventricular dysfunction and that the contractile indices are the least sensitive indicator of left ventricular dysfunction.

Hypoglycemia complicating the use of solution of glucose, insulin and potassium

A patient is described who developed hypoglycemia and generalized neurologic depression after cardiac surgery, while receiving an infusion of glucose, insulin, and potassium (GIK). Hypoglycemia as a complication of the use of GIK solution in patients with hepatic dysfunction, malnutrition and low cardiac output is discussed.