This study examines the changing presentation of coronary heart disease (CHD) in an inpatient population at Brooke Army Medical Center. The specific objectives of the study were to examine the presentation of CHD in a population unbiased... more
This study examines the changing presentation of coronary heart disease (CHD) in an inpatient population at Brooke Army Medical Center. The specific objectives of the study were to examine the presentation of CHD in a population unbiased by diagnosis-related group (DRG) reimbursements and to assess the importance of unstable angina and prior history of disease in the presentation of CHD. One thousand fifteen discharges in 1985 and 1,304 discharges in 1990 with the diagnosis of CHD were reviewed by cardiologists for evidence of symptomatic heart disease at the time of hospitalization. Forty percent of these charts were accepted into this study. The presentation rates of CHD were 1% with sudden death, 26% with myocardial infarction, 64% with angina, and 9% with congestive heart failure (CHF). During the study period, stable angina, Q-wave infarctions, and the myocardial infarction case fatality rate decreased (p < 0.05) and CHF and non-Q wave infarcts increased (p < 0.001). However, unstable angina was the most common presentation of CHD, and differences (p < 0.05) were noted in the presentation of CHD in patients with and without a prior history of disease. This study demonstrates the significance of unstable angina and prior history of CHD in an environment free of bias from DRG reimbursements.
Research Interests: Military Medicine, Cardiology, Medicine, Electrocardiography, Heart Failure, and 15 morePopulation, Humans, Internal Medicine, Female, Male, Aged, Middle Aged, Myocardial Infarction, Adult, Coronary heart disease, Public health systems and services research, Angina pectoris, Angina, Military Personnel, and Case fatality rate
This study compares the effects of quiet breathing on the heart structure and function of pentathlon athletes (n = 11) and a less-conditioned control group (n = 12). Two-dimensional echocardiography was employed to direct an M-mode beam... more
This study compares the effects of quiet breathing on the heart structure and function of pentathlon athletes (n = 11) and a less-conditioned control group (n = 12). Two-dimensional echocardiography was employed to direct an M-mode beam through the heart to minimize measurement errors due to respiratory motion of the heart. Respiration was simultaneously recorded with M-mode echocardiograms from a minimum of five respiratory and an average of 25 cardiac cycles. Athletes had greater (p less than 0.01) end-diastolic transverse dimensions (10%), and interventricular septal and left ventricular posterior wall thicknesses (25%). During inspiration right ventricular internal end-diastolic dimensions increased (8 vs 12%) and left ventricular end-diastolic dimension (LVIDd) decreased (7 vs 8%) in athletes and controls, respectively. Although significant reciprocal changes in LVIDd (p less than 0.01) occurred during respiration, no respiratory change was noted in the transverse diameter of the heart, interventricular septal, posterior wall thickness, LV end-systolic volume or ejection fraction. Inspiration caused a 21% fall (p less than 0.01) in LV stroke volume in both groups. Eighty-four to 92% of the inspiratory decrease in LV stroke volume in the subjects studied could be attributed to ventricular interdependence; no significant interaction was found between level of conditioning and respiration.
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Heart sounds provide clinicians with valuable diagnostic and prognostic information. They are repetitive in nature, but reflect complex mechano-acoustical events which have been inadequately described by traditional digital signal... more
Heart sounds provide clinicians with valuable diagnostic and prognostic information. They are repetitive in nature, but reflect complex mechano-acoustical events which have been inadequately described by traditional digital signal processing methods. In this study, left ventricular and aortic intravascular phonocardiograms were obtained from six patients by catheter-mounted piezoelectric transducers. Phonocardiograms (PCGs) were bandpass filtered (50-500 Hz), digitized at 4kHz and analyzed by three separate techniques: (1) Short-Time Fourier Transform (STFT), (2) Fast Wavelet Transform (FWT), and (3) a pulse-counting time-domain method based on an Order Statistic (OS) filter. The resulting time-frequency distributions were employed to examine intra-patient and inter-patient acoustic variability. Results suggest that STFT and FWT provide comparable temporal and frequency resolution of cardiac acoustical events. However, the time-varying and multicomponent nature of heart sounds was poorly characterized by the OS technique employed in this study. This study suggests that improved localization of acoustic events during the cardiac cycle may prove useful in the development of automated auscultation devices.
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Advances in heart transplantation and post-operative rejection therapy have given new hope to patients with end-stage congestive heart failure and cardiomyopathies. The growing numbers of pre- and post-transplant patients and the... more
Advances in heart transplantation and post-operative rejection therapy have given new hope to patients with end-stage congestive heart failure and cardiomyopathies. The growing numbers of pre- and post-transplant patients and the complexity of their care underscore the need for a multispecialty approach to patient management. This study examines the success of a multi-service program at Brooke Army Medical Center which offers pre- and post-transplant care to active duty, dependent, and retired military personnel.
Research Interests: Military Medicine, Medicine, Heart Failure, Humans, Female, and 14 moreMale, Follow-up studies, Middle Aged, Medical Emergency, Adult, Patient Care Team, Public health systems and services research, Survival Rate, Graft Rejection, Heart Transplantation, Military Personnel, Heart Diseases, quality assurance in health care, and active duty
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Research Interests: Military Medicine, Incidence Geometry, Medicine, Military, Echocardiography, and 15 moreHumans, Female, Male, Follow-up studies, Aged, Middle Aged, Implant, Time Factors, Retrospective Studies, Implantable defibrillators-cardioverters, Ventricular Fibrillation, Defibrillation, Adverse effect, Equipment failure, and Population surveillance
Critical measurement of patient body temperature in the PACU is an important parameter in patient management. Failure to achieve minimal acceptable body temperature standards has been associated with physiological derangement, the... more
Critical measurement of patient body temperature in the PACU is an important parameter in patient management. Failure to achieve minimal acceptable body temperature standards has been associated with physiological derangement, the application of additional therapy, and prolonged PACU stays. Newer methods to monitor temperature have been introduced into the PACU that have been touted to be adequate for detecting clinically significant changes in temperature. This study compares skin core temperature-corrected liquid crystal thermography, axillary electronic, and oral electronic thermistor readings with temperatures obtained by infrared tympanic membrane thermometry in 215 PACU patients. Regression analysis suggests that when compared with tympanic temperature, the oral method is more accurate and has greater precision than either the liquid crystal or axillary methods. That the incidence of hypothermia depends on the method chosen to assess body temperature is a significant nursing i...
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Technetium-99m apcitide (AcuTect) is a peptide with high affinity and specificity for glycoprotein IIb/IIIa receptors on platelets and is currently approved for the diagnosis of deep venous thrombosis. This study evaluates the use of... more
Technetium-99m apcitide (AcuTect) is a peptide with high affinity and specificity for glycoprotein IIb/IIIa receptors on platelets and is currently approved for the diagnosis of deep venous thrombosis. This study evaluates the use of Tc-99m apcitide for detecting intracardiac thrombus in an animal model with atrial fibrillation. Thrombogenic material (0.23+/- 0.03 g) was implanted within the left atrium of 5 swine with induced atrial fibrillation. Scintigraphy was performed with a small field of view gamma camera (minimum of 400000 counts) 1 hour after implantation at 10, 60, and 120 minutes after the injection of the Tc-99m apcitide. Animals were then euthanized and a postmortem examination performed to confirm thrombus formation. : In all animals, thrombi and microthrombi were confirmed within the left atrial appendage. The average wet weight of the thrombus was 1.4 +/- 0.2 g. Tc-99m apcitide detected left atrial thrombus in all animals. This study suggests that AcuTect may prove useful for detecting intracardiac thrombus in future clinical studies in man.
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Computed tomographic myocardial perfusion (CTP) imaging is a tool that shows promise in emergent settings for defining the hemodynamic significance of coronary artery disease. In this study, we examined the accuracy with which the... more
Computed tomographic myocardial perfusion (CTP) imaging is a tool that shows promise in emergent settings for defining the hemodynamic significance of coronary artery disease. In this study, we examined the accuracy with which the transmuralperfusion ratio (TPR) derived through semiautomated CTP analysis reflected segmental perfusion defects associated with intermediate coronary artery lesions in swine. Lesions (diameter stenosis, 65% ± 11%) of the left anterior descending coronary artery (LAD) were created in 10 anesthetized female swine (weight, 47.5 ± 1.9 kg) by using a pneumatic occlusion device implanted on the LAD. Occluder inflation pressures were adjusted to maintain fractional flow reserve (FFR, 74.3 ± 1.7) during adenosine infusion (140ug/kg/min). Static CTP imaging using a stress-rest protocol and segmental TPR derived from semiautomated CT perfusion software was compared with microsphere-derived TPR (mTPR) by using a 16-segment model and polar mapping. Intermediate LAD s...
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Aortic input impedance was calculated in seven subjects in the control state (normal reflection) and during the Mueller maneuver (increased reflection) to evaluate "effective arterial length" under altered physiological... more
Aortic input impedance was calculated in seven subjects in the control state (normal reflection) and during the Mueller maneuver (increased reflection) to evaluate "effective arterial length" under altered physiological conditions. Regional foot-to-foot pulse wave velocities and pressure waveforms along the aorta were used to define an "apparent anatomic length" or distance to a dominant discrete site of reflection "seen" by the ejecting ventricle. Time of wave travel was taken to be one-half the interval from the foot of the incident wave to the midsystolic inflection point. Knowing the time of travel from the returning reflection and velocity, distances calculated to the "apparent anatomic length" were 35 +/- 2 and 34 +/- 2 during control and Mueller maneuver, respectively (P = NS). The frequency of the first minimum of the modulus (fmin) and the first zero crossing of the phase angle (f phi) were determined from the input impedance spectra....
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This study describes results of iCPET from the past, which used submaximal stress and multisensor high-fidelity catheters to exclude heart disease in a unique population of young adults. There has been resurgence in comprehensive... more
This study describes results of iCPET from the past, which used submaximal stress and multisensor high-fidelity catheters to exclude heart disease in a unique population of young adults. There has been resurgence in comprehensive hemodynamic evaluation of complex cardiovascular patients. Although dynamic assessments during cardiac catheterization have become commonplace, there remains limited information regarding left and right heart hemodynamic changes during supine exercise in young adults. The study population was derived from a retrospective review of catheterization records at Brooke Army Medical Center for active duty patients (ages: 19-40 years) in whom hemodynamic waveforms were obtained with multisensor high-fidelity catheters and supine exercise testing (53.1 ± 12.6 watts) and angiography performed to exclude heart disease. We report findings from 41 males and 1 female (ages: 19-40 years) found free of heart disease. Submaximal exercise was associated with ≈ fourfold (P &...
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Research Interests: Medicine and Circulation
ABSTRACT Background: Atherosclerotic vascular disease remains a significant etiology of morbidity and mortality in the United States. Coronary artery calcium (CAC) is associated with increased stroke incidence and coronary atherosclerotic... more
ABSTRACT Background: Atherosclerotic vascular disease remains a significant etiology of morbidity and mortality in the United States. Coronary artery calcium (CAC) is associated with increased stroke incidence and coronary atherosclerotic burden. Uncertainty remains regarding how best to interpret non-zero CAC scores, particularly in symptomatic patients. Methods: A review of the first 1122 patients who underwent coronary CT angiography (CCTA) with CAC scoring from January 2005 until July 2012 was performed. Patients were dichotomized into 2 groups, zero CAC score and non-zero CAC score. Non-zero CAC patients were further subdivided based on the specific coronary artery containing calcium. Rates of major adverse cardiovascular events (MACE) defined as all-cause mortality, non-fatal myocardial infarction (MI), ischemic stroke, and late revascularization (>90 days following CCTA) were evaluated in each group. Results: 505 patients (63% male, mean age 60 ± 11) with non-zero CAC scores were analyzed over a six year period with resultant median follow up period of 22 months (IQR25,75 13-34 months). Major adverse cardiovascular events were observed in 11 patients. Receiver-operator curve (ROC) analysis on each coronary segment showed significance with the presence of left main (LM) CAC (AUC 0.752, p=0.004). Conclusions: The presence of CAC at any value inthe LM in this case series appears to predispose patients to increased rates of MACE.
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Small, observational trials have suggested a reduction in adjacent gastric activity with ingestion of soda water in myocardial perfusion imaging (MPI). We report our findings prior to and after implementation of soda water in 467... more
Small, observational trials have suggested a reduction in adjacent gastric activity with ingestion of soda water in myocardial perfusion imaging (MPI). We report our findings prior to and after implementation of soda water in 467 consecutive MPI studies. Consecutive MPI studies performed at a high-volume facility referred for vasodilator (VD) or exercise treadmill testing (ETT) were retrospectively reviewed before and after implementation of the soda water protocol. Patients undergoing the soda water protocol received 100 ml of soda water administered 30 min prior to image acquisition and after stress. Studies were performed using a same day rest/stress protocol. Incidence of adjacent gastric activity, diaphragmatic attenuation, stress and rest perfusion defects, and major adverse cardiovascular events (MACE) outcomes defined as death, myocardial infarction, stroke, reevaluation for chest pain, and late revascularization (>90 days from MPI) were abstracted using International Cla...
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Postoperative atrial fibrillation following cardiothoracic surgery is common and frequently managed with intravenous (IV) amiodarone. Phlebitis is the most common complication with peripheral infusion of this agent. Current practice... more
Postoperative atrial fibrillation following cardiothoracic surgery is common and frequently managed with intravenous (IV) amiodarone. Phlebitis is the most common complication with peripheral infusion of this agent. Current practice guidelines for peripheral IV administration of <2 mg/mL amiodarone were established to reduce the risk of phlebitis. The present study examines the incidence of phlebitis in a postoperative patient population given current dose recommendations. A total of 273 patient charts were reviewed. The incidence of phlebitis in patients given IV amiodarone (n = 36) was 13.9% (95% confidence interval, 2.6-25.2%; p = 0.001). Logistic regression analysis with backward elimination of other therapeutic risk factors suggests that the odds ratio for phlebitis using current dose regimens without IV filters is 19-fold greater than baseline risk in this population. Phlebitis remains a significant complication associated with peripheral infusion of amiodarone within recom...
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Late potentials (LPs) are harbingers of sudden cardiac death (SCD) for certain patient populations, including SCD survivors and patients post myocardial infarction. This retrospective study examined the sensitivity and specificity of... more
Late potentials (LPs) are harbingers of sudden cardiac death (SCD) for certain patient populations, including SCD survivors and patients post myocardial infarction. This retrospective study examined the sensitivity and specificity of time-frequency distributions (TFDs) in detecting late potentials in 90 patients using time-domain signal average ECG criteria as a standard for comparison. Three time-domain criteria were employed: QRS duration > 114 msec; LAS > 30 msec; and RMS40 < 20 microV. Time domain criteria were compared with TFD results derived using the binomial transform. TFDs were considered positive if small magnitude (-30 dB) signals > 40 Hz were present 114 msec after the onset of the QRS complex. Results from the binomial transform are comparable to those from the SAECG method (sensitivity = 92.0-100%, specificity = 78-92%).
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Phase-contrast magnetic resonance imaging (PC-MRI) is useful for assessing coronary artery flow reserves (CFR) in man and acute animal models with intermediate coronary lesions. The present study examines the use of PC-MRI for assessing... more
Phase-contrast magnetic resonance imaging (PC-MRI) is useful for assessing coronary artery flow reserves (CFR) in man and acute animal models with intermediate coronary lesions. The present study examines the use of PC-MRI for assessing CFR in a model with critical stenosis and collateral dependence. PC-MRI quantitative flow measurements from the proximal left anterior descending (LAD) and left circumflex (LCX) coronary arteries were compared with myocardial tissue perfusion reserve measurements (microsphere techniques) after placement of a 2.25-mm ameroid constrictor on the proximal LCX in a porcine model; measurements were obtained at implantation (n = 4) and at 3 to 4 weeks (n = 4) and 6 weeks (n = 5) postimplantation. CFR is defined as the ratio of maximal hyperemic flow to baseline flow. Hyperemia was induced using intravenous adenosine (140 mg/kg/min). Collateral dependence in the LCX distri bution was evidenced by angiographic findings of critical stenosis with minimal myocar...
Research Interests: Cardiology, Magnetic Resonance Imaging, Hydrogels, Medicine, Comparative Medicine, and 11 moreBiological Sciences, Adenosine, Animals, Myocardium, Coronary Circulation, Sus Scrofa, Blood Flow Velocity, Magnetic resonance angiography, Medical and Health Sciences, Fractional Flow Reserve, and Coronary Vessels
Abstract Study hypothesis. The primary study objective was to delineate the procedural aspects of intraosseous (IO) infusions responsible for fat intravasation by testing the hypothesis that the fat content of effluent blood increases... more
Abstract Study hypothesis. The primary study objective was to delineate the procedural aspects of intraosseous (IO) infusions responsible for fat intravasation by testing the hypothesis that the fat content of effluent blood increases during IO infusions. Methods. IO cannulas were inserted into the proximal tibiae of 35 anesthetized swine (Sus scrofa, 50.1 ± 3.5 kg) and intravasated fat was assessed using a lipophilic fluoroprobe (Nile red) and by vascular ultrasound imaging. Effluent blood bone marrow fat was assessed at baseline, during flush, and with regimens of controlled infusion pressures (73-300 mmHg) and infusion flow rates (0.3-3.0 mL per second). Fat intravasation was also assessed with IO infusions at different tibial cannulation sites and in the distal femur. In 7 animals, the lipid uptake of alveolar macrophages and lung tissue assessed for fat embolic burden using oil red O stain 24 hours post infusion. Additionally, bone marrow shear-strain was assessed radiographically with IO infusions. Results. Fat intravasation was observed during all IO infusion regimens, with subclinical pulmonary fat emboli persisting 24 hours post infusion. It was noted that initial flush was a significant factor in fat intravasation, low levels of intravasation occurred with infusions ≤300 mmHg, fat intravasation and bone marrow shear-strain increased with IO infusion rates, and intravasation was influenced by cannula insertion site. Ultrasound findings suggest that echogenic particles consistent with fat emboli are carried in fast and slow venous blood flow fields. Echo reflective densities were observed to rise to the nondependent endovascular margins and coalesce in accordance with Stoke&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s law. In addition, ultrasound findings suggested that intravasated bone marrow fat was thrombogenic. Conclusion. Results suggest that in swine the intravasation of bone marrow fat is a common consequence of IO infusion procedures and that its magnitude is influenced by the site of cannulation and infusion forces. Although the efficacy and benefits of IO infusions for emergent care are well established, emergency care providers also should be cognizant that infusion procedures affect bone marrow fat intravasation.
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... SATECHO Investigators) for their support in this project: Brooke Army Medical Center; Bobby Dean, VTC &amp;amp;amp;amp; Telemedicine Administrator, IMD; Vicky Hamlin, Chief ... American College of Cardiology Learning Center... more
... SATECHO Investigators) for their support in this project: Brooke Army Medical Center; Bobby Dean, VTC &amp;amp;amp;amp; Telemedicine Administrator, IMD; Vicky Hamlin, Chief ... American College of Cardiology Learning Center Highlights 1993;9:712 4 Finley JP, Sharratt GP, Nanton MA, et ...
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Abstract The Pacific Island Health Care Project cares for 250-500 patients from the US-associated Pacific Islands. Unique to the Pacific Basin is a high incidence of acute rheumatic fever, a condition that not uncommonly results in... more
Abstract The Pacific Island Health Care Project cares for 250-500 patients from the US-associated Pacific Islands. Unique to the Pacific Basin is a high incidence of acute rheumatic fever, a condition that not uncommonly results in valvular heart disease. Identification of ...
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Research Interests: Cardiology, Medicine, Humans, Intervention, Female, and 14 moreMale, Follow-up studies, Angioplasty, Pressure, Middle Aged, Myocardial Infarction, Coronary heart disease, Retrospective Studies, Chi Square Distribution, Coronary Artery Disease, Logistic Models, Cardiovascular medicine and haematology, Coronary Artery Bypass, and Coronary Vessels
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-.250, p <0.014). Correlations within platelet aggregation tests ranged from r = 0.33 to 0.757 (p ≤ 0.001) and between platelet aggregation (ADP 10 M) and Accumetrics measures (aspirin and P2Y12) were r = .338 and .352 (p <0.001),... more
-.250, p <0.014). Correlations within platelet aggregation tests ranged from r = 0.33 to 0.757 (p ≤ 0.001) and between platelet aggregation (ADP 10 M) and Accumetrics measures (aspirin and P2Y12) were r = .338 and .352 (p <0.001), respectively. Only fair agreement was observed between PFA-100 EPI/COLL and Accumetrics aspirin (kappa = 0.274, p=0.006). These data suggest that there is generally poor agreement between methods for assessing platelet function in this study population. Given recent clinical data suggesting an increasing role for platelet function testing in patients with ischemic coronary heart disease, these findings suggest that alternative methods for rapid assessment of efficacy of anti-platelet therapy will be required.
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The cardiac profile of nine AIAW softball champions (SC) was compared with the cardiac profile of 10 sedentary women who were matched according to age and body size (SW). Standard M-mode echocardiography and a maximum graded stress test... more
The cardiac profile of nine AIAW softball champions (SC) was compared with the cardiac profile of 10 sedentary women who were matched according to age and body size (SW). Standard M-mode echocardiography and a maximum graded stress test were performed on each subject. The mean (+/- SE) resting heart rate (50.6 +/- 2.6 bpm) and VO2max (55.3 +/- 2.0 ml O2 x kg-1 x min-1) of the SC were significantly different (P less than 0.001) than the heart rate (71.2 +/- 3.1 bpm) and VO2max (40.3 +/- 1.4 ml x kg-1 x min-1) of the SW. Significantly greater (P less than 0.05) interventricular septal thickness (IST), and left ventricular end-diastolic dimension (LVIDd) and volume (LVIDd3) were noted in the SC. The means (+/- SE) for IST, LVIDd, and LVIDd3 for the athletes were 8.9 +/- 0.4 mm, 4.8 +/- 0.1 cm, and 110 +/- 5.9 cm3, respectively; and for the SW were 7.5 +/- 0.5 mm. 4.4 +/- 0.2 cm, and 87.8 +/- 8.0 cm3, respectively. Although there was no difference in the left ventricular cavity/muscle volume ratio, the athletes had an increased (P less than 0.02) left ventricular mass (168 +/- 15 g) when compared with SW (123 +/- 9 g). Therefore, the cardiac adaptations noted during rest in moderate-endurance trained AIAW softball champions included a relative bradycardia and eccentric hypertrophy.
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Research Interests: Ultrasound, Medicine, Echocardiography, Humans, Feasibility Studies, and 15 moreReal Time, Time Factors, Reproducibility of Results, Local Area Network, Heart Ventricles, Early Diagnosis, Predictive value of tests, First Responder, The American, Random Allocation, Transmission Loss, Left Ventricular, Diagnostic Tool, chest trauma, and Cardiovascular medicine and haematology
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... En: JA López-Geta, JC Rubio y M. Martín Machuca (Eds.), VI Simposio del Agua en Andalucía. ... La metodología empleada ha consistido en la generación de lixiviados a partir de la muestra M-02 (Tabla 2), de forma similar a lo que... more
... En: JA López-Geta, JC Rubio y M. Martín Machuca (Eds.), VI Simposio del Agua en Andalucía. ... La metodología empleada ha consistido en la generación de lixiviados a partir de la muestra M-02 (Tabla 2), de forma similar a lo que sucede en el terreno por acción de la lluvia. ...
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The objectives of this study were to assess the efficacy of parenteral magnesium sulfate (MgSO4), digoxin, and combined MgSO4-digoxin therapies in acutely lowering ventricular rates in patients with newly recognized atrial fibrillation. A... more
The objectives of this study were to assess the efficacy of parenteral magnesium sulfate (MgSO4), digoxin, and combined MgSO4-digoxin therapies in acutely lowering ventricular rates in patients with newly recognized atrial fibrillation. A randomized, double-blinded, placebo-controlled clinical study. US Army tertiary care facility. Fifteen adults (mean age, 62 +/- 19 years) presenting with newly recognized atrial fibrillation and rapid ventricular rate (more than 99). Patients were given an initial parenteral MgSO4 bolus with continuous infusion or placebo. After 30 minutes, all patients were given 0.5 mg IV digoxin and followed for 3.5 hours. Ventricular rates were obtained at baseline, every 5 minutes for the first 30 minutes, and then every 30 minutes for 3.5 hours. At 5 minutes, ventricular rates decreased 16 +/- 7% (P &lt; .02) with MgSO4; this was comparable with rate control with digoxin (18 +/- 9%) at 4 hours. Rate control tended (26 +/- 7%) to improve with combined therapy. Parenteral MgSO4 may be useful in the acute management of rapid ventricular rates in patients with atrial fibrillation.
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Beta-blocker therapy remains controversial in patients with mitral stenosis. In this randomized, double-blind, crossover, placebo-controlled study, the effects of atenolol (50 and 100 mg/day) were assessed in 15 patients (aged 46 +/- 11... more
Beta-blocker therapy remains controversial in patients with mitral stenosis. In this randomized, double-blind, crossover, placebo-controlled study, the effects of atenolol (50 and 100 mg/day) were assessed in 15 patients (aged 46 +/- 11 years) with mitral stenosis (mean valve area 1.0 +/- 0.4 cm2; New York Heart Association class II or III) at rest and during upright bicycle ergometry. Doppler echocardiography was used to compare heart rate, cardiac and stroke volume indexes, diastolic filling period, and peak and mean transmitral gradients; a metabolic cart was used to obtain maximal oxygen consumption, carbon dioxide production, and anaerobic threshold. Beta-blocking therapy did not improve exercise time, external work, maximal oxygen consumption rate, or anaerobic threshold. Compared with placebo, maximal oxygen consumption rate and cardiac index decreased (p &amp;amp;lt; 0.05) &amp;amp;gt; 11% and &amp;amp;gt; 20%, respectively, with atenolol at peak exercise. Although heart rate was reduced &amp;amp;gt; 20% and diastolic filling period prolonged &amp;amp;gt; 40% by atenolol at rest and exercise (p &amp;amp;lt; 0.05), stroke volume index changed little compared with placebo. The data suggest that despite lower transvalvular pressure gradients, little benefit in exercise performance is achieved with beta-blocker therapy in patients with severe mitral stenosis.
Research Interests: Cardiology, Medicine, Humans, Internal Medicine, Hemodynamics, and 15 moreFemale, Male, Heart rate, Exercise, Middle Aged, Adult, Beta Blockers, Oxygen Consumption, Maximal Oxygen Consumption, Mitral Valve Stenosis, Atenolol, Anaerobic Threshold, Mitral stenosis, Cardiovascular medicine and haematology, and Doppler echocardiography
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Research Interests: Military Medicine, Sports Medicine, Adolescent, Medicine, Electrocardiography, and 15 moreEchocardiography, Sports, Humans, Female, Male, Athletes, Questionnaires, Public health systems and services research, Sudden Cardiac Death, Physical examination, Cardiovascular Diseases, Chi Square Distribution, Heart Diseases, Medical History Taking, and mass Screening
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ABSTRACT Background: The use of noninvasive medical imaging has increased over the past decade at a cost of significant lifetime radiation exposure to study subjects. We report the implementation of radiation dose reduction methods and... more
ABSTRACT Background: The use of noninvasive medical imaging has increased over the past decade at a cost of significant lifetime radiation exposure to study subjects. We report the implementation of radiation dose reduction methods and associated reduction in ionizing radiation exposure with Coronary Computed Tomography Angiography (CCTA) over time. Methods: Radiation doses and total number of studies performed were evaluated constantly from January 2010 to September 2012 for CCTA (N=2613), as well as Single photon emission computed tomography (SPECT, N=8060) part of an ongoing effort to minimize radiation exposure. Analysis of variance was used to evaluate the radiation exposure reduction among modalities. We compared CCTA radiation doses in the era of retrospective protocols coupled with dose modulation (40%-80%phase) using Siemens® 64-slice Dual Source technology, with prospective scanning on the same equipment, as well as radiation doses on the newer Siemens® Flash Equipment and the implementation of nursing/technologist aggressively driven protocol for heart rate control and image acquisition independent of imaging provider presence during acquisition. Results: The radiation dose reduction with implementation of multiple measures of radiation reduction to include physician independent-technician driven CCTA protocol resulted in a reduction from mean of 9.85±5.96 (median 8.8mSv) to mean of 3.00±2.53(median 2.1mSv) (p&lt;0.0001). CCTA radiation dose has decreased by 69.2% since January of 2010 while SPECT radiation dose remained constant at 14mSv (p&lt;0.0001). Conclusion: Continued advances in software and hardware technology, combined with “physician independent-technician driven” CCTA protocol have drastically reduced radiation dosing in CCTA to annual background radiation exposure, while maximizing the benefit of the study and without sacrificing patient safety.
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The 'water-wheel' or 'mill-wheel' murmur is classically associated with large intracardiac air emboli and described as a "characteristic splashing auscultatory sound due to the presence of gas in the cardiac... more
The 'water-wheel' or 'mill-wheel' murmur is classically associated with large intracardiac air emboli and described as a "characteristic splashing auscultatory sound due to the presence of gas in the cardiac chambers." We used 64-slice computed tomography (slice thickness, 0.5 mm; revolution time, 400 msec) and 3D fly-through software imagery to capture previously unreported intracardiac air-blood interface dynamics associated with this murmur and ineffective right ventricular contraction in a porcine model.