Daniel J. Ullyot

Regional Myocardial Blood Flow in Lambs with Concentric Right Ventricular Hypertrophy

Chronically hypertrophied right ventricles function normally under high systolic pressures, whereas normal right ventricles fail when they are acutely subjected to similar pressures. This phenomenon may be partly due to adaptation of the coronary circulation as well as to hypertrophy. Knowledge of the magnitude and distribution of coronary blood flow and the degree of coronary vascular reserve are important in understanding the function of hypertrophied myocardium. We studied these variables in 16 awake, 5–12-week-old, tranquilized lambs; 9 of the lambs had had their main pulmonary artery banded at 2 days of age. Pressures, cardiac output, and coronary blood flow (radioactive microsphere method) were measured at rest and during two stress states—isoproterenol and dextran infusion. Ventricular function was similar in control and banded lambs. We found significant right ventricular hypertension and both right ventricular and septal hypertrophy in the banded lambs. Total coronary blood flow per gram was slightly higher in banded lambs in all states, and right ventricular flow per gram was significantly elevated at rest and during isoproterenol infusion. Right ventricular coronary resistance per gram was significantly lower in banded lambs in all states. These changes demonstrate that hypertrophied right ventricular tissue is not ischemic at rest, since there is vascular reserve. The changes also raise the question of increased vascularity in hypertrophied myocardium. Right ventricular oxygen supply per unit oxygen demand was increased in banded lambs at rest and during isoproterenol infusion. This finding suggests that hypertrophied myocardium has inefficient oxygen utilization, low oxygen extraction, or both.

Look ma, no hands!

New updated! The latest book from a very famous author finally comes out. Book of look ma no hands, as an amazing reference becomes what you need to get. Whats for is this book? Are you still thinking for what the book is? Well, this is what you probably will get. You should have made proper choices for your better life. Book, as a source that may involve the facts, opinion, literature, religion, and many others are the great friends to join with.

Reentry confined to the atrioventricular node: Electrophysiologic and anatomic findings

A patient with recurrent disabling, paroxysmal supraventricular tachycardia refractory to drug treatment underwent electrophysiologic studies. The paroxysmal supraventricular tachycardia was found to be due to atrioventricular (A-V) nodal reentry. The patient died shortly after surgical His bundle section and detailed anatomic studies were performed. These showed fatty infiltration of the approaches to the sinoatrial node, atrial preferential pathways, and A-V node and common bundle. The A-V node was mechanically damaged and the common His bundle was completely severed. These abnormalities were clearly delineated and there was no evidence of an atrio-His bundle bypass tract to an accessory A-V node. Specifically, the central fibrous body and pars membranacea were defined and no atrial muscular fibers pierced these structures to joint the A-V bundle. It is concluded that paroxysmal supraventricular tachycardia due to A-V nodal reentry can be confined to the A-V node.

Evaluation of early postoperative coronary artery bypass graft patency by contrast-enhanced computed tomography

Fifty patients with 117 coronary bypass grafts were studied by contrast-enhanced computed tomography at an average of 5 +/- 4 days after surgery to determine if this technique was a feasible method for detecting early postoperative graft occlusion. The study was limited in only three patients because of incisional chest pain (one patient) or multiple metal clips attached to the graft (two patients). The distal patency of sequential grafts cannot be determined by current techniques. There was a lower graft patency rate (70%) in the 10 patients with perioperative myocardial infarction than in the 40 (95%) without (p less than 0.025), but most regions of infarcted myocardium were perfused by patent grafts. There were eight graft occlusions in eight patients. The graft occlusion rate (30%) was significantly higher (p less than 0.025) in grafts with intraoperative flows less than 45 ml/min. The postoperative complications of myocardial dysfunction, arrhythmia and coronary artery spasm did not correlate with graft occlusion. Early graft occlusion is uncommon (7%) and usually occurs in grafts with low flows or severe distal disease (seven of eight grafts), or both. Thus, the need for early reoperation is very infrequent. It is concluded that contrast-enhanced computed tomography is feasible for the assessment of coronary bypass graft patency. Because early graft occlusion is unusual the technique may be an ideal noninvasive screening method.

Graft patency in patients with coronary artery bypass operation complicated by perioperative myocardial infarction.

Coronary artery bypass graft patency was examined by contrast-enhanced computed tomography in 18 patients with perioperative myocardial infarction soon after surgery to determine the role of graft occlusion. Preoperative coronary angiograms were reviewed to assess native coronary disease and visible collateral channels in the distribution of the myocardial infarction. Perioperative myocardial infarction was diagnosed if creatine kinase-MB was elevated, characteristic electrocardiographic changes occurred and, in the majority of cases, the pyrophosphate scan was positive. Fourteen patients (78%) had patent grafts and perioperative myocardial infarction in the distribution of the grafted vessel. Four patients had an occluded graft with infarction in the distribution of the grafted vessel. Among the 14 patients with patent grafts, there was a significant difference ( p It is concluded that the majority of perioperative myocardial infarcts associated with coronary artery bypass operations are not caused by graft occlusion. The severity of coronary obstruction in the grafted vessel and the lack of collateral vessels to the region of perioperative infarction in patients with patent grafts suggests that an island of jeopardized myocardium exists that is subject to inadequate intraoperative preservation.

Evaluation of thoracic aortic dissection using breath-holding cine MRI

OBJECTIVE Our goal was to determine if breath-hold cine MRI in transaxial planes can be used for the evaluation of thoracic aortic dissection instead of conventional cine MRI since rapid imaging is required in this clinical setting. MATERIALS AND METHODS Twelve patients with thoracic aortic dissection were imaged using a 1.5 T imager. Breath-hold images were acquired with fast cine MR sequence (TR/TE = 9/2.8, 20 degrees flip angle) using segmented k-space data acquisition. Conventional non-breath-hold cine MR images (TR/TE = 22/7.5, 35 degrees flip angle, 2 averages) were taken with flow and respiratory compensation. RESULTS Sharpness of edges of the vessels on fast cine MR images was better than that on conventional cine MR images in 34 (57%) of 60 images. Inhomogeneous blood signal in aortic lumen due to motion artifacts was found in 2 (3%) of fast cine MR images and in 15 (25%) of conventional cine MR images. The contrast-to-noise ratios of fast cine MR images were significantly better than those of conventional cine MR images (26.4 +/- 9.1 vs. 18.5 +/- 10.1; p < 0.05) when the region of interest for noise was placed to include ghosting artifacts. CONCLUSION Breath-hold cine MRI is a rapid technique that gives high quality images of thoracic aortic dissection and can provide a diagnosis in < 10 min of imaging time.

Effect of Managed Care on Cardiovascular Specialists: Involvement, Attitudes and Practice Adaptations

OBJECTIVES This study was undertaken to determine the extent to which cardiovascular specialists are involved with and affected by managed care and to ascertain their attitudes toward it. This survey also served as the follow-up to an initial study on the subject performed by the American College of Cardiology in 1993. BACKGROUND The initial 1993 study was performed to address the lack of any comprehensive examination of the impact of managed care on cardiovascular specialists. In 1995, to reexplore this question and follow up the 1993 findings, the College conducted a survey of its membership in the following areas: 1) physician relationship with managed care plans; 2) number of managed care contracts; 3) breakdown of revenue by payment source; 4) changes in practice in response to managed care; and 5) physician attitudes toward managed care. To the extent feasible, the 1995 questionnaire paralleled the 1993 instrument to facilitate comparisons. METHODS A questionnaire was mailed to 5,147 practicing College members in the United States, who were categorized by specialty as pediatric cardiologists, adult cardiologists or cardiovascular surgeons. Mailings were sent to 1) all pediatric cardiologists and cardiovascular surgeons; 2) randomly selected adult cardiologists practicing in 10 states with high managed care penetration; and 3) randomly selected adult cardiologists in the nine U.S. census areas who were not practicing in the 10 states with high managed care penetration. RESULTS Usable surveys were returned by 1,236 respondents, for an overall response rate of 24%. Involvement with at least one type of managed care organization was reported by 89% of respondents, up from 76% in 1993. Although managed care relationships had increased across physician age, region, practice and specialty, respondents indicated that, on average, well below 50% of their practice revenues stem from managed care contracts. To adapt to the managed care environment, strategic practice changes, such as joining a cardiovascular network, implementing continuous quality improvement systems and adopting clinical pathways, were being instituted by most respondent practices of nine or more physicians. Smaller groups were less active. Most respondents involved with managed care disliked its effects, particularly in clinical matters. Their attitudes toward the assumption of risk, managed fee-for-service arrangements and a private versus single-payer system show that there is no uniformity of opinion regarding the best means to contain costs and promote efficiency. CONCLUSIONS Managed care has become an established part of cardiovascular specialist practice in the United States. Although this trend is viewed with some disfavor, most respondents are making practice changes to adapt to this new environment.

Task force II: The relation of cardiovascular specialists to patients, other physicians and physician-owned organizations

1. The American College of Cardiology acknowledges the continuum of changing societal, medical and economic perspectives affecting traditional medical ethics. Primacy of patient responsibility remains paramount to the cardiovascular specialist who at the same time should participate in the development of broader societal programs. 2. Medical decisions should be freely and jointly formulated by the patient and the cardiovascular specialist with appropriate sensitivity to such matters as mental competence, pertinent medical information and standards of care, sufficient time for contemplation, informed consent, patient right of refusal, physician right to refuse to provide inappropriate care and the right of patient, physician or third party payer to seek consultation or additional opinions. 3. The cardiovascular specialist should make a special effort to clarify and document patient preferences regarding end-of-life treatment through some form of advance directive. 4. The cardiovascular specialist bears a moral obligation to provide medical care to any patient who is HIV positive or has AIDS. 5. A conflict of interest occurs when a cardiovascular specialist places personal or financial interest ahead of the welfare and health of a patient. Professional accountability should be established through local or regional peer review. 6. The American College of Cardiology encourages and supports a renewed dedication to the principles of medical ethics, particularly in the field of cardiovascular disease. Cardiovascular specialists are encouraged to participate in the promulgation of medical ethics by teaching and by example, individually and with others.

American College of Cardiology policy statement on nuclear cardiology services

Nuclear cardiology is a cardiovascular subspecialty with a definable body of knowledge and skills critical for its optimal performance. Recognizing the special training and experience needed to deliver nuclear cardiology services, the American College of Cardiology (ACC), the American Society of Nuclear Cardiology (ASNC), and the American Heart Association (AHA) have developed and published guidelines for appropriate professional training and the clinical use of radiographic devices and cardiac radionuclide imaging. TM The 1995 ACC/ASNC Training Guidelines, 1 for example, require training or experience equivalent to Level II training in nuclear cardiology, including 4 to 6 months of formal training. Based on those guidelines, a certification examination has been developed by the Certification Council of Nuclear Cardiology* that outlines the body of knowledge and the clinical training recommended to perform nuclear cardiology procedures.

An Improved Chest Dressing

Abstract An improved and more comfortable method for holding a chest dressing in place is described.