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Biomedical subjects

R M Savage

Publications and source records attributed to R M Savage.

33 records · Page 2Linked to original sources
PubMed1994

Systolic anterior motion of mitral valve after the posterior leaflet sliding advancement procedure.

The posterior leaflet sliding advancement procedure was developed to prevent the occurrence of systolic anterior motion of mitral valve and consequently outflow obstruction after mitral annuloplasty. We present a patient with extremely redundant posterior mitral leaflet in whom outflow obstruction developed despite employment of this procedure. This case underscores the utility of preoperative and intraoperative echocardiography in surgical decision making. Systolic anterior motion can develop in some patients despite this new surgical technique.

Humans↗
PubMed1994

Perioperative management and outcome of patients having cardiac surgery combined with abdominal aortic aneurysm resection.

Patients with abdominal aortic aneurysms (AAA) have a high incidence of associated cardiac disease. If a patient presents with both severe coronary artery disease and a large AAA, a staged procedure of cardiac surgery (CS) followed by AAA resection may present too great a risk of aneurysm rupture and death. A combined procedure may be recommended in this circumstance; however, the literature contains only individual successful case reports of such a procedure. A series of 10 patients who underwent CS and AAA repair to define the risks and outcome of this complex patient population is presented. Methods used included a retrospective analysis of hospital chart data from patients undergoing combined CS and AAA resection from 1980 to the present at this institution. The data analyzed included age, sex, chief complaint, past medical history, indications for surgery, abdominal aneurysm size, coronary anatomy, valvular pathology, preoperative left ventricular function, anesthetic agent and dose, order of surgery, prebypass complications, intraoperative complications, cardiopulmonary bypass time, aortic cross-clamp time, abdominal aortic cross-clamp time, blood product use, and postoperative complications. Seven of the 10 patients had a successful outcome (S group), whereas 3 of the 10 patients died postoperatively (D group). The staged procedure of first performing CS and then the AAA resection has a combined operative mortality of 4%. When the nature of both lesions is severe and a combined procedure is necessary, there is an associated in-hospital mortality of approximately 30% at this institution. The S group patients had an unremarkable postoperative course with a relatively short hospital stay when compared to the staged procedure.

Age Factors↗
PubMed1994

Implantable left ventricular assist device. Approaching an alternative for end-stage heart failure. Implantable LVAD Study Group.

BACKGROUND: The implantable left ventricular assist device (LVAD) was designed to provide circulatory support as an alternative to heart transplantation or to continued medical therapy of end-stage heart failure. Initial experience with the implantable LVAD used as a bridge to heart transplantation provides a clinical opportunity to study the function of the device and adaptation by the patient. METHODS AND RESULTS: Nineteen heart transplant candidates (mean age, 50 years; 17 males) underwent insertion of the HeartMate LVAD as a bridge to heart transplantation from December 1991 to November 1993. All patients were in cardiogenic shock on inotropes, and 16 (84%) were on an intra-aortic balloon pump. Three patients died because of multiple organ failure; all had right ventricular (RV) dysfunction (2 required RV assist devices). Sixteen patients (84%) improved markedly and were rehabilitated to New York Heart Association functional class I-II. Three patients are still on support. Significant improvements in hemodynamic function (based on analysis of the percent change from pre-LVAD condition to pretransplantation) were observed: cardiac index rose from 1.6 +/- 0.2 to 3.2 +/- 0.9 L/min per m2 (P = .0002), left atrial pressure fell from 22.9 +/- 9.5 to 8.0 +/- 5.5 mm Hg (P = .003), RV ejection fraction increased from 19.8 +/- 11.3% to 40.8 +/- 8.9% (P = .0004), pulmonary vascular resistance decreased from 5.2 +/- 2.6 to 2.0 +/- 0.8 Wood units (P = .004). Thirteen patients had successful transplants after a mean duration of 66 days on the LVAD (range, 22 to 101 days). There were no thromboembolic events while the patients were on the LVAD. Only aspirin with dipyridamole was given for anticoagulation during a total of > 1100 patient days of support. CONCLUSIONS: Bridge to transplant implantable LVAD experience indicates that hemodynamic improvement should be significant after insertion of the devices and that the risk of thromboembolic events with the HeartMate LVAD should be extremely low. Rehabilitation and quality of life should be markedly improved. Limitations of extrapolating this clinical experience to the permanent implantable LVAD include that these patients were hospitalized (permanent implants will be outpatients); the "vented-electric" HeartMate LVAD was not tested (it is a portable, battery-powered device), and true "chronic" LVAD support (> 1 year) was not tested, so questions regarding long-term device reliability and the chronic risk of infection are unknown.

Equipment Design↗
PubMed1993

Dynamics of germ plasm localization and its inhibition by ultraviolet irradiation in early cleavage Xenopus embryos.

In the spawned Xenopus egg, germ plasm is found as cytoplasmic islands spread over a wide cortical region of the vegetal pole. However, by the blastula stage, the same material is found concentrated into a few large blastomeres at the floor of the blastocoel. Components of the germ plasm can be specifically labeled with a fluorescent dye, DiOC6(3), permitting the dynamic movements of germ plasm localization to be followed in live embryos via time-lapse confocal scanning optical microscopy. During the first cell cycle, the small islands initially appear to be fixed to the vegetal yolk mass and to move with it during the cortical rotation. After rotation, the islands appear to be released from the vegetal yolk mass and to begin fusing with one another. During early cleavages, the germ plasm aggregates into large islands at the vegetal pole in a movement dependent on microtubules. Two distinct actions can be discerned: (1) a continuous process of local fusing and (2) periodic surface contraction waves (SCWs) that gather the islands toward the vegetal pole. These SCWs are inhibited by ultraviolet irradiation of the vegetal pole. Near the vegetal pole, germ plasm patches ingress into the embryo's interior along the cleavage furrow in periodic movements contemporaneous with the SCWs.

Animals↗
PubMed1992

Rey Auditory-Verbal Learning Test: the effects of age and gender, and norms for delayed recall and story recognition trials.

Immediate recall and three measures of delayed memory performance were evaluated in 134 healthy adults aged 16-76. Gender of subjects had no Influence on performance for any of the acquisition or retention trials. Age influenced acquisition as memory load began to exceed five to six words, with older subjects exhibiting decreased capacity. There was little loss of information between the immediate and delayed recall trials for any age group. Norms for a 30-min delayed recall trial, commission errors on delayed recall, and delayed recognition using Rey's story recognition procedure are presented, and implications for clinical use are discussed.

Journal Article↗
PubMed1983

Evaluation of a QRS scoring system for estimating myocardial infarct size. III. Correlation with quantitative anatomic findings for inferior infarcts.

This study evaluated by quantitative autopsy correlation a previously developed scoring system for estimating the size of myocardial infarcts based on the QRS complex of the electrocardiogram. This system was tested using electrocardiograms from patients with infarcts shown by autopsy to predominate in the inferior third of the left ventricle. The study was limited to patients whose electrocardiogram did not indicate left or right ventricular hypertrophy, left or right bundle branch block, or left anterior or posterior fascicular block. Thirty-one patients from 6 medical centers met these criteria. In the electrocardiogram of 28 of the 31 patients (90%), lead a VF exhibited a Q wave of at least 30 ms. The correlation coefficient between the total QRS score and the percent infarction of the left ventricle was 0.74. In patients without confounding factors in the electrocardiogram and with single infarcts, the electrocardiogram provides a marker for infarcts in the inferior third of the left ventricle and a quantitative QRS scoring system provides an estimate of infarct size.

Aged↗
PubMed1982

Evaluation of a QRS scoring system for estimating myocardial infarct size. II. Correlation with quantitative anatomic findings for anterior infarcts.

The ability of an independently developed QRS point score to estimate the size of infarcts predominantly within the anterior third of the left ventricular was evaluated by quantitative pathologic-electrocardiographic correlation. The study was limited to 21 patients with a single infarct documented by postmortem examination, for whom an appropriately timed standard 12 lead electrocardiogram was available that did not exhibit signs of left or right ventricular hypertrophy, left or right bundle branch block or anterior or posterior fascicular block. At necropsy the heart was cut into five to seven slices. The location and size of the infarct was quantitated by computer-assisted planimetry of the slices. The electrocardiogram of 19 (90 percent) of the patients exhibited either a Q wave or an R wave of no more than 20 ms in lead V2. The infarct in the two patients without this electrocardiographic finding was small, occupying 2 and 3 percent of the left ventricle, respectively. The percent infarction of the left ventricle correlated with the QRS point score (r=0.80). Thus in patients without complicating factors in the electrocardiogram and with a single infarct, the electrocardiogram provides a marker for infarction in the anterior third of the left ventricle and permits estimation of infarct size.

Adult↗
PubMed1981

Correlation of regional myocardial blood flow and function with myocardial infarct size during acute myocardial ischemia in the conscious pig.

Regional myocardial function and blood flow were determined for 48 hours after permanent occlusion of the left circumflex coronary artery in conscious swine. Systolic wall thickening and end-diastolic wall thickness (EDWTh) were correlated with regional myocardial flow (RMBF) at 15 minutes, 24 and 48 hours after occlusion. Both regional function and blood flow were compared with the extent of myocardial necrosis (determined histologically) after 48 hours in functionally distinct zones. Group 1 (control zones) was characterized by increased systolic wall thickening, EDWTh, RMBF and had no necrosis. Group 2 (marginal zones) had depressed systolic wall thickening (35 +/- 3% [mean +/ SEM] of preocclusion level at 48 hours) and RMBF (64 +/- 6% of preocclusion values), transiently decreased EDWTh and 46 +/- 5% necrosis. In Group 3 (ischemic zones), all values were greatly reduced: systolic wall thickening was 3.6 +/- 1.2%, EDWTh 76 +/- 8% and RMBF 25 +/- 9% preocclusion values; necrosis was 90 +/- 5%. Groups 2 and 3 had increased RMBF at 24 and 48 hours from that at 15 minutes after occlusion; however, in neither case was systolic wall thickening greater than that at 15 minutes after occlusion. We conclude that there is close correlation between RMBF, systolic wall thickening and the extent of necrosis present after 48 hours of coronary artery occlusion in the conscious swine; subsequent increases in RMBF to the marginal zone after occlusion are not accompanied by improved regional function.

Animals↗
PubMed1981

Myocardial infarction. How representative are autopsied subjects with this clinical entity?

We documented the differences in clinical features between 86 autopsied and 54 nonautopsied subjects who died of myocardial infarction to ascertain any bias that might be present in use of postmortem data. More than 200 historical, clinical, noninvasive, and hemodynamic aspects were compared. Of noninvasive aspects examined in all subjects, only 13 had significant differences (by chi 2 or unpaired t tests) between autopsied and nonautopsied subjects. However, there had been greater impairment of vital signs and hemodynamic aspects during early hospitalization in the autopsied vs the nonautopsied subjects. Further, the one-month survival rate was lower in autopsied subjects (31% vs 72%; P less than .01). We conclude that patients in severe congestive heart failure or shock and, presumably, with relatively large or complicated myocardial infarcts are more likely to die early and be autopsied. Those with better cardiac function live longer, and often die after having been released from the initial hospitalization; these subjects, presumably with smaller and uncomplicated infarcts, do not undergo autopsy. Before correlating pathological and clinical data from subjects with acute myocardial infarction, it is important to carefully analyze bias inherent in the selection of subjects to undergo autopsy.

Arrhythmias, Cardiac↗
PubMed1977

Correlation of postmortem anatomic findings with electrocardiographic changes in patients with myocardial infarction: retrospective study of patients with typical anterior and posterior infarcts.

This retrospective study correlates electrocardiographic and histopathologic findings in 24 patients with single well-circumscribed infarcts to determine 1) whether ECG terms commonly used to describe the location of myocardial infarcts are significant, and 2) whether the extent of infarct can be determined using QRS characteristics. Transverse sections of the hearts were photographed. Based on histologic sections, the infarct was outlined on the photograph and each section was planimetered via a sonic digitizer into a computer that was programmed to divide the left ventricle into 8 radial sectors and also into basal, mesial, and apical thirds. The percentage of infarct in each of these areas was then calculated. Of the 24 hearts evaluated 12 had posterior infarcts and 12 had anterior infarcts. Posterior infarcts principally involved the basal and mesial levels, whereas the anterior infarcts were more extensive in the apical and mesial thirds, with relative or total sparing of the base. Posterior infarcts were associated with Q waves in leads II, III and aVF in 11 instances. The other posterior infarct was associated with markedly diminished R waves in leads II, III and aVf in the presence of a horizontal axis. All anterior infarcts were associated with Q waves or markedly diminished R waves in the right precordial leads. Eight of the anterior infarcts exhibited circumferential apical involvement and all eight were associated with Q waves or markedly diminished R waves in the left precordial leads. This study documents the electrocardiographic identification of anterior, posterior, and apical infarcts by correlation with pathologic anatomy.

Adult↗
PubMedDate not supplied

Experimental and numerically modeled effects of altered loading conditions on pulmonary venous flow and left atrial pressure in patients with mitral regurgitation.

Pulmonary venous flow measured by pulsed-wave Doppler transesophageal echocardiography reflects the effects of mitral regurgitation on left atrial pressure contour. To assess the relationship between pulmonary venous flow and left atrial pressure in patients with mitral regurgitation under altered loading conditions, we studied 25 patients with 3+ or 4+ mitral regurgitation and a control group by measuring pulmonary venous flow with transesophageal echocardiography and left atrial pressures after administering saline solution (n = 6), nitroglycerin (n = 6), phenylephrine (n = 6), or nitroprusside (n = 7). After administration, the left atrial pressure v wave increased in the group given phenylephrine, concomitant with an increased diastolic flow. In contrast, the left atrial pressure v wave decreased in the group given nitroglycerin, concomitant with a decreased diastolic flow. Changes in diastolic flow were closely related to changes in the left atrial pressure v wave under all loading conditions (r = 0.91; p < 0.0001). Numeric modeling of left atrial pressure and pulmonary venous diastolic flow corroborated the experimental findings. We conclude that changes in pulmonary venous diastolic flow are closely related to changes in the left atrial pressure v wave in mitral regurgitation, under altered loading conditions.

Adult↗