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F L Mikell

Publications and source records attributed to F L Mikell.

35 records · Page 2Linked to original sources
PubMed1984

Embolic potential of left ventricular thrombi detected by two-dimensional echocardiography.

We sought to determine whether an association existed between the echocardiographic appearance of left ventricular thrombi and systemic embolization. We reviewed the clinical and echocardiographic characteristics of 60 patients who underwent diagnostic two-dimensional echocardiography for left ventricular thrombi. Sixteen of these 60 patients (27%) had evidence of systemic embolization. Multiple echocardiographic characteristics of left ventricular thrombi were analyzed, including mobility, shape, heterogeneity, echo density, layering, central echo lucency, presence within an aneurysm, and association with low-density swirling echoes. Incidence of embolization was significantly higher in patients with thrombi that were mobile or protruded into the left ventricular cavity (p less than .002 and p less than .05, respectively). Bayesian analysis indicated that the pretest likelihood for embolization was 27% and increased in the presence of mobility, central echo lucency, and protrusion to 60%, 50%, and 40%, respectively. A stepwise regression indicated that mobility was the first and protrusion the second most helpful echocardiographic characteristic in identifying patients with embolic phenomena. Clinical features were of less help in identifying the risk for embolization of patients with left ventricular thrombi. Nine of 31 patients (29%) with recent myocardial infarction (less than 3 weeks) has emboli in contrast to five of 26 patients (19%) with remote myocardial infarction (greater than 3 weeks) (p = NS). The three patients without infarction had congestive cardiomyopathy and two had emboli.

Echocardiography↗
PubMed1983

Functional consequences of interventricular septal involvement in right ventricular infarction: echocardiographic, clinical, and hemodynamic observations.

Although ischemic involvement of the interventricular septum (IVS) may occur in patients with right ventricular infarction (RVI), the potential functional significance of such involvement has not been explored. In 10 patients with hemodynamically evident RVI, ischemic involvement of the IVS was assessed by measuring IVS systolic thickening on M-mode echocardiography. Six patients (group I) had decreased IVS systolic thickening, an echocardiographic indicator of ischemia, or infarction, while four (group II) did not. Group I had significantly higher right ventricular filling pressures (19 +/- 3 vs 12 +/- 5 mm Hg, p = 0.04) and right ventricular end-diastolic echocardiographic dimensions (32 +/- 8 vs 20 +/- 3 mm; p = 0.02) than group II. Paradoxic septal motion was noted only in group I patients (p = 0.01). Left ventricular filling pressures, left ventricular end-diastolic dimensions, and systolic thickening of the left ventricular posterior wall (LVPW) were not significantly different between the groups. Three group I patients died; all had decreased systolic thickening of both the IVS and LVPW. In each, autopsy confirmed infarction of the right ventricular free wall, IVS, and LVPW. In patients with right ventricular infarction, ischemic involvement of the interventricular septum may have important consequences for both right and left ventricular function.

Adult↗
PubMed1982

Myocardial injury after phenylpropanolamine ingestion.

Three patients developed clinical evidence of myocardial injury after acute ingestion of phenylpropanolamine, a sympathomimetic amine found in a large number of decongestant and appetite suppressant formulations. Increases in the serum creatine kinase and MB isoenzyme levels, ventricular arrhythmias, and electrocardiographic repolarisation abnormalities were seen. Excessive catecholamine stimulation has been shown to produce acute myocardial necrosis experimentally, and a similar mechanism may be present in these patients.

Adolescent↗
PubMed1982

Suppression of ventricular ectopic depolarizations by flecainide acetate, a new antiarrhythmic agent.

Flecainide acetate, a new antiarrhythmic agent, was given orally to 11 hospitalized patients with chronic high-frequency ventricular ectopic depolarizations. Drug effectiveness was evaluated with a dose-ranging single-blind protocol, which included placebo control and washout periods. Twice-daily dosing (average daily dose 436 mg) completely suppressed all ventricular ectopic activity in five of 11 patients; average suppression in the 11 patients was 96.3%. Complex ventricular arrhythmias, which were present in all 11 patients during the placebo control period, were completely suppressed in eight patients and markedly suppressed in the other three patients during flecainide therapy. Ejection fraction and velocity of circumferential fiber shortening measured by M-mode echocardiography did not change significantly during flecainide dosing. Ventricular arrhythmias returned in all patients during the placebo washout period. During subsequent outpatient therapy with flecainide, significant suppression was present after 1 and 2 weeks of treatment (94.4% and 93.3%, respectively). Drug elimination was slow (average plasma half-life 20 hours). Ninety-five percent suppression of ventricular ectopic depolarization during dosing and 5% reappearance of arrhythmias during washout occurred with flecainide concentrations of 200-800 ng/ml. Side effects occurred in five of 11 patients, but did not require discontinuation of the drug. These results indicate that flecainide is a very effective antiarrhythmic agent that merits further clinical investigation.

Aged↗
PubMed1981

Incidence of left-ventricular thrombosis after acute transmural myocardial infarction. Serial evaluation by two-dimensional echocardiography.

To study the incidence of left-ventricular thrombosis after transmural myocardial infarction, we performed serial two-dimensional echocardiography in 70 consecutive patients. Thirty-five patients had inferior-wall infarction: none had a left-ventricular thrombus. The other 35 had anterior-wall infarction: 12 had left-ventricular thrombi. Thrombi were diagnosed an average of five days after the infarction (range, one to 11 days). All patients with left-ventricular thrombi had severe apical-wall-motion abnormalities (akinesis or dyskinesis). Twenty-six of the 35 patients with anterior infarctions had apical akinesis or dyskinesis on echocardiography; left-ventricular thrombi developed in 12 of these 26 (46 per cent). We conclude that patients with severe apical-wall-motion abnormalities during acute transmural anterior myocardial infarction are at high risk for left-ventricular thrombosis. This high-risk group can be identified before the development of left-ventricular thrombi. Patients with inferior infarction or anterior infarction without a severe apical-wall-motion abnormality are at low risk.

Adult↗
PubMed1981

Observations on detecting left ventricular thrombus with two dimensional echocardiography: emphasis on avoidance of false positive diagnoses.

Observations made in detecting left ventricular thrombus with two dimensional echocardiography in 25 patients are reviewed. In 20 patients thrombus was documented on angiography, surgery postmortem examination or serial two dimensional echocardiographic findings; in the remaining five patients two dimensional echocardiographic findings of thrombus were unequivocal. In all 25 patients wall motion abnormalities ranging from hypokinesia to frank dyskinesia were present at the site of the thrombus. Twenty-three patients had an apical thrombus; two had thrombus adjacent to the inferior wall. Clear delineation of the endocardium and thrombus margin was considered essential to the correct diagnosis of thrombus. Both intracavitary motion of the thrombus margin and a layering effect were noted infrequently although they were of benefit in identifying an intracardiac mass as thrombus. In addition, serial evaluations were helpful in establishing the correct diagnosis. False positive diagnoses can be minimized if one understands certain technical limitations of this method and correctly identifies apical structures that are not thrombi. Axial and lateral resolution problems inherent with this technique can produce intracavitary echoes that may simulate thrombi. In addition, normal or pathologic structures at the apex may also simulate thrombi. These structures include the papillary muscles, muscular trabeculae, chordal structures and tangential information from normal myocardium. Varying the sector orientation or acoustic window, or both, will aid in correctly identifying these structures and distinguishing them from left ventricular thrombi.

Blood Coagulation↗
PubMed1981

Perioperative risk of complete heart block in patients with bifascicular block and prolonged PR interval.

Because there is a paucity of information on the perioperative risk of developing complete heart block among patients with bifascicular block (either right bundle branch block and left anterior hemiblock or left bundle branch block) and a long PR interval on the surface electrocardiogram, we undertook an analysis of 76 such patients. Twenty-three patients had right bundle branch block and left axis deviation with a long PR interval and 53 had left bundle branch block with along PR interval. Thirty patients had 37 general anaesthetics, 23 had 32 spinal anaesthetics, and 50 had 64 local anaesthetics or endoscopic procedures. No patient developed complete heart block. Four patients developed sinus bradycardia during general anaesthetics, responsive to atropine or isoproterenol. Similarly, none of the 23 such patients in the literature reviewed had developed complete heart block. Because placement to temporary pacemakers is not without risk, we conclude that prophylactic pacing is not necessary in asymptomatic patients with bifascicular block even in the presence of a long PR interval. Since we did not study patients with recent syncope or myocardial infarction, caution should be exercised in applying these results to such patients.

Aged↗
PubMed1981

Echocardiography in diagnostic assessment of stroke.

We assessed the use of echocardiography in the evaluation of stroke by recording M-mode and two-dimensional (2D) echocardiograms in 100 consecutive hospitalized patients. Of the 95 persons satisfactorily imaged with 2D echocardiography, 47 lacked clinical and routine laboratory evidence of heart disease; no potential embolic source or other finding that altered therapy was diagnosed by echocardiography. In the remaining 48 patients with clinical or routine laboratory evidence of heart disease, two with left ventricular thrombus as a potential embolic source were identified by 2D echocardiography. M-mode echocardiograms failed to detect the thrombus in either patient. No patients with left atrial thrombi, mitral stenosis, cardiac tumor, or vegetations suggesting endocarditis were identified. One patient had possible mitral valve prolapse. Echocardiograms in patients lacking other available evidence of heart disease are unlikely to yield findings that alter the clinical approach to patients with stroke; echocardiography in stroke patients with clinically evident heart disease may have greater clinical utility; additional study of the role of echocardiography in selected subgroups of stroke patients is indicated.

Adult↗
PubMed1979

Two-dimensional echocardiographic demonstration of left atrial thrombi in patients with prosthetic mitral valves.

Although M-mode echocardiography (MME) is not a reliable method for detecting left atrial thrombi, recent reports suggest that two-dimensional echo (2DE) may be more effective than MME in identifying intracardiac thrombi. In three patients with prosthetic mitral valves who presented with either arterial embolization or prosthetic valvular dysfunction, 2DE demonstrated left atrial masses consistent with thrombi, while MME was either negative (two patients) or suspicious (one patient) for left atrial thrombus. Thrombi were documented by surgical or postmortem examination in all cases. Clear delineation of the atrial cavity and the margins of the masses, visualization on multiple echocardiographic views and comparison of serial examinations were helpful in identifying these masses as thrombi. In addition, the masses visualized had certain patterns of motion which seem unique and may allow characterization of atrial masses as thrombi.

Blood Coagulation↗
PubMedDate not supplied

The primary care physician and thrombolytic therapy for acute myocardial infarction: comparison of intravenous streptokinase in community hospitals and the tertiary referral center.

From September 1982 through December 1987, 1012 patients were treated with intravenous streptokinase within 6 hours of acute myocardial infarction. Most of them (816/1012, 81 percent) were treated in community hospitals by primary care physicians. The remaining 196 (19 percent) were treated in the referral center, usually by a cardiologist. Cardiac catheterization within 2 days showed an open infarct artery in 87 percent of the community hospital and 83 percent of the referral center patients (P = NS). Predischarge ejection fraction was similar for community hospital and referral center patients (49 percent +/- 14 percent versus 51 percent +/- 14 percent, respectively), and there was a similar rate of bleeding complications (10 percent versus 13 percent, respectively). We conclude that primary physicians can use intravenous streptokinase effectively and safely in the treatment of patients in community hospitals.

Academic Medical Centers↗