Posterior mediastinal masses: rare causes of cardiac compression.
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Aged↗
Biomedical subjects
S E Warren
Publications and source records attributed to S E Warren.
Diastolic dysfunction in hypertrophic cardiomyopathy. Effect on active force generation during systole.
We tested the hypothesis that intracellular Ca++ [( Ca++]i) overload underlies the diastolic dysfunction of patients with hypertrophic cardiomyopathy. Myocardial tissue was obtained at the time of surgery or transplantation from patients with hypertrophic cardiomyopathy and was compared with control myocardium obtained from patients without heart disease. The isometric contractions and electrophysiologic properties of all myocardial specimens were recorded by standard techniques and [Ca++]i was measured with the bioluminescent calcium indicator aequorin. In contrast to the controls, action potentials, Ca++ transients, and isometric contraction and relaxation were markedly prolonged in the hypertrophic myocardium, and the Ca++ transients consisted of two distinct components. At 38 degrees C and 1 Hz pacing frequency, a state of relative Ca++ overload appeared develop, which produced a rise in end-diastolic [Ca++]i, incomplete relaxation, and fusion of twitches with a resultant decrease in active tension development. We also found that drugs with increase [Ca++]i, such as digitalis, exacerbated these abnormalities, whereas drugs that lower [Ca++]i, such as verapamil, or agents that increase cyclic AMP, such as forskolin, prevented them. These results may explain why patients with hypertrophic cardiomyopathy tolerate tachycardia poorly, and may have important implications with regard to the pharmacologic treatment of patients with hypertrophic cardiomyopathy.
Adult↗
Prognosis in heart failure: is systolic or diastolic dysfunction more important?
The clinical syndrome of congestive heart failure can result from inadequate myocardial contraction (systolic myocardial failure), from pseudo-heart failure due to circulatory overload, or from failure of the ventricles to fill at low pressure (diastolic myocardial failure). The presence of systolic or diastolic heart failure is most precisely defined by an examination of left ventricular pressure-volume relations. Diastolic failure commonly coexists with systolic dysfunction. However, in many patients, diastolic dysfunction may exist alone or as the predominant physiologic disturbance. This is especially true in such common disease states as systemic hypertension and ischemic heart disease. Like systolic heart failure, diastolic failure results in significant morbidity and mortality. Diastolic heart failure may correlate better with prognosis for symptoms and survival than traditional indices of systolic function. The presence of predominantly diastolic dysfunction in large numbers of patients with the diagnosis of congestive heart failure has important therapeutic implications.
Diastole↗
Therapeutic approaches affecting diastolic ventricular function.
The therapeutic approaches affecting diastolic ventricular function are conditional on underlying physiology, especially as it relates to calcium cycling, early relaxation and rapid filling abnormalities, atrial function, hemodynamics, the presence of hypertrophy, and neurohormonal milieu. A wide variety of treatment considerations are discussed, with particular attention to the management of cardiomyopathy characterized by pure or predominant diastolic failure (Table 1).
Cardiovascular Agents↗
Inotropic and lusitropic effects of MCI-154 (6-[4-(4- pyridyl)aminophenyl]-4,5-dihydro-3(2H)-pyridazinone) on human myocardium.
We studied the inotropic and lusitropic responses to MCI-154 in 12 right or left ventricular trabeculae carneae isolated from 7 organ donors (non-cardiac) without known cardiovascular disease who met accepted criteria for brain death. Isometric tension was recorded from muscles superfused with a physiologic salt solution at 30 degrees C, and stimulated to contract at three-second intervals. Concentration-response curves were developed over a range of MCI-154 organs bath concentrations (10(-7) M to 3 x 10(-4) M; n = 9). Six experiments were conducted using 10(-6) M carbachol, a muscarinic agonist, in the presence of a maximally effective concentration of MCI-154 to test for dependence of tension development on cyclic adenosine monophosphate. Three experiments were conducted with MCI-154, 3 x 10(-5) M, in muscles loaded with the bioluminescent calcium indicator aequorin. MCI-154 produced a concentration-dependent rise in peak tension in the human muscle (positive inotropic effect), equivalent to 70% of the maximal response to calcium (P less than 0.001). Relaxation was enhanced (positive lusitropic effect), as evidenced by a fall in the time to 80% relaxation from 311 +/- 13 ms (baseline) to 248 +/- 15 ms at 10(-5) M (P less than 0.01). Aequorin studies showed the increase in tension to be accompanied by large increases in cystolic calcium, the principal mechanism of action. Carbachol caused MCI-154--induced maximum peak tension to decrease by 5 +/- 1%. While not excluding a cyclic adenosine monophosphate--mediated MCI action, this modest carbachol inhibition suggests the existence of additional mechanism(s) of action. MCI-154 had a negative lusitropic effect at high concentrations (greater than 10(-4)M) which may have been due to intracellular calcium overload, evidenced by the large amplitude aequorin signals. This does not exclude sensitization of the myofilaments to calcium as a possibility. Extrapolated to the in vivo setting, these experiments suggest that MCI-154 may be an effective positive inotropic agent in man.
Aequorin↗
Balloon aortic valvuloplasty in 170 consecutive patients.
Between October 1, 1985, and April 1, 1988, we performed balloon aortic valvuloplasty in 170 patients (mean age [+/- SD], 77 +/- 5 years) who had symptomatic aortic stenosis. The procedure was completed successfully in 168 patients and resulted in significant increases in the mean (+/- SD) aortic-valve area (from 0.6 +/- 0.2 to 0.9 +/- 0.3 cm2) and cardiac output (from 4.6 +/- 3.4 to 4.8 +/- 1.4 liters per minute) and decreases in the peak aortic-valve pressure gradient (from 71 +/- 20 to 36 +/- 14 mm Hg) (P less than 0.01 for all three comparisons). There were six in-hospital deaths, and five patients required early aortic-valve replacement. Follow-up data were available for all patients, for a period averaging 9.1 months. In addition to the 6 patients who died in the hospital, 25 patients died an average of 6.4 +/- 5.3 months after discharge. Symptoms recurred in 44 patients; they were managed by repeat valvuloplasty in 16 patients, by aortic-valve replacement in 17, and by medical therapy in 11. At the most recent follow-up examination, the symptoms of 103 patients had improved after valvuloplasty; this number includes 15 patients with restenosis who successfully underwent redilation. Life-table analysis indicates that the probability of survival 12 months after the procedure was 74 percent. We conclude that balloon aortic valvuloplasty is an effective palliative therapy for some elderly patients with symptomatic aortic stenosis. Symptoms improve in the majority of patients; although restenosis is common, it can be managed in some patients by repeat balloon dilation.
Adult↗
Time course of left ventricular dilation after myocardial infarction: influence of infarct-related artery and success of coronary thrombolysis.
Dilation of the left ventricle after myocardial infarction is common, occurs rapidly (within 2 weeks of infarction) and may be self-limited. To evaluate the time course of postinfarction left ventricular dilation and to assess the impact of successful coronary thrombolysis, serial radionuclide left ventricular volume analyses were performed in 36 patients undergoing attempted thrombolysis for acute transmural myocardial infarction. All patients underwent cardiac catheterization, coronary angiography and attempted thrombolysis within 7 h of the onset of symptoms. The site of coronary occlusion was the left anterior descending coronary artery in 17 patients, the right coronary artery in 18 and, in 1 patient, occluded bypass grafts to the right and left circumflex coronary arteries. Attempted reperfusion using a thrombolytic agent was successful in 22 individuals, occurring 5 +/- 1 h after the onset of symptoms. Gated radionuclide ventriculography was performed early (mean time 1 day after admission, n = 36), subacutely (mean time 11 days postinfarction, n = 36) and late after infarction (mean time 10.5 months, n = 25), and a geometric technique was used to measure serial left ventricular end-diastolic volume. Left ventricular end-diastolic volume for the entire group increased significantly (p less than 0.01) from 153 +/- 30 ml at baseline to 172 +/- 45 ml (at 11 days) to 220 +/- 63 ml (at 10.5 months). Twenty of 36 patients showed greater than 20% increase in left ventricular end-diastolic volume (dilation) with time. This appeared early in seven patients, occurred remote from infarction in seven others and showed a progressive pattern in six.(ABSTRACT TRUNCATED AT 250 WORDS)
Adult↗
Diastolic function in patients with aortic stenosis: influence of left ventricular load reduction.
Pressure overload hypertrophy of the left ventricle due to aortic stenosis is associated with abnormalities of left ventricular isovolumic relaxation and early diastolic filling. The relative contribution of the hemodynamic load on the left ventricle to the impairment of diastolic function observed in this disorder remains poorly understood. To study this relation, the vasodilator nitroprusside was administered to eight patients with aortic stenosis and normal systolic function. The effect of a short-term reduction in left ventricular preload and afterload on left ventricular isovolumic relaxation and early diastolic filling was assessed by analysis of simultaneous micromanometer left ventricular pressure and radionuclide angiographic volume measurements. At baseline, left ventricular systolic and end-diastolic pressures were markedly elevated, and associated with prolongation of the time constant of left ventricular relaxation and depression of the left ventricular peak filling rate. Infusion of nitroprusside resulted in reduction of left ventricular systolic (204 +/- 31 to 176 +/- 31 mm Hg, p less than 0.05) and end-diastolic (31 +/- 8 to 18 +/- 6 mm Hg, p less than 0.05) pressures, with no associated improvement in time constant of left ventricular pressure decay (T) (68 +/- 25 to 80 +/- 37 ms, p = NS), T 1/2 (34 +/- 8 to 34 +/- 14 ms, p = NS), left ventricular peak filling rate (2.3 +/- 0.5 to 2.3 +/- 0.8 end-diastolic volume/s, p = NS) or time to left ventricular peak filling rate (150 +/- 50 to 144 +/- 37 ms, p = NS).(ABSTRACT TRUNCATED AT 250 WORDS)
Aged↗
Improvement in symptoms and left ventricular performance after balloon aortic valvuloplasty in patients with aortic stenosis and depressed left ventricular ejection fraction.
The application of balloon aortic valvuloplasty to elderly patients with severe aortic stenosis and a low ventricular ejection fraction is undefined. Balloon aortic valvuloplasty was performed in a subset of 28 patients with low left ventricular ejection fraction (37 +/- 11%), severe aortic stenosis, and a mean age of 79 +/- 5 years. After valvuloplasty, significant increases were seen in aortic valve area (from 0.5 +/- 0.1 to 0.9 +/- 0.2 cm2), aortic systolic pressure (from 120 +/- 12 to 135 +/- 22 mm Hg), and cardiac output (from 4.2 +/- 1.1 to 4.8 +/- 1.6 l/min) (p less than 0.01), and significant decreases were seen in transaortic pressure gradient (from 69 +/- 25 to 35 +/- 15 mm Hg) and pulmonary capillary wedge pressure (from 24 +/- 9 to 20 +/- 7 mm Hg) (p less than 0.01). All patients had symptomatically improved at the time of discharge. Serial radionuclide ventriculography showed an increase in left ventricular ejection fraction from 37 +/- 11% before valvuloplasty to 44 +/- 14% within 48 hours after dilatation and to 49 +/- 13% at 3 months after dilatation. However, there was substantial heterogeneity of response. Thirteen patients (group A) showed progressive increases in left ventricular ejection fraction (from 34 +/- 11% to 49 +/- 15% to 58 +/- 11%, p less than 0.0001), whereas 15 patients (group B) showed no significant change in ejection fraction (from 41 +/- 10% to 40 +/- 13% to 41 +/- 10%, p = NS) over 3 months. There was no difference between these groups with respect to age, extent of coronary artery disease, history of myocardial infarction, and aortic valve area before and after valvuloplasty. However, peak systolic wall stress and left ventricular dimensions were higher in group B compared with group A. In conclusion, balloon aortic valvuloplasty may result in symptomatic improvement in patients with aortic stenosis and depressed left ventricular ejection fraction; some patients develop progressive increases in ejection fraction, whereas others fail to show improvement.
Aged↗
Noninvasive external cardiac pacing for thallium-201 scintigraphy.
Improvements in noninvasive external cardiac pacing have led to a technique with reliable electrical capture and tolerable patient discomfort. To assess the use of this modality of pacing in combination with thallium scintigraphy as a noninvasive pacing stress test, we applied simultaneous noninvasive cardiac pacing, hemodynamic monitoring, and thallium-201 scintigraphy in 14 patients undergoing cardiac catheterization for chest pain syndromes. Two patients had normal coronary arteries, while the remaining 12 had significant coronary artery disease. Thallium scintigraphic responses to pacing were compared to routine exercise thallium stress testing in nine of these 14 patients. All patients were noninvasively paced to more than 85% of the age-predicted maximum heart rate. Twelve patients demonstrated reversible thallium defects, which corresponded in 11 cases to significant lesions seen on coronary angiography. Of nine patients who underwent both pacing and exercise thallium stress tests, comparable maximal rate-pressure products were achieved. Moreover, thallium imaging at peak pacing and during delayed views did not differ significantly from exercise thallium scintigraphy. A limiting factor associated with the technique was local patient discomfort, which occurred to some degree in all patients. We conclude that noninvasive external cardiac pacing together with thallium scintigraphy is capable of detecting significant coronary artery disease and may be comparable to routine exercise thallium stress testing. This new modality of stress testing could be useful in patients unable to undergo the exercise required for standard exercise tolerance testing, particularly if improvements in the technology can be found to reduce further the local discomfort.
Cardiac Catheterization↗
Late onset dilated cardiomyopathy in a unique familial syndrome of hypogonadism and metabolic abnormalities.
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Adult↗
Balloon dilation of mitral stenosis in adult patients: postmortem and percutaneous mitral valvuloplasty studies.
Preliminary reports have documented the utility of percutaneous balloon valvuloplasty of the mitral valve in adult patients with mitral stenosis, but the mechanism of successful valve dilation and the effect of mitral valvuloplasty on cardiac performance have not been studied in detail. Accordingly, mitral valvuloplasty was performed in five postmortem specimens and in 18 adult patients with rheumatic mitral stenosis, using either one (25 mm) or two (18 and 20 mm) dilation balloons. Postmortem balloon dilation resulted in increased valve orifice area in all five postmortem specimens, secondary to separation of fused commissures and fracture of nodular calcium within the mitral leaflets. In no case did balloon dilation result in tearing of valve leaflets, disruption of the mitral ring or liberation of potentially embolic debris. Percutaneous mitral valvuloplasty in 18 patients with severe mitral stenosis (including 9 with a heavily calcified valve) resulted in an increase in cardiac output (4.3 +/- 1.1 to 5.1 +/- 1.5 liters/min, p less than 0.01) and mitral valve area (0.9 +/- 0.2 to 1.6 +/- 0.4 cm2, p less than 0.0001), and a decrease in mean mitral pressure gradient (15 +/- 5 to 9 +/- 4 mm Hg, p less than 0.0001), pulmonary capillary wedge pressure (23 +/- 7 to 18 +/- 7 mm Hg, p less than 0.0001) and mean pulmonary artery pressure (36 +/- 12 to 33 +/- 12 mm Hg, p less than 0.01). Left ventriculography before and after valvuloplasty in 14 of the 18 patients showed a mild (less than or equal to 1+) increase in mitral regurgitation in five patients and no change in the remainder.(ABSTRACT TRUNCATED AT 250 WORDS)
Adult↗
Assessment of left ventricular and aortic valve function after aortic balloon valvuloplasty in adult patients with critical aortic stenosis.
Preliminary reports have documented the utility of balloon aortic valvuloplasty as a palliative treatment for high-risk patients with critical aortic stenosis, but the effect of this procedure on cardiac performance has not been studied in detail. Accordingly, 32 patients (mean age 79 years) with long-standing, calcific aortic stenosis were treated at the time of cardiac catheterization with balloon dilatation of the aortic valve, and serial changes in left ventricular and valvular function were followed before and after valvuloplasty by radionuclide ventriculography, determination of systolic time intervals, and Doppler echocardiography. Prevalvuloplasty examination revealed heavily calcified aortic valves in all patients, a mean peak-to-peak aortic valve gradient of 77 +/- 27 mm Hg, a mean Fick cardiac output of 4.6 +/- 1.4 liters/min, and a mean calculated aortic valve area of 0.6 +/- 0.2 cm2. Subsequent balloon dilatation with 12 to 23 mm valvuloplasty balloons resulted in a fall in aortic valve gradient to 39 +/- 15 mm Hg, an increase in cardiac output to 5.2 +/- 1.8 liters/min, and an increase in calculated aortic valve area to 0.9 +/- 0.3 cm2. Individual hemodynamic responses varied considerably, with some patients showing major increases in valve area, while others demonstrated only small increases. In no case was balloon dilatation accompanied by evidence of embolic phenomena. Supravalvular aortography obtained in 13 patients demonstrated no or a mild (less than or equal to 1+) increase in aortic insufficiency. Serial radionuclide ventriculography in patients with a depressed left ventricular ejection fraction (i.e., that less than or equal to 55%) revealed a small increase in ejection fraction from 40 +/- 13% to 46 +/- 12% (p less than .03). In addition, for the study group as a whole there was a decrease in left ventricular end-diastolic volume index (113 +/- 38 to 101 +/- 37 ml/m2, p less than .003), a fall in stroke-volume ratio (1.49 +/- 0.44 to 1.35 +/- 0.33, p less than .04), and no immediate change in left ventricular peak filling rate (2.05 +/- 0.77 to 2.21 +/- 0.65 end-diastolic counts/sec, p = NS). Serial M mode echocardiography and phonocardiography showed an increase in aortic valve excursion (0.5 +/- 0.2 to 0.8 +/- 0.2 cm, p less than .001), a decrease in time to one-half carotid upstroke (80 +/- 30 to 60 +/- 10 msec, p less than .001), and a small decrease in left ventricular ejection time (0.44 +/- 0.03 to 0.42 +/- 0.02 sec, p less than .001).(ABSTRACT TRUNCATED AT 400 WORDS)
Adult↗
Deficient production of cyclic AMP: pharmacologic evidence of an important cause of contractile dysfunction in patients with end-stage heart failure.
We studied the effects of different classes of inotropic drugs on human working myocardium in vitro that was isolated from the hearts of patients with end-stage heart failure, and compared the responses to these drugs with those noted in muscles from nonfailing control hearts. Although peak isometric force generated in response to increased extracellular calcium reached control levels in the muscles from patients with heart failure, the time course of contraction and rate of relaxation were greatly prolonged. The inotropic effectiveness of the beta-adrenergic agonist isoproterenol and the phosphodiesterase inhibitors milrinone, caffeine, and isobutylmethylxanthine was markedly reduced in muscles from the patients with heart failure. In contrast, the effectiveness of inotropic stimulation with acetylstrophanthidin and the adenylate cyclase activator forskolin was preserved. After a minimally effective dose of forskolin was given to elevate intracellular cyclic AMP levels, the inotropic responses of muscles from the failing hearts to phosphodiesterase inhibitors were markedly potentiated. These data indicate that an abnormality in cyclic AMP production may be a fundamental defect present in patients with end-stage heart failure that can markedly diminish the effectiveness of agents that depend on generation of this nucleotide for production of a positive inotropic effect.
1-Methyl-3-isobutylxanthine↗
Comparison of methods for determining absolute left ventricular volumes from radionuclide ventriculography.
Several radionuclide techniques have been used in routine clinical nuclear medicine practice as a means of quantitating left ventricular chamber volumes in man. Despite wide use and availability of the different techniques, however, there has not been a thorough comparison of radionuclide and contrast angiographic measurements performed in the same patients in close temporal proximity. Accordingly, in order to validate traditional methods of ventricular volume measurement, we have performed contrast ventriculography followed immediately (upon return of baseline hemodynamics) by gated radionuclide ventriculography in 34 patients undergoing diagnostic cardiac catheterization. Absolute left ventricular end-diastolic volumes were determined from single-plane, right anterior oblique, end-diastolic contrast silhouettes using a standard area-length method. Radionuclide ventriculographic volumes were determined by three methods: planimetry (32 patients), counts-based (19 patients), and thermodilution stroke volume/radionuclide ejection fraction (32 patients). With planimetry, an area-length method was used in which the modified left anterior oblique left ventricular image was assumed to be a prolate ellipsoid whose volume can be determined by measuring surface area and the ventricular long axis. With the counts-based technique, a blood sample was drawn at the midpoint of the radionuclide ventriculogram acquisition and counted with a gamma camera with appropriate attenuation factor correction. With the thermodilution stroke volume/radionuclide ejection fraction technique, the left ventricular stroke volume was determined by dividing thermodilution cardiac output by the heart rate.(ABSTRACT TRUNCATED AT 250 WORDS)
Cardiac Catheterization↗
Assessment of the end-systolic pressure-volume relationship in human beings with the use of a time-varying elastance model.
The analysis of left ventricular end-systolic pressure-volume relationships in human beings has been hindered by the lack of a practical method of serial volume assessment and by an imprecise definition of end-systole. Modifications of the end-systolic relationship that have been used to circumvent these problems have included the use of single-point end-systolic pressure-volume ratios, the use of peak systolic pressure/minimum ventricular volume points for end-systolic points, and the use of end-ejection as a marker for end-systole. To assess the correlation between the parameters generated by these modifications with the slope (Emax) and volume intercept (VO) of the end-systolic line as defined by Sagawa's model of time-varying elastance, simultaneous measurement of left ventricular pressure and gated radionuclide volume was made in 26 patients under various loading conditions and pressure-volume diagrams were constructed for each loading condition from 32 simultaneous pressure-volume coordinates. Two pressure-volume diagrams were recorded in 14 patients and three pressure-volume diagrams were recorded in 12 patients. Emax and VO were determined in all patients from the slope and volume intercept of the isochronic pressure-volume line with the maximum time-varying elastance as described by Sagawa's model and were designated true Emax and true VO, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)
Blood Pressure↗
Complex wound closure, excisional biopsy, and use of simple flaps.
The primary care physician can utilize the various techniques discussed in this article to close complex lacerations, modify scars, and perform excisional biopsies. Various methods for closure of square, triangular, semicircular, circular, and rectangular defects were described. The principle of flap advancement and Z-plasties was explained, and the method for performing excisional biopsies was detailed. These techniques can be mastered by the primary care practitioner and can lead to improved patient satisfaction. These techniques can be practiced using pig's feet. These minor plastic surgery techniques are an important component in a primary care practice.
Biopsy↗
A comparison of family practice clinics and free-standing emergency centers: organizational characteristics, process of care, and patient satisfaction.
Because of the increasing popularity of free-standing emergency care centers as a source of primary care services, this cross-sectional study was conducted to compare four of them with two family practice centers that provided extended hours. A total of 2,339 patient encounters were examined with data obtained from both physicians and patients. The factors that were found to be a basis for discrimination between the two types of practice were the cost of care and the patient's satisfaction with convenience and personal attention from the physicians. The overall average costs were significantly higher for the free-standing centers ($45) as compared with the family practice clinics ($27). Convenience and time factors, including waiting time, time spent with the physician, time to get an appointment, clinic location, and out-of-pocket cost, all produced a higher level of satisfaction for the free-standing clinic patients. Conversely, the personal concern of the physician and the ability to see the same physician brought higher levels of satisfaction for the family practice clinic patients. The free-standing emergency center is clearly becoming a significant factor in the delivery of primary care with evidence to suggest that patients are willing to pay a premium for convenience.
Ambulatory Care Facilities↗