Does ischemic preconditioning limit infarct size in non-Q-wave myocardial infarction?
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Animals↗
Biomedical subjects
S S Kushwaha
Publications and source records attributed to S S Kushwaha.
Pattern of changes over time in myocardial blood flow and microvascular dilator capacity in patients with normally functioning cardiac allografts.
This study tests the hypothesis that myocardial blood flow and coronary microvascular dilator capacity vary as a function of time after orthotopic heart transplantation in humans. Positron emission tomography measurements of myocardial blood flow were obtained at rest and during adenosine in 24 patients between 1 and 86 months after heart transplantation. At the time of the study all patients were clinically well and had angiographically normal epicardial coronary artery vessels. Patients were divided into 3 groups based on time from transplant to positron emission tomography measurement of myocardial blood flow: group 1 to 12 months (n = 9); group 13 to 34 months (n = 8); and group > or = 37 months (n = 7). Basal myocardial blood flow in group 1 to 12 months (1.86+/-1.01 ml/min/g) exceeded (p <0.05) that of group 13 to 34 months (1.17+/-0.73) and group > or = 37 months (0.98+/-0.34). In group 13 to 34 months, basal myocardial blood flow and maximal dilator capacity (minimal coronary vascular resistance with adenosine 36+/-12 mm Hg/ml/min/g) were comparable to that of normal volunteers (1.01+/-0.20 and 37+/-, respectively). In group > or = 37 months, maximal flow response to adenosine was reduced (2.54+/-1.25 vs 3.16+/-0.52, respectively, p = 0.06). Maximal dilator capacity in group > or = 37 months (60+/-34) was impaired versus group 1 to 12 months (36+/-10) and group 13 to 34 months (36+/-12; both p <0.05) as well as normals (37+/-9, p <0.05). During the first year after cardiac transplantation basal myocardial blood flow is elevated out of proportion to external determinants of myocardial oxygen demand, but maximal dilator capacity of the coronary microcirculation is normal. Between 1 and 3 years both basal myocardial blood flow and microvascular function tend to normalize. After 3 years, although basal myocardial blood flow is normal, microvascular dilator capacity is impaired.
Adult↗
New preexcitation following cardiac transplant.
Preexcitation developed post-operatively in a cardiac transplant recipient whose donor electrocardiogram was normal. An electrophysiology study revealed evidence of a mid-septal atrioventricular (AV) bypass tract. The patient is clinically well fourteen months after transplant and has intermittent preexcitation.
Arrhythmias, Cardiac↗
Cardiac troponin T: a noninvasive marker for heart transplant rejection?
BACKGROUND: Diagnosis of acute rejection remains a major concern in heart transplant recipients. Currently, endomyocardial biopsy is the gold standard for detecting rejection. Given the risks and cost of endomyocardial biopsy, a noninvasive marker for rejection would be ideal. Cardiac troponin T (cTnT) is an established marker of myocyte damage, and a rat transplantation model of heart transplant rejection has suggested that cTnT may be of value in detecting rejection. METHODS: The cTnT levels were measured in 90 transplant recipients (67 men and 23 women) at the time of endomyocardial biopsy. There were a total of 256 cTnT levels and 256 biopsy samples. The cTnT levels were compared by use of International Society of Heart and Lung Transplantation rejection grades. RESULTS: Only one of the 12 grade 3 biopsy specimens had a corresponding elevated cTnT level. Of the 29 biopsy specimens with myocyte necrosis (grade 2 or grade 3), three had a corresponding elevated cTnT. The cTnT levels were elevated during the first 1 to 2 months after transplantation. There was no correlation between ischemic time and cTnT levels. CONCLUSION: CTnT is an insensitive marker of acute rejection, both early and late after heart transplantation. Elevation of cTnT after transplantation does not seem to be directly related to ischemic time.
Acute Disease↗
Restrictive cardiomyopathy.
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Amyloidosis↗
Enhanced myocardial 18F-2-fluoro-2-deoxyglucose uptake after orthotopic heart transplantation assessed by positron emission tomography.
OBJECTIVES: We sought to assess the relation between glucose metabolism, myocardial perfusion and cardiac work after orthotopic heart transplantation. BACKGROUND: The metabolic profile of the transplanted cardiac muscle is affected by the lack of sympathetic innervation, impaired inotropic function, chronic vasculopathy, allograft rejection and immunosuppressive therapy. In relation to myocardial perfusion and cardiac work, glucose metabolism has not previously been studied in heart transplant recipients. METHODS: Regional myocardial blood flow (ml.min-1.g-1) and 18F-2-fluoro-2-deoxyglucose (18FDG) uptake rate (ml.s-1.g-1) were measured after an overnight fast in 9 healthy male volunteers (mean age +/- SD 32 +/- 7 years) and in 10 male patients (mean age 50 +/- 10 years) who had a nonrejecting heart transplant, normal left ventricular function and no angiographic evidence of epicardial coronary sclerosis. Measurements were made by using dynamic positron emission tomography (PET) with 15O-labeled water and 18FDG, respectively. Heart rate and blood pressure were also measured for calculation of rate-pressure product. RESULTS: 18FDG uptake was similar in all heart regions in the patients and volunteers (intrasubject regional variably 12 +/- 8% and 16 +/- 12%, respectively, p = 0.51). Regional myocardial blood flow was similarly evenly distributed (intrasubject regional variability 14 +/- 10% and 12 +/- 8%, respectively, p = 0.67). Mean 18FDG uptake and myocardial blood flow values for the whole heart are given because no regional differences were identified. 18FDG uptake was on average 196% higher in the patients than in the volunteers (2.90 +/- 1.79 x 10(-4) vs. 0.98 +/- 0.38 x 10(-4) ml.s-1.g-1, p = 0.006). Regional myocardial blood flow and rate-pressure product were similarly increased in the patient group, but by only 41% (1.14 +/- 0.3 vs. 0.81 +/- 0.13 ml.min-1.g-1, p = 0.008) and 53% (11,740 +/- 2,830 vs. 7,689 +/- 1,488, p = 0.001), respectively. CONCLUSIONS: 18FDG uptake is homogeneously increased in normally functioning nonrejecting heart transplants. This finding suggests that glucose may be a preferred substrate in the transplanted heart. The magnitude of this observed increase is significantly greater than that observed for myocardial blood flow or cardiac work. In the patient group, the latter two variables were increased to a similar degree over values in control hearts, indicating a coupling between cardiac work load and myocardial blood flow. The disproportionate rise in 18FDG uptake may be accounted for by inefficient metabolic utilization of glucose by the transplanted myocardium or by the influence of circulating catecholamines, which may stimulate glucose uptake independently of changes in cardiac work load.
Adult↗
Mirizzi syndrome: its awareness and management.
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Adult↗
Late endothelial function of free and pedicled internal mammary artery grafts.
The internal mammary artery has greater long-term patency than the saphenous vein when used for coronary bypass grafting. Therefore, bilateral use of the internal mammary artery for grafting with the right internal mammary artery used as a "free" graft may result in improved graft survival. The study objectives were to compare the endothelial-dependent and -independent vasodilatory response in free and pedicled internal mammary artery grafts in patients who had previously undergone coronary surgery. Free (group 1, n = 8) and pedicled (group 2, n = 7) internal mammary artery grafts were studied by comparing the response to selective infusion of the endothelial-dependent vasodilator substance P (1.4 up to 22.4 pmol/min in doubling dose increments) followed by isosorbide dinitrate (2 mg over 2 minutes), in patients undergoing coronary angiography, 1 month to 6 years after coronary surgery. Maximal dilatory response to substance P was 8.7% +/- 1.8% in pedicled grafts compared with 8.8% +/- 2.3% in free grafts (p = not significant), with the dose response for both groups being similar. Infusion of isosorbide dinitrate produced only minimal further dilatation in both groups. No significant difference was found in endothelium-dependent and -independent vasodilatory response between free and pedicled internal mammary artery grafts, suggesting that the use of the free right internal mammary artery and other arterial grafts may enhance graft survival.
Adult↗
Coronary endothelial function in cardiac transplant recipients with accelerated coronary disease.
BACKGROUND: Previous studies with the endothelium-dependent vasodilator substance P have shown a preserved vasodilator response in cardiac transplant recipients with angiographically normal coronary arteries. Although endothelial dysfunction is known to occur in cardiac transplant recipients with accelerated coronary disease, the degree to which the endothelium is affected is not known precisely. The aim of the present study was to examine endothelial function in accelerated coronary disease following cardiac transplantation. METHODS: Thirteen cardiac transplant recipients with epicardial coronary disease underwent substance P infusion. The response to incremental doses of substance P was measured in smooth segments of affected coronary arteries. Substance P was infused over 2 min with a starting dose of 1.4 pmol/min and a maximum of 22.4 pmol/min, reached by doubling the dose in steps, followed by an infusion of 2 mg isosorbide dinitrate over 2 min. RESULTS: Substance P caused less vasodilation at lower concentrations, with a significantly higher dose required to achieve half maximal dilation compared with cardiac transplant recipients with no coronary disease. The mean maximal dilatation achieved with substance P was 22.98 +/- 4.62% compared to 21.95 +/- 4.9% with isosorbide dinitrate; the latter value was not significantly different from the maximal dilation achieved in cardiac transplant recipients without coronary disease. CONCLUSIONS: In cardiac transplant recipients with accelerated coronary disease the functional vasodilatory ability of the coronary endothelium is impaired in segments of apparently unaffected epicardial arteries, which may lead to an increase in the resting vasoconstrictor tone and have important functional and therapeutic implications.
Adult↗
Effect of beta blockade on the neurohumoral and cardiopulmonary response to dynamic exercise in cardiac transplant recipients.
OBJECTIVE: To determine the effects of a small dose of beta blocker on neurohumoral and cardiopulmonary responses after cardiac transplantation. BACKGROUND: Cardiac transplant recipients have a reduced exercise capacity and abnormal cardiovascular responses to exercise. The sympathoadrenal response to exercise has been shown to be abnormal with high venous noradrenaline. The effect of beta blockade on these neurohumoral mechanisms has not been defined. METHODS: 10 non-rejecting cardiac transplant recipients were studied. Patients carried out graded exercise to a symptom limited maximum. Blood samples were taken during exercise. Concentrations of noradrenaline, adrenaline, and atrial natriuretic peptide and plasma renin activity were measured. The next day, the exercise and sampling procedure were repeated after an oral dose of propranolol (40 mg). RESULTS: Patients tolerated exercise poorly after beta blockade, which was reflected in the maximum workload reached. Heart rate and blood pressure were significantly higher at rest and during exercise before beta blockade. Although there was no significant difference when resting, mean (SEM) noradrenaline concentrations during peak exercise were higher after beta blockade (16.2 (2) v 23.6 (2.9) nmol/l, p = 0.001). Adrenaline concentrations at peak exercise were also greater after beta blockade (0.89 (0.31) v 1.18 (0.38) nmol/l, p = 0.055). Atrial natriuretic peptide concentrations tended to be higher after beta blockade (118.75 (50.2) v 169.79 (39.3) pmol/l, p = 0.36). There was no significant change in plasma renin activity. CONCLUSIONS: A small oral dose of a competitive beta blocker such as propranolol has an adverse effect on exercise tolerance and cardiovascular response to exercise in cardiac transplant recipients. There are also increased concentrations of circulating noradrenaline and therefore, sympathetic activity during exercise. beta blockers should be used with caution in cardiac transplant recipients.
Administration, Oral↗
Dipyridamole vasodilator response after human orthotopic heart transplantation: quantification by oxygen-15-labeled water and positron emission tomography.
To assess coronary vasodilator reserve after orthotopic heart transplantation, regional myocardial perfusion was measured with oxygen-15-labeled water and dynamic positron emission tomography in 14 cardiac allograft recipients who were not experiencing rejection and who had no angiographic evidence of epicardial coronary sclerosis 15 to 73 months (mean +/- SD 43 +/- 19) after transplantation (group I). Twelve normal men with an average age of 31 years (group II) served as a control group. Regional perfusion was measured at rest and after the intravenous administration of 0.6 mg/kg body weight of dipyridamole. Rest regional myocardial blood flow was homogeneously distributed throughout the left ventricle and was significantly higher in transplant recipients (mean 1.16 +/- 0.26 ml/g per min [range 0.8 to 1.73] than in normal subjects (mean 0.85 +/- 0.13 ml/g per min [range 0.57 to 0.99]; p = 0.001) as was rest heart rate-systolic blood pressure product (rate-pressure product 11,255 +/- 2,540 vs. 7,073 +/- 1,306; p less than 0.001). After dipyridamole, perfusion in the transplant recipients was homogeneous and slightly lower (2.73 +/- 1.03 vs. 3.40 +/- 1.09 ml/g per min; p = NS), whereas rate-pressure product was slightly higher (12,179 +/- 2,266 vs. 10,885 +/- 1,895; p = NS) than the value in normal subjects. Dipyridamole vasodilator response (dipyridamole/rest myocardial blood flow) ranged from 1.23 to 4.92 (mean 2.50 +/- 1.13) in group I and from 2.65 to 5.45 (3.97 +/- 0.89) in group II (p = 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)
Adult↗
Changes in myocardial echo amplitude during reversible ischaemia in humans.
OBJECTIVE: This study investigated the changes in regional myocardial ultrasonic backscatter, measured as myocardial echo amplitude, that occur during reversible myocardial ischaemia in humans. DESIGN: Left anterior descending coronary angioplasty was used to produce reversible myocardial ischaemia in human subjects. Regional myocardial echo amplitude was studied in the interventricular septum and left ventricular posterior free wall before, during, and after coronary occlusion with the angioplasty balloon. Wall motion analysis of the left ventricle was performed from simultaneous cross sectional echocardiographic imaging. Patients were studied prospectively. PATIENTS: Six patients (mean age 56 (SD 11), range 46 to 69 years) with single vessel, left anterior descending coronary artery stenoses, were investigated during elective coronary angioplasty. A total of 11 balloon inflations were studied. SETTING: All patient studies were performed at Harefield Hospital. Echo amplitude analysis was performed at the Royal Brompton Hospital. INTERVENTIONS: Angioplasty was performed by the usual procedure at Harefield Hospital for elective coronary angioplasty. All routine medication including beta blockers and calcium antagonists were continued. Inflation pressures were up to 12 atm (1212 kPa) and mean inflation time ranged from 30 to 120 (86 (31)) s. In four studies the first inflation was examined, in three the second, in two the third, and in one each the fourth and fifth inflations. Echo amplitude and cross sectional echo-cardiographic studies were recorded with a 3.5 MHz Advanced Technology Laboratories (ATL) (720A/8736 series) mechanical sector scanner and an ATL Mark III (860-1 series) echocardiograph system with 45 dB logarithmic grey scale compression. MAIN OUTCOME MEASURES: Regional echo amplitude was examined in four regions of the left ventricle--namely, the basal and mid-septum, and basal and mid-posterior wall. Consecutive end diastolic and end systolic frames were analysed and cyclic variation was determined as the difference between the level of echo amplitude at end diastole and at end systole. Measurements were made before balloon inflation, at peak inflation, and after balloon deflation. Regional wall motion and systolic wall thickening were analysed qualitatively. RESULTS: Before balloon inflation, cyclic variation in echo amplitude was noted in all regions (basal septum, 2.4 (SD 1.1) dB; mid-septum, 2.5 (1.1) dB; basal posterior wall, 3.3 (2.1) dB; mid-posterior wall, 3.9 (1.6) dB). During balloon inflation there was a significant fall in cyclic variation to 0.4 (0.9) dB (p < 0.0002) in the mid-septum. This was predominantly owing to an increase in end systolic echo amplitude from 5.4 (2.0) dB to 9.3 (1.9) dB (p < or = 0.01). This was associated with the development of severe hypokinesis or akinesis in the mid-septum. No significant changes in echo amplitude occurred in the three other regions examined. Changes were completely reversed after balloon deflation. CONCLUSIONS: These results suggest a causal relation between occlusion of the supplying coronary artery and blunting of myocardial echo amplitude cyclic variation. It is suggested that balloon occlusion produced myocardial ischaemia. The resultant impairment of myocardial contraction then caused a blunting of cyclic variation in echo amplitude. The results of this study provide further data about the ability of quantitative studies of ultrasonic backscatter to identify alterations in the myocardium during injury.
Aged↗
Cauda equina syndrome associated with ankylosing spondylitis in a female.
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Cauda Equina↗
Substance P for evaluation of coronary endothelial function after cardiac transplantation.
The endothelium-dependent vasodilator substance P dilates normal and diseased coronary vessels in humans in vivo and produces a maximal response similar to that seen with intracoronary isosorbide dinitrate. Twelve cardiac transplant recipients underwent intracoronary infusion of substance P after routine annual investigations. All patients were well, with no evidence of rejection and with angiographically normal coronary arteries. Substance P was infused at 2 ml/min for 2 min into the coronary artery, starting at a dose of 1.4 pmol/min and increasing by doubling increments, and followed by isosorbide dinitrate (1 mg/min) infused over 2 min. Coronary artery diameter was measured in 23 vessel segments from 12 transplant recipients. The following doses were infused: saline solution (1 ml/min), substance P (0.7 [three patients], 1.4, 2.8, 5.6, 11.2, 22.4 pmol/min) and isosorbide dinitrate (1 mg/min). The mean percent increase in diameter (+/- SEM) in response to increasing doses of substance P was as follows: 0, 6.5 +/- 2.9%, 10.9 +/- 2.9%, 12.1 +/- 2.9%, 16.5 +/- 2.6%, 19.2 +/- 3.1% and 25.8 +/- 2.2%, respectively. Half maximal dilation was produced with 1.4 to 2.8 pmol/min of substance P; the maximal response (mean percent diameter change) was 22 +/- 2.5%. This was not significantly different from that achieved with isosorbide dinitrate. It is concluded that coronary endothelial function as assessed by response to substance P is preserved in cardiac transplant recipients with angiographically normal coronary arteries. Substance P may be a suitable agent for testing endothelial function in these patients.
Coronary Angiography↗
Relation between cyclic variation in echo amplitude and segmental contraction in normal and abnormal hearts.
OBJECTIVE: To study the relation between cardiac systolic activity and cardiac cycle dependent variation in the ultrasound signal arising from within the myocardium. DESIGN: Regional echo amplitude was used as a measure of the myocardial ultrasound signal. Relative echo amplitude values were assigned by standardising echo gain using the posterior parietal pericardium as an in-vivo calibration. M mode measurements of the left ventricle were used to assess cardiac systolic activity. Subjects were studied prospectively. Analysis of echo amplitude was performed by investigators who were blinded to the results of the M mode analysis. The influence of impaired left ventricular performance and abnormal wall motion were assessed. PATIENTS: 11 cardiomyopathy patients with impaired ventricular function, eight patients with severe pulmonary hypertension and reversed septal motion, and 19 healthy controls. SETTING: All subject studies were performed at Harefield Hospital. Echo amplitude analysis was performed at the Royal Brompton Hospital. MAIN OUTCOME MEASURES: Cyclic variation in echo amplitude was determined as the change in echo amplitude from end diastole to end systole. Additionally, an index of cyclic variation defined as the ratio of the cyclic change in echo amplitude to end diastolic echo amplitude was measured. Both cyclic variation and the cyclic variation index were analysed to see whether they correlated with left ventricular dimensions, fractional shortening, and systolic wall thickening. RESULTS: Stepwise regression analysis showed systolic wall thickening to be the most significant independent variable that correlated with the cyclic variation index for both the septum and posterior wall (r = 0.68, p = 0.0001, septum; r = 0.69, p = 0.0001, posterior wall). The slopes and intercepts for both regression equations were similar (y = 0.005x + 0.006, septum; y = 0.006x + 0, posterior wall). Subgroup analysis showed that the healthy controls, patients with cardiomyopathy, and patients with pulmonary hypertension had similar slopes and intercepts for their individual regression equations. CONCLUSIONS: These data support the hypothesis of a quantitative relation between the extent of cyclic variation of echo amplitude and the degree of segmental myocardial shortening, as measured by systolic wall thickening, which is not significantly influenced by location within the myocardium, left ventricular performance, or wall motion. They provide further evidence of the usefulness of quantitative analysis of myocardial echo amplitude in the study of regional myocardial function in both normal and injured myocardium.
Adult↗
Valvular regurgitation in heart-lung transplant recipients: a Doppler color flow study.
To assess the frequency and degree of valvular regurgitation in combined heart and lung transplant recipients, 50 patients were investigated using Doppler color flow echocardiography 20 to 909 days (mean 369) after heart-lung transplantation. The mean age (+/- SD) of the patients was 25 +/- 9 years. No patient had evidence of rejection at the time of the study. Fifty normal volunteers acted as control subjects. Tricuspid, mitral and pulmonary regurgitation were commonly observed in the patients undergoing heart-lung transplantation (78%, 52% and 68%, respectively), but were not significantly more frequent than in the normal subjects (68%, 42% and 70%, respectively). Aortic regurgitation was uncommon in both groups (4% and 2%, respectively). However, tricuspid and mitral regurgitant jet areas were significantly greater (p less than 0.01) in heart-lung transplant recipients than in normal subjects (156 +/- 120 and 84 +/- 52 mm2 compared with 40 +/- 38 and 28 +/- 26 mm2, respectively); pulmonary regurgitant jet area was not significantly different in the two groups (32 +/- 26 and 28 +/- 26 mm2, respectively). Regurgitant jet area was not significantly correlated with patient or donor age, donor organ total ischemic time, time after operation, use of steroids for immunosuppression or total number of rejection episodes. These results show that valvular regurgitation is not significantly more frequent after heart-lung transplantation than in normal subjects, but atrioventricular (AV) valve regurgitation, when present, is significantly greater in degree. This suggests that the degree but not the frequency of AV valve regurgitation is related to transplantation.
Adolescent↗
Leprosy deformities. II. As parameters to monitor the effectivity of leprosy control programme.
Leprosy deformities have been considered as the main reason for dehabilitation and social ostracism. Prevention of deformities is considered as one of the most important objectives of leprosy control programme. In present work based on deformity status, efforts have been made to evolve new parameters and their possible application in assessment of leprosy control programme.
Age Factors↗
Leprosy deformities. I. An epidemiological study in a rural area of Rajasthan.
Leprosy deformities have been the cause of dehabilitation, destitution and social ostracism. Present study was planned and conducted in a rural area situated in eastern districts of Rajasthan. Out of 426 cases of leprosy, ninety cases were found suffering with deformities. The influences of various host factors and disease factors, in causation of deformities have been discussed.
Age Factors↗