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Nayak HK, Daga MK, Kumar R, Garg SK, Kumar N, Mohanty PK. A series report of autoimmune hypothyroidism associated with Hashimoto's encephalopathy: an under diagnosed clinical entity with good prognosis. BMJ Case Rep 2010; 2010:2010/nov22_1/bcr0120102630. [PMID: 22797195 DOI: 10.1136/bcr.01.2010.2630] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Thyroid dysfunctions may be accompanied by numerous neurological and psychiatric disorders. The most well-known is cognitive impairment and depression in hypothyroid patients, as well as an increased risk of cerebrovascular accidents. A separate, although a rare entity, is Hashimoto's encephalopathy. Unlike encephalopathy associated with other conditions, management in Hashimoto's encephalopathy highly responds to steroid treatment and may be associated with normal thyroid profile at presentation. Hashimoto's encephalopathy, while rare, may have been under-recognised since its clinical presentation overlaps several more common disorders, such as depression, seizures or anxiety. We present two cases of hypothyroidism with peculiar presentation. The first case has rapidly progressive neurological dysfunction, normal thyroid function at presentation, normal MRI finding and responds to steroid treatment. The second case has a subacute progressive neurological deterioration with elevated thyroid-stimulating hormone titre at presentation. Both these cases are known hypothyroidism on regular thyroxin replacement therapy with elevated anti-thyroid peroxidase antibodies. We conclude that Hashimoto's encephalopathy can present with a wide spectrum of neurological illnesses in the setting of hypothyroidism. Thyroid status may vary from hypothyroid, normothyroid to even hyperthyroid. This condition usually has an abnormal electroencephalography (EEG) background and usually responds to high dose steroids.
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Basu U, Mohanty PK. Totally asymmetric exclusion process on a ring with internal degrees of freedom. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2010; 82:041117. [PMID: 21230248 DOI: 10.1103/physreve.82.041117] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2010] [Indexed: 05/30/2023]
Abstract
A totally asymmetric exclusion process on a ring with ν nonconserved internal degrees of freedom, where particles hop forward with a rate that depends on their internal state, has been studied. We show, using a mapping of the model to a zero range process with ν different kinds of boxes, that steady-state weights can be written in a matrix product form and calculate the spatial correlations exactly. A comparison of the model with an equivalent conserved system reveals that unequal hopping rates of particles belonging to different internal states are responsible for the nontrivial correlations.
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Abstract
Thermoinduction for 1 week, followed by 48 hours of vitamin treatment of seeds, resulted in complete annihilation of the cold effect, the plants from the treated seeds having shown a significant increase in elongation of the root and shoot and an increase in the fresh weight as well as in the dry matter over vernalized and unvernalized controls. An increase in vegetative vigor was also noted after treatment with vitamins at lower concentrations in the unvernalized series. Cold treatment not combined with vitamin treatment resulted in a decrease in vegetative vigor.
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Basu U, Mohanty PK. Active-absorbing-state phase transition beyond directed percolation: a class of exactly solvable models. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2009; 79:041143. [PMID: 19518209 DOI: 10.1103/physreve.79.041143] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2009] [Indexed: 05/27/2023]
Abstract
We introduce and solve a model of hardcore particles on a one-dimensional periodic lattice which undergoes an active-absorbing-state phase transition at finite density. In this model, an occupied site is defined to be active if its left neighbor is occupied and the right neighbor is vacant. Particles from such active sites hop stochastically to their right. We show that both the density of active sites and the survival probability vanish as the particle density is decreased below half. The critical exponents and spatial correlations of the model are calculated exactly using the matrix product ansatz. Exact analytical study of several variations of the model reveals that these nonequilibrium phase transitions belong to a new universality class different from the generic active-absorbing-state phase transition, namely, directed percolation.
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Mohanty PK, Jalan S. Analytical results for stochastically growing networks: connection to the zero-range process. Phys Rev E 2008; 77:045102. [PMID: 18517678 DOI: 10.1103/physreve.77.045102] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2007] [Revised: 02/08/2008] [Indexed: 11/07/2022]
Abstract
We introduce a stochastic model of growing networks where both the number of new nodes which join the network and the number of connections vary stochastically. We provide an exact mapping between this model and the zero-range process, and calculate analytically the degree distribution for any given evolution rule. We argue that this mapping can be used to infer a possible evolution rule for any given network. This is being demonstrated for a protein-protein interaction network of Saccharomyces cerevisiae.
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Mohanty PK. Generic features of the wealth distribution in ideal-gas-like markets. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2006; 74:011117. [PMID: 16907070 DOI: 10.1103/physreve.74.011117] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2006] [Indexed: 05/11/2023]
Abstract
We provide an exact solution to the ideal-gas-like models studied in econophysics to understand the microscopic origin of Pareto law. In these classes of models the key ingredient necessary for having a self-organized scale-free steady-state distribution is the trading or collision rule where agents or particles save a definite fraction of their wealth or energy and invest the rest for trading. Using a Gibbs ensemble approach we could obtain the exact distribution of wealth in this model. Moreover we show that in this model (a) good savers are always rich and (b) every agent poor or rich invests the same amount for trading. Nonlinear trading rules could alter the generic scenario observed here.
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Padhi PK, Patel DK, Mohanty PK, Sahoo SC, Khan S. Factors predicting morbidity and mortality in idiopathic dilated cardiomyopathy--an inhospital survey. THE JOURNAL OF THE ASSOCIATION OF PHYSICIANS OF INDIA 2006; 54:587-8. [PMID: 17089913] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
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Mohanty PK, Politi A. A new approach to partial synchronization in globally coupled rotators. ACTA ACUST UNITED AC 2006. [DOI: 10.1088/0305-4470/39/26/l01] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Kale SB, Reddy V, Mohanty PK, Patil R, Jariwala P. Absent Right Superior Vena Cava in Visceroatrial Situs Solitus : Surgical and Anaesthetic Implications. Ann Card Anaesth 2006. [DOI: 10.4103/0971-9784.37914] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/03/2023] Open
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Mohanty PK. First-order synchronization transition in locally coupled maps. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2004; 70:045202. [PMID: 15600449 DOI: 10.1103/physreve.70.045202] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2004] [Indexed: 05/24/2023]
Abstract
We study several diffusively coupled chaotic maps on periodic d -dimensional square lattices. Even and odd sublattices are updated alternately, introducing an effective delay. As the coupling strength is increased, the system undergoes a first-order phase transition from a multistable to a synchronized phase. At the transition point, the largest Lyapunov exponent of the system changes sign contrary to the earlier studies which predicted the same to be negative. Further increase in coupling strength shows desynchronization where the phase space splits into two ergodic regions. We argue that the nature of desynchronization transition strongly depends on the differentiability of the maps.
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Mohanty PK, Dhar D. Generic sandpile models have directed percolation exponents. PHYSICAL REVIEW LETTERS 2002; 89:104303. [PMID: 12225197 DOI: 10.1103/physrevlett.89.104303] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2002] [Indexed: 05/23/2023]
Abstract
We study sandpile models with stochastic toppling rules and having sticky grains so that with a nonzero probability no toppling occurs, even if the local height of pile exceeds the threshold value. Dissipation is introduced by adding a small probability of particle loss at each toppling. Generically for the models with a preferred direction, the avalanche exponents are those of critical directed percolation clusters. For undirected models, avalanche exponents are those of directed percolation clusters in one higher dimension.
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Hanrahan JS, Eberly C, Mohanty PK. Substance abuse in heart transplant recipients: a 10-year follow-up study. Prog Transplant 2001. [PMID: 11871277 DOI: 10.7182/prtr.11.4.nh5002x563h657p1] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
CONTEXT Active substance abuse is widely accepted as a contraindication for heart transplantation because of the theory that relapse would occur after transplantation and result in compromise of graft function, lowering long-term survival. Listing "recovering" substance abusers for heart transplantation has been controversial. OBJECTIVE To determine if substance abuse plays an unfavorable role in the outcome of heart transplantation. METHODS The medical records of all patients at our center who received a heart transplant more than 10 years ago were retrospectively reviewed for history of substance abuse. RESULTS From a pool of 189 transplant recipients, 47 patients had a definite history of substance abuse (group 1) and were considered in recovery, whereas 142 patients were clearly without any history of substance abuse (group 2). Group 1 had a significantly greater percentage of patients with a pretransplantation diagnosis of idiopathic cardiomyopathy (P = .003), a higher occurrence of heart-related cause of death (P = .017), and a significant prevalence of noncompliance (P = .0001) and death because of noncompliance (P = .0004). In contrast, group 2 surprisingly had a significantly higher incidence of death related to infection (P = .0062), which is unexplained. Despite higher incidence of noncompliance in group 1, there was no significant difference in the overall survival rate between the 2 groups. CONCLUSION These results suggest that patients with a history of substance abuse can undergo successful heart transplantation with acceptable long-term survival, though they are at greater risk for substance abuse relapse and resulting noncompliance with the treatment regimen. The extent to which relapse of substance abuse and its consequences affect the cost of posttransplantation care remains to be determined.
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Topaz O, Shah R, Mohanty PK, McQueen RA, Janin Y, Bernardo NL. Application of excimer laser angioplasty in acute myocardial infarction. Lasers Surg Med 2001; 29:185-92. [PMID: 11553909 DOI: 10.1002/lsm.1108] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
BACKGROUND AND OBJECTIVE Patients presenting with acute myocardial infarction who fail to respond to standard therapy with thrombolytics or have contraindications for their use oftentimes need revascularization with a mechanical device for removal of an occlusive coronary thrombus and its underlying atherosclerotic plaque. As both thrombi and plaques absorb laser energy in the ultraviolet wavelength (308 nm), we studied the feasibility and safety of excimer laser angioplasty in selective patients with complicated acute myocardial infarction. STUDY DESIGN/MATERIALS AND METHODS Fifty patients with acute myocardial infarction complicated by continuous chest pain and/or ischemia who had a total of 54 obstructive lesions were treated with percutaneous excimer coronary laser angioplasty (ELCA). A Q-wave myocardial infarction was documented in 56% and a non-Q-wave myocardial infarction in 44%. The baseline left ventricular ejection fraction was reduced at 43 +/- 13% and six patients (12%) presented to the cardiac catheterization laboratory in cardiogenic shock. Twenty-nine patients failed to respond to thrombolytic therapy and 16 had contraindications for thrombolytics and IIb/IIIa receptor antagonists. Following laser debulking, all patients received adjunct balloon dilation and then stents were deployed in 83% of the target lesions. Quantitative coronary arteriography (QCA) was performed at an independent core laboratory. RESULTS Ninety-eight percent laser success and 100% procedural success were achieved. By QCA the minimal luminal diameter increased from baseline of 0.7 +/- 0.5 to 1.3 +/- 0.5 mm post-lasing and then to 2.0 +/- 0.6 with balloon dilation to a final of 3.0 +/- 0.5 mm. Pre-laser percent stenosis diameter of 77 +/- 17% was reduced to 51 +/- 22% post-laser to 3.0 +/- 17% post-balloon and to a final of 15 +/- 25%. An 83% laser-induced reduction of thrombus burden area was achieved as well as an increase in TIMI flow from baseline of 1.7 +/- 1.1 to 2.8 +/- 0.4 by laser to a 2.9 +/- 0.4 final. There were no deaths, emergency bypass surgery, cerebral vascular accident, neurologic injury, or major perforation. In one case, a laser-induced major dissection was successfully treated by stenting. All 50 patients survived the procedure, improved clinically, and were discharged. CONCLUSION Application of excimer laser coronary angioplasty is feasible and safe in selected patients with acute myocardial infarction who either fail to respond to thrombolytics or have contraindications to these agents. Intracoronary thrombus at the target lesion can be successfully dissolved with this wavelength laser energy without adverse effect on the procedure results.
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Davis FA, Mohanty PK, Burns DM, Andemichael YW. Sulfinimine-mediated asymmetric synthesis of 1,3-disubstituted tetrahydroisoquinolines: a stereoselective synthesis of cis- and trans-6,8-dimethoxy-1,3-dimethyl-1,2,3,4-tetrahydroisoquinoline. Org Lett 2000; 2:3901-3. [PMID: 11101449 DOI: 10.1021/ol006654u] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
[reaction: see text] The highly diastereoselective addition of lateral lithiated o-tolunitriles to sulfinimines followed by treatment of the resulting sulfinamide with MeLi, hydrolysis, and reduction represents a concise new methodology for the asymmetric synthesis of 1,3-disubstituted tetrahydroisoquinolines.
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Topaz O, Janin Y, Bernardo N, Bailey NT, Mohanty PK. Coronary revascularization in heart transplant recipients by excimer laser angioplasty. Lasers Surg Med 2000; 26:425-31. [PMID: 10861697 DOI: 10.1002/1096-9101(2000)26:5<425::aid-lsm1>3.0.co;2-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
BACKGROUND AND OBJECTIVE Aggressive development of allograft coronary artery disease is a major cause of death in heart transplant recipients. Percutaneous balloon angioplasty is considered suboptimal for complex lesions in native coronary vessels and heart transplant recipients, alike. Excimer laser energy (308-nm wavelength) can successfully remove and vaporize atherosclerotic plaques in native coronary vessels; however, its application in heart transplant recipients has not been studied clinically yet. STUDY DESIGN/MATERIALS AND METHODS Six heart transplant recipients underwent percutaneous excimer laser (CVX-300, Spectranetics, Colorado Springs, CO) coronary angioplasty for treatment of a total of 10 discrete, obstructive coronary artery lesions. By using concentric or eccentric multifiber laser catheters, energy parameters were set at a fluence of 45 mJ/mm(2) or 60 mJ/mm(2) with a frequency of 25 Hz and 40 Hz, respectively, with a pulse duration of 135 ns and output of 200 mJ/pulse. The "saline flush" and "pulse and retreat" lasing techniques were used. In each case, adjunct balloon angioplasty was performed; in five lesions, an intracoronary stent was implanted. Angiographic evaluation was performed by visual assessment. RESULTS Each procedure was successful as defined by laser recanalization of the target lesion (reduction of target lesion stenosis in more than 20%) and subsequent adequate final luminal patency (reduction of target lesion stenosis to less than 50%) and absence of any major in-cardiac catheterization complication (such as perforation, acute closure, dissection, emergency coronary artery bypass surgery), or in-hospital complications (such as death, myocardial infarction, cardiac enzyme elevation, major bleeding), or need for surgical revascularization. A 92 +/- 5% preprocedural percent diameter stenosis was reduced by laser to 35 +/- 16% and by adjunct balloon angioplasty in all lesions and stenting in five lesions, to final residual stenosis of 2 +/- 6%. Angiographic follow-up between 2 and 6 months after the procedure demonstrated a target lesion restenosis rate of 22%. CONCLUSION Percutaneous excimer laser is safe and efficacious in the treatment of focal obstructive lesions caused by allograft coronary artery disease. These data represent an early clinical experience; thus, the long-term outcome of this revascularization method in recipients of heart transplantation will have to be determined by a large scale prospective, randomized, multicenter clinical study.
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Akosah KO, Denlinger B, Mohanty PK. Safety profile and hemodynamic responses to beta-adrenergic stimulation by dobutamine in heart transplant patients. Chest 1999; 116:1587-92. [PMID: 10593781 DOI: 10.1378/chest.116.6.1587] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
STUDY OBJECTIVE Dobutamine stress echocardiography (DSE) has been used as a screening tool for coronary artery disease after heart transplantation and in the identification of patients at risk for development of cardiac events. However, the safety profile of high-dose dobutamine in heart transplant patients has not been systematically examined. Accordingly, we studied the safety profile and hemodynamic responses to escalating doses of dobutamine to determine the influence of denervation. DESIGN We assessed the hemodynamic responses, heart rate (HR), and arterial BP indexes (mean arterial pressure, systolic BP [SBP], diastolic BP [DBP], and pulse pressure) to dobutamine in 87 heart transplant patients ([mean +/- SD] age, 51 +/- 1 years) and compared the results with 97 nontransplant patients (age, 63.0 +/- 1 years) who served as innervated control subjects. MEASUREMENTS AND RESULTS The baseline HR (84 +/- 2 vs 69 +/- 1 beats/minute, respectively; p < 0.001) and peak HR response (144 +/- 2 vs 117 +/- 2 beats/minute, respectively; p < 0.001) were significantly higher in heart transplant patients than in the nontransplant patients. SBP was lower in heart transplant patients than in nontransplant patients at baseline (131 +/- 2 vs 138 +/- 2 mm Hg, respectively; p < 0.02) and at peak (150 +/- 3 vs 158 +/- 3 mm Hg, respectively; p < 0.03). However, baseline DBP was higher in transplant patients than in nontransplant patients (86 +/- 1 vs 77 +/- 1 mm Hg, respectively; p < 0.001). The decrease in DBP was similar in both groups (15 mm Hg). The dose-response curve for HR was shifted leftward in heart transplant patients. Heart transplant patients attained a higher absolute HR at each infusion stage and higher rates of increase, but the decrease in DBP was not significantly different in the two groups. CONCLUSIONS These results show that there is augmented chronotropic response and expected decline in DBP in response to dobutamine infusion in heart transplant patients. This increase in myocardial oxygen demand and a decrease in coronary perfusion pressure may be important mechanisms in the development of ischemic abnormalities that are detectable as regional dysynergy on echocardiography.
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Rossignol DA, Kipreos B, Akosah K, Mohanty PK. Accelerated transplant coronary artery disease and massive silent acute myocardial infarction in a heart transplant patient--a case report and brief review of literature. Angiology 1999; 50:947-53. [PMID: 10580360 DOI: 10.1177/000331979905001110] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
This case report describes an aggressive form of accelerated atherosclerosis predicted early after transplant by dobutamine stress echocardiography in a patient who died of massive myocardial infarction 32 months after transplantation. The main objective finding of this event was markedly increased cardiac filling pressures during an elective cardiac catheterization and coronary angiography. The literature is briefly reviewed.
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Abstract
Accelerated allograft vasculopathy significantly limits the survival of heart transplant recipients. The prevalence of allograft coronary artery disease is as high as 18% by 1 year and 50% by 5 years following heart transplant. Heart failure and sudden cardiac death are the two most common clinical presentations. In heart transplant recipients with severe, discrete focal allograft vascular disease, percutaneous balloon angioplasty is a viable palliative option. However, its application is limited by a significant restenosis rate and progression of allograft disease in nontreated segments. Diffuse disease with tapering of vessels may be approached by debulking devices. Emerging revascularization modalities for focal stenoses and some of the diffuse tapering vessels include coronary stents, rotational atherectomy, various wavelength lasers, and, to a lesser extent, directional atherectomy. Conceivably, stents will reduce restenosis rates related to focal, discrete plaques; yet it is unknown whether they will be efficacious in short- and long-term treatment of diffusely diseased segments affected by allograft disease. Accurate assessment of clinical outcomes and long-term evaluation is imperative prior to acceptance of these devices as fundamental interventional tools for treatment of allograft coronary artery disease.
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Prinz A, Akosah KO, Jackson P, Mohanty PK. Acquired atrial septal defect as a complication of endocarditis--a case report. Angiology 1998; 49:865-9. [PMID: 9783653 DOI: 10.1177/000331979804900912] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Bacterial endocarditis predominantly involves cardiac valves and is associated with many potential complications. Valvular dysfunction resulting from disruption of the structural integrity of valves are not infrequent. This report illustrates a rare case of endocarditis involving the interatrial septum which subsequently produced destruction of the structure resulting in an acquired atrial septal defect.
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Quigg R, Salyer J, Mohanty PK, Simpson P. Impaired exercise capacity late after cardiac transplantation: influence of chronotropic incompetence, hypertension, and calcium channel blockers. Am Heart J 1998; 136:465-73. [PMID: 9736138 DOI: 10.1016/s0002-8703(98)70221-2] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
BACKGROUND AND METHODS Patients undergoing orthotopic cardiac transplantation manifest reduced exercise capacity during the first postoperative year, which is related primarily to chronotropic incompetence of the denervated heart. To determine whether exercise capacity improves during the long term after transplantation, we prospectively studied 45 patients from 1 month to 6 years after cardiac transplantation by use of maximal treadmill exercise testing for measurement of exercise duration, peak heart rate, and peak VO2. All had normal left ventricular ejection fractions. Patients were categorized according to length of time since transplant and compared to 14 untrained normal subjects. RESULTS Peak exercise heart rate and exercise duration were progressively higher as time after transplantation increased. However, patients who had undergone transplantation more than 2 years earlier continued to manifest a significant reduction in peak exercise heart rate (157+/-3 beats/min vs 178+/-14 beats/min) and reduced exercise duration (8.6+/-0.5 minutes vs 13.2+/-2.0 minutes) compared with controls. In contrast, peak VO2 was similar at all times after transplant and remained markedly reduced in patients who underwent transplantation more than 2 years earlier as compared with controls (22.1+/-0.7 mL/kg/min vs 42.1+/-9.1 mL/kg/min). The potential effects of 14 clinical variables on exercise performance were evaluated by regression modeling. Patients with poorly controlled hypertension had a shorter median exercise duration (7.4 minutes vs 9.7 minutes) and a lower median peak VO2 (20.3 mL/kg/min vs 23.2 mL/kg/min) compared with patients with normal or well-controlled blood pressure. Patients treated with calcium channel blockers for hypertension had greater chronotropic incompetence during exercise (peak heart rate 139 beats/min vs 158 beats/min). There was no relation between exercise capacity and recipient age, donor age, recipient sex, donor ischemic time, pretransplant diagnosis, length of peritransplant hospitalization, percentage of ideal body weight, left ventricular ejection fraction, frequency or severity of allograft rejection, or long-term use of oral prednisone therapy. CONCLUSIONS Exercise capacity, as measured by treadmill exercise time and peak heart rate, improves in the first 2 years after transplantation, but does not reach normal values in patients up to 6 years after transplant. Peak VO2 remains significantly reduced at all times after transplantation despite the presence of normal resting left ventricular systolic function.
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Akosah KO, McDaniel S, Hanrahan JS, Mohanty PK. Dobutamine stress echocardiography early after heart transplantation predicts development of allograft coronary artery disease and outcome. J Am Coll Cardiol 1998; 31:1607-14. [PMID: 9626841 DOI: 10.1016/s0735-1097(98)00169-7] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
OBJECTIVES This study sought to determine the prognostic significance of serial dobutamine stress echocardiography (DSE) in new heart transplant recipients and to examine the relation between persistent wall motion abnormalities and the eventual development of coronary artery disease (CAD) as assessed by angiography. BACKGROUND Allograft CAD is a major cause of graft failure. However, clinical diagnosis of the early disease remains difficult. The reasons for this include the diffuse nature of the disease and its predilection for the microvasculature, which are not easily detected by coronary angiography. Identifying patients at risk for the development of angiographic CAD early after transplantation may allow such patients to be targeted for aggressive treatment options to prevent subsequent cardiac events and early graft failure. METHODS Twenty-two new heart transplant recipients were selected to undergo serial DSE at the time of their regularly scheduled endomyocardial biopsy. In addition, patients underwent scheduled annual coronary angiography. DSE was performed in 5-min stages with infusion of intravenous dobutamine at 5, 10, 20, 30 and 40 microg/kg body weight per min. RESULTS Twenty-two patients had 91 DSE studies and 45 coronary angiograms. The patients were categorized into three groups based on the echocardiographic results. Group 1 (n = 7) had normal serial stress echocardiographic studies. Group 2 (n = 4) had transient inducible wall motion abnormalities. Group 3 (n = 11) developed persistent wall motion abnormalities. During a mean follow-up time of 32 +/- 11 months (range 5 to 50), 8 (73%) of 11 patients in Group 3 developed events. The events included angiographic CAD (n = 7), myocardial infarction (MI) (n = 1) and cardiac death (n = 3). The patient who developed an MI had a normal coronary angiogram. No cardiac event or angiographic disease occurred in either Group 1 or 2 patients. CONCLUSIONS These results suggest that dobutamine-induced wall motion abnormalities, which are persistent in new heart transplant recipients, are predictive of the development of angiographic CAD, MI or death.
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Topaz O, Bailey NT, Mohanty PK. Application of solid-state pulsed-wave, mid-infrared laser for percutaneous revascularization in heart transplant recipients. J Heart Lung Transplant 1998; 17:505-10. [PMID: 9628570] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Severe allograft coronary artery disease is a significant cause of death in heart transplant recipients. Percutaneous revascularization has thus far been attempted with balloon angioplasty and, to a lesser extent, with directional atherectomy. The new, investigational, solid-state pulsed-wave mid-infrared laser (holmium:YAG) can vaporize and remove atheromatous and thrombotic plaques. This mechanism of plaque ablation may be useful for allograft coronary artery disease associated with focal stenoses deemed unsuitable for standard balloon angioplasty, especially thrombus-containing lesions. METHODS Five adult heart transplant recipients with severe focal stenoses related to allograft coronary artery disease underwent six laser angioplasty procedures. Laser catheters (2.1 microm, 250 to 600 mJ, 5 Hz) varying from 1.2 mm to 2.0 mm delivered 45 +/- 7.4 pulses (mean +/- SD). Five laser procedures were completed with adjunct balloon angioplasty and one with directional atherectomy. RESULTS Laser success (defined as stenosis reduction > 20%, no cardiac catheterization laboratory or in-hospital major complication) was achieved in six of seven lesions (85%), and the overall (laser and adjunct balloon) procedural success rate was 100%. No major complications occurred. Laser-assisted angioplasty reduced mean stenosis from 90% +/- 3% to 9% +/- 11%. All five patients recovered and were discharged. Angiographic follow-up demonstrated a 50% restenosis rate. CONCLUSIONS In selected heart transplant recipients laser-assisted angioplasty can provide safe and successful acute revascularization. Focal lesions considered "nonideal" for balloon angioplasty and, in particular, thrombotic lesions can benefit from application of this device; however, long-term reduction of restenosis rates is not expected from this modality.
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Abstract
The objective of this focused review is to describe the rationale, methods, and potential clinical applications of dobutamine stress echocardiography (DSE) in heart transplant recipients. More than 500 studies in 150 heart transplant patients who underwent this procedure (1991-96) are reviewed. Relevant studies from the medical literature that have assessed the utility of DSE in the diagnosis of transplant coronary artery disease (TCAD) are discussed, the predictive ability of DSE for development of TCAD is determined, and the prognostic value of this test in the heart transplant population is evaluated. The protocol of DSE used in the laboratory for this study is presented and discussed with reference to other major studies that have determined the sensitivity, specificity, and positive and negative predictive accuracies. Since many noninvasive cardiac tests have not been consistently optimal to detect TCAD, a substantial number of patients undergo routine surveillance with coronary angiography to define the presence and magnitude of TCAD. Recent studies with DSE have shown it to be valuable in the noninvasive diagnosis of TCAD and to have an accuracy unmatched by other widely used imaging modalities. Other important evolving indications for DSE in heart transplant patients, such as prediction of prognosis and occurrence of cardiac events, are briefly discussed. Based on this study and the currently available literature, DSE appears to be a highly reproducible noninvasive test which can be serially employed in the routine surveillance of coronary artery disease in heart transplant patients.
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Gangopadhyay AN, Mohanty PK, Gopal SC, Gupta DK, Sahi UP, Aryya NC, Khanna S. Adenocarcinoma of the esophagus in an 8-year-old boy. J Pediatr Surg 1997; 32:1259-60. [PMID: 9269985 DOI: 10.1016/s0022-3468(97)90698-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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Akosah KO, Olsovsky M, Kirchberg D, Salter D, Mohanty PK. Dobutamine stress echocardiography predicts cardiac events in heart transplant patients. Circulation 1996; 94:II283-8. [PMID: 8901761] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
BACKGROUND Cardiac transplantation is an accepted treatment modality for end-stage heart failure. Coronary artery disease remains a major cause of mortality in the long term after heart transplantation. Despite the high prevalence of coronary artery disease in heart transplant recipients, currently used noninvasive tests as well as invasive tests are highly unreliable in predicting prognosis. We sought to test the hypothesis that the abnormalities induced by dobutamine stress echocardiography (DSE) may be of prognostic value in predicting acute cardiac events and mortality in heart transplant patients. METHODS AND RESULTS We prospectively studied 86 survivors of orthotopic heart transplantation and followed them for a mean period of 2 years after the DSE. The patients' median age was 51 +/- 10 years, and mean duration since transplant was 57.7 +/- 29 months (range, 3 to 120 months, mean +/- SD). DSE was performed by a standard protocol (dobutamine 5, 10, 20, 30, and 40 micrograms.kg-1.min-1 at 5-minute stages). DSE was defined as positive for development of new or worsening regional wall motion abnormality or failure of augmentation. Nine patients were excluded from analysis (5 because of acute allograft rejection and 4 because of poor acoustic window). Thus, data from 77 patients were analyzed. Fifty-seven of 77 (74%) had positive DSE. After 24 months of follow-up, 19 of 57 patients with abnormal DSE (33%) experienced 22 major cardiac events. In contrast, no event occurred in patients with normal DSE. Of the 19 with cardiac events, there were 7 episodes of heart failure (including 3 deaths), 4 had unstable angina, and 5 died of cardiac causes. Three patients had myocardial infarction, and 3 others died of noncardiac causes. Among the variables examined, the baseline left ventricular ejection fraction was lower (44 +/- 3.8 versus 51 +/- 1.4) and peak wall motion score index was higher (2.01 +/- 0.4 versus 1.44 +/- 0.4) in the patients group with cardiac events than in those without events. CONCLUSIONS These results suggest that DSE has significant value in predicting prognosis in post-heart transplant patients. Further studies are needed to define the role of DSE as a routine test for predicting prognosis in cardiac transplant recipients.
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