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Biomedical subjects

N D Masani

Publications and source records attributed to N D Masani.

9 recordsLinked to original sources
PubMed2006

Clozapine-induced effuso-constrictive pericarditis. Case report and review of the literature.

Clozapine is a widely used antipsychotic medication and is effective against both positive and negative symptoms of schizophrenia. However, clozapine use should be monitored closely due to its side effects profile. The main side effects include cardiorespiratory symptoms, seizures and agranulocytosis. We report a case of effuso-constrictive pericarditis soon after being started on clozapine therapy, whose symptoms improved after discontinuation of clozapine. The literature is reviewed and importance of monitoring is discussed.

Antipsychotic Agents↗
PubMed1999

Effect of repetitive episodes of exercise induced myocardial ischaemia on left ventricular function in patients with chronic stable angina: evidence for cumulative stunning or ischaemic preconditioning?

BACKGROUND: Myocardial stunning is known to occur following a single episode of effort angina in patients with coronary artery disease. The effect on left ventricular (LV) function of repeated episodes of ischaemia is unknown. OBJECTIVES: To investigate the effects of repeated episodes of exercise induced ischaemia on LV function in patients with chronic stable angina. METHODS: Patients with significant coronary artery disease and normal LV function underwent two episodes of symptom limited treadmill exercise separated by three different time intervals: either 30 minutes (group A, n = 14); 60 minutes (group B, n = 14); or 240 minutes (group C, n = 14). Quantitative stress echocardiography was performed at repeated intervals between the two exercises and for 240 minutes following the second test. RESULTS: For all groups there was no difference between the degree of ischaemia judged by maximal ST depression during the two tests. All episodes of exercise induced ischaemia produced prolonged abnormalities of LV systolic and diastolic function despite rapid normalisation of haemodynamic and ECG changes. In group A (30 minutes) these abnormalities were less pronounced after the second test than after the first, while in group B (60 minutes) they were more severe and long lasting. In group C (240 minutes) the two tests produced similar abnormalities of LV function. CONCLUSIONS: Prolonged abnormalities of LV function occurred following exercise induced ischaemia with a time course consistent with myocardial stunning. The severity and degree of LV dysfunction caused by a further episode of ischaemia appear to be dependent on the time interval between ischaemic episodes.

Analysis of Variance↗
PubMed1998

Randomized, double-blind crossover study to investigate the effects of amlodipine and isosorbide mononitrate on the time course and severity of exercise-induced myocardial stunning.

BACKGROUND: Myocardial stunning may cause prolonged left ventricular dysfunction after exercise-induced ischemia that can be attenuated by calcium antagonists in animal models. To assess their effects in humans, we performed a randomized, double-blind crossover study comparing the calcium antagonist amlodipine (10 mg once daily) versus isosorbide mononitrate (ISMN, 50 mg once daily) on postexercise stunning. METHODS AND RESULTS: Twenty-four men with chronic stable angina and normal left ventricular function underwent serial quantitative exercise stress echocardiography after 3 weeks on each treatment to assess the degree of postexercise stunning with simultaneous sestamibi single-photon emission computed tomography perfusion scans at peak stress to quantify the ischemic burden. Exercise time (P=1), maximum ST depression (P=0.48), and sestamibi single-photon emission computed tomography scores (P=0.17) were unchanged between treatments. Stunning occurred more often with ISMN than amlodipine (82% versus 48%). The global and segmental stress echocardiography parameters of stunning were attenuated in patients while taking amlodipine compared with ISMN. Shortening fractions and ejection fractions were less impaired 30 minutes after exercise in patients receiving amlodipine (3.5+/-1.4% versus 2.5+/-1.4%, P=0.014, and 59.7+/-5.4% versus 54.5+/-8%, P<0.001); similarly, the isovolumic relaxation period was less prolonged with amlodipine (93+/-15.5 versus 106.3+/-14.9 ms, P=0.018). CONCLUSIONS: Despite comparable levels of ischemia, amlodipine attenuated stunning when compared with ISMN. This beneficial effect may relate to a prevention of the calcium overload implicated in the pathogenesis of stunning.

Aged↗
PubMed1998

Clinical application of transthoracic volume-rendered three-dimensional echocardiography in the assessment of mitral regurgitation.

Two-dimensional echocardiography (2-DE) and Doppler methods are generally used for assessing mechanisms and severity of mitral regurgitation (MR). Recently, 3-dimensional echocardiography (3-DE) has been applied successfully in various cardiac disorders, but its value in evaluating the mechanism and the severity of MR are not known. We studied 30 patients with MR using 2-DE and 3-DE. Volume-rendered gray-scale 3-DE images of the mitral valve apparatus and MR jets were reconstructed. Maximal volume of the MR jet by 3-DE was compared with mitral regurgitant volume and fraction, regurgitant jet area and the ratio of jet area to left atrial area, and semiquantitative grading derived from 2-DE methods. Our results demonstrated that 3-DE aided in a better depiction of the mitral apparatus and its abnormalities in 70% of the patients. The origin, direction, and morphology of the MR jet were better delineated in 3-DE volumetric display. Quantitative analysis, however, showed only a weak to moderate correlation between 3-DE maximal MR jet volume and 2-DE mitral regurgitant volume (y = 0.5x + 11.4, r = 0.7), regurgitant fraction (y = 0.5x + 8.2, r = 0.65), mitral regurgitant jet area (y = 0.2x + 5, r = 0.51), jet area to left atrial area ratio (y = 0.53x + 7.6, r = 0.54), and semiquantitative grading of MR (y = 9.1x - 1.8, r = 0.74). In conclusion, 3-DE aids in a better understanding of the mechanisms of MR and morphology of the regurgitant jets. Its quantitative ability, when reconstruction of the jet alone is used, may be limited.

Adult↗
PubMed1996

Follow-up of chronic thoracic aortic dissection: comparison of transesophageal echocardiography and magnetic resonance imaging.

Because survivors of thoracic aortic dissection require follow-up to detect prognostic factors such as intimal tears, persistent flow in the false lumen, and complications associated with grafts, we compared transesophageal echocardiography (TEE) with magnetic resonance imaging (MRI) prospectively in 14 patients 1 year after their initial examination. Residual dissection was identified by both techniques in 11 patients. Flow and/or thrombus in the false lumen were detected by TEE in 10 (91 %) and 6 (55%) patients, respectively, and by MRI in 9 (82%) and 5 (45%), respectively (p = NS); more tears were detected by TEE (2.5 +/- 1.4 per patient vs 0.2 +/- 0.4; p < 0.005). Satisfactory delineation of a graft in the ascending aorta was noted in all 8 (100%) of the surgically treated patients by TEE compared with 4 (50%) by MRI (p < 0.005). The upper ascending aorta was visualized clearly in fewer patients by TEE than by MRI (7 [50%] vs 13 [93%]; p < 0.05), as were the origins of the head and neck vessels (10 [71%] vs 13 [93%], p = NS). We conclude that TEE and MRI are both suitable techniques for the follow-up of patients with aortic dissection. TEE is more sensitive in identifying prognostic factors. MRI has a complementary role, particularly in visualization of the upper ascending aorta and the head and neck vessels.

Adult↗
PubMed1995

Severe coronary vasospasm associated with hyperthyroidism causing myocardial infarction.

A 48 year old woman presented with angina after an anterior myocardial infarction and was found to be hyperthyroid. Coronary angiography showed a stenosis of the left coronary os and a long, severe stenosis of the left anterior descending artery which was partially relieved by glyceryl trinitrate. Three months later, after radioactive iodine treatment had rendered her euthyroid, repeat coronary angiography showed entirely normal coronary arteries. This unusual case establishes an association between hyperthyroidism and coronary vasospasm resulting in myocardial infarction.

Acute Disease↗
PubMed1994

Transoesophageal echocardiography as the sole diagnostic investigation in patients with suspected thoracic aortic dissection.

OBJECTIVES: To assess the value and limitations of using transoesophageal echocardiography as the sole diagnostic test in patients with suspected thoracic aortic dissection. DESIGN: Retrospective data review over a two year period. SETTING: A regional cardiothoracic centre. PATIENTS: Data were compiled from admission records, surgical records, and lists of patients undergoing diagnostic investigations in the hospital. Patient's notes were used to identify presentation, management, and outcome. INTERVENTIONS: Patients were managed according to the policy of our unit, which is to treat patients with dissection affecting the ascending aorta by an operation. Patients with uncomplicated dissection sparing the ascending aorta are initially managed medically. MAIN OUTCOME MEASURES: In hospital and two year follow-up of patients who were investigated by transoesophageal echocardiography alone. RESULTS: Of 48 patients referred, 45 underwent transoesophageal echocardiography. Dissection was confirmed in 22 patients. Transoesophageal echocardiography showed the proximal extent of the dissection in 21/22 (96%) and only one patient required a further diagnostic investigation. Ten patients with dissection of the ascending aorta underwent graft replacement of the ascending aorta; operative mortality was 10% and their two year survival was 80%. Of the eight patients with dissection of the descending aorta, six were discharged home, and five were alive at two years. No patient without evidence of dissection on their initial transoesophageal echocardiographic examination required re-investigation into possible dissection in the two years after discharge. CONCLUSIONS: In patients with suspected thoracic dissection transoesophageal echocardiography rapidly and safely gives all the necessary diagnostic information. Further investigations, including coronary angiography, before surgery are unnecessary.

Adult↗