Biomedical subjects

A K Patel

Publications and source records attributed to A K Patel.

59 records · Page 4Linked to original sources

PubMedDate not supplied

Medulloblastoma--a retrospective analysis.

A retrospective review of 45 patients was undertaken at the All India Institute of Medical Sciences to assess the outcome and prognostic factors for these patients who received post operative radiotherapy with or without chemotherapy for medulloblastoma. The median age at diagnosis was 11 years, with 34 males and 11 female patients. Thirty four tumours were confined to midline structures, and 11 were localised to one cerebellar hemisphere or involved midline and lateral structures. Complete macroscopic removal was achieved in 24 patients and subtotal removal in 21 patients. Forty one patients underwent craniospinal irradiation and 27 patients received adjuvant chemotherapy. Median overall and disease free survival was 57 and 31 months respectively and 3 year overall survival was 76%. The addition of adjuvant chemotherapy was a significant factor for disease free survival (p = 0.01) whereas extent of surgery (total vs subtotal, p = 0.01) was a significant factor for overall survival only. Eleven patients developed recurrent disease, with ten relapsing first in the posterior fossa.

Adolescent↗

PubMedDate not supplied

Surgical resection of cor triatriatum in a 74-year-old man. Review of echocardiographic findings with emphasis on Doppler and transesophageal echocardiography.

A 74-year-old man was admitted to the hospital with congestive heart failure secondary to cor triatriatum. He also had sick sinus syndrome with complete heart block and syncope that had been treated with a permanent pacemaker 20 years earlier. The patient underwent successful surgical resection of the atrial membrane with closure of an atrial septal defect. M-mode, two-dimensional, Doppler, and transesophageal echocardiographic findings are reviewed. A unique "spike and dome" pattern on continuous-wave Doppler echocardiography is described that may suggest diagnosis of cor triatriatum.

Aged↗

PubMedDate not supplied

Reliability of M-mode, two-dimensional and Doppler echocardiography in diagnosing a flail mitral valve leaflet.

The purpose of this study was to evaluate the M-mode, two-dimensional, and Doppler echocardiographic signs for a flail mitral valve leaflet. This was a retrospective evaluation of 54 patients who had (1) significant mitral regurgitation, (2) a technically adequate echocardiographic study, and (3) description of valve anatomy done at surgery or necropsy. The following M-mode signs were examined for their ability to detect a flail valve: (1) systolic flutter of the mitral valve closure line, sensitivity 29%, specificity 76%; (2) abnormal diastolic posterior leaflet motion, sensitivity 73%, specificity 71%; (3) abnormal diastolic anterior leaflet motion, sensitivity 67%, specificity 86%; (4) systolic atrial echoes, sensitivity 28%, specificity 68%; (5) multiple independent systolic closure lines, sensitivity 71%, specificity 52%. The two-dimensional echocardiographic signs evaluated were (1) diastolic inversion of the anterior leaflet toward the left atrium, sensitivity 29%, specificity 96%; (2) diastolic inversion of the posterior leaflet toward the left atrium, sensitivity 54%, specificity 93%, (3) systolic inversion of the anterior leaflet into the left atrium, sensitivity 57%, specificity 93%; (4) systolic inversion of the posterior leaflet into the left atrium, sensitivity 79%, specificity 86%; (5) systolic whipping of the mitral leaflets, sensitivity 73%, specificity 74%; (6) presence of floating apical chordae, sensitivity 30%, specificity 91%. Doppler echocardiographic signs evaluated were (1) presence of left atrial systolic antegrade flow, sensitivity 30%, specificity 91%; (2) vertical striations superimposed on the typical regurgitant flow pattern, sensitivity 75%, specificity 69%. When all the two-dimensional signs except systolic whipping and the M-mode signs for abnormal diastolic leaflet motion were combined, the sensitivity for detecting a flail mitral valve was maximized at 97%, but specificity was reduced to 64%. In conclusion, two-dimensional echocardiographic signs are more sensitive and specific than either M-mode or Doppler signs for detecting a flail mitral valve. The various M-mode, two-dimensional, and Doppler echocardiographic signs, however, are complementary to each other, and sensitivity is maximized when they are combined.

Adult↗

PubMedDate not supplied

Intraoperative transesophageal echocardiography: correlation of echocardiographic findings and surgical pathology.

Before the introduction of transesophageal echocardiography (TEE) in the operating room, intraoperative echocardiography relied on epicardial imaging. The disadvantages of this approach included interference with the surgical procedure, limited windows, and potential distortion of cardiac structures. Consequently, multiplane TEE has now emerged as the intraoperative imaging method of choice. It provides high-resolution images of cardiac structures and excellent portraits of flow abnormalities. Intraoperative TEE does not interfere with the surgical field and procedure. TEE provides better imaging of the valves, atria, aorta, pulmonic vasculature, and pericardium, which are sometimes difficult to visualize by transthoracic echocardiography. TEE is especially beneficial in surgeries for valve replacement, valve repair, cardiac mass, aortic disease, congenital heart disease, and pericardial disease. Presurgical TEE provides information for surgical planning. TEE is helpful for the assessment of the immediate result of surgery and detection of complications that may need a prompt response. Thus, intraoperative TEE has a vital impact on management of cardiac surgery.

Echocardiography, Transesophageal↗

PubMedDate not supplied

Drug-induced torsade de pointes.

Three patients who developed torsade de pointes associated with antiarrhythmic or psychotropic drugs are described, and the electrocardiographic characteristics, clinical presentation, predisposing factors, and management of this form of ventricular tachycardia are reviewed. The first patient was a 56-year-old schizophrenic man receiving thioridazine hydrochloride, trifluoperazine hydrochloride, and benztropine mesylate who was admitted to a hospital after a syncopal episode. Subsequently, the patient experienced several episodes of ventricular tachycardia combined with multifocal premature ventricular contractions (PVCs) and torsade de pointes; the arrhythmias were attributed to antipsychotic therapy. The second patient was a 69-year-old man who experienced ventricular tachycardia that progressed to ventricular fibrillation 41 days after surgery. Quinidine sulfate probably induced the ventricular tachycardia, which was identified as torsade de pointes. The third patient was a 71-year-old man admitted to the hospital for treatment of refractory ventricular arrhythmias. Previous drug therapy with quinidine sulfate and procainamide hydrochloride had been associated with torsade de pointes. Despite unsuccessful treatment of ventricular ectopy, the patient was discharged on maintenance therapy with pindolol, topical nitrates, and phenytoin. No additional episodes of torsade de pointes have been observed. Torsade de pointes is characterized by polymorphous electrocardiographic appearance and delayed repolarization (prolonged QT interval). It may occur in association with a number of disease states and also as a complication of treatment with therapeutic doses of drugs that affect repolarization (quinidine, disopyramide, procainamide, and phenothiazines). Clinical outcomes range from asymptomatic, self-terminating arrhythmias to ventricular fibrillation resulting in cardiac arrest. The definitive emergency therapy for torsade de pointes is overdrive pacing; cautious isoproterenol administration can also be used. Lidocaine and bretylium are often ineffective in treating this form of ventricular tachycardia. Potassium and magnesium repletion appear to be essential in abolishing drug-induced torsade de pointes. Drug-induced torsade de pointes is best prevented by avoiding agents known to induce arrhythmias in patients with a pre-existing prolonged QT interval. Periodic serum electrolyte assessment is warranted, and new drugs that prolong the QT interval should be considered potential causative agents of torsade de pointes.

Acecainide↗