Biomedical subjects
Publications and source records attributed to J C Mohan.
Left ventricular apical aneurysms were observed in six of 84 (7.1%) patients consecutively catheterised after closed mitral valvotomy for relief of mitral stenosis. All these patients had angiographically normal coronary arteries. Such aneurysms represent a potential source of cardiovascular complications.
A case who developed severe and potentially fatal reaction to an angiographic contrast medium despite adequate pretreatment with steroids for 2 weeks is reported. This is the second such case reported in the English literature.
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We determined echocardiographic (M-mode) indices of left ventricular mass and function serially at 1-month intervals in 10 patients with uncomplicated mild or moderate essential hypertension, before and after adequate control of blood pressure with labetalol, a combined alpha- and beta-receptor blocking agent. Seven patients had pretreatment echocardiographic evidence of left ventricular hypertrophy with disproportionate septal thickness in 4. Systolic blood pressure in the untreated state correlated well (r = 0.96) with left ventricular mass but poorly (r = 0.30) with diastolic pressure. Following a satisfactory blood pressure reduction, achieved in all patients, left ventricular mass decreased from 240.5 +/- 71.1 g to 159.5 +/- 40.7 g (P less than 0.01), interventricular septal thickness from 1.33 +/- 0.3 cm to 0.92 +/- 0.25 cm (P less than 0.01) and posterior wall thickness from 1.03 +/- 0.23 cm to 0.93 +/- 0.23 cm (P less than 0.05). While the maximum changes in left ventricular mass were noted by the end of first month (P less than 0.01) with insignificant changes thereafter, the correlation of fall in blood pressure with change in left ventricular mass was significant only after 2 months of treatment (P less than 0.05). Indices of left ventricular function (end-diastolic volume, ejection fraction, fractional diameter shortening, left atrial dimension and posterior aortic wall motion) were normal before treatment and remained unchanged during 3 months of treatment. In this short-term study, labetalol reduced left ventricular hypertrophy (expressed as left ventricular mass and wall thickness) without altering left ventricular function indices in patients with uncomplicated essential hypertension. This has important implications in the treatment of hypertensive patients.
Forty cardiac pacing threshold studies were conducted in 20 patients during temporary pacing prior to permanent pacemaker implantation using the following intravenously administered anti-arrhythmic drugs: Lignocaine 2 mg/kg (10 patients), mexiletine 5 mg/kg (5 patients), ajmaline 1 mg/kg (5 patients), verapamil 0.15 mg/kg (10 patients) and propranolol 0.1 mg/kg (10 patients). Changes in voltage (volts), current (mA), energy (micro-joules) and resistance (ohms), were measured using a pacemaker system analyzer at a constant pulse width (0.6 msec) and pacing rate (70/minute). Lignocaine increased the voltage threshold significantly (p less than 0.05) with insignificant (p greater than 0.05) change in current, energy and resistance. Mexiletine and ajmaline significantly (p less than 0.01 and p less than 0.02) increased the voltage and current thresholds but did not change the energy level and resistance (p greater less 0.05). Verapamil caused a significant increase in the current and energy threshold (p less than 0.05), without changing the voltage threshold significantly (p greater than 0.05). The resistance values showed a consistently decreasing trend. Propranolol on the other hand did not affect any parameter significantly (p greater than 0.05). Anti-arrhythmic drugs appear to produce variable effects on different pacing threshold parameters. This has important clinical implications.
Left ventricular filling pressures as reflected by pulmonary capillary wedge pressure (PCWP) were measured in 20 adult subjects of chronic severe anemia before and after transfusing one unit of blood. The cases were divided into two groups of ten each. In both groups blood was transfused at a speed of 5 ml/mt; group II cases received, in addition, 40 mg furosemide intravenously just before the start of the transfusion. Pretransfusion PCWP was normal in all the cases. Following transfusion, 'wedge' pressure increased significantly (P less than 0.001) in group I but not in group II patients, in whom it actually decreased (P less than 0.001). It is concluded that prior administration of furosemide completely prevents any increase in LVFP following transfusion of one unit of blood at a moderately rapid speed, and makes such a transfusion quite safe, at any rate, so far as pulmonary haemodynamics are concerned.
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Atrial flutter with a structurally well-defined macro-reentrant circuit in the right atrium has recently become amenable to radiofrequency ablation with the recognition of isthmus as a narrow zone of slow conduction. This study describes 20 consecutive and symptomatic patients with atrial flutter (15 males, 5 females; mean age 38.5 +/- 10.2 years) who underwent radiofrequency ablation in our institute in the last 18 months. Fourteen patients had structurally normal hearts, while the remaining six patients had specific disorders (prior surgery for closure of atrial septal defect-2, idiopathic restrictive cardiomyopathy-1, primary sinus node dysfunction-2, tachycardiomyopathy-1). The endpoints of a complete isthmus block and conversion to sinus rhythm were achieved in 19 of the 20 patients. Total number of pulses needed to attain the endpoints was a mean of 4.2 (range 1-5), each pulse being delivered for 90 seconds. At a mean follow up of 9.4 +/- 3.2 months (range 6-12 months), recurrence of atrial flutter was seen in one patient, atrial fibrillation in two and sinus node reentrant tachycardia in one. These results are comparable to those reported in the literature. Achievement of a complete isthmus block appears to be an important endpoint in obtaining optimal results. The issues of alternative sites of ablation, long-term results and advantages of an 8 mm tip catheter need to be examined further. In conclusion, radiofrequency ablation appears to be the preferred mode of treatment for patients with atrial flutter with excellent short-term and mid-term results.
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Congenitally unguarded tricuspid valve orifice, a variant of tricuspid valve dysplasia, is a rare malformation with protean manifestations. This report describes an asymptomatic adult who, on echocardiographic examination ordered in view of an abnormal 12-lead surface electrocardiogram and plain chest X-ray, was found to have an unguarded tricuspid valve orifice with a giant right atrium (12 x 10 cm), intense spontaneous echo contrast and a large right atrial clot.
We describe an adult patient with a hitherto unreported association of severe aortic stenosis with extensive noncompaction of the left ventricular myocardium without any hypertrophy; however, there was severe left ventricular systolic dysfunction in the presence of a normal-sized left ventricular cavity on two-dimensional echocardiography. This condition was differentiated from persistence of embryonic intramyocardial sinusoids by selective coronary angiography.
Cross-sectional echocardiographic left ventricular ejection fraction (LVEF) by five different Methods (Teichholz, Area-length, single-plane Simpson, Bullet and Baran Formulae) was determined in 24 normal healthy volunteers (male-17, female-7, age range 16-80 years, mean 37 +/- 13) to assess the method-dependent variability in left ventricular volumes and LVEF. Although the Teichholz and Bullet methods gave somewhat higher values, there was no significant difference between LVEF determined by any of the methods (F = 0.16, p greater than 0.50). There was an a symmetrical distribution of LVEF in this normal group with an absolute mean positive skewness of 6 per cent (range 4-7 percent, coefficient of skewness = +0.43 to +0.87). A cut-off normal lower limit of LVEF at 50 per cent encompassed 88-100 per cent (mean 93.3) of subject population depending upon the method used. Similarly there was no significant difference between left ventricular volumes obtained by various methods. Therefore all the above five methods for quantitation of left ventricular global function are equally useful in clinical studies in patients with normal left ventricular geometry and in absence of segmental asynergy.