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Biomedical subjects

K K Sethi

Publications and source records attributed to K K Sethi.

At least 145 records · Page 8Linked to original sources
PubMedDate not supplied

Verapamil responsive ventricular tachycardia: clinical and electrophysiologic characteristics.

Ventricular tachycardia is a rare arrhythmia in young patients without associated heart disease. Electrophysiologic studies were performed in thirteen young patients (mean age 26.4 +/- 7 years) with recurrent sustained ventricular tachycardia (VT) responsive to intravenous verapamil. The QRS duration during VT was less than 0.14 sec in all patients. The VT showed a right bundle branch block (RBBB) morphology in all cases, with left axis deviation in 12 and right axis deviation in one. Eleven patients were free of organic heart disease. VT could be induced in the laboratory in 10 patients, out of whom the electrophysiologic mechanism of VT could be assessed in 9 cases. The data were consistent with reentry in 8 patients and suggested triggered activity in one patient. Atrial pacing induced the VT in two cases. Nine patients were restudied 48 to 72 hours after oral verapamil (240 to 320 mg/day). VT was not inducible in 8 patients and was markedly slowed in one. VT of RBBB morphology occurring in young patients has distinct electrocardiographic and electropharmacologic properties. Reentry is the usual underlying mechanism. Verapamil is highly effective in terminating and preventing the VT.

Adolescent↗
PubMedDate not supplied

Electrophysiologic effects of oral propafenone in Wolff-Parkinson-White syndrome studied by programmed electrical stimulation.

We studied the electrophysiologic effects of oral propafenone on induction of supraventricular tachycardia (SVT) in 10 patients with Wolff-Parkinson-White syndrome (5 manifest and 5 concealed accessory pathways). Nine patients had orthodromic SVT and one patient had atrial fibrillation with preexcited QRS (shortest RR 220 msec). Electrophysiologic studies were performed during control and 48 hours after oral propafenone administered in a dose of 300 mg every eight hours. Propafenone caused complete anterograde accessory pathway conduction block in 4 of 5 patients with manifest delta waves. Retrograde conduction through the accessory pathway was abolished in 6 of 9 patients in whom it was present during control. Sustained SVT was inducible in all 9 patients during control. Propafenone prevented induction of SVT in 8 of 9 patients (88.9%) and slowed the rate of induced SVT in one patient. In the patient with atrial fibrillation (AF) the accessory pathway was blocked and AF was not inducible. There was a significant increase in the effective refractory period (ERP) of the atrium (208 +/- 40 msec to 257 +/- 25 msec, p less than 0.01), atrioventricular (AV) node (less than or equal to 256 +/- 34 msec to greater than or equal to 324 +/- 35 msec, p less than 0.001) and ventricle (204 +/- 14 msec to 262 +/- 51 msec, p less than 0.01). The atrial paced cycle length at AV nodal block also increased from 288 +/- 51 msec to 389 +/- 51 msec (p less than 0.01) after the drug. Thus propafenone has potent inhibitory effects on accessory pathways and has additional significant effects on atrial, AV nodal and ventricular refractoriness.

Administration, Oral↗
PubMedDate not supplied

Evaluation of lesions suitable for percutaneous transluminal coronary angioplasty after thrombolytic therapy of acute myocardial infarction.

Forty-two patients of acute myocardial infarction (AMI) and clinically successful thrombolysis underwent coronary angiography 7.6 +/- 3.6 days after the AMI. The infarct related artery was patent in 33 of 42 (78.5%) patients, and 27 of these 33 (82%) had residual diameter stenosis of 70 per cent or more. Arteries showing more than 70 per cent luminal diameter narrowing were considered suitable for percutaneous transluminal coronary angioplasty (PTCA) if the lesion was less than 1 cm in length and there was no significant left main or distal lesion. Based on the above criteria, 22 of the 33 patients (66%) with recanalised infarct-related artery were found to have lesions suitable for PTCA. Thus, after successful thrombolysis, significant proportion of patients of acute myocardial infarction have residual lesions that are suitable for PTCA.

Adult↗
PubMedDate not supplied

Non-surgical mitral valvuloplasty for rheumatic mitral stenosis.

One hundred and twenty-six patients of rheumatic mitral stenosis (MS), aged 10-30 (mean 19.5 +/- 5.9) years underwent balloon mitral valvuloplasty (BMV). All valvuloplasties were done by the anterograde transvenous, transatrial route. The procedure was successful in 120 (95%) cases. Single balloon was used in 10 patients early in the series and double balloon was used in the other 110 patients. BMV resulted in a significant increase in the mitral valve area (MVA) from 0.96 +/- 0.35 to 2.3 +/- 0.8 cm2 (p less than 0.0001) and a significant fall in the transmitral pressure gradient (TMG) from 28.2 +/- 3.2 to 7.4 +/- 4.8 mmHg (p less than 0.001). The MVA achieved by BMV was found to have a significant positive correlation with the balloon diameter to body surface area ratio (BD/BSA) (r = 0.69, p less than 0.001). New mitral regurgitation (MR) developed in 15 patients--trivial in 11, 2+ in 2 and 3+ in 2. One patient required emergency mitral valve replacement. Procedure induced MR did not have a significant relation to the balloon size, degree of mitral sub-valvular pathology or the severity of mitral stenosis. Iatrogenic atrial septal defect was detected by oximetry in none, by angiography in one patient, and by Doppler color flow imaging in 5 patients. Cardiac tamponade was the most frequent serious complication, occurring in 6 patients, 4 of whom died following emergency surgery. Sixty-five patients have been followed up for at least 6 months (range 6-30, mean 16.3 +/- 6.3 months) following BMV.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMedDate not supplied

Long term performance of dual chamber pacemakers.

Records of 98 patients who had dual chamber pacemakers implanted at our institution and had a follow up for at least 6 months (range 6-90 months, mean 47.8 months) were analysed for long term performance of the pacemakers. There were 78 males and 20 females in the age range of 14 to 81 (mean 51.1 +/- 13.6) years. The mode of pacing was VDD in 12, DVI in 9 and DDD in 77 patients. Atrial malsensing was seen in 15 (16.7%) cases and generally occurred within the first week of implantation. Atrial lead dislodgement occurred in 4 cases (4.1%). Most of the problems related to atrial lead could be managed conservatively and re-operation was performed in only 4 cases. Other problems encountered on follow up included cross talk in one, endless loop tachycardia in 4, and pulse generator pocket erosion or infection in 4 (4.1%) patients. There were two instances of ventricular undersensing and one instance of insulation failure in the ventricular lead. A total of 16 patients underwent elective replacement of pulse generator 53-84 months (mean 66.3) following the initial implants. It is concluded that the incidence of pacemaker malfunction and other problems with dual chamber pacemaker implantation are not high; and most cases can be managed by conservative measures such as reprogramming.

Adolescent↗
PubMedDate not supplied

Clinical and haemodynamic effects of oral metoprolol therapy in dilated cardiomyopathy.

The clinical and haemodynamic effects of oral metoprolol therapy were assessed in thirty patients of dilated cardiomyopathy, aged 14-58 (33 +/- 10.9) years. After baseline haemodynamic study, metoprolol was administered in a dose of 25-100 mg/day (mean 87.0 +/- 25.1 mg/day). Before start of therapy, 13 patients were in NYHA symptom class IV, 14 were in NYHA class III and 3 were in NYHA class II. Symptomatic improvement was seen on oral metoprolol therapy in all patients except one. Six months after therapy 13 patients were asymptomatic, 16 were in NYHA class II, while 1 patient continued to be in NYHA class III. Repeat haemodynamic study in 15 patients done at a mean of 5.7 months showed a significant fall in the right ventricular end diastolic pressure (from 9.1 +/- 4.4 to 5.7 +/- 2.9 mm Hg, p less than 0.01), mean pulmonary artery pressure (from 32.3 +/- 13 to 24.5 +/- 10.3 mmHg, P less than 0.01) and mean pulmonary capillary pressure (from 23.3 +/- 10.3 mmHg to 14.7 +/- 7.4 mmHg, P less than 0.01). The left ventricular ejection fraction increased from 18.8 +/- 6.3 to 24.0 +/- 7.3 per cent, (P less than 0.05), while no significant change was observed in the cardiac index (2.43 +/- 0.47 to 2.66 +/- 0.83 L/min/m2, p = NS). These data suggest improvement in diastolic and systolic left ventricular function after metoprolol therapy.

Administration, Oral↗
PubMedDate not supplied

Comparison of atrial and VVI pacing modes in symptomatic sinus node dysfunction without associated tachyarrhythmias.

The natural course of patients with symptomatic sinus node dysfunction who did not have associated tachyarrhythmias before pacemaker implantation was compared after VVI and atrial pacemaker implantation. Between April 1981 and June 1989, forty-seven such patients (mean age 52 + 13 years) received VVI pacemakers and forty patients (mean age 54 + 13 years) received AAI or DDD pacemakers. Baseline clinical characteristics and severity of sinus node dysfunction were comparable in the two groups. Over a follow up of 10 to 96 months (mean 49.2 + 26 months), 11 (23.4%) VVI patients were in functional class II or more compared to 2 (5%) atrially paced patients (p less than 0.01). Other complication rates were also higher in the VVI group as compared to AAI group viz. atrial fibrillation (21.2% vs 2.5% p less than 0.01) and stroke (10.6% vs 2.5%) though the number of deaths (14.9% vs 10%) was not significantly different in the two groups. Two patients in atrial paced group and one patient in VVI group developed first degree heart block. There was no incidence of second or third degree heart block. Transient loss of atrial sensing occurred in 3 patients and atrial lead displacement in 2 cases, but overall incidence of lead related problems was low and comparable in both groups. Thus atrial pacing is superior to ventricular pacing in sinus node dysfunction and risk of developing high grade atrioventricular block on follow up is low.

Adult↗
PubMedDate not supplied

Determinants of left ventricular function in isolated rheumatic mitral stenosis.

Left ventricular end-diastolic volume (preload), peak systolic wall stress (afterload), instant Emax (contractility index = peak systolic left ventricular pressure/end-systolic volume), left ventricular mass, left ventricular ejection fraction (LVEF) alone and normalised for mass index, were studied in 30 patients with isolated rheumatic mitral stenosis (group 1) and compared with 24 normal individuals (group II) who served as control. Preload was not different in the two groups (p = NS), afterload was increased in group I (p = 0.01), while LVEF, Emax, left ventricular mass and mass normalised LVEF were reduced in mitral stenosis as compared to normal control (p less than 0.01- less than 0.001). Comparison of patients with reduced ejection performance (LVEF less than 50%, n = 9, group IA) with those having normal LVEF (n = 21 group IB) revealed increased left ventricular end-diastolic volume and reduced left ventricular mass, mass normalised ejection fraction and Emax (in IA p less than 0.05). Peak systolic wall stress was comparable in these two subgroups. This study shows that the major determinant of left ventricular dysfunction in isolated rheumatic mitral stenosis is impaired contractility and not the loading factors.

Adolescent↗
PubMedDate not supplied

Detection of multivessel coronary artery disease by early exercise testing after first myocardial infarction.

The ability of a symptom limited treadmill exercise test (TMT) to predict the presence of multivessel coronary artery disease (MVD) three weeks after a first myocardial infarction was assessed in 76 male patients aged 25-65 (mean 40.9 +/- 10.1) years. There were 6 patients with normal coronaries, 36 with single vessel disease (SVD), 20 with double vessel disease (DVD), and 14 with three vessel disease (TVD). TMT was positive in 20/34 (58.8%) patients with MVD, and 4/42 (9%) patients with SVD or normal coronaries. The predictive accuracy of a positive TMT in detecting MVD was 83.3%, and the predictive accuracy of a negative TMT in excluding MVD was 73.1%. It is concluded that TMT is useful test for predicting the presence or absence of MVD in survivors of a first transmural myocardial infarction.

Adult↗
PubMedDate not supplied

Dominant right ventricular dilated cardiomyopathy: clinical, echocardiographic and haemodynamic profile.

Ten patients of dominant right ventricular dilated cardiomyopathy (RVDCM) seen over a period of three years in this institution are described. There were six males and four females in the age range of 6.50 years. Presenting features were right ventricular failure (7), paroxysmal supraventricular tachycardia (2), and one patient was detected on routine chest skiagram. All patients had characteristic electrocardiographic and radiologic features. 2D-echocardiographic examination revealed enormous dilatation of right atrium, ventricular cavity and outflow tract, interatrium and ventricular septum concave to the right, pre-systolic pulmonary valve opening, small left atrium and ventricle. Pulsed doppler echocardiogram revealed varying degree of tricuspid incompetence in all. Four patients underwent haemodynamic and cineangiographic studies showing left ventricular involvement in one. The patients have been followed up on digitalis, diuretics and quinidine with variable response to treatment. One patient died of uraemia, and one female patient recovered completely following delivery. Dominant RVDCM is a distinct clinical entity with typical features and with typical features and ill-defined natural history.

Adult↗
PubMedDate not supplied

Coronary angioplasty of 'complex lesions' in patients with unstable angina.

Out of 55 patients subjected to coronary angioplasty over the past 12 months, there were 33 (60%) who had unstable angina. Amongst these, 22 patients had coronary lesions classified as 'complex' on coronary angiography. These included tandem lesions, branch stenoses, distal lesions, total occlusions, vein graft stenoses, lesions with ulceration and intraluminal clot and associated with valvular lesions. We describe our experience of coronary angioplasty in these 22 patients of unstable angina having 'complex lesions'. All were males with a mean age of 48.7 +/- 13 years. Fourteen patients had single vessel and 8 multivessel disease. A total of 35 lesions were subjected to dilatation. The angiographic primary success was achieved in 85.7% of the lesions attempted. Except total occlusions and very distal lesions, all other types of 'complex lesions' could be dilated with a success rate of greater than 75%. There were 4 (11.4%) failures because of inability to cross the lesion with the guidewire or balloon catheter. One patient developed non-Q wave inferior wall infarction. There were no deaths. We conclude that coronary angioplasty of various types of 'complex lesions' can be performed with a good primary success and negligible complications in our setting.

Adult↗