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Biomedical subjects

K S Channer

Publications and source records attributed to K S Channer.

At least 127 records · Page 7Linked to original sources
PubMed1989

Improved control of atrial fibrillation with combined pindolol and digoxin therapy.

This study has compared the effect on heart rate control of the addition of pindolol 15 mg bd or verapamil 40 mg tds to maintenance digoxin therapy in 12 patients with chronic atrial fibrillation. The study was performed in a randomized cross-over fashion. Treatment effects were assessed by 24-h ambulatory electrocardiography and symptomatic improvement by symptom scores. The results show that the combination of pindolol and digoxin provides better control of atrial fibrillation. With an attenuation of daytime tachycardia, prevention of nocturnal bradycardia and reduction in the length of nocturnal pauses in rhythm. Overall heart rate variability was significantly less with digoxin and pindolol (523 beats min-1 h-1) than with digoxin and verapamil (745 beats min-1 h-1). We conclude that, in the dosages employed, combined digoxin and pindolol therapy is superior to either digoxin and verapamil in combination or digoxin alone for the treatment of atrial fibrillation.

Adult↗
PubMed1989

The contribution of atrial systole to mitral diastolic blood flow increases during exercise in humans.

1. The change in the relative contribution of the early passive and later active phases of transmitral flow to left ventricular filling was studied using Doppler echocardiography in ten normal male subjects during mild exercise. 2. The peak velocity of passive flow increased during exercise by a mean of 16% whereas peak velocity of active flow increased by a mean of 89%. Hence the ratio of the peak velocities decreased in a linear fashion with a correlation coefficient of r = -0.95. 3. The ratio of the Doppler-derived velocity-time integrals (equivalent to the ratio of flow) of the two phases of transmitral flow also showed a significant negative linear correlation of r = -0.97. 4. Active atrial transport (atrial systole) progressively increases its contribution to overall transmitral blood flow with increasing heart rate during mild exercise. This effect is mainly mediated by an increase in flow velocity which is related to increased atrial contractility.

Adult↗
PubMed1988

Unruptured aneurysm of the sinus of Valsalva presenting with ventricular tachycardia.

We report a case of a large unruptured aneurysm of the right sinus of Valsalva which caused severe right ventricular outflow tract obstruction and presented dramatically with a life threatening ventricular tachycardia. Despite severe aortic incompetence prior to surgery it was possible to resect the aneurysm and repair the aortic root without resort to aortic valve replacement and thus return the anatomy to normal.

Aortic Aneurysm↗
PubMed1988

Cardiomyopathy in the Kearns-Sayre syndrome.

The Kearns-Sayre syndrome is a mitochondrial myopathy characterised by ptosis, chronic progressive external ophthalmoplegia, abnormal retinal pigmentation, and cardiac conduction defects. A unique case is reported in which there was rapid development of progressive congestive cardiac failure that required cardiac transplantation. A review of published reports of mitochondrial myopathy shows that a minority of cases (less than 20%) have cardiac involvement. This had previously been limited to abnormalities of cardiac conduction with progressive heart block. Myocardial biopsy has, however, shown ultrastructural evidence of a generalised mitochondrial disorder which hitherto has not been associated with a functional deficit.

Adult↗
PubMed1988

Psychological factors influence the success of coronary artery surgery.

Thirty-six patients with angina were investigated by treadmill exercise testing and coronary angiography prior to coronary artery surgery. Severity of angina was judged by interview and self-assessment visual analogue scale and all patients were psychiatrically assessed. Further physical and psychiatric assessments were made at 3 and 6 months postoperatively. Eleven patients (31%) had significant psychiatric morbidity preoperatively and these had worse symptom scores and exercise tolerance compared with non-psychiatric cases, despite equivalent coronary angiographic findings and left ventricular function. Post-operatively, exercise tolerance improved equally in both groups but psychiatric cases remained significantly more symptomatic. Psychiatric morbidity remained unchanged throughout the study. We conclude that almost one third of patients with severe angina have psychiatric morbidity which is associated with a poor symptomatic response to coronary artery surgery, despite objective improvement in exercise tolerance. Ways of improving the symptomatic response to surgery in patients with coexisting psychiatric morbidity should be studied.

Adult↗
PubMed1987

Towards improved control of atrial fibrillation.

Patients with atrial fibrillation frequently show a wide variation in heart rate with digoxin therapy. We have compared the effect on heart rate variability, of doubling the digoxin dosage or adding verapamil 120 mg daily in a randomized cross-over study in 14 patients. Twenty-four hour ambulatory electrocardiographic recordings, six minute walking tests and palpitation and breathlessness scores were obtained on each regime. All patients exhibited a diurnal pattern in heart rate variability. Both treatments significantly lowered heart rate but high dose digoxin lowered minimum heart rate significantly more than digoxin and verapamil, causing more night time bradycardia. Overall, digoxin with verapamil produced significantly less heart rate variability than digoxin alone. Day time but not night time pauses were prolonged by digoxin and verapamil but were prolonged more by high dose digoxin. Five (36%) patients had serum digoxin levels in the toxic range when taking high dose digoxin. Palpitations were significantly reduced by both treatments but most improvement occurred with digoxin and verapamil. No significant effect was found on six minute walking distances or breathlessness scores. In conclusion, the addition of verapamil to digoxin was superior to increasing the dose of digoxin alone, producing significantly better control of heart rate variability with less night time bradycardia.

Aged↗
PubMed1987

Failure of a negative exercise test to reassure patients with chest pain.

Seventy-two patients with chest pain and negative exercise tests were observed. Twenty-one (29 per cent) became pain free but 51 (71 per cent) continued to complain of chest pain. Patients with persistent pain were significantly more anxious and depressed at presentation and later compared with those who had become pain free. Anxiety and particularly depression, at presentation and later, were significantly associated with severe symptoms. Patients with chest pain associated with neurosis and depression are not reassured by physiological stress testing because their physical symptoms are a feature of underlying psychiatric disease.

Adult↗
PubMed1986

Estimation of left ventricular end-diastolic pressure by pulsed Doppler ultrasound.

Left ventricular end-diastolic pressure (LVEDP) measured at cardiac catheterisation and simultaneous mitral flow patterns obtained by pulsed Doppler ultrasound scanning were assessed in twenty patients (fourteen males) with ischaemic heart disease. The ratio of passive and active components of mitral flow showed a significant linear correlation with LVEDP. Active (left atrial) mitral flow diminished as left ventricular end-diastolic pressures increased. Mitral flow ratios greater than 2 were always associated with LVEDP greater than 20 mmHg. This application of Doppler echocardiography provides a simple non-invasive method of estimating LVEDP.

Adult↗
PubMed1986

The effect of size and shape of tablets on their esophageal transit.

The esophageal transit times of small- and medium-sized barium sulfate tablets were measured using x-ray fluoroscopy in 50 patients after swallowing while in both erect and supine positions with a 15-mL drink, and the esophageal transit times of large round and oval barium sulfate tablets were similarly measured in 25 patients. When tablets were swallowed by subjects who were standing, no difference was found between the transit times of small and medium tablets, but large oval tablets had significantly shorter times than did large round tablets (P less than .04). The transit times of both small and medium tablets were significantly shorter than those of oval (P less than .05) and large round tablets (P less than .02). Retention of large oval and round tablets in the esophagus occurred in 20% of patients after swallowing while in the standing position. No medium-sized tablet was retained, but in 4% of patients, a small tablet remained in the esophagus. Tablets that were retained in the esophagus remained there for five minutes, when they were washed down by a further drink. When tablets were swallowed in the lying position, no significant differences in transit times were found between any of the four tablets. Retention of tablets within the esophagus occurred in over 60% of patients with all four tablets after ingestion while in the supine position. Tablets stuck mainly in the lower esophagus above the lower esophageal sphincter, but after swallowing in the standing position, a significant proportion (33% [P less than .01]) stuck in the upper esophagus.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗