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Biomedical subjects

F Akhras

Publications and source records attributed to F Akhras.

29 records · Page 2Linked to original sources
PubMed1985

Oral labetalol in the management of stable angina pectoris in normotensive patients.

The efficacy of labetalol, an alpha and beta receptor antagonist, was evaluated in 12 normotensive patients with stable angina pectoris in a single blind dose ranging study. After a two week period of placebo treatment, labetalol was given in doses of 100, 150, 200, and 300 mg twice daily, each for two weeks. Frequency of angina attacks decreased from 9.4 (SEM 2.3)/week in the control period to 7.3 (2.8), 5.2 (2.6), 3.8 (1.8), and 3.3 (1.9)/week in the four successive treatment periods. In the same periods the number of glyceryl trinitrate tablets consumed decreased from 7.0 (2.6)/week to 5.8 (3.3), 3.9 (2.9), 2.7 (1.8), and 2.6 (2.1)/week. Maximal symptom limited treadmill exercise tests were performed three and 12 hours after dosage at each dose. Exercise tolerance (expressed as seconds of the Bruce protocol) increased from 266 (44) with placebo to 306 (44), 369 (50), 396 (48), and 413 (51) in the four treatment periods. This improvement was accompanied by a significant blunting of the heart rate and blood pressure responses to exercise. Trough point exercise tolerance did not differ significantly from that at three hours after dosage. Thus labetalol is effective as an antianginal agent at doses of 150-300 mg twice daily and is well tolerated by the normotensive patient with angina.

Adult↗
PubMed1985

Increased diastolic blood pressure response to exercise testing when coronary artery disease is suspected. An indication of severity.

One hundred and two consecutive patients with a history of chest pain or recent previous myocardial infarction underwent maximal treadmill stress testing and coronary angiography. The diastolic blood pressure response to exercise was evaluated independently of ST segment change and systolic blood pressure. In the presence of a normal systolic blood pressure response an increase in diastolic blood pressure of 15 mm Hg on at least two determinations during the same stage of exercise was considered abnormal. In 99 patients an accurate diastolic reading was possible. Of these, 61 had a normal diastolic blood pressure response; in 25 of these the ST segment was ischaemic and seven had three vessel coronary artery disease. Thirty eight patients had an abnormal diastolic blood pressure response and 27 of these had an ischaemic ST response. Of the 11 with a negative ST response for ischaemia one had left main stem disease, seven three vessel disease, and three two vessel disease. Patients with an abnormal diastolic response had greater ST depression with more angina at a reduced workload than those with a normal diastolic response. In patients with chest pain an abnormal increase in diastolic blood pressure on exercise reflects severe coronary artery disease. Although no false positives occurred in this study there was an appreciable number of false negatives (sensitivity 46%) in both patients with chest pain and those with infarction. An abnormal diastolic response therefore represents a useful additional diagnostic indicator of coronary artery disease when the ST segment response is normal or borderline. When the diastolic pressure becomes increased with or without ST changes the likelihood of severe coronary artery disease is increased.

Blood Pressure↗
PubMed1985

Isosorbide-5-mononitrate--effective monotherapy in chronic stable angina.

Isosorbide-5-mononitrate (ISMN) is not subject to first-pass metabolism and has more predictable blood concentrations than isosorbide dinitrate. In order to evaluate its efficacy as monotherapy in patients with chronic stable angina, 14 patients were studied. All had angiographically proven coronary artery disease and were limited by angina on a treadmill exercise test. After a 2-week placebo period ISMN was administered in a single-blind fashion with the dosage being titrated at 2-week intervals. The dosage increments were 20 mg once daily, 20 mg twice daily, 40 mg once daily and 40 mg twice daily. Patients were assessed subjectively by anginal attack rate and glyceryl trinitrate (GTN) consumption and objectively by treadmill exercise testing at 12 hours post dosage. ISMN increased the exercise ability significantly on all dosage regimes. However, a significant reduction in ST depression occurred only with the twice-daily regime. The increased exercise performance was associated with a significant decrease in anginal attack rate and GTN consumption from the 20 mg b.i.d. increment. ISMN is an effective antianginal agent with a more favourable profile in twice-daily dosage. Whilst no significant differences emerged between 20 mg and 40 mg twice daily, individual variation occurred, indicating a need for dosage flexibility.

Administration, Oral↗
PubMed1984

Early exercise testing and elective coronary artery bypass surgery after uncomplicated myocardial infarction. Effect on morbidity and mortality.

One hundred and nineteen consecutive patients were studied prospectively after uncomplicated myocardial infarction by maximal exercise electrocardiography at two weeks and coronary angiography at six weeks. At angiography 87 patients had a stenosis greater than 70% in one major coronary artery supplying residual viable myocardium outside the infarction zone. In 82 (94%) of these the 12 lead maximal exercise electrocardiogram correctly identified these areas of ischaemic but viable myocardium. Based on ST criteria alone five patients had a false negative exercise electrocardiogram for additional disease. Nevertheless, three developed angina or a significant fall in systolic blood pressure or both at a low workload. On the basis of the anatomical lesions, symptoms, and the results of the European Coronary Surgery Study Group 55 patients were allocated for surgery. Of these, 54 underwent coronary artery bypass grafting within three months of myocardial infarction. One patient died perioperatively and another died after a reinfarction at four months while awaiting surgery. The remaining 53 were symptom free during a mean follow up period of 37 months. Sixty four patients received medical treatment. At angiography 32, 24, and eight patients had one, two, and three vessel coronary disease respectively. The exercise electrocardiogram correctly predicted the anatomy in 60 (94%), with two false positive and two false negative results for additional disease. The eight patients with three vessel disease treated medically had generalised inoperable disease, and at follow up three had died after a further infarction and five remained symptomatic with full medical treatment. Thus of those designated as at high risk and considered suitable for surgery the 37 month survival was 53 or 54 patients treated surgicall7y.

Adult↗
PubMed1983

The appropriate dosage regime for the transition from intravenous lignocaine to oral tocainide after acute myocardial infarction.

To define the appropriate regime for the transition from intravenous lignocaine to oral tocainide after uncomplicated acute myocardial infarction, 43 patients received lignocaine to steady state. Each patient then received a tocainide dosage schedule. Plasma concentration of lignocaine and tocainide was measured frequently until the third peak plasma tocainide level. Tocainide 400 mg 8 hourly starting 4 h before cessation of lignocaine and tocainide 400 mg 4 hourly starting at the end of the infusion produced therapeutic plasma tocainide concentration (3.5-9 mg/l) only after the second dose. Tocainide 600 mg 12 hourly starting 6 h before cessation of lignocaine and tocainide 600 mg 6 hourly starting at the end of the infusion quickly achieved therapeutic plasma tocainide concentration which declined to give subtherapeutic first dose troughs of 2.42 mg/l (+/- 0.28 SEM) and 2.79 mg/l (+/- 0.27 SEM) respectively. Consistently therapeutic plasma tocainide concentrations were achieved by both of these regimens after the second dose. The short plasma half-life of lignocaine which for these regimes was 3.71 h (+/- 0.25 SEM), resulted in subtherapeutic lignocaine concentrations before consistently therapeutic plasma tocainide concentrations had been achieved. On the basis of these results, the 600 mg 6 hourly tocainide dosage schedule was studied with cessation of lignocaine infusion either two or six h after the first tocainide dose. With the former regime only three of 5 patients had therapeutic lignocaine at the subtherapeutic tocainide trough.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMed1983

Traumatic right coronary artery--right atrial fistula.

Traumatic coronary artery fistulae and intracardiac shunts due to penetrating wounds of the heart are rare, with only 19 reported cases in the literature. The communication, which may involve one or both coronary arteries, is classified into two major types depending on whether the drainage is into the left or right heart. We report a right coronary artery (RCA) right atrial fistula (RA) secondary to shrapnel injury in 1944.

Angina Pectoris↗
PubMed1982

Early exercise testing and coronary angiography after uncomplicated myocardial infarction.

In a prospective study 61 patients aged 55 years or less with uncomplicated myocardial infarction underwent treadmill stress testing at two weeks and coronary angiography at six weeks after infarction. Of the 44 patients who had a positive stress test, 43 had additional severe coronary artery disease confirmed by coronary angiography. Of the 17 patients who had a negative stress test for additional disease, coronary angiography identified only single-vessel disease in the infarct area in 15. The sensitivity of the stress test was 95% and the specificity 94%, though the number of patients in the study was small. Thus, exercise testing has considerable potential for the early identification of multiple-vessel disease in patients with uncomplicated myocardial infarction.

Coronary Angiography↗
PubMed1981

The relationship between QT interval and heart rate during physiological exercise and pacing.

Conventional doctrine states that the QT interval is related to heart rate in an inverse exponential relationship, so that with increasing rate the QT interval shortens. This relationship has recently been studied in a group of patients undergoing physiological exercise stress tests, atrial pacing stress test, and in a further group of patients with complete heart block undergoing exercise at a fixed ventricular rate controlled by cardiac pacemaker. Examinations of recordings made during physiological exercise do show the expected shortening in QT interval, we believe that this shortening is only in part due to the intrinsic effect of increased rate as patient who were atrially paced to similar rates and within the same age group showed only a small decrease in measured QT interval and patients undergoing exercise at fixed ventricular rate showed shortening in QT interval which was related to the independent atrial rate. It appears, therefore, that the QT interval is governed mainly by extrinsic factors and not intrinsically rate related. The physiological control of QT interval is being used now to construct a cardiac pacemaker which senses the interval between the delivered stimulus and the evoked T wave so that the stimulus-evoked T wave interval could be used to set the subsequent escape interval and subsequently the overall pacing rate. Physiological control of cardiac pacing rate using conventional unipolar lead systems and independent of atrial activity is possible and currently being investigated.

Cardiac Pacing, Artificial↗
PubMedDate not supplied

The long-term safety and tolerability of transdermal glyceryl trinitrate, when used with a patch-free interval in patients with stable angina.

The safety and tolerability of intermittent (16 hours on/8 hours off) nitrate patch therapy (0.2, 0.4 or 0.6 mg/hr: dose adjusted as required) was studied for a median duration of 356 days in 106 patients (mean age 60.9 +/- 8.6 years) with angina pectoris. Most patients (82%) were on existing beta-blocker and/or calcium antagonist therapy. Safety, tolerability and efficacy data were obtained by means of patient diary cards and regular clinic visits. Almost 90 treatment years revealed no significant or serious adverse events, and there were no changes in haematology or biochemistry associated with intermittent nitrate patch therapy. The most frequently reported side-effects were headache, skin reactions and dizziness (53%, 20% and 8% of patients respectively). Treatment resulted in a sustained reduction in the frequency and severity of angina attacks, reduced sublingual GTN consumption, an improvement in general wellbeing and a rise in the proportion of patients in whom angina was controlled.

Administration, Cutaneous↗