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Biomedical subjects

J E Pohl

Publications and source records attributed to J E Pohl.

At least 19 recordsLinked to original sources
PubMed2000

Determinants of successful direct current cardioversion for atrial fibrillation and flutter: the importance of rapid referral.

Direct current (DC) cardioversion is an effective means of restoring sinus rhythm in patients with atrial fibrillation or flutter; however, the existing literature contains conflicting evidence on which factors are useful predictors of success. In a study of 171 patients undergoing DC cardioversion, we found that duration of arrhythmia prior to DC cardioversion was the only significant predictor of both successful cardioversion and subsequent maintenance of sinus rhythm (P < 0.001). Rapid DC cardioversion after the onset of atrial fibrillation or flutter significantly increases the likelihood of a successful outcome in both the short-term and long-term.

Aged↗
PubMed1996

Meteorological factors and the time of onset of chest pain in acute myocardial infarction.

Analysis of the time of onset of chest pain in 2254 patients with a myocardial infarction admitted to a coronary care unit in Leicester during a 10-year period shows an association with temperature and humidity. During both the most cold and humid times of the year, the relationship is a strong one. A generalized linear model with a log link was used to fit the data and the backward elimination selection procedure suggested a humid, cold day might help to trigger the occurrence of myocardial infarction. In addition, cold weather was found to have a stronger effect on the male population while those men aged between 50 and 70 years were more sensitive to the effect of high humidity.

Chest Pain↗
PubMed1994

Side effects with amiodarone therapy.

Amiodarone hydrochloride is increasingly being used in the treatment of ventricular and supraventricular arrhythmias. Although a highly effective anti-arrhythmic agent, its use is restricted by the high incidence of side effects. To elucidate the value of monitoring serum level of both the parent drug and its active metabolite in predicting the occurrence of side effects, the investigators examined 109 patients from a register of patients treated with amiodarone for the prevalence of known side effects of the drug. The register contained over 90% of patients treated with amiodarone at the Leicester General Hospital during the period of the study. The findings suggest cutaneous side effects and abnormal thyroid function tests (without overt gland dysfunction) are more likely to occur with increasing duration of treatment and cumulative dosage. However, neither the serum amiodarone level nor the serum metabolite level had any predictive power for the occurrence of side effects. In view of this finding, it is recommended that close attention be paid to the continued clinical monitoring of side effects and that there is utility in measuring the serum amiodarone level in each patient to avoid the prescription of unnecessarily high doses. This is necessary not only to lessen the occurrence of cumulative dose-related side effects, but also because the variable but very long half-life of the drug leads to difficulties in relating spot drug levels to long-term effects.

Aged↗
PubMed1994

A comparison of stress test referral rates and outcome between Asians and Europeans.

The Asian population is at greater risk from a myocardial infarction than their European counterparts. Fewer Asians are referred for coronary angiography. We studied referral rates for exercise stress testing following acute myocardial infarction in Asians and Europeans and also examined stress test outcome. A retrospective analysis was performed using hospital activity analysis data, ward admission book and stress test referral forms and reports. There were 962 acute myocardial infarctions with 90% being European. Fewer Asian patients were referred for stress testing (32.3% versus 45%, P < 0.001). Asian patients were more likely to have a positive test (42.9% versus 31.3%, P < 0.02). Fewer Asian patients completed the test (14.3% versus 31.3%, P < 0.001). Possible reasons for the decreased referral rates include communication difficulties and real or perceived poor exercise tolerance. More Asian patients should be referred for stress testing. Interpreters and information leaflets in multiple languages may help achieve this aim.

Aged↗
PubMed1991

Circadian variation in the frequency of onset of chest pain in acute myocardial infarction.

The time of onset of chest pain was studied prospectively in 1154 consecutive patients admitted to a coronary care unit with myocardial infarction during a five year period. Statistical analysis confirmed a previous finding in a retrospective study of a bimodal frequency distribution with peaks in the time of onset of chest pain between 2330 and 0030 hours and between 0630 and 0830 hours.

Angina Pectoris↗
PubMed1989

Temporary transvenous cardiac pacing: 6 years experience in one coronary care unit.

The role of temporary percutaneous endocardial pacing has been examined in a retrospective analysis of all paced patients admitted to one coronary care unit over a 6 year period. The majority of 162 cases (84.6%) were paced for complete heart block complicating acute myocardial infarction. These patients had a higher incidence of previous hypertension, myocardial infarction and diabetes, compared to matched controls (P less than 0.05, less than 0.02 and less than 0.001, respectively). Admission blood glucose levels were also higher (P less than 0.05). The in-hospital mortality was high (46.7%), especially for those with anterior myocardial infarction (74.5%). Twenty-five (15.4%) patients without recent myocardial infarction were paced for symptomatic brady-dysrhythmias, usually due to chronic complete heart block (Lenegre's disease) or sick sinus syndrome. Most later required permanent pacing. Complications of temporary pacing were more frequent in those who died, the most common being dysrhythmias during pacemaker insertion. Review of our cases suggests that whilst facilities for temporary pacing were extremely valuable, many cases treated were not haemodynamically compromised and probably did not require pacing. Guidelines should be established on coronary care units to prevent the unnecessary morbidity, mortality and expense of the procedure.

Adult↗
PubMed1988

Acute inotropic effects of intravenous nifedipine and its vehicle compared with saline: a double-blind study of systolic time intervals in normal subjects.

1. The inotropic effects of intravenous nifedipine and its vehicle were studied noninvasively in a double-blind placebo controlled crossover fashion using systolic time intervals in 12 normal subjects. 2. Nifedipine caused vasodilation, a fall in systolic and diastolic blood pressure, and increased heart rate. The vehicle alone caused vasodilation and decreased systolic blood pressure, without a change in heart rate. 3. Nifedipine increased left ventricular ejection time (LVET) and decreased pre-ejection period (PEP) and the ratio PEP/LVET, whereas the vehicle alone had the opposite effect. Neither treatment affected the total duration of electromechanical systole. 4. These results suggest that the vehicle has a negative inotropic effect, which is overcome by the indirect positive inotropic effect of nifedipine when they are administered together systemically.

Adult↗
PubMed1988

The haemodynamic effects of intravenous nifedipine in normotensive and hypertensive subjects.

The antihypertensive effects of intravenous nifedipine, given by bolus and 2 hour infusion, were studied at two dose levels in seven hypertensive (mean BP 178/114 mmHg) and five age-matched normotensive controls (mean BP 128/81 mmHg). Nifedipine significantly reduced systolic and diastolic blood pressure in the hypertensive patients by approximately 20%, but not in the normotensive controls. Similar changes in heart rate and forearm blood flow were seen after bolus injection in both groups, but these were not sustained during infusion. Intravenous nifedipine may be a useful acute treatment for hypertensive emergencies.

Adult↗
PubMed1987

Nifedipine infusion in acute myocardial infarction: experience in twelve patients.

Studies of nifedipine have not shown that it reduces myocardial infarct size in humans. These studies did not consider the pharmacokinetics and dynamics of nifedipine. Oral doses of nifedipine cause high plasma concentrations and possibly harmful hemodynamic changes. Intravenous nifedipine infusion can rapidly achieve and maintain a steady concentration without repeated hemodynamic upsets. We studied 24-h intravenous nifedipine infusion in 12 patients with acute myocardial infarct, starting within 6 (mean 4.0 +/- 0.7) h of onset of pain, to determine its safety, pharmacokinetics, and dynamics. An intravenous nifedipine bolus of 15 micrograms/kg was followed by an infusion of 0.9 mg/h for 24 h. After the bolus, pulse rate rose 12.5 +/- 8.0 p less than 0.01) and blood pressure fell (systolic by 20 +/- 34, p less than 0.05, and diastolic by 7.5 +/- 15.6, p less than 0.05). There were similar but lesser changes during the infusion. Myocardial oxygen requirements, as measured by the rate-pressure product, did not increase. The mean nifedipine concentration at steady state was 17.2 +/- 4.2 ng/ml and mean elimination T 1/2 3.57 +/- 2.70 h. Nifedipine was discontinued in 3 patients because of hypotension (SBP less than 90), rapid atrial fibrillation, and complete heart block in one patient each. Seven patients developed thrombophlebitis. Large studies of this preparation examining infarct size limitation and mortality are feasible, although in view of the problems of thrombophlebitis in peripheral veins, shorter infusion times or infusion via central lines would be more acceptable.

Administration, Oral↗
PubMed1987

Pharmacokinetics and pharmacodynamics of nifedipine infusion in normal volunteers.

Two studies of the pharmacokinetics and pharmacodynamics of intravenous nifedipine infusion were performed: the first, a randomised double-blind crossover study of nifedipine and its vehicle in eight subjects, the second a dose ranging study in nine subjects. Nifedipine pharmacokinetics did not vary with dose or duration of infusion up to 8 h, and are similar to those reported for other nifedipine preparations. Nifedipine increased heart rate and forearm blood flow and decreased blood pressure after bolus injection but not during prolonged infusion. The vehicle decreased blood pressure and increased forearm blood flow after bolus injection but not during prolonged infusion. It did not affect heart rate. The vehicle's haemodynamic activity has not been previously recognised and is of potential importance in the study of this and similar preparations of calcium antagonists.

Adult↗
PubMed1985

Treatment of essential hypertension: changes in blood pressure, echocardiography and electrocardiography on three therapeutic regimes.

Forty-three patients with essential hypertension were randomly allocated to one of the following treatment regimes; - atenolol, atenolol and hydralazine or methyl dopa. Blood pressure fell into the normal range at 3 months and was similar in all 3 groups. Blood pressure remained controlled over the period of study. M-mode echocardiography was assessed initially, at 3, 6 and 12 months. All groups showed a fall in the measured indices towards the normal range with a significant reduction in left ventricular wall thickness at 3 months in the methyl dopa group and left ventricular mass in the atenolol group alone of 6 months. In conclusion, no one treatment regime appeared to have sustained advantages over another and none of the groups showed any deterioration on echocardiographic criteria during the study.

Adult↗