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Biomedical subjects

K Jennings

Publications and source records attributed to K Jennings.

At least 55 records · Page 3Linked to original sources
PubMed1993

Measurement of cardiac output with the Quantascope, a novel Doppler device: comparison with thermodilution.

The Quantascope is a novel non-imaging echo-Doppler device designed to measure cardiac output. We have compared this device with thermodilution. Twenty-five patients with suspected coronary artery disease undergoing diagnostic coronary arteriography simultaneously had cardiac output measured with the Quantascope and with thermodilution. Doppler systematically underestimated cardiac output, when compared with thermodilution, by a mean (SD) of 0.9 (1.5) l.min-1 (P < 0.01). The cardiac output derived by the Doppler technique did not correlate with that derived by thermodilution (r = 0.36, P = NS). Compared with the currently accepted reference technique of thermodilution, we found measurement of cardiac output by the Quantascope to be inaccurate: this contradicts previous reports.

Aged↗
PubMed1993

Study of left and right ventricular function in Romano-Ward syndrome.

OBJECTIVE: To examine left and right ventricular contraction in Romano-Ward syndrome: does abnormal myocardium affect the predisposition to arrhythmia? DESIGN: Tomographic radionuclide ventriculography was performed after the red blood cells were labelled conventionally with stannous pyrophosphate and technetium-99m. SETTING: Department of Nuclear Medicine, Aberdeen Royal Infirmary. PATIENTS: Eight subjects from two families known to have Romano-Ward syndrome, four of whom (two from each family) had had symptoms. RESULTS: The five subjects from family 1 had normal left ventricular contraction; two had subtle abnormalities of right ventricular phase. in family 2 all three subjects had abnormal left ventricular contraction (reduced amplitude in three, abnormal phase in two). All had subtle abnormalities of right ventricular phase. CONCLUSION: Abnormal right or left ventricular myocardium may be partly or wholly responsible for the repolarisation changes seen on the electrocardiogram of these families or may act as an ectopic focus to start ventricular tachycardias in a susceptible heart.

Adult↗
PubMed1993

First myocardial infarction in patients under 60 years old: the role of exercise tests and symptoms in deciding whom to catheterise.

OBJECTIVE: To determine the role of exercise tests and assessment of angina in the detection of potentially threatening disease in young patients with infarcts. DESIGN: Elective readmission of patients at a mean (SD) of 60 (30) days after acute myocardial infarction for assessment of angina, treadmill exercise tests, and cardiac catheterisation. SETTING: Cardiology department of a teaching hospital. PATIENTS: 186 consecutive survivors, aged under 60 years and discharged from the coronary care unit after a first myocardial infarction. MAIN OUTCOME MEASURES: Coronary arteriography, presence of angina, result of exercise tests, and referral for revascularisation. RESULTS: 31% of patients had either two vessel disease (with proximal left anterior descending involvement), three vessel disease, or left main stem disease. 49% of all patients had angina. Of the 173 patients who had an exercise test 34% had 1 mm and 24% had 2 mm of exercise induced ST depression. Thirty percent had no angina and a negative exercise test: after a mean (SD) follow up of 16 (4) months none of this symptom free sub-group had died, had experienced a further myocardial infarction, or had been referred for revascularisation. 79% of patients with either two vessel disease (with proximal left anterior descending involvement), three vessel disease, or left main stem disease had either angina or a 1 mm ST depression during the exercise test. CONCLUSION: Patients without cardiac pain after myocardial infarction and without ST changes during an exercise do not need arteriography.

Adult↗
PubMed1993

Evidence of genetic and phenotypic heterogeneity in the Romano-Ward syndrome.

We report two families with phenotypically different forms of Romano-Ward syndrome. In one family, only five of 18 affected subjects are symptomatic, whereas in the other the proportion is three out of five. The families show distinct ECG morphologies, in addition to QT prolongation. Previous reports have shown genetic linkage either to the HLA locus on chromosome 6 or the Harvey-ras oncogene on chromosome 11. No linkage was found to either locus in the families reported here. The implications of phenotypic and genotypic heterogeneity in Romano-Ward syndrome are discussed in relation to the neurogenic and intrinsic models of pathogenesis.

Chromosomes, Human, Pair 11↗
PubMed1993

Improved detection of abnormal left ventricular wall motion using tomographic radionuclide ventriculography compared with planar radionuclide and single plane contrast ventriculography.

Tomographic radionuclide ventriculography is a technique which could have major advantages over conventional planar imaging, such as better assessment of ventricular wall motion abnormalities. This possibility was therefore investigated in 100 consecutive patients undergoing routine cardiac catheterization. Following angiography, planar blood pool images were conventionally acquired and tomographic imaging performed using the Aberdeen Section Scanner. All derived wall motion data were subsequently analysed in an objective and blinded manner. The mean age was 56 (range 33-71) and 79% were male. 67 patients had experienced prior myocardial infarction, 27 were categorized as having significant and six insignificant coronary artery disease. The detection rates for patients with prior myocardial infarction were 95% for angiography, 57% for planar imaging and 90% for tomography. Even taking patients with only prior anterior myocardial infarction, the detection rates were 94%, 63% and 91% respectively. For those residual patients with significant coronary artery disease, the rates were 7%, 0% and 59% respectively. Overall for the detection of patients with significant coronary artery disease, the sensitivity was 70%, 40% and 81% respectively. Patients with insignificant coronary artery disease did not demonstrate any abnormalities using any method. These results demonstrate that tomography and angiography have similar detection rates in the presence of significant coronary artery disease and both are superior to planar imaging.

Adult↗
PubMed1990

Association of patient delay with symptoms, cardiac enzymes, and outcome in acute myocardial infarction.

The delay between the onset of symptoms and the call for help is the longest single component of the time taken for patients with acute myocardial infarction to come under coronary care and receive thrombolytic therapy. In order to investigate factors influencing patient delay, visual analogue scores for pain, shortness of breath, and anxiety were obtained retrospectively from 250 patients with acute myocardial infarction, for the time of onset of symptoms, and for the time of the call for help. The predominant symptom was chest pain, followed by anxiety and breathlessness. Although all symptoms increased in severity after their onset, the initiation of a call was largely unexplained in terms of worsening symptoms. Patient delay had a skewed distribution with modal, median and mean values of up to 1 h, 1.5 h, and 11 h respectively. Patient delay was negatively correlated with the pain score at the time of calling, but most of the variance of patient delay could not be explained in terms of symptom scores. However, patient delay was independently and negatively related to maximum serum aspartate aminotransferase. During acute myocardial infarction, patients with higher cardiac enzyme levels experience more pain and delay less. This tendency for patients with more severe infarction and a greater risk of death to call for help sooner is an added reason for administering thrombolytic treatment at the first opportunity: those patients who call early have most to gain from prompt therapy.

Adult↗
PubMed1990

Time of occurrence, duration, and ventricular rate of paroxysmal atrial fibrillation: the effect of digoxin.

One hundred and thirty nine episodes of atrial fibrillation were identified from Holter recordings in 72 patients with paroxysmal atrial fibrillation. Paroxysms occurred more often by day than by night, suggesting that attacks are more closely associated with sympathetic than with vagal activity. In 41 patients who were not taking digoxin there were 79 episodes, and in 31 patients who were taking digoxin there were 60 episodes. Significantly more of the episodes that lasted for 30 minutes or more occurred in patients taking digoxin (13/17); the relative risk of a prolonged paroxysm associated with taking digoxin was 4.3 (95% confidence intervals 1.6-11.9). The mean (SD) ventricular rate at the onset of the paroxysms was not significantly different in those taking digoxin (140 (25) beats/min) and in those who were not (134 (22) beats/min). In paroxysmal atrial fibrillation, pretreatment with digoxin does not seem to reduce the frequency of paroxysms, or the ventricular rate when paroxysms occur, but it is associated with longer attacks.

Adult↗
PubMed1990

Six year follow up of a consecutive series of patients presenting to the coronary care unit with acute chest pain: prognostic importance of the electrocardiogram.

In a retrospective 6 year follow up data were obtained for 536 of 566 (95%) consecutive patients admitted to a coronary care unit with acute chest pain. Their diagnoses were acute myocardial infarction in 290 (54%), myocardial ischaemia in 164 (31%), pericarditis in 16 (3%), and non-cardiac in 66 (12%). Six year mortality was 36%, 24%, 0%, and 16% respectively. In patients with acute myocardial infarction a higher mortality rate during follow up was associated with a higher than average age, a higher than average creatine kinase, previous myocardial infarction, Q wave infarction, and the presence of reciprocal changes. The presence of reciprocal changes was associated with higher than average concentration of serum creatine kinase, indicating more extensive infarction. Infarction complicated by ventricular fibrillation or left bundle branch block was associated with a higher death rate. The electrocardiogram recorded at the time of acute myocardial infarction contains much useful prognostic information.

Adult↗
PubMed1989

The effects of treatment with felodipine as a single agent in coronary artery disease.

In an earlier study one dose of the vasodilator felodipine improved haemodynamic function in patients with angina without having a negative inotropic effect. The haemodynamic response of sustained treatment with felodipine as a single agent in stable angina was investigated in a double blind crossover study of 25 patients. The dosage of felodipine was increased from 5 mg twice daily to 10 mg twice daily after two weeks. Twenty one patients completed the study, two were withdrawn because of acute myocardial infarction, and a further two because of symptoms of vasodilatation. Felodipine reduced both supine and erect blood pressure and increased the resting heart rate. Median exercise time was increased by 10% at two weeks and 7% at four weeks. There was a sustained reduction in the number of angina attacks and use of sublingual nitrate on active treatment. Felodipine has antianginal effects but these are limited and seem less than those of other related compounds. This finding is unexpected and possibly related to increased heart rate.

Adult↗
PubMed1989

Low-field cine magnetic resonance imaging in aortic valve disease.

Cine magnetic resonance imaging (MRI) holds considerable promise as a means of detecting abnormal blood flow patterns with the heart and great vessels. To date, the majority of techniques employed have required moderate to high field strengths. We describe a novel, low-field-strength approach that is technically undemanding and faster than conventional methods, which we have applied to the detection of aortic valve disease. A series of 26 patients with aortic stenosis or aortic regurgitation was compared with 21 normal subjects. All 20 patients with aortic stenosis and 15 of 16 patients with aortic regurgitation were identified. There were four false positives in the aortic stenosis group; all these patients had significant aortic regurgitation. There were no false positives in the aortic regurgitation group. Low-field cine MRI is a practical and useful technique for the detection of aortic valve disease.

Adolescent↗
PubMed1987

The effect of thrombolytic therapy with anisoylated plasminogen streptokinase activator complex on the indicators of myocardial salvage.

The role of anisoylated plasminogen streptokinase activator complex (APSAC) in acute myocardial infarction, in effecting thrombolysis, in limiting infarct size and in preserving myocardial function, was assessed by comparing APSAC and placebo in a double-blind, randomised trial. Between October 1984 and April 1985, 43 patients (mean age 57.3 years) with evolving infarctions (19 anterior/24 inferior) were randomised. All patients received treatment within 3 hours of the onset of pain. Patients over 70 years of age or with contraindications to thrombolytic therapy were excluded. Response to therapy was assessed by comparing reductions in summated ECG R wave amplitude and changes in QRS score at 24 hours and 7 days in the leads with ST abnormalities on admission. Radionuclide ejection fractions (EF) were performed 2 to 6 months after infarction. Evidence of successful reperfusion was based on non-invasive parameters. Mean time to peak cardiac enzyme release was shorter in the active treatment group, indicating effective thrombolysis (11.5 hours vs 17.6 hours; p less than 0.01). No differences were found in R wave reduction or QRS score at either 24 hours or 7 days, between active and placebo groups in total or when divided by infarct site. No difference was seen between the EFs of the groups in total or between inferior infarct groups. The mean EF of the treated anterior group was higher than that of the untreated group (p less than 0.05). Successful thrombolysis was seen in the actively treated group. Evidence of myocardial salvage and preservation was seen among treated patients with anterior infarcts only.

Adult↗
PubMed1986

Detection of occult cardiac invasion by two dimensional echocardiography in patients with bronchial carcinoma.

Cardiac invasion by bronchial carcinoma may prevent successful resection but may be undetected before operation. In a retrospective analysis of 100 consecutive thoracotomies nine patients had unsuspected cardiac invasion by tumour. A prospective study of preoperative two dimensional echocardiography was therefore undertaken in patients with bronchial carcinoma who had no clinical evidence of cardiac tumour. Comparison with anatomical findings was possible in 65 patients in whom an echocardiogram of suitable quality had been obtained. There was one false negative among 55 negative echocardiograms and three false positives among 10 positive echocardiograms; non-malignant pericardial disease accounted for the echocardiographic finding in one of the latter. The predictive value of a negative test was 98%, and the predictive value of a positive test was highest (80%) if the echocardiogram suggested atrial invasion.

Carcinoma, Bronchogenic↗