Quality of life of cancer patients.
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Humans↗
Biomedical subjects
D W Davies
Publications and source records attributed to D W Davies.
High-risk coronary angioplasty with elective intra-aortic balloon pump support.
Percutaneous transluminal coronary angioplasty was attempted with elective percutaneous intra-aortic balloon pump support in 21 patients (mean age 60 years, range 40-82; 18 males) with unstable angina (n = 2), multivessel coronary disease requiring multivessel angioplasty (n = 2), severe left ventricular dysfunction (ejection fraction 10-30%; n = 16) or ventricular fibrillation at diagnostic angiography (n = 1). Fourteen patients had 3-vessel disease (1 with vein grafts also diseased), 6 had 2-vessel disease and 1 had isolated left anterior descending disease. Twenty-five procedures were performed (one in 18 patients, two in 2 patients and three in one patient) on 42 lesions in 34 vessels/grafts. There was no angioplasty-related death. Successful dilatation was achieved in 38/42 lesions (90%) in 21/25 procedures (84%) without major complication. Three procedures were complicated: one by major coronary dissection without sequelae, one by haemodynamic deterioration due to distal occlusion and one by an unstable residual stenosis in the attempted vessel necessitating urgent bypass surgery. The only complication related to the intra-aortic balloon pump was local haematoma in 2 patients. In conclusion, elective intra-aortic balloon pump support may be safely used to stabilise high-risk patients undergoing coronary angioplasty, leading to a satisfactory primary success rate.
Adult↗
Cultured human granulosa cells as a model for corpus luteum function: relative roles of gonadotrophin and low density lipoprotein studied under defined culture conditions.
In primates, corpus luteum development involves both gonadotrophin stimulation and exposure to low density lipoprotein (LDL) delivered through vascularization of the granulosa cell-derived layer. These regulatory influences were modelled in vitro using granulosa cells obtained during in-vitro fertilization (IVF) cycles controlled with gonadotrophin releasing hormone (GnRH) analogue, human menopausal gonadotrophin (HMG) and human chorionic gonadotrophin (HCG). Granulosa cells were cultured in defined medium on extracellular matrix. Without gonadotrophin or LDL in the medium, progesterone production declined progressively. With LDL alone, there was a short-lived elevation of progesterone output which subsequently declined. Culture with HCG alone resulted in a relatively unchanged rate of steroid production over 5 days despite morphological development. This contrasted with a marked and sustained increase in progesterone output over the same time when granulosa cells were cultured with combined HCG/LDL. Cultures were challenged with combined HCG/LDL on day 5. Where initial incubation included HCG, the challenge resulted in a recovery of progesterone output to values comparable to those of granulosa cells exposed to continuous HCG/LDL. Initial incubation without gonadotrophin led to a reduced response. Results suggest that LDL delivery to granulosa cells of the early corpus luteum causes a short-lived period of progesterone production. Sustained luteinization of granulosa cells and maintenance of gonadotrophin responsiveness requires continued exposure to gonadotrophin in the luteal phase.
Cells, Cultured↗
The detrimental influence of functional ovarian cysts during in-vitro fertilization cycles.
Reviewing 780 in-vitro fertilization (IVF) cycles, where buserelin was commenced in the preceding luteal phase and human menopausal gonadotrophin on day 4 of the ensuing menses, 53 cycles were identified with sonolucent cysts (30-50 mm diameter). Of the latter 53 cycles, the serum oestradiol was significantly greater on day 4 in 22 cycles abandoned for poor follicular development than in 31 cycles which proceeded to oocyte retrieval (P less than 0.05). Of the 31 cycles proceeding to oocyte retrieval, nine had a day 4 serum oestradiol greater than 200 pmol/l (95th centile for day 4 oestradiol in patients without apparent cysts), and these cycles produced significantly fewer grade 1 embryos than the cycles with day 4 oestradiol levels less than or equal to 200 pmol/l (P less than 0.05). Six of the 53 cycles with cysts resulted in conception, and all of these cycles had a day 4 serum oestradiol less than 200 pmol/l. Among the 53 cycles with ovarian cysts, the serum progesterone on the day of abandonment in four cycles and on the day of human chorionic gonadotrophin administration in one non-abandoned cycle, was above the range established for 104 cycles without cysts. No significant difference was seen in day 4 serum androstenedione levels, and the day 4 serum progesterone was less than 5 nmol/l in all but one patient. Functional activity of ovarian cysts is associated with an adverse influence on IVF cycles.
Androstenedione↗
Is VVI pacing outmoded?
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Cardiac Pacing, Artificial↗
Topical anaesthesia of the larynx: cocaine or lignocaine?
A double-blind, randomized study compared the cardiovascular responses and extubation conditions using lignocaine or cocaine for topical anaesthesia of the larynx. Absorption of both agents from the trachea was quantified by serial venous plasma concentrations. Serial blood pressure, ECG, O2 saturation and end-tidal carbon dioxide measurements were obtained. Conditions at extubation were assessed on duration of coughing, graded on a scale of 1-4 (1 = no coughing, 2 = single cough, 3 = coughing lasting less than 30 s, 4 = coughing lasting 30 s or more). No difference was found in cardiovascular measurements between the two groups. The patterns of absorption of cocaine and lignocaine from the laryngeal mucosa were very similar, with peak absorption occurring at 10-15 min after laryngeal spraying. Although cocaine reduced the incidence of post-operative coughing when compared with lignocaine, this did not reach statistical significance.
Absorption↗
The role of surgery in the management of solitary coronary artery aneurysm.
A 55-year-old lady presenting with angina was diagnosed on angiography as having a solitary aneurysm of a lateral circumflex artery. She underwent clipping of the aneurysm and a long saphenous vein bypass graft to the distal vessel. The role of surgery in the management of coronary aneurysms is discussed.
Angina Pectoris↗
Lack of placental protein 14 production in pregnancy after frozen embryo transfer, down-regulation of anterior pituitary and administration of exogenous oestradiol and progesterone.
The circulating levels of placental protein 14 (PP14) and progesterone were measured in three pregnancies resulting from the transfer of cryopreserved embryos. Two of these women had suppressed ovarian activity as a result of pituitary down-regulation with the luteinizing hormone-releasing hormone agonist (buserelin) prior to treatment with exogenous oestradiol and progesterone. After 14 days of oral oestradiol treatment and if the endometrial thickness was greater than 7 mm, progesterone was given intramuscularly for a further 14 days with embryo transfer on the third day of this treatment. On confirmation of pregnancy by human chorionic gonadotrophin analysis, progesterone administration was altered to transvaginal pessaries for maintenance of adequate progesterone levels and endometrial support. In the two women with ovarian suppression, PP14 levels remained below the 2.5th centile of the normal range for pregnancy. In the third pregnancy, embryo transfer was performed 3 days after a spontaneous luteinizing hormone surge in a normal menstrual cycle. In this pregnancy, PP14 levels were within the normal range. Ultrasonic examination confirmed three normal ongoing singleton pregnancies. These results suggest that the majority of PP14 production in normal pregnancy is under ovarian or anterior pituitary control and that the influence of progesterone is of a secondary nature.
Buserelin↗
Comparison of 'poor' responders with 'good' responders using a standard buserelin/human menopausal gonadotrophin regime for in-vitro fertilization.
This study identifies a group of 87 patients, who demonstrated a 'poor' response to a standard buserelin/human menopausal gonadotrophin (HMG) regime. The subsequent outcome in 61 of these 'poor' responders when treated with a higher dose of HMG to achieve a satisfactory response was compared with 250 patients, who showed a 'good' response to the standard regime. 'Poor' responders were significantly older than 'good' responders (P less than 0.001), but no significant difference was demonstrated in the indication for in-vitro fertilization (IVF). Even on higher doses of HMG, 'poor' responders took longer for their follicles to achieve maturity than the 'good' responders (P less than 0.01). 'Poor' responders produced 8.9 oocytes per oocyte collection compared to 11.8 in the 'good' responders (P less than 0.01). The fertilization rate was significantly lower in the 'poor' responders compared to the 'good' responders (P less than 0.01). Although there was no significant difference in morphometric grading between 'poor' responder embryos and 'good' responder embryos, the rate of cell division was significantly slower in embryos of the 'poor' responders than the 'good' responders (P less than 0.01). The pregnancy rate per oocyte retrieval was 9% in the 'poor' responders compared to 29% in the 'good' responders (P less than 0.01). The implantation rate in the 'poor' responders was 4.4% compared to 16.1% in the 'good' responders (P less than 0.001).
Adult↗
Biochemical monitoring during hormone replacement therapy cycles for transfer of cryopreserved embryos in patients with functional ovaries.
Biochemical monitoring was undertaken in 22 treatment cycles for women with normal ovarian function who underwent pituitary suppression with buserelin and administration of exogenous oestradiol (E2) and progesterone (P) for cryopreserved embryo transfer (ET). Eighteen transfers of 1-4 thawed embryos, on the third day of exposure to progesterone, resulted in five clinical pregnancies (27.8%) and one biochemical pregnancy. There was no difference between pregnant and non-pregnant patients in the number and quality of embryos transferred, age, weight or infertility diagnosis. Serum E2 level from days 10-17 (the late proliferative phase) of the therapy cycle were significantly higher in the pregnant group compared with the non-pregnant group (P less than 0.05--P less than 0.005). There were no significant differences in P levels between the two groups from the onset of progesterone administration to the end of the cycle. However, as might be expected, the mean E2/P molar ratio in the pregnant group was significantly higher at the time of ET (P less than 0.02). It is concluded that biochemical monitoring during the embryo replacement cycle is necessary to tailor drug dosages for individual requirements to achieve adequate E2 levels before ET. Alternative routes of oestradiol administration need to be considered in patients with poor E2 profiles.
Buserelin↗
Automatic recognition of ventricular arrhythmias using temporal electrogram analysis.
Future antitachycardia devices must be able to deliver a variety of therapies according to the requirements of the underlying arrhythmia. To ensure that appropriate treatment is prescribed the device must use a detection algorithm that is able to discriminate between multiple arrhythmias. Current criteria such as rate, change of rate, duration at high rate, and high rate stability are inadequate for this purpose. Many algorithms that evaluate the morphology of the endocardial electrogram are of too great a complexity to be incorporated in implantable devices that require real-time analysis without undue power consumption. In this study the sensitivity of a simple morphological technique (temporal electrogram analysis) is examined. The method sets threshold 'rails' above and below the isoelectric line and classifies ECG complexes according to the sequence and duration of rail excursions. A total of 27 ventricular tachyarrhythmias were induced in 25 patients (17 with a history of recurrent arrhythmias and eight undergoing risk stratification postmyocardial infarction). Temporal electrogram analysis (TEA), initially detected the onset of the ventricular arrhythmia in all patients whose surface ECG showed polymorphic or right bundle branch block pattern tachycardia, in 5/8 of cases with left bundle branch block pattern and in 4/5 of patients with concordant complexes across the precordial leads. After minor modifications the overall sensitivity of the method was improved to 95% (26/27 arrhythmias detected). TEA is a technique of low computational demands, which in this study, reliably discriminated between resting sinus rhythm and ventricular arrhythmias.
Adult↗
Recognition of multiple tachyarrhythmias by rate-independent means using a small microcomputer.
New implantable devices are now available that can offer different therapies for different arrhythmias but they need a method of discriminating between these rhythms. Heart rate analysis is predominantly used to discern between sinus rhythm (SR) and pathological tachycardias but this may be of limited value when the rates of the rhythms are similar. An enhanced form of Gradient Pattern Detection (GPD) has been developed using an 8-bit microcomputer that can distinguish between SR and up to three other arrhythmias in real time. This is a method based on electrogram morphology where each rhythm's specific electrogram is classified by a sequence of gradient 'zones'. The microprocessor of the computer is of similar processing power to ones used in current pacemakers. Five patients with multiple arrhythmias were studied. Four had ventricular tachycardia (VT) and one had three conduction patterns during supraventricular tachycardia (SVT). Bipolar endocardial right ventricular electrograms were recorded during SR and tachycardia in all patients. The computer would first 'learn' about each different rhythm by a semi-automatic means. Once all the rhythms were learned the program would enter the GPD analysis phase. The computer would output a series of real-time rhythm specific marker codes onto a chart recorder as it recognized each rhythm. Sixteen different arrhythmias (13 VT, 3 SVT) were examined for this study. All rhythms (including SR) were distinguished from each other except in the case of one patient with six VTs where two VTs had identical shapes and therefore could not be detected apart. The method would be a useful addition to heart rate analysis for future generations of microprocessor assisted pacemakers.
Algorithms↗
Extensive endocardial resection for recurrent ventricular tachyarrhythmias.
Twenty-two consecutive patients underwent elective map-guided extensive endocardial resection (EER) for recurrent ventricular tachyarrhythmias (VT) of whom 20 were male. The ages ranged from 43 to 74 years (mean 57). All arrhythmias were ischaemic in origin. The mean ejection fraction was 29%. The presenting arrhythmias were ventricular tachycardia in 14, ventricular fibrillation (VF) alone in 1 and ventricular tachycardia and VF in 7. Useful additional intraoperative mapping was obtained in 19 patients. Under cardioplegic arrest, the scarred left (22) and where indicated right (4) ventricular endocardium was extensively resected. Resection of scarred papillary muscles was avoided and where indicated, localised cryoablation was performed: 21/22 had concomitant aneurysmectomy and/or coronary artery bypass grafting. There was 1 (4.5%) operative death. All survivors (95.5%) underwent postoperative electrophysiological studies at around 1 week. None had inducible arrhythmias. There were 3 (13.5%) late cardiac deaths, all due to primary cardiac failure without recurrence of arrhythmia. Of 17 (77%) long-term survivors, 16 (94%) are VT-free on no anti-arrhythmic medication at a mean follow-up of 37.2 months. One developed a new arrhythmia at 1 year which is controlled on medication. EER offers a high rate of success in ablating VT in association with a low operative mortality and good prospect of VT-free long-term survival.
Adult↗
An acute study of the electrophysiological and haemodynamic effects of intravenous UK-52,046, a novel alpha 1-adrenoceptor antagonist.
The acute electrophysiological and haemodynamic effects of UK-52,046, a novel alpha 1-adrenoceptor antagonist (0.5 microgram kg-1) were studied in 10 patients. Resting and paced conduction intervals, refractory periods, Wenckebach cycle length and sinus node recovery time were measured and compared with baseline values. Haemodynamic measurements including cardiac output were measured before and after drug administration. Changes in QRS interval (83 to 105 ms) and QRS duration during sinus rhythm (83 to 105 ms) or during constant atrial pacing (85 to 109 ms), were not significant (P greater than 0.05). Myocardial refractoriness and sinus node recovery time were not altered by the drug. Slight increases in mean heart rate (72.5 to 78.8 beats min-1), mean right atrial pressure (4.5 to 5.5 mm Hg) and mean cardiac output (5.4 l min-1 to 5.7 l min-1), were not significant (P greater than 0.05). Systolic and diastolic arterial pressure, cardiac work indices, and vascular resistance remained unchanged. These results demonstrate the safety of this drug given intravenously in a non-ischaemic setting, and warrant its further investigation as an antiarrhythmic agent in myocardial ischaemia.
Adrenergic alpha-Antagonists↗
Simultaneous intrauterine and cervical pregnancies after in vitro fertilization and embryo transfer in a patient with a history of a previous cervical pregnancy. Case report.
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Adult↗
Clinical cardiac electrophysiologic evaluation of the positive inotropic agent, DPI 201-106.
DPI201-106 is a new positive inotropic agent. The cardiac electrophysiology of 16 patients was studied before and during DPI 201-106 administration (loading dose of intravenous DPI 201-106, 1.8 mg kg-1 h-1 administered over 10 min, followed by a maintenance dose of 0.2 mg kg-1 h-1). DPI 201-106 had no effect on the sinus node. The AH interval during fixed-rate atrial pacing became prolonged during DPI 201-106 infusion. There was a significant prolongation of the QT interval [QT (corrected), 417 +/- 22 to 502 +/- 35 ms, P less than 0.05; QT (atrial pacing at 600 ms), 374 +/- 17 to 419 +/- 23 ms, P less than 0.05; QT (ventricular pacing at 600 ms), 409 +/- 37 to 449 +/- 30 ms, P less than 0.05]. The ventricular effective refractory period significantly prolonged during DPI 201-106 administration (242 +/- 21 to 287 +/- 56 ms, P less than 0.05), but the supernormal-period duration decreased. The atrial effective refractory period was shortened in four patients and prolonged in one (261 +/- 67 to 240 +/- 53 ms, NS). The corrected atrial repolarization time (PTac) shortened significantly during DPI 210-106 infusion (479 +/- 26 to 445 +/- 22 ms at 20 min of the maintenance dose, P less than 0.05). Atrial fibrillation was initiated in five patients during DPI infusion, but no ventricular arrhythmia was provoked. These findings suggest that DPI 201-106 has novel differential electrophysiological effects on atria and ventricles.
Adolescent↗
Modification of the DDD pacing mode to prevent junctional reentry tachycardia: computer modelling experiments.
This paper examines the possibility of using short atrioventricular (AV) delay dual chamber pacing to prevent junctional reentry tachycardia mediated by an accessory pathway or by an intra-AV nodal circuit. For this purpose, a clinically realistic computer simulation model of cardiac rhythm and heart-pacemaker interactions has been used. The computational experiments compared the actions of two pacemaker models: (A) a clinically realistic DDD mode operating with quasi-Wenckebach prolongation of the AV delay; and (B) a new modification of the DDD mode introducing independent counters for the atrial and ventricular refractory periods of the heart, and the possibility of instantaneous or shortly delayed atrial pacing triggered by a sensed or paced ventricular event. The pathological phenomena modelled in the experiments simulate different possibilities of tachycardia initiation. These disorders include: (1) single atrial premature beats (APBs), (2) salvos of APBs, (3) closely coupled pairs of APBs, (4) ventricular premature beats initiating an antidromic reentry tachycardia, and (5) ventricular ectopic beats initiating an AV nodal reentry tachycardia. The computational results prove that many possible mechanisms of initiation of junctional reentry tachycardia are beyond the prophylactic capabilities of current sophisticated DDD pacemakers (A). The results also show that the suggested pacing mode (B) improves anti-tachycardia prophylaxis even when responding to complex pathological episodes of the natural cardiac activity. Future development of the suggested mode (B) is discussed.
Atrioventricular Node↗
Duration of action of tiapamil in stable exercise induced angina.
The duration of action of tiapamil was assessed in ten patients with stable exertional angina. Maximal symptom-limited treadmill exercise electrocardiography was performed before and at 1, 3, 6 and 9 h after therapy. Significant differences were only found at 1 h after tiapamil with increases in mean exercise duration (312 vs 399 s), the time to onset of angina (221 vs 310 s) and exercise work load (5.9 vs 7.3 METS). Tiapamil had no significant effect on the exercise heart rate but increased the resting heart rate by 6 beats/minute. The resting systolic blood pressure fell by 17 mmHg (p less than 0.01), and the diastolic blood pressure by 14 mmHg. Exercise systolic and diastolic blood pressures fell by 19 and 17 mmHg respectively. Side-effects were short-lived and attributable to vasodilatation. Tiapamil is effective for the relief of angina with minimal side-effects, but its duration of action is short. For effective chronic oral use, a sustained release preparation is required.
Adult↗