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Biomedical subjects

O J Ormerod

Publications and source records attributed to O J Ormerod.

At least 19 recordsLinked to original sources
PubMed2006

Anomalous circumflex artery: intravascular ultrasound imaging of dynamic compression and "two wire-two vessel" percutaneous intervention.

An anomalous origin of the left circumflex is the most common congenital abnormality encountered in coronary angiography and it may selectively predispose to focal accelerated atherosclerotic disease. We report the case of a 54-year-old man who presented with non-ST elevation myocardial infarction and a characteristic retroaortic (proximal) culprit lesion in his anomalous circumflex artery. Intravascular ultrasound images illustrate the dynamic nature of the lumen compression. A "two wires-two vessel" angioplasty technique provided extra support and is recommended to facilitate successful anomalous circumflex percutaneous coronary interventions.

Angioplasty, Balloon, Coronary↗
PubMed2002

Does a selective adenosine A(1) receptor agonist protect against exercise induced ischaemia in patients with coronary artery disease?

BACKGROUND: The "warm up" effect in angina may represent ischaemic preconditioning, which is mediated by adenosine A(1) receptors in most models. OBJECTIVE: To investigate the effect of a selective A(1) agonist, GR79236 (GlaxoSmithKline), on exercise induced angina and ischaemic left ventricular dysfunction in patients with coronary artery disease. DESIGN: A double blind crossover study. PATIENTS: 25 patients with multivessel coronary artery disease. INTERVENTIONS: On mornings one week apart, patients received intravenous GR79236 10 microgram/kg or placebo, and then carried out two supine bicycle exercise tests separated by 30 minutes. Equilibrium radionuclide angiography was done before and during exercise. RESULTS: The onset of chest pain or 1 mm ST depression was delayed and occurred at a higher rate-pressure product during the second exercise test following either placebo or GR79236. Compared with placebo, GR79236 did not affect these indices during equivalent tests. GR79236 reduced resting global ejection fraction from (mean (SD)) 63 (7)% to 61 (5)% (p < 0.05) by a selective reduction in the regional ejection fraction of "ischaemic" left ventricular sectors (those where the ejection fraction fell during the first exercise test following placebo). Ischaemic sectors showed increased function during the second test following placebo (72 (21)% v 66 (20)%; p = 0.0001), or during the first test following GR79236 (69 (21)% v 66 (20)%; p = 0.0001). Sequential exercise further increased the function of ischaemic sectors even after drug administration. CONCLUSIONS: GR79236 failed to mimic the warm up effect, and warm up occurred even in the presence of this agent. This suggests that ischaemic preconditioning is not an important component of this type of protection. The complex actions of the drug on regional left ventricular function at rest and during exercise suggest several competing A(1) mediated actions.

Adenosine↗
PubMed2001

The warm-up effect protects against ischemic left ventricular dysfunction in patients with angina.

OBJECTIVES: The goal of this study was to investigate whether the "warm-up" effect in angina protects against ischemic left ventricular (LV) dysfunction. BACKGROUND: After exercise, patients with coronary disease demonstrate persistent myocardial dysfunction, which may represent stunning, as well as warm-up protection against further angina, which may represent ischemic preconditioning. The effect of warm-up exercise on LV function during subsequent exercise has not been investigated. METHODS: Thirty-two patients with multivessel coronary disease and preserved LV function performed two supine bicycle exercise tests 30 min apart. Equilibrium radionuclide angiography was performed before, during and up to 60 min after each test. Global LV ejection fraction and volume changes and regional ejection fraction for nine LV sectors were calculated for each acquisition. RESULTS: Onset of chest pain or 1 mm ST depression was delayed and occurred at a higher rate-pressure product during the second exercise test. Sectors whose regional ejection fraction fell during the first test showed persistent reduction at 15 min (68 +/- 20 vs. 73 +/- 20%, p < 0.0001). These sectors demonstrated increased function during the second test (71 +/- 20 vs. 63 +/- 20%, p = 0.0005). The reduction at 15 min and the increase during the second test were both in proportion to the reduction during the first test. Effects on global function were only apparent when the initial response to exercise was considered. CONCLUSIONS: The warm-up effect is accompanied by protection against ischemic regional LV dysfunction. The degree of stunning and protection after exercise is related to the severity of dysfunction during exercise, consistent with results from experimental models.

Aged↗
PubMed1997

Coronary stenting of unprotected left main stem stenoses in elderly patients unsuitable for coronary surgery.

We describe five patients with severe unstable angina refractory to medical management in whom coronary angiography demonstrated a severe stenosis of the left main stem. Due to severe co-existing illnesses bypass surgery was deemed inappropriate. Angioplasty to the left main stem stenosis followed by stent deployment was performed. All five patients were successfully discharged from hospital.

Aged↗
PubMed1997

Noninvasive beat-to-beat arterial blood pressure measurement during VVI and DDD pacing: relationship to symptomatic benefit from DDD pacing.

To noninvasively assess the hemodynamic effects of VVI and DDD pacing modes we measured beat-to-beat arterial blood pressure during VVI and DDD pacing in 30 patients with complete heart block (CHB), using fingertip photoplethysmography. Of these patients, 15 undertook a double-blind cross-over comparison of the symptomatic effects of VVI versus DDD pacing to determine the relationship between blood pressure changes and the occurrence of symptoms suggestive of the pacemaker syndrome during ventricular pacing. Mean (SD) systolic blood pressure was 11.7 (15.4) mmHg lower during VVI pacing compared to DDD pacing (P < 0.0005). The mean (SD) beat-to-beat variability of systolic blood pressure was 5.20 (2.87%) in VVI mode versus 2.12 (1.07%) in DDD mode (P < 0.0000005). In comparison with DDD pacing, the excess of symptoms experienced by patients during VVI pacing did not correlate with the change in mean systolic blood pressure, but was significantly correlated with the increase in beat-to-beat systolic blood pressure variation during VVI pacing (r = 0.58, P = 0.024). We conclude that noninvasive measurement of fingertip arterial beat-to-beat blood pressure is a rapid and simple method of assessing the hemodynamic effect of VVI pacing. Beat-to-beat blood pressure variability was related to symptomatic intolerance of VVI pacing and may have potential utility as an aid to diagnosis or as a predictor of pacemaker syndrome.

Aged↗
PubMed1997

Cardiac catheterisation performed by a clinical nurse specialist.

OBJECTIVE: To establish the feasibility and safety of an appropriately trained clinical nurse specialist performing diagnostic cardiac catheterisation. DESIGN: Non-randomised retrospective comparison between the first 100 and second 100 consecutive investigations by a clinical nurse specialist and 200 consecutive patients investigated by two cardiology registrars over a similar period. SETTING: Regional cardiac centre performing 3200 catheterisation procedures per annum. PATIENTS: 200 patients undergoing routine (non-emergency) cardiac catheterisation for investigation of ischaemic heart disease. MAIN OUTCOME MEASURES: Procedural complications, image quality, fluoroscopy times. RESULTS: Satisfactory diagnostic images in all nurse specialist cases with no deaths and two complications (coronary artery dissection and femoral pseudoaneurysm). Procedure duration and fluoroscopy times slightly shorter for clinical nurse specialist by 3 and 1.6 minutes, respectively (P < 0.05). CONCLUSIONS: Non-medical practitioners can be trained to perform straightforward cardiac angiography in low risk patients with consultant supervision, as for cardiology registrars. With important restrictions such posts may have a limited role in supporting future consultant based services.

Aged↗
PubMed1995

Comparison of dual chamber and ventricular rate responsive pacing in patients over 75 with complete heart block.

OBJECTIVE: To compare symptoms and exercise tolerance during dual chamber universal (DDD) and ventricular rate response (VVIR) pacing in elderly (> or = 75) patients. DESIGN: Randomised, double blind, crossover study. SETTING: Regional cardiac department. PATIENTS: Twenty elderly patients (mean age 80.5 (1) years) with high grade atrioventricular block and sinus rhythm. Patients with pre-existing risk factors for the pacemaker syndrome and chronotropic incompetence were excluded. INTERVENTION: After four weeks of VVI pacing following pacemaker implantation, patients underwent consecutive two week periods of VVIR and DDD pacing. MAIN OUTCOME MEASURES: Patient preference, symptom scores, "daily activity exercises," and perceived level of exercise (Borg score). RESULTS: Eleven patients preferred DDD mode to either VVI or VVIR mode. Mean (SE) total symptom scores during VVI, VVIR, and DDD pacing were 5.9 (1.1), 6.1 (1.0), and 3.5 (0.9) respectively (P < 0.01). The corresponding mean (SE) pacemaker syndrome symptom scores were 4.8 (0.7), 5.2 (0.8), and 2.9 (0.8) (P < 0.05). Symptom scores during VVI and VVIR pacing were not significantly different. Exercise performance and Borg scores were significantly worse during VVI pacing compared with VVIR or DDD pacing but did not significantly differ between VVIR and DDD modes. CONCLUSIONS: In active elderly patients with complete heart block both DDD and VVIR pacing are associated with improved exercise performance compared with fixed rate VVI pacing. The convenience and reduced cost of VVIR systems, however, may be offset by a higher incidence of the pacemaker syndrome. In elderly patients with complete heart block VVIR pacing results in suboptimal symptomatic benefit and should not be used instead of DDD pacing.

Aged↗
PubMed1994

Computerized analysis of ambulatory monitoring in the quantification of sinoatrial disease.

A computer program was written to allow quantitative beat-by-beat analysis of 24-h tapes acquired during standard ambulatory monitoring. Compared with a control group, subjects with sinoatrial disease were found to have significantly more tachy-brady events, more heart rate variability, more beat-to-beat variability and had fewer beats within a normal heart rate range. This technique, complementary to conventional analysis of 24-h tapes, may be useful in detecting more frequent but less severe abnormalities of heart rhythm in sinoatrial disease, strengthening the diagnostic power of ambulatory monitoring and allowing quantification of a further range of heart rhythm abnormalities.

Adolescent↗
PubMed1994

DDD vs. VVI pacing in patients aged over 75 years with complete heart block: a double-blind crossover comparison.

We studied 16 patients aged 77-88 years to determine whether elderly patients gain significant benefit from dual-chamber (DDD) compared with single-chamber ventricular demand (VVI) pacing. The study was designed as a double-blind randomized two-period crossover study--each pacing mode was maintained for 7 days. End points included: (i) overall symptoms scores; (ii) exercise tests related to daily activities; and (iii) perceived level of difficulty (Borg score). The mean symptom score in DDD mode was 7.07 (6.38) vs. 12.27 (7.29) in VVI mode (p < 0.006). Dizziness, breathlessness and fatigue were the most noticed symptoms during VVI pacing. One patient dropped out from follow-up and three patients requested early reprogramming, all from VVI mode. Overall, no patient preferred VVI mode, 11 preferred DDD mode and four expressed no preference. There were significant improvements in all objective test performances in DDD mode. Mean (SD) total Borg scores in DDD mode and VVI mode were 36.57 (5.85) and 41.93 (6.49), respectively (p < 0.002). Ventricular demand pacing in elderly patients with complete heart block is associated with higher symptom scores, reduced exercise ability and greater perceived exercise difficulty compared with dual-chamber pacing.

Aged↗
PubMed1993

Nasal continuous positive airway pressure in chronic heart failure with sleep-disordered breathing.

Nasal continuous positive airway pressure (NCPAP) has been reported to improve daytime symptoms in patients with sleep disordered breathing due to heart failure. To examine this in a controlled manner, eight men with stable chronic heart failure (mean left ventricular ejection fraction 18% and mean frusemide dose 160 mg) were entered into a controlled trial of domiciliary nocturnal NCPAP. At polysomnography (with sleep apnea quantified as the number of > 4% dips in arterial saturation per hour), seven had nocturnal Cheyne-Stokes respiration (SaO2 dip rate 3 to 27/hr), and one both central and obstructive apneas (SaO2 dip rate 8/hr). After 2 wk nocturnal domiciliary NCPAP at < 1.5 cm H2O (placebo) and 7.5 cm H2O (active) in random order, bicycle exercise tolerance and heart failure symptoms (modified Likert questionnaire) were assessed by an observer unaware of the patients' NCPAP status. Pulse oximetry (all subjects) and radionuclide estimated left ventricular ejection fraction (three subjects) were also measured at the end of each period. Two subjects withdrew from the study because of worsening heart failure during active NCPAP (7.5 cm H2O), and one of these subjects died. In the remaining six subjects exercise tolerance, symptom scores, and the severity of sleep apnea were similar on active NCPAP compared with placebo. When it was measured, resting left ventricular ejection fraction was lower on active therapy than on placebo. These data exclude a 25% improvement in exercise tolerance with 95% confidence and suggest that a study of 160 subjects would be needed to exclude a 10% change in symptom score.(ABSTRACT TRUNCATED AT 250 WORDS)

Cheyne-Stokes Respiration↗
PubMed1991

Transatrial repair of ventricular septal defect subsequent to myocardial infarction.

We describe successful transatrial repair of a ventricular septal defect occurring secondary to myocardial infarction. This approach avoids the need for ventriculotomy and may be technically simpler and safer than repair across the zone of infarction in a subset of patients with posterior defects and right ventricular dysfunction who survive the early period subsequent to their infarct.

Aged↗
PubMed1991

Does Fourier phase shift correlate with conduction delay in bundle branch block?

Fourier analysis of radionuclide ventriculography is adept at qualitatively demonstrating interventricular conduction delay in bundle branch block. In this study of eighteen patients, there is a considerable individual variation when the phase delay is expressed as an absolute conduction delay (milliseconds). Much of this variability persists after curve representation by the Fourier function has been optimized. It is suggested that this variability is due to differences in the shape of the right and left ventricular time-activity curves, reflecting differences in contraction and relaxation in the two ventricles. Such differences may be more pronounced in some subjects than others. These results suggest that absolute conduction delay cannot be reliably achieved by this method.

Bundle-Branch Block↗
PubMed1991

Preoperative silent myocardial ischaemia: incidence and predictors in a general surgical population.

We have studied before operation 156 patients aged more than 40 yr presenting for elective vascular or non-vascular surgery, using ambulatory ECG monitoring to detect silent myocardial ischaemia (SMI). The prevalence of SMI was 18.2% in the vascular group (n = 102) and 7.6% in the non-vascular group (n = 54). A history of ischaemic heart disease, or an abnormal ECG suggestive of a previous myocardial infarction, predicted a high risk of SMI (28% compared with 9% in the absence of these variables). However, a significant amount of SMI (36% of the total) occurred in patients without one of the defined risk factors. In addition, 24 of the patients with abdominal aortic disease underwent cardiac gated blood pool (MUGA) scans. Abnormal ventricular wall function was observed in 62.5% of the patients. Twenty-nine percent of the patients studied with MUGA scans had SMI and 21% had ejection fractions less than 40%. A significant association (P less than 0.05) existed between the presence of SMI and a ventricular ejection fraction of less than 40%.

Adult↗
PubMed1991

Diagnostic delay and outcome in surgery for type A aortic dissection.

Twenty-two patients with acute type A aortic dissection presented to this hospital over a three-year period. The initial diagnosis was incorrect in 12 (54.5 per cent) and in 11 of these the error occurred in peripheral hospitals before referral. This diagnostic mistake lead to a delay in surgical treatment of 2-9 days (median 5 days). Three deaths occurred without surgery, and two of these could have been considered for repair if the correct diagnosis had been made earlier. In the surgically treated group, a 30-day survival of 16 out of 19 (84.2 per cent) was achieved and the three deaths were all related to late referral. Two died because of bowel infarction and one because of respiratory failure. An increased general awareness of acute aortic dissection is necessary as early diagnosis, before the onset of irreversible ischaemic events, allows a high surgical success rate.

Acute Disease↗
PubMed1989

Haemopericardium in rheumatoid arthritis.

We report two cases of haemopericardium presenting as tamponade in patients with rheumatoid arthritis. Pericardial aspiration produced a good clinical response with no reaccumulation. We suggest that, although rare, haemopericardium can be a feature of rheumatoid disease and may be associated with significant haemodynamic disturbance.

Aged↗