Biomedical subjects
Publications and source records attributed to F G Dunn.
The publisher regrets that this was an accidental duplication of an article that has already been published in Eur. J. Echocardiogr., 4 (2003) 178-181, . The duplicate article has therefore been withdrawn.
BACKGROUND: Electrocardiographic left ventricular hypertrophy (ECG LVH) is a powerful independent predictor of cardiovascular morbidity and mortality in hypertension. OBJECTIVE: To determine the contemporary prevalence and prognostic implications of ECG LVH in a broad spectrum of patients with heart failure with and without reduced left ventricular ejection fraction (LVEF). METHODS AND OUTCOME: The Candesartan in Heart failure: Assessment of Reduction in Mortality and morbidity (CHARM) programme randomised 7599 patients with symptomatic heart failure to receive candesartan or placebo. The primary outcome comprised cardiovascular death or hospital admission for worsening heart failure. The relative risk (RR) conveyed by ECG LVH compared with a normal ECG was examined in a Cox model, adjusting for as many as 31 covariates of prognostic importance. RESULTS: The prevalence of ECG LVH was similar in all three CHARM trials (Alternative, 15.4%; Added, 17.1%; Preserved, 14.7%; Overall, 15.7%) despite a more frequent history of hypertension in CHARM-Preserved. ECG LVH was an independent predictor of worse prognosis in CHARM-Overall. RR for the primary outcome was 1.27 (95% confidence interval (CI) 1.04 to 1.55, p = 0.018). The risk of secondary end points was also increased: cardiovascular death, 1.50 (95% CI 1.13 to 1.99, p = 0.005); hospitalisation due to heart failure, 1.19 (95% CI 0.94 to 1.50, p = 0.148); and composite major cardiovascular events, 1.35 (95% CI 1.12 to 1.62, p = 0.002). CONCLUSION: ECG LVH is similarly prevalent in patients with symptomatic heart failure regardless of LVEF. The simple clinical finding of ECG LVH was an independent predictor of a worse clinical outcome in a broad spectrum of patients with heart failure receiving extensive contemporary treatment. Candesartan had similar benefits in patients with and without ECG LVH.
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AIMS: The significance of left ventricular hypertrophy in hypertension is well documented, being an independent risk factor for cardiovascular morbidity and mortality. Normal values for left ventricular mass and partition values for left ventricular hypertrophy come from measurements obtained by fundamental echocardiography. Secondary harmonic imaging improves definition of cardiac borders. We hypothesise that this overestimates left ventricular mass compared to fundamental imaging. METHODS AND RESULTS: Thirty patients had four parasternal long-axis M-modes performed, two using 1.7 mHz output frequency, receiving at two octaves higher and two using fixed frequency of 2.5 mHz (fundamental imaging). Absolute left ventricular mass and left ventricular mass index were calculated for each modality. Intra-observer variability was <7%. Range on fundamental imaging was 54-264 g/m2 compared to 80-293 g/m2 on secondary harmonic imaging. Mean left ventricular mass index for the group was 118 g/m2 (fundamental imaging) vs 147 g/m2, P<0.001. Twenty-nine of 30 patients had higher left ventricular mass index on secondary harmonic imaging compared to fundamental imaging. Left ventricular mass index was an average of 26% higher on secondary harmonic imaging, range (-7 to 65%) corresponding to average absolute left ventricular mass difference of 55 g. Eleven of 30 patients had left ventricular hypertrophy on fundamental imaging and 17/30 on secondary harmonic imaging. CONCLUSION: Secondary harmonic imaging overestimates left ventricular mass index compared to fundamental imaging. Normal left ventricular mass index range is based on equations using fundamental imaging measurements. Management decisions and prognostic implications made on the basis of raised left ventricular mass index using secondary harmonic imaging should be done so with caution.
Rapid access chest pain clinics are expanding across the country with marked resource implications despite a paucity of data regarding their efficacy. Early assessment of patients in this manner potentially delays review of patients referred via the traditional route. We conducted a prospective observational study of patients referred with chest pain to the Cardiology Outpatient Department over a four-week period in a District General Hospital to compare demographics and outcomes in patients referred to the rapid access with those referred to the general cardiology clinics. There were no significant differences in baseline demographics, exercise test result or clinic outcome. Both populations were low risk. Discussion is needed between primary and secondary care to achieve a consensus as to the purpose of a rapid access system and how best to utilise the service appropriately. Further studies are required to assess the efficacy and health economics of this system.
Atrial fibrillation (AF) is a common arrhythmia associated with increased morbidity and mortality. Current practice aims to restore sinus rhythm (SR), although the question of whether rate or rhythm control is the optimal approach for these patients remains unanswered. The most established method of restoring SR in patients with AF of duration greater than 48 hours is external direct-current cardioversion (DCC). This is a descriptive paper summarising how we utilised the hospital's day surgery unit for the provision of DCC for patients with AF in order to provide a more efficient service and allow an increased number of procedures to be conducted. We describe the reasons for setting up the service and the methods involved. We also summarise the advantages associated with this new system.
We report the first case of permanent pacing via the coronary sinus in a patient with a Bjork-Shiley tricuspid valve replacement. This may be the route of choice in this group of patients.
The objective was to prospectively validate a method of increasing the sensitivity, specificity and negative predictive value of a normal ECG in the exclusion of left ventricular systolic dysfunction by the addition of clinical history. We performed a prospective three year study of all referrals to our direct access ECHO service for assessment of LV function. The ECG was reported blind of the result of the ECHO, history of MI or not was noted, and result of the ECHO predicted. Over three years 416 patients were assessed for the presence or absence of left ventricular systolic dysfunction and consequent changes in clinical management. A total of 320(77%) of patients referred with suspected left ventricular dysfunction were found to have normal left ventricular function. Of the 250(60%) patients treated prior to referral for assessment, 183(73%) were treated inappropriately. The combination of a normal ECG and a negative history of myocardial infarction had a sensitivity of 98% and a negative predictive value of 99% in the assessment of LV function. This was an improvement over a normal ECG alone. Our study shows that diagnosis and treatment of heart failure in the community remains sub-optimal. The combination of a normal ECG and no previous history of myocardial infarction is shown to be a sensitive and accurate predictor of normal left ventricular function. If adopted by general practitioners this would be a valuable method of optimising the use of echocardiography in patients with suspected left ventricular dysfunction.
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Four hundred seventy-three patients with acute myocardial infarction (AMI) were treated with either saruplase (80 mg/hour, n = 236) or alteplase (100 mg every 3 hours, n = 237). Comedication included heparin and acetylsalicylic acid. Angiography was performed at 45 and 60 minutes after the start of thrombolytic therapy. When flow was insufficient, angiography was repeated at 90 minutes. Coronary angioplasty was then performed if Thrombolysis In Myocardial Infarction (TIMI) trial 0 to 1 flow was seen. Control angiography was at 24 to 40 hours. Baseline characteristics were similar. Angiography showed comparable and remarkably high early patency rates (TIMI 2 or 3 flow) in both treatment groups: at 45 minutes, 74.6% versus 68.9% (p = 0.22); and at 60 minutes 79.9% versus 75.3% (p = 0.26). Patency rates at 90 minutes before additional interventions were also comparable (79.9% and 81.4%). Angiographic reocclusion rates were not significantly different: 1.2% versus 2.4% (p = 0.68). After rescue angioplasty, angiographic reocclusion rates of 22.0% and 15.0% were observed. Safety data were similar for both groups. Thus, (1) early patency rates were high for saruplase and alteplase treatment, (2) reocclusion rates for both drugs were remarkably low, and (3) complication rates were similar. Thus, saruplase seems to be as safe and effective as alteplase.
Hypertension is one of the major risk factors for coronary artery disease. This risk is considerably magnified by the presence of left ventricular hypertrophy. The likeliest dominant factor in this increased risk is myocardial ischaemia, the recognition of which is of key importance. Antihypertensive agents ideally should also protect against occurrence of the clinical syndromes associated with coronary artery disease.
BACKGROUND: Electrocardiography is the fundamental investigation for decision making regarding thrombolytic treatment in acute myocardial infarction (MI). Increasing the accuracy of ECG analysis by input from consultant staff may assist in management decisions in patients with suspected MI. AIMS: To evaluate a system whereby out of hours ECGs can be faxed to the consultant to aid in decision making regarding thrombolytic treatment. METHODS: 112 patients with suspected MI were assessed on admission by the senior house officer (SHO) who faxed to a cardiology consultant the ECG trace and a predesigned form with information on: clinical assessment of the patient; interpretation of the ECG; and views regarding administration of thrombolytic treatment including choice of agent. The consultant reviewed the information and communicated his views to the SHO. Subsequent diagnosis was recorded in all patients and the forms were analysed in regard to areas of agreement and disagreement between the SHO and the consultant. RESULTS: A diagnosis of MI was confirmed in 52 of the 112 patients (46.4%). The consultant agreed with the SHO's decision on thrombolysis in 98 patients (87.5%). The reason for disagreement in the remaining 14 patients (12.5%) was SHO misinterpretation of the ECG (10 patients) and clinical assessment (four patients). Eight patients were saved unnecessary thrombolytic treatment and four received it when they otherwise would not have. Additionally the choice of thrombolytic agent was changed in six patients from streptokinase to tissue plasminogen activator. CONCLUSION: The use of fax machine assists in decision making with regard to thrombolytic treatment and provides support to junior doctors in what can be a difficult, yet critical decision.
BACKGROUND: Direct access to the coronary care unit (CCU) for general practitioner (GP) referred cases of suspected acute myocardial infarction (AMI) (fast track admission) substantially reduces the time to thrombolysis. Until now, this policy has been confined to GP referrals. OBJECTIVES: To determine the time taken to admission to CCU under the fast track policy (ambulance referrals and GP referrals) and the time taken to start administration of thrombolytics (ambulance referrals, GP referrals, and accident and emergency referrals). METHODS: Fast track admission policy was extended to include referrals from ambulance personnel who respond to emergency service calls. Ambulance personnel referred cases were also examined to see if they were referred appropriately to the CCU. RESULTS: 100 ambulance personnel referrals and 260 GP referrals to CCU with chest pain were studied. Forty accident and emergency referrals who had AMI requiring thrombolysis were also studied. In the ambulance referred group the time to admission from phone call was a median of 10 minutes (range 2 to 45), a saving of 30 minutes compared with GP referrals (median 40 minutes, range 2 to 217). The median diagnostic electrocardiogram (ECG) to thrombolysis time was longer in the accident and emergency referrals with AMI than either ambulance referrals or GP referrals admitted under the fast track policy. Diagnostic ECG to thrombolysis time: accident and emergency 50 minutes (range 15 to 385); ambulance referrals median 33 minutes (range 6 to 69); GP referrals median 29.5 minutes (range 5 to 110 minutes); (p = 0.056 accident and emergency compared with ambulance referrals, p < 0.002 accident and emergency compared with GP referrals). Of 100 ambulance referrals 52 patients exhibited symptoms suggestive of ischaemic heart disease (confirmed AMI, unstable angina, and angina) and a further 18 patients were required to stay in CCU for other cardiac problems. Thus a total of 70 (70%) were considered appropriate compared with 155 of 260 (55.8%) GP referred cases. CONCLUSIONS: Extending the fast track admission policy to ambulance personnel reduces delay to admission for patients with suspected MI without adversely affecting the appropriateness of admissions.
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Because abnormalities in hemostatic factors may in part account for the risk of stroke and thromboembolism in atrial fibrillation, we measured plasma fibrinogen and fibrin D-dimer levels in 33 patients (18 men and 15 women, mean age 60.8 +/- 1.4 years [mean +/- SEM]) with paroxysmal atrial fibrillation (PAF) and 12 patients (3 men and 9 women, mean age 51.0 +/- 4.2 years) with paroxysmal supraventricular tachycardia (PSVT). Levels of these markers were compared to levels in (1) patients with chronic atrial fibrillation; (2) hospital controls (age-matched [age +/- 5 years] and sex-matched patients in sinus rhythm with coronary artery disease and normal left ventricular function); and (3) healthy population controls in sinus rhythm. Patients with PAF had intermediate levels of median plasma fibrinogen and fibrin D-dimer when compared to patients with chronic atrial fibrillation and controls in sinus rhythm (both p < 0.001). There was no relation with atrial size or ventricular function on echocardiography. Patients with PSVT had plasma fibrinogen and fibrin D-dimer levels that were similar to the median levels of the population controls, suggesting that there was no excess in thrombogenesis. These findings are consistent with the hypothesis that atrial fibrillation is related to the increases in plasma fibrinogen and fibrin D-dimer levels. Patients with PAF have intermediate levels of these markers, a finding that is consistent with the intermediate risk of thromboembolism in such patients.
The exact mechanisms for thrombus formation in patients with valvular heart disease have not been clearly defined. Abnormalities in plasma coagulation factors indicative of a prothrombotic state may in part account for the risk of stroke and thromboembolism in such patients. The aim of this study was, therefore, to determine the effects of mitral regurgitation (MR) and aortic stenosis (AS) on plasma fibrinogen or fibrin D-dimer levels as indices of a thrombogenic (or prothrombotic) state. A total of 25 patients with valve disease in sinus rhythm were studied: 12 patients (all women; mean age fifty-five years, sem 3.3) with MR; and 13 patients (7 men, 6 women; mean age fifty-seven years, sem 3.5) with AS were studied. Patients with MR had a median plasma fibrinogen that was significantly elevated when compared with female population values (median difference 0.62 g/L; 95% confidence intervals (CI) 0.27 to 1.05, P = 0.0016). However, these patients had a median plasma fibrin D-dimer that was lower than that for population controls (median difference 21 ng/mL; 95% CI 0 to 38, P = 0.05). Patients with aortic valve disease had a median plasma fibrinogen that was significantly increased when compared with population controls (median difference 0.82 g/L; 95% CI 0.34 to 1.24, P = 0.001). These patients had a plasma fibrin D-dimer level that was similar to population values (median difference 3 ng/mL; 95% CI -25 to 22, P = 0.80). Patients with MR or AS have higher plasma fibrinogen levels when compared with "normal" population values, suggesting possible hemorheologic abnormalities in these patients. Subjects with MR had lower plasma fibrin D-dimer levels, suggesting lesser intravascular clotting, consistent with clinical echocardiographic studies. Subjects with AS had plasma fibrin D-dimer levels similar to the "normal" population values, suggestive of a different pathophysiological mechanism for thromboembolism. These findings add to an improved understanding of the relationship between clinical observations and the significance of plasma fibrinogen and fibrin D-dimer levels in thrombogenesis.