Identification of the need for pharmaceutical care within the prevention strategy of CHD: a study in acute MI patients

Focal points

Effect of moderate walnut consumption on lipid profile, arterial stiffness and platelet activation in humans

Background/Objectives

A large intake of walnuts may improve lipid profile and endothelial function. The effect of moderate walnut consumption is not known. We investigated whether a moderate intake of walnuts would affect lipid profile, arterial stiffness and platelet activation in healthy volunteers.

Subjects/Methods

Thirty healthy males were recruited into a single-blind randomised controlled crossover trial of 4 weeks dietary walnut supplementation (15 g/day) and 4 weeks control (no walnuts). Arterial stiffness was assessed using pulse waveform analysis to determine the augmentation index and augmented pressure. Platelet activation was determined using flow cytometry to measure circulating platelet-monocyte aggregates.

Results

There were no differences in lipid profile after 4 weeks of walnut supplementation compared with control. Dietary intake of alpha-linolenic acid was increased during the walnut diet (2.1±0.4 g/day versus 0.7±0.4 g/day, P<0.0001). There were no differences in augmentation index or augmented pressure during walnut supplementation. Walnut supplementation did not affect platelet-monocyte aggregation .

Conclusions

Dietary intervention with a moderate intake of walnuts does not affect lipid profile, arterial stiffness or platelet activation in man. Our results suggest that the potentially beneficial cardiac effects of walnuts may not be apparent at lower and more practical levels of consumption.

Treating ST elevation myocardial infarction by primary percutaneous coronary intervention, in-hospital thrombolysis and prehospital thrombolysis. An observational study of timelines and outcomes in 625 patients

OBJECTIVE

To describe the effects of implementing of a percutaneous coronary intervention (PPCI) service and compare the distribution of reperfusion therapies 12 months pre and post introduction of PPCI.

DESIGN

Observational study with data collected 12 months pre and post-availability of Primary PCI as routine treatment.

SETTING

Lothian region in South-East Scotland. Patients 625 Patients who received reperfusion treatment between December 2005 and November 2007.

RESULTS

PHT was given to 96/328 patients (29%) prior to availability of PPCI as routine treatment. Following routine availability, PPCI was delivered to 248/297 patients who received reperfusion treatment (84%). Median diagnosis-to-PCI balloon inflation time and hospital door-to-balloon time were 84 and 54 min, respectively. Patients received PPCI balloon inflation within 90 min of diagnosis in 60% of cases. PPCI-related delay was 74 min compared with prehospital thrombolysis (PHT). PHT (152 min) and PPCI (166 min) had shorter symptom onset-to-assessment of reperfusion times than in-hospital thrombolysis (IHT) (226 min).

CONCLUSIONS

More than two-thirds of the total-ischaemic-time in (ST-segment elevation myocardial infarction) STEMI occurs before the patient reaches hospital, with less than one-third being accounted for by door-to-needle (IHT) or door-to-balloon (PPCI) time. The magnitude of difference in the time between symptom onset-and-assessment of reperfusion treatment efficacy is short and should be considered, particularly in patients treated with thrombolysis in hospitals without cath-lab facilities. Optimal reperfusion treatment including a combination of PHT, IHT and PPCI, as recommended in international guidelines, is feasible in the UK although the balance between the use of different treatments will differ between urban and rural areas.

Acute cardiovascular effects of apelin in humans: potential role in patients with chronic heart failure

BACKGROUND

Apelin, the endogenous ligand for the novel G protein-coupled receptor APJ, has major cardiovascular effects in preclinical models. The study objectives were to establish the effects of acute apelin administration on peripheral, cardiac, and systemic hemodynamic variables in healthy volunteers and patients with heart failure.

METHODS AND RESULTS

Eighteen patients with New York Heart Association class II to III chronic heart failure, 6 patients undergoing diagnostic coronary angiography, and 26 healthy volunteers participated in a series of randomized, double-blind, placebo-controlled studies. Measurements of forearm blood flow, coronary blood flow, left ventricular pressure, and cardiac output were made by venous occlusion plethysmography, Doppler flow wire and quantitative coronary angiography, pressure wire, and thoracic bioimpedance, respectively. Intrabrachial infusions of (Pyr(1))apelin-13, acetylcholine, and sodium nitroprusside caused forearm vasodilatation in patients and control subjects (all P<0.0001). Vasodilatation to acetylcholine (P=0.01) but not apelin (P=0.3) or sodium nitroprusside (P=0.9) was attenuated in patients with heart failure. Intracoronary bolus of apelin-36 increased coronary blood flow and the maximum rate of rise in left ventricular pressure and reduced peak and end-diastolic left ventricular pressures (all P<0.05). Systemic infusions of (Pyr(1))apelin-13 (30 to 300 nmol/min) increased cardiac index and lowered mean arterial pressure and peripheral vascular resistance in patients and healthy control subjects (all P<0.01) but increased heart rate only in control subjects (P<0.01).

CONCLUSIONS

Acute apelin administration in humans causes peripheral and coronary vasodilatation and increases cardiac output. APJ agonism represents a novel potential therapeutic target for patients with heart failure.

Collaborative decision-making between paramedics and CCU nurses based on 12-lead ECG telemetry expedites the delivery of thrombolysis in ST elevation myocardial infarction

OBJECTIVES

To describe a prehospital thrombolysis (PHT) and expedited inhospital thrombolysis (IHT) programme in south-east Scotland using prehospital 12-lead ECG recordings transmitted by telemetry and autonomous paramedic-administered thrombolysis with decision support being provided by coronary care nurses.

DESIGN

Retrospective observational study.

SETTING

Three hospitals in south-east Scotland covering a population of 778,468 served by 54 ambulance vehicles.

PATIENTS

11,840 patients who telephoned the ambulance service with "chest pain" over 20 months, during which 812 patients were admitted with ST segment elevation myocardial infarction (STEMI).

MAIN OUTCOME MEASURES

All calls and cardiac/potential cardiac calls to the ambulance service, type/time of patient presentation, symptoms/call/door-to-thrombolysis times.

RESULTS

Of the 11,840 calls to the ambulance service for chest pain over 20 months of the initiative, 60% were cardiac/potentially cardiac-related by Scottish Ambulance Service triage. ST segment elevation was present in 8% of the 5150 12-lead ECGs transmitted by paramedics to the ECG receiving station in the CCU. Over the 20 months, 812 patients were admitted to the three hospitals with STEMI and 71% received thrombolysis. Median symptom-to-thrombolysis times were 91, 148 and 184 min, respectively, in the PHT, telemetry-facilitated IHT and self-presenting IHT groups. Median call-to-needle time for the PHT group was 40 min. In 2/146 cases the cardiologists judged that the patient should not have been administered PHT.

CONCLUSIONS

Based on prehospital 12-lead ECG telemetry, it is possible for paramedics and CCU nurses to conduct live reperfusion decision-making in patients with STEMI, with resultant benefits in symptoms-to-thrombolysis time.

Hospital volume of throughput and periprocedural and medium-term adverse events after percutaneous coronary intervention: retrospective cohort study of all 17,417 procedures undertaken in Scotland, 1997-2003

OBJECTIVE

To determine whether percutaneous coronary intervention (PCI) hospital volume of throughput is associated with periprocedural and medium-term events, and whether any associations are independent of differences in case mix.

DESIGN

Retrospective cohort study of all PCIs undertaken in Scottish National Health Service hospitals over a six-year period.

METHODS

All PCIs in Scotland during 1997-2003 were examined. Linkage to administrative databases identified events over two years' follow up. The risk of events by hospital volume at 30 days and two years was compared by using logistic regression and Cox proportional hazards models.

RESULTS

Of the 17,417 PCIs, 4900 (28%) were in low-volume hospitals and 3242 (19%) in high-volume hospitals. After adjustment for case mix, there were no significant differences in risk of death or myocardial infarction. Patients treated in high-volume hospitals were less likely to require emergency surgery (adjusted odds ratio 0.18, 95% confidence interval (CI) 0.07 to 0.54, p = 0.002). Over two years, patients in high-volume hospitals were less likely to undergo surgery (adjusted hazard ratio 0.52, 95% CI 0.35 to 0.75, p = 0.001), but this was offset by an increased likelihood of further PCI. There was no net difference in coronary revascularisation or in overall events.

CONCLUSION

Death and myocardial infarction were infrequent complications of PCI and did not differ significantly by volume. Emergency surgery was less common in high-volume hospitals. Over two years, patients treated in high-volume centres were as likely to undergo some form of revascularisation but less likely to undergo surgery.

Electrical cardioversion for atrial fibrillation and flutter

BACKGROUND

Atrial fibrillation increases stroke risk and adversely affects cardiovascular haemodynamics. Electrical cardioversion may, by restoring sinus rhythm, improve cardiovascular haemodynamics, reduce the risk of stroke, and obviate the need for long-term anticoagulation.

OBJECTIVES

To assess the effects of electrical cardioversion of atrial fibrillation or flutter on the risk of thromboembolic events, strokes and mortality (primary outcomes), the rate of cognitive decline, quality of life, the use of anticoagulants and the risk of re-hospitalisation (secondary outcomes) in adults (>18 years).

SEARCH STRATEGY

We searched the Cochrane CENTRAL Register of Controlled Trials (1967 to May 2004), MEDLINE (1966 to May 2004), Embase (1980 to May 2004), CINAHL (1982 to May 2004), proceedings of the American College of Cardiology (published in Journal of the American College of Cardiology 1983 to 2003), www.trialscentral.org, www.controlled-trials.com and reference lists of articles. We hand-searched the indexes of the Proceedings of the British Cardiac Society published in British Heart Journal (1980 to 1995) and in Heart (1995 to 2002); proceedings of the European Congress of Cardiology and meetings of the Joint Working Groups of the European Society of Cardiology (published in European Heart Journal 1983-2003); scientific sessions of the American Heart Association (published in Circulation 1990-2003). Personal contact was made with experts.

SELECTION CRITERIA

Randomised controlled trial or controlled clinical trials of electrical cardioversion plus 'usual care' versus 'usual care' only, where 'usual care' included any combination of anticoagulants, antiplatelet drugs and drugs for 'rate control'. We excluded trials which used pharmacological cardioversion as the first intervention, and trials of new onset atrial fibrillation after cardiac surgery. There were no language restrictions.

DATA COLLECTION AND ANALYSIS

For dichotomous data, odds ratios were calculated; and for continuous data, the weighted mean difference was calculated.

MAIN RESULTS

We found three completed trials of electrical cardioversion (rhythm control) versus rate control, recruiting a total of 927 participants (Hot Cafe; RACE; STAF) and one ongoing trial (J-RHYTHM). There was no difference in mortality between the two strategies (OR 0.83; CI 0.48 to 1.43). There was a trend towards more strokes in the rhythm control group (OR 1.9; 95% CI 0.99 to 3.64). At follow up, three domains of quality of life (physical functioning, physical role function and vitality) were significantly better in the rhythm control group (RACE 2002; STAF 2003).

AUTHORS' CONCLUSIONS

Electrical cardioversion (rhythm control) led to a non-significant increase in stroke risk but improved three domains of quality of life.

Antiplatelet treatment in unstable angina: aspirin, clopidogrel, glycoprotein IIb/IIIa antagonist, or all three?

Evidence on the role of antiplatelet agents in patients with non-ST elevation acute coronary syndrome is reviewed, and a strategy for their use in unstable angina is presented

Electrical cardioversion for atrial fibrillation and flutter

BACKGROUND

Atrial fibrillation increases the risk of stroke, increases the risk of cognitive impairment, and adversely affects cardiovascular haemodynamics. Electrical cardioversion for atrial fibrillation has been in use since the 1960s; the rationale is that restoration of sinus rhythm improves cardiovascular haemodynamics, reduces the risk of stroke, and obviates the need for long-term anticoagulation.

OBJECTIVES

To assess the effects of electrical cardioversion of atrial fibrillation or atrial flutter on the annual risk of thromboembolic events, strokes and mortality (primary outcomes measures), the rate of cognitive decline, quality of life, the use of anticoagulants and the risk of re-hospitalisation (secondary outcome measures) in adults (>18 years) with acute, paroxysmal or sustained atrial fibrillation or atrial flutter, of any duration and any aetiology.

SEARCH STRATEGY

One reviewer searched the Cochrane Controlled Clinical Trials Register (2000 Issue 4), MEDLINE (1966 to December 2000), EMBASE (1980 to December 2000), CINAHL (1982 to November 2000) and proceedings of the American College of Cardiology (published in the Journal of the American College of Cardiology 1983 to 2000). Reference lists of articles were searched. Personal contact was made with experts in the field. A second reviewer handsearched proceedings of the British Cardiac Society (published in British Heart Journal (1980 to 1995) and in Heart (1995 to May 2001); proceedings of the European Congress of Cardiology and meetings of the Joint Working Groups of the European Society of Cardiology (published in European Heart Journal 1983-2000); scientific sessions of the American Heart Association (published in Circulation 1990-2000).

SELECTION CRITERIA

Randomised controlled trial or controlled clinical trials of electrical cardioversion plus 'usual care' versus 'usual care' only, where 'usual care' included any combination of the following: anticoagulants, antiplatelet drugs and drugs for 'rate control', in adults (>18 years) with acute, paroxysmal or sustained atrial fibrillation or atrial flutter, of any duration and any aetiology.

DATA COLLECTION AND ANALYSIS

It was planned to extract study data onto data extraction forms. The planned analysis was by the statistical package in RevMan.

MAIN RESULTS

No completed randomised trials or controlled clinical trials of electrical cardioversion were found. Two ongoing trials were identified.

REVIEWER'S CONCLUSIONS

There were no data from completed randomised controlled trials or controlled clinical trials to either support or refute the use of electrical cardioversion for atrial fibrillation. Randomised trials of electrical cardioversion are required.

Long-term clinical safety and efficacy of NIROYAL vs. NIR intracoronary stent

Research in vitro and in animal models suggested that gold electroplating of stents can attenuate neointimal hyperplasia and reduce thrombogenicity. The objective of this study was to evaluate the safety and efficacy of the gold-coated NIROYAL stent in the treatment of stenosed coronary arteries and bypass grafts. We retrospectively studied 181 consecutive patients undergoing deployment of NIR (n = 87) or NIROYAL (n = 94) coronary stents in a single tertiary referral center from July 1997 to December 1998. Mean follow-up duration for the NIR and NIROYAL patient groups were 11.6 and 11.4 (range, 3-12) months, respectively. Stent thrombosis rates were 3/87 (3%) in the NIR and 0/94 (0%) in the NIROYAL group (P = 0.07). The need for target lesion revascularization (TLR) in the NIR patient group was 8/87 (9%) compared to 11/94 (12%) in the NIROYAL patient group (P = 0.6). The overall MACE rates for the NIR and NIROYAL patient groups were 24/87 (28%) and 22/94 (23%), respectively (P = 0.5). The present study, hence, implies equivalence between the stainless steel NIR and the gold-plated NIROYAL stent with no significant difference in immediate and long-term clinical performance profiles.

The impact of QT lag compensation on dynamic assessment of ventricular repolarization: reproducibility and the impact of lead selection

In cardiac disease, abnormalities exist in the rate-corrected QT interval and the relationship between QT and heart rate. The QT/RR relationship is known to be dynamic and show circadian variation. The availability of automated methods for measurement of QT and RR intervals allows monitoring of the QT/RR relationship and may provide insights into arrhythmia onset. Using a method for analyzing 24-hour recordings that incorporates beat-by-beat QT and RR measurement and an automated mechanism for compensating for lag in adaptation of QT to changes in RR, the authors evaluated the impact of lag compensation on assessment of the QT/RR relationship, reproducibility, and the effect of lead selection in 15 normal subjects. The QT/RR relationship is continuously estimated from the lag compensated data over a 5-minute scrolling time frame. The relationship is expressed as an exponential formula, QT = QTo.RRJ where QTo is the QT interval at a standardized RR interval of 1 second and J is a variable exponent. We found that the use of lag compensation significantly improves the mean 24-hour correlation between QT and RR data (r = 0.87 vs 0.65). The 24-hour mean of QTo and J were highly reproducible (coefficients of variation 2% and 8%, respectively). The mean 24-hour QT/RR relationship for the population was QT = 0.415.(RR)0.32. There was a small difference between leads in QTo and J. Compensating for QT adaptation lag provides a means of assessing the QT/RR relationship over long and short periods. This method allows investigation of the effect of acute interventions on the dynamic QT/RR relationship, which has previously been restricted by the presence of QT hysteresis.

The relationship between QT intervals and mortality in ambulant patients with chronic heart failure. The united kingdom heart failure evaluation and assessment of risk trial (UK-HEART)

AIMS

Mortality in patients with heart failure remains high and is difficult to predict. QT interval parameters on a 12-lead ECG have been shown to predict arrhythmic events in patients with a variety of myocardial diseases. There is some, but not consistent, evidence that QT interval parameters may act as predictors of mortality, in particular sudden death, in patients with heart failure. In an adequately powered prospective study we have studied QT interval parameters in patients with stable chronic heart failure in order to determine whether they are predictive of all-cause mortality or mode of death.

METHODS AND RESULTS

Five hundred and fifty-four ambulant outpatients with chronic heart failure were recruited. A 12-lead ECG, chest radiograph, echocardiogram, 24 h ambulatory electrocardiogram and serum for biochemical analysis were obtained at baseline. Patients were followed for 471+/-168 days. QT intervals were measured in all leads blinded to patient's characteristics and outcome, were corrected for heart rate, and the maximum QT intervals, and QT dispersion (range of QT intervals) were determined. The same parameters were determined for JT intervals. The primary end-point was all-cause mortality, secondary end-points were sudden cardiac death and death due to progressive heart failure. Multivariate analysis with the Cox's proportional hazards model was used to determine which variables were independently related to outcome. Four hundred and ninety-five patients had analysable ECGs at study entry and of these 71 died during follow-up. The heart rate corrected QT dispersion and maximum QT interval were significant univariate predictors of all-cause mortality (P=0.026 and <0.0001 respectively), and also of sudden death and progressive heart failure death, but were not related to outcome in the multivariate analysis. The independent predictors of all-cause mortality were cardiothoracic ratio (P=0.0003), creatinine (P=0.0009), heart rate (P=0.007), echocardiographically derived left ventricular end-diastolic dimension (P=0.007) and ventricular couplets on 24 h electrocardiographic monitoring (P=0.015).

CONCLUSION

In an adequately powered prospective study none of the QT or JT parameters were shown to be independent predictors of outcome in patients with mild to moderate congestive heart failure. These variables do not therefore add to the prognostic information which can be gained from simple radiographic, biochemical, echocardiographic and Holter data in this group of patients.

Effects of acute angiotensin II type 1 receptor antagonism and angiotensin converting enzyme inhibition on plasma fibrinolytic parameters in patients with heart failure

BACKGROUND

Angiotensin converting enzyme (ACE) inhibition after myocardial infarction is associated with an improvement in plasma fibrinolytic parameters. The aim of the present study was to determine whether acute ACE inhibition and angiotensin II type 1 (AT1) receptor antagonism have similar effects in patients with heart failure.

METHODS AND RESULTS

Twenty patients with moderately severe chronic heart failure received enalapril 10 mg and losartan 50 mg on 2 separate occasions in a single-blind, randomized, crossover design. Plasma tissue plasminogen activator (t-PA) and plasminogen activator inhibitor type 1 (PAI-1) antigen and activity were measured at baseline and 6 hours after the dose. Acute administration of losartan but not of enalapril reduced plasma t-PA (11%; P=0.003) and PAI-1 (38%; P<0.001) antigen concentrations, which was associated with increases in t-PA (29%; P=0.03) and decreases in PAI-1 (48%; P=0.01) activity. Changes in plasma fibrinolytic parameters were more marked during losartan treatment (P<0.02), with a 3-fold greater reduction in plasma PAI-1 antigen concentrations (P<0.05).

CONCLUSIONS

Acute AT1 antagonism in patients with heart failure is associated with a significant improvement in plasma fibrinolytic parameters that is greater than during ACE inhibition. These beneficial effects of AT1 antagonism and ACE inhibition would therefore appear to be mediated principally through suppression of angiotensin II.

Cardioversion for atrial fibrillation: the views of consultant physicians, geriatricians and cardiologists

BACKGROUND AND AIMS

Atrial fibrillation (AF) increases the risk of stroke and also has adverse haemodynamic consequences. Cardioversion of AF to sinus rhythm may obviate the need for long-term anticoagulation and improve cardiovascular haemodynamics, but is probably underused. We therefore investigated the views of hospital consultants about cardioversion for AF.

METHODS

336 Postal questionnaires were sent to all 186 consultant physicians, 54 cardiologists and 96 geriatricians in Scotland, followed by one reminder letter to non-responders.

RESULTS

71% Of questionnaires were returned. Cardiologists referred 18% of AF patients for cardioversion, while physicians referred 11% and geriatricians 5%. Cardiologists had better access to cardioversion facilities and were less likely to consider an enlarged left atrium and organic heart disease to be contra-indications to cardioversion. Anticoagulation was given for less than 3 weeks before cardioversion by 9% of cardiologists, 39% of physicians and 65% of geriatricians (P<0.001), and for less than 3 weeks after cardioversion by 17% of cardiologists, 45% of physicians and 47% of geriatricians (P = 0.7).

SUMMARY

The wide variation in practice both between and within the different specialties suggests that consensus guidelines based on the best available evidence should be developed.

Excessive morphine requirements after pre-hospital nalbuphine analgesia

Nalbuphine hydrochloride is an opioid agonist-antagonist that has gained acceptance as a pre-hospital analgesic agent. Nalbuphine has equal analgesic properties to morphine, has a low addiction potential, and can be stored and administered without restrictions, unlike morphine. To date no clinical evidence has been published to support the theoretical difficulty that the action of opioids administered after nalbuphine could be altered or negated. The following case reports highlight 10 patients who received nalbuphine pre-hospital and subsequently required higher doses of opioid analgesia than expected. The discussion summarises the properties of nalbuphine and identifies potential reasons why excessive amounts of opioid analgesia were required.

Prospective study of heart rate variability and mortality in chronic heart failure: results of the United Kingdom heart failure evaluation and assessment of risk trial (UK-heart)

BACKGROUND

Patients with chronic heart failure (CHF) have a continuing high mortality. Autonomic dysfunction may play an important role in the pathophysiology of cardiac death in CHF. UK-HEART examined the value of heart rate variability (HRV) measures as independent predictors of death in CHF.

METHODS AND RESULTS

In a prospective study powered for mortality, we recruited 433 outpatients 62+/-9.6 years old with CHF (NYHA functional class I to III; mean ejection fraction, 0.41+/-0.17). Time-domain HRV indices and conventional prognostic indicators were related to death by multivariate analysis. During 482+/-161 days of follow-up, cardiothoracic ratio, SDNN, left ventricular end-systolic diameter, and serum sodium were significant predictors of all-cause mortality. The risk ratio for a 41.2-ms decrease in SDNN was 1.62 (95% CI, 1.16 to 2.44). The annual mortality rate for the study population in SDNN subgroups was 5.5% for >100 ms, 12.7% for 50 to 100 ms, and 51.4% for <50 ms. SDNN, creatinine, and serum sodium were related to progressive heart failure death. Cardiothoracic ratio, left ventricular end-diastolic diameter, the presence of nonsustained ventricular tachycardia, and serum potassium were related to sudden cardiac death. A reduction in SDNN was the most powerful predictor of the risk of death due to progressive heart failure.

CONCLUSIONS

CHF is associated with autonomic dysfunction, which can be quantified by measuring HRV. A reduction in SDNN identifies patients at high risk of death and is a better predictor of death due to progressive heart failure than other conventional clinical measurements. High-risk subgroups identified by this measurement are candidates for additional therapy after prescription of an ACE inhibitor.

Regulation of peripheral vascular tone in patients with heart failure: contribution of angiotensin II

OBJECTIVE

To determine directly the contribution of angiotensin II to basal and sympathetically stimulated peripheral arteriolar tone in patients with heart failure.

DESIGN

Parallel group comparison.

SUBJECTS

Nine patients with New York Heart Association grade II-IV chronic heart failure, and age and sex matched controls.

INTERVENTIONS

Forearm plethysmography, lower body negative pressure, local intra-arterial administration of losartan, angiotensin II, and noradrenaline, and estimation of plasma hormone concentrations.

MAIN OUTCOME MEASURES

Forearm blood flow responses, plasma hormone concentrations.

RESULTS

Baseline blood pressure, heart rate, and forearm blood flow did not differ between patients and controls. In comparison with the non-infused forearm, losartan did not affect basal forearm blood flow (95% confidence interval -5.5% to +7.3%) or sympathetically stimulated vasoconstriction in controls. However, the mean (SEM) blood flow in patients increased by 13(5)% and 26(7)% in response to 30 and 90 micrograms/min of losartan respectively (p < 0.001). Lower body negative pressure caused a reduction in forearm blood flow of 20(5)% in controls (p = 0.008) and 13(5)% (p = 0.08) in patients (p = 0.007, controls v patients). Blood flow at 90 micrograms/min of losartan correlated with plasma angiotensin II concentration (r = 0.77; p = 0.03). Responses to angiotensin II and noradrenaline did not differ between patients and controls.

CONCLUSIONS

Losartan causes acute local peripheral arteriolar vasodilation in patients with heart failure but not in healthy control subjects. Endogenous angiotensin II directly contributes to basal peripheral arteriolar tone in patients with heart failure but does not augment sympathetically stimulated peripheral vascular tone.

A prospective controlled study of the association of Streptococcus bovis with colorectal carcinoma

AIM

To investigate the ability of Streptococcus bovis to colonise colorectal cancers.

PATIENTS

19 patients with colorectal cancer and 23 controls without malignancy.

SETTING

University teaching hospital.

METHODS

Prospective study comparing unselected patients with known colorectal cancer with age and sex matched controls. Carcinoma tissue from patients with colorectal cancer and normal colonic mucosa, stool, and blood from both patients and control subjects were cultured.

RESULTS

In contrast to published data, the faecal carriage rate was similar in cancer (11%) and control groups (13%).

CONCLUSIONS

Faecal colonisation by Str bovis in colorectal cancer patients is lower than previously reported and does not differ significantly from controls.

Cell adhesion molecules in cardiovascular disease: a clinical perspective

In summary, there is increasing evidence that cell adhesion molecules play an important role in cardiovascular pathology. They are involved in the main processes that underlie cardiac disease including thrombosis, leucocyte infiltration, smooth muscle proliferation, and cell migration. Anti-integrin treatment is already widely used to treat thrombotic complications, and it seems likely that manipulation of other cell adhesion molecules will be used clinically in the near future.

Effect of DC shock on serum levels of total creatine kinase, MB-creatine kinase mass and troponin T

After successful resuscitation from cardiac arrest, it is important to identify whether the event has been triggered by a myocardial infarction, since this determines subsequent investigations and management. Previous studies have shown that biochemical indices of infarction become elevated after resuscitation in patients without myocardial infarction. This can lead to overdiagnosis of myocardial infarction in the post-arrest setting. The cause of the elevated enzyme levels is not known, but may involve electrical or mechanical injury to the heart during resuscitation. In this study we aimed to identify the effects of isolated direct current shock on serum levels of creatine kinase (CK), MB creatine kinase mass (MB-CK), and troponin T, and examined the relationships between enzyme levels and the dose of electrical energy used. Thirteen patients were studied who underwent DC cardioversion for atrial fibrillation. Serum was obtained for CK, MB-CK and troponin T estimation before and 10 min after cardioversion, at hourly intervals for 8 h, and 18 h after cardioversion. Total serum CK became significantly elevated after only 3 h and rose to a peak of 1294.4 IU l(-1) (P < 0.02) at 18 h. Post-shock CK levels were strongly correlated with total shock energy (r = 0.8, P < 0.01). Serum MB-CK was significantly elevated at 18 h among patients receiving total shock energies greater than 1000 J than in those receiving lower doses, reflecting a positive correlation (r = 0.64, P < 0.05) between shock energy and peak MB-CK level. Troponin T levels were not significantly elevated after cardioversion. In conclusion, total serum CK levels become significantly elevated early after cardioversion, suggesting rapid wash-out from injured skeletal muscle. MB-CK levels become significantly elevated in individuals receiving high energy shocks, probably due to release of small quantities of the CK-MB isoform from skeletal muscle. The negligible troponin T levels seen after high energy cardioversion indicate that significant myocardial injury does not occur. Electrical injury is not likely to account for the elevated troponin T levels seen after out-of-hospital resuscitation in patients without myocardial infarction.

Effects of digoxin on time domain measures of heart rate variability in patients with stable chronic cardiac failure: withdrawal and comparison group studies

The effect on heart rate variability of adding digoxin to a diuretic and ACE inhibitor was studied in patients with chronic stable cardiac failure. Digoxin was found to increase heart rate variability, especially those measures of heart rate variability thought to represent parasympathetic activity. The withdrawal of digoxin led to a decrease in heart rate variability to pre-treatment levels. Whilst digoxin in standard doses does not alter prognosis in chronic cardiac failure, it does have potentially beneficial neurohumoral effects. If the increase in heart rate variability, which represents beneficial neurohumoral modulation, can be divorced from the potentially detrimental effects, perhaps by using smaller doses, then there may be a role for digoxin in the treatment of chronic cardiac failure.

Management after a first myocardial infarction

Treadmill exercise testing is the most important risk-stratifying technique, because of its ability to assess residual ischemia, left ventricular dysfunction, and a tendency toward arrhythmias. Cessation of smoking is the most important lifestyle change. Among prophylactic medications, aspirin can be considered for most patients, beta-blockers for many, and ACE inhibitors for some.

Measurement of parasympathetic activity from 24-hour ambulatory electrocardiograms and its reproducibility and sensitivity in normal subjects, patients with symptomatic myocardial ischemia, and patients with diabetes mellitus

The parasympathetic nervous system plays a major role in the pathophysiology of many cardiovascular disease, particularly in modulating myocardial electrical stability. Measurements of heart rate variability have been widely used to assess parasympathetic activity. The reproducibility of measurements obtained from 24-hour ambulatory electrocardiograms has not been well documented. We have developed a technique for measuring parasympathetic activity from clinical quality 24-hour ambulatory electrocardiograms by counting beat-to-beat increases in RR interval that are > 50 ms. To determine the reproducibility and sensitivity of our technique, we analyzed repeated 24-hour electrocardiograms of 173 subjects (19 normal subjects, 67 patients with ischemic heart disease, and 87 diabetics) followed up over periods of 2 to 16 weeks. In all subject groups, mean values for repeated measurements were virtually identical. Measurements were stable in all 3 groups throughout the course of the study, as assessed by intraclass correlation coefficients. This technique is sensitive enough to detect relatively small changes in parasympathetic activity in subjects, as demonstrated by the calculated Bland and Altman coefficients of repeatability. Reproducibility and sensitivity of our technique are particularly good in normal subjects and in patients with ischemic heart disease. The results obtained with this technique imply that other related measurements of parasympathetic activity will show similar excellent short- and long-term reproducibility and sensitivity.

A comparison of cylindrical and Inoue balloon techniques for mitral valvotomy in patients in the United Kingdom

OBJECTIVES

To compare the use of cylindrical balloons and the Inoue balloon for percutaneous mitral valvotomy in patients in the United Kingdom.

DESIGN

Comparison of the haemodynamic results, complications, and symptomatic outcome of balloon dilatation for mitral stenosis in consecutive patients treated by cylindrical balloons and a second consecutive series of patients treated by the Inoue balloon.

SETTING

A tertiary cardiac referral centre in Scotland.

PATIENTS

70 patients (mean age 60.6 years) treated by the single or double cylindrical balloon technique and 70 patients (mean age 58.9 years) treated with the Inoue balloon method.

MAIN OUTCOME MEASURES

Success in obtaining dilatation at the mitral orifice, procedure and screening times, increase in valve area, complications, and early symptomatic outcome.

RESULTS

Dilatation of the mitral valve was obtained in 91% of patients when cylindrical balloons were used and in 99% of patients treated with the Inoue balloon. Use of the Inoue balloon gave significantly shorter procedure and screening times. Technical problems in obtaining and maintaining the position at the mitral orifice were more common with cylindrical balloons. Improvements in valve area and symptoms were not significantly different with use of the two types of balloon. The Inoue balloon avoided cardiac tamponade and the creation of larger atrial septal defects, but had a higher incidence of increase in mitral reflux.

CONCLUSIONS

In these elderly patients, the Inoue balloon method was safer and faster for percutaneous mitral valvotomy, with a higher success rate for dilatation within the valve orifice. Haemodynamic and symptomatic improvement was similar with the two techniques.

Management of patients after their first myocardial infarction

In the past 20 years there has been a steady improvement in the short term prognosis of patients with myocardial infarction, following the introduction of beta blockers, thrombolysis, and aspirin. Patients treated with thrombolytic drugs have a lower overall mortality after myocardial infarction but remain at risk of non-fatal reinfarction or death, and in one study almost half of all survivors of acute myocardial infarction died or suffered a further ischaemic event within three years. It is therefore important to have a strategy to identify patients at high risk, to reduce the subsequent development of cardiac failure and mortality, and to have effective measures for secondary prevention to reduce the incidence of reinfarction as well as to promote rehabilitation.

Effects of captopril therapy on endogenous fibrinolysis in men with recent, uncomplicated myocardial infarction

OBJECTIVES

This study investigated the effects of captopril therapy on endogenous fibrinolysis in men with recent, uncomplicated myocardial infarction.

BACKGROUND

Angiotensin-converting enzyme inhibitors reduce the incidence of acute coronary syndromes in patients with mild left ventricular dysfunction after myocardial infarction. Abnormal endogenous fibrinolysis, reflected in increased levels of endogenous tissue-type plasminogen activator (t-PA) antigen and plasminogen activator inhibitor type 1 activity, is associated with an increased risk of myocardial infarction in patients with ischemic heart disease.

METHODS

In a randomized, double-blind crossover study beginning 8 weeks after uncomplicated myocardial infarction, patients received 4 weeks of placebo and 4 weeks of captopril (75 mg daily) therapy. At the end of each treatment period, we measured t-PA antigen and plasminogen activator inhibitor type 1 antigen and activity.

RESULTS

Median values in the 15 patients after placebo and in 12 normal men matched for age and body mass index were, respectively, t-PA antigen 16.0 versus 9.5 ng/ml (p = 0.001), plasminogen activator inhibitor type 1 antigen 17.3 versus 8.6 ng/ml (p = 0.29) and plasminogen activator inhibitor type 1 activity 13.2 versus 6.3 AU/ml (p = 0.04). After 4 weeks of treatment with captopril in the 15 patients, the estimated (95% confidence interval) median reduction in t-PA antigen was 7.3 ng/ml (-4.6 to -10.3 ng/ml, p = 0.001), in plasminogen activator inhibitor type 1 antigen 3.1 ng/ml (+1.5 to -8.4 ng/ml, p = 0.17) and in plasminogen activator inhibitor type 1 activity -2.2 AU/ml (-1.0 to -4.3 AU/ml, p = 0.02).

CONCLUSIONS

Treatment with captopril after uncomplicated myocardial infarction is associated with a significant decrease in elevated levels of t-PA antigen and plasminogen activator inhibitor type 1 activity. This may help to explain the reduction in risk of coronary thrombosis associated with the use of angiotensin-converting enzyme inhibitors.

Cardiac parasympathetic activity in severe uncomplicated coronary artery disease

BACKGROUND

Previous studies have suggested that coronary artery disease is independently associated with reduced cardiac parasympathetic activity, and that this is important in its pathophysiology. These studies included many patients with complications that might be responsible for the reported autonomic abnormalities.

OBJECTIVE

To measure cardiac parasympathetic activity in patients with uncomplicated coronary artery disease.

PATIENTS AND METHODS

44 patients of mean (SD) age 56 (8) with severe uncomplicated coronary artery disease (symptoms uncontrolled on maximal medical treatment; > 70% coronary stenosis at angiography; normal ejection fraction; no evidence of previous infarction, diabetes, or hypertension). Heart rate variability was measured from 24 hour ambulatory electrocardiograms by counting the number of times successive RR intervals exceeded the preceding RR interval by > 50 ms, a previously validated sensitive and specific index of cardiac parasympathetic activity.

RESULTS

Mean (range) of counts were: waking 112 (range 6-501)/h, sleeping 198 (0-812)/h, and total 3912 (151-14 454)/24 h. These mean results were unremarkable, and < 10% of patients fell below the lower 95% confidence interval for waking, sleeping, or total 24 hour counts in normal people. There was no relation between the severity of coronary artery disease or the use of concurrent antianginal drug treatment and cardiac parasympathetic activity.

CONCLUSION

In contrast with previous reports no evidence of a specific independent association between coronary artery disease and reduced cardiac parasympathetic activity was found. The results of previous studies may reflect the inclusion of patients with complications and not the direct effect of coronary artery disease itself.

Hyperinsulinaemia in ischaemic heart disease: the importance of myocardial infarction and left ventricular function

Elevated circulating insulin levels have been reported in ischaemic heart disease, and may be of aetiological importance. Previous studies have not considered the potential influence of heart failure or of previous myocardial infarction, as opposed to stable angina. We therefore measured the insulin response to a 75 g oral glucose tolerance test in five groups with normal glucose tolerance, comparing normal male controls to men with chronic stable angina, men with recent myocardial infarction (two groups, 3 weeks and 3 months post infarction), and men with chronic severe heart failure. Only patients with chronic heart failure had fasting hyperinsulinaemia, probably reflecting associated neuroendocrine abnormalities. Stimulated hyperinsulinaemia was present in all patient groups, but was less pronounced and of shorter duration in patients with angina. At 120 min, only patients with heart failure or previous myocardial infarction were hyperinsulinaemic. The degree of stimulated hyperinsulinaemia was not influenced by the presence of heart failure or by the length of time from infarction. Hyperinsulinaemia is associated with impaired peripheral muscle glucose uptake and metabolism, and might contribute to muscular fatigue on exertion in patients with previous myocardial infarction or heart failure.

Differing patterns of cardiac parasympathetic activity and their evolution in selected patients with a first myocardial infarction

OBJECTIVES

The purpose of the study was to compare cardiac parasympathetic activity during the early and convalescent phases of acute anterior and inferior myocardial infarction.

BACKGROUND

Previous studies have shown that cardiac parasympathetic activity may vary with the site of infarction and that recovery may occur after infarction.

METHODS

Cardiac parasympathetic activity was measured from 24-h electrocardiograms by counting the number of times that successive RR intervals (counts) differed by > 50 ms. Recordings began within 12 h of admission and at 7, 42 and 140 days after acute myocardial infarction in 20 patients (mean age 57 +/- 7.9 years). All patients were treated with streptokinase, aspirin and oral beta-adrenergic blocking agents.

RESULTS

For the entire group, mean total 24-h RR counts increased from 592 (range 78 to 3,812) at 48 h to 648 (range 109 to 5,473) at 7 days, 1,145 (range 162 to 6,268) at 42 days and 1,958 (range 344 to 9,632) at 140 days. Patients with anterior infarction had significantly lower counts (mean 277, range 78 to 2,708; n = 11) compared with those with inferior infarction (mean 2,172, range 897 to 3,812; n = 9) at 48 h (p < 0.05). There was no significant difference in counts between patients with anterior (mean 1,051, range 212 to 6,268) and inferior (mean 1,321, range 162 to 3,265) infarction after 42 or after 140 days (anterior: mean 1,655, range 344 to 9,632; inferior: mean 2,588, range 1,700 to 5,767).

CONCLUSIONS

These data suggest that after anterior myocardial infarction there is impaired cardiac parasympathetic function that improves within 6 weeks, whereas in inferior infarction there is relative preservation of cardiac parasympathetic function.

Contrasting patterns of arterial and venous dilatation after intravenous captopril in patients with chronic cardiac failure and their relationship to plasma angiotensin II concentrations

A 25 mg intravenous bolus injection of captopril caused an abrupt and rapid decrease in systemic vascular resistance (time to maximum effect 15 minutes), but a more gradual decrease in right atrial pressure (time to maximum effect 75 minutes) in 12 patients with chronic cardiac failure. Plasma angiotensin II concentrations fell significantly, reaching their lowest concentrations at 75 minutes after the injection of captopril, at which time systemic vascular resistance had begun to return toward control values. There was no correlation between the acute arteriodilator response and pretreatment plasma renin activity or plasma angiotensin II concentrations, or the decrease in plasma angiotensin II concentrations. There was a significant correlation between the decrease in plasma angiotensin II concentrations and the decrease in right atrial pressure (r = 0.67, p < 0.05). These findings suggest that in contrast to the venous response to intravenous captopril, the arterial response is not entirely dependent on a decrease in the circulating plasma angiotensin II concentration.

The relationship between diuretic dose, and the haemodynamic response to captopril in patients with cardiac failure

The effect of diuretic dose on the haemodynamic response to captopril was assessed in nine patients with chronic cardiac failure. Each patient was given an intravenous dose of captopril while maintained on (a) a low dose diuretic regime, and (b) a high dose diuretic regime. Activity of the renin angiotensin aldosterone system, as assessed by plasma concentrations of these hormones, was greater when patients were receiving the higher dose diuretic regime. The magnitude of haemodynamic response produced by intravenous captopril was greater when the patients were maintained on the high dose diuretic regime, although no significant correlation was found between resting plasma renin activity and resting plasma angiotensin II concentration and the change produced by captopril in any haemodynamic response on either diuretic regime. An increased dosage of loop diuretic potentiates the haemodynamic effects of captopril in patients with cardiac failure. Reduction of diuretic dose prior to introduction of captopril may protect against severe first dose hypotension.

Lack of correlation between the acute haemodynamic response to intravenous captopril and plasma concentrations of angiotensin II in patients with chronic cardiac failure

We have given a series of incremental intravenous injections of captopril to ten patients with chronic cardiac failure. Small doses of captopril produced significant changes in pulmonary artery end-diastolic pressure and right atrial pressure, up to a total cumulative dose of captopril of 2.5 mg, after which further injections had no significant effect. There were large changes in systemic vascular resistance and blood pressure up to a cumulative dose of captopril of 5.0 mg, after which the injection of larger doses caused no further significant changes. Small doses of intravenous captopril produced large increases in plasma renin activity and plasma angiotensin I concentrations up to a total cumulative dose of captopril of 1.25 mg, after which there were no significant further changes in either plasma renin activity or plasma angiotensin I concentration. However the plasma concentration of angiotensin II fell more slowly, no further change being recorded after a total cumulative dose of captopril of 10 mg. These results suggest that plasma renin activity is not the only determinant of plasma angiotensin II concentrations.

Percutaneous balloon dilatation of the mitral valve in patients who were unsuitable for surgical treatment

OBJECTIVE

To assess the effects on haemodynamic function and symptoms of percutaneous balloon dilatation of mitral stenosis in patients unable to undergo surgical treatment because of associated medical/cardiac problems.

DESIGN

A review of clinical outcome in 28 patients (of 108 undergoing balloon dilatation of the mitral valve) who were unsuitable for surgery.

SETTING

A tertiary cardiac referral centre: some patients referred were from other cardiac centres in Scotland.

PATIENTS

28 patients judged by cardiac surgeons to be unsuitable for valve replacement or valvotomy because of respiratory disease (15 patients), nonmitral cardiac disease (6), multi-organ impairment (5), psychiatric problems (1) or dense intrathoracic adhesions (1).

INTERVENTIONS

Percutaneous anterograde balloon dilatation of the mitral valve with polyethylene/polyvinyl balloons in 20 patients and the Inoue balloon in eight patients.

MAIN OUTCOME MEASURES

Haemodynamic variables were measured before and immediately after mitral valve dilatation. Patient survival and symptom class (New York Heart Association) were followed for a year after the procedure.

RESULTS

Dilatation at the mitral orifice was achieved in all cases. The mean (SD) pressure drop across the valve fell from 13.9 (5.3) to 5.6 (2.5) mm Hg, cardiac output rose from 3.18 (1.02) to 3.96 (2.5) l/min, and valve area increased from 0.78 (0.32) to 1.58 (0.56) cm2. The procedure was well tolerated by most patients, even those with metabolic/electrolyte disturbance, severe obstructive airways disease, myocardial impairment, and coronary disease. In three patients a small shunt developed at the atrial level: none developed severe mitral reflux. The two patients who required assisted ventilation died soon after the procedure and in one patient with severe coronary artery disease myocardial infarction developed and she died in cardiogenic shock. Early symptomatic improvement was reported by 23 of the 25 survivors, though the increase in exercise capacity was often limited by their non-mitral disease. At one year follow up a further 6 patients had died because of their additional disease: 15 continued to show symptomatic improvement.

CONCLUSIONS

Percutaneous balloon dilatation of the mitral valve is a useful new option in patients who are too ill to undergo cardiac surgery; but longer term benefit can be limited by the associated disease.

The influence of posture on the response to loop diuretics in patients with chronic cardiac failure is reduced by angiotensin converting enzyme inhibition

The diuretic and natriuretic response to an intravenous dose of frusemide 40 mg was assessed in the erect and supine positions in 10 patients with cardiac failure who were being treated with enalapril 10 mg twice daily in addition to diuretics (Enalapril group) and in 10 patients with cardiac failure taking diuretics alone (Control group). Total 4 h diuresis in the erect position was 728 ml and in the supine position was 824 ml in the patients taking enalapril compared to 655 ml in the erect position and 1166 ml in the supine position in those patients taking diuretics alone. Total 4 h natriuresis in the erect positions was 78 mmol and in the supine position was 85 mmol in patients taking enalapril 10 mg twice daily but in those patients taking diuretics alone total 4 h natriuresis in the erect position was 67 mmol increasing to 120 mmol in the supine position. Measurements of plasma renin activity and plasma angiotensin II concentration confirmed effective converting enzyme inhibition, in the group of patients taking enalapril, but in those patients taking diuretics alone the erect position was associated with an increase in plasma renin activity, and plasma concentrations of angiotensin II and aldosterone. We conclude that the renin angiotensin system is a major factor in mediating the effect of posture on loop diuretic drugs.

Decreased cardiac parasympathetic activity in chronic heart failure and its relation to left ventricular function

BACKGROUND

Activation of the sympathetic nervous system has been extensively studied in patients with chronic heart failure, but the parasympathetic nervous system has received relatively little attention. The objective in this study was to investigate cardiac parasympathetic activity in chronic heart failure and to explore its relation to left ventricular function.

METHODS

Heart rate variability was measured from 24 hour ambulatory electrocardiograms by counting the number of times each RR interval exceeded the preceding RR interval by more than 50 ms (counts). This method provided a sensitive index of cardiac parasympathetic activity.

RESULTS

Mean (range) of counts were: waking 48 (1-275)/h, sleeping 62 (0-360)/h, and total 1310 (31-7278)/24 h. These were lower than expected, and in 26 (60%) of the 43 patients counts fell below the lower 95% confidence intervals (95% CI) for RR counts in normal subjects. A significant correlation between total 24 hour RR counts and left ventricular ejection fraction was present (r = 0.49, p less than 0.05).

CONCLUSIONS

These results indicate that most patients with chronic heart failure have reduced heart rate variability and therefore reduced cardiac parasympathetic activity. The degree of parasympathetic dysfunction is related to the severity of left ventricular dysfunction. This may be relevant to the high incidence of ventricular arrhythmias and poor prognosis of patients with chronic heart failure.

Effect of captopril on cardiac parasympathetic activity in chronic cardiac failure secondary to coronary artery disease

Thirty-two patients with chronic cardiac failure underwent 24-hour ambulatory electrocardiographic monitoring on 2 separate occasions: 20 patients before and during treatment with captopril, and 12 acting as controls. Heart rate variability was calculated by counting the number of times successive RR interval differences were greater than 50 ms (this measurement being a reliable index of cardiac parasympathetic activity). During treatment with captopril, group mean total counts increased to 1,032 (range 48 to 7,437) from 482 (range 23 to 6,120) (p = 0.002). There was no change in mean hourly waking or sleeping heart rates. In the control group, no changes were seen: group mean total counts on the first occasion were 340 (range 120 to 3,255) and on the second occasion 400 (range 154 to 3,300) (p = not significant). These results show that treatment with angiotensin-converting enzyme inhibitors increases cardiac parasympathetic activity in patients with chronic cardiac failure. This may be relevant to the improved prognosis of this group of patients when treated with angiotensin-converting enzyme inhibitors.

Posture determines the nature of the interaction between angiotensin converting enzyme inhibitors and loop diuretics in patients with chronic cardiac failure

The effects of inhibition of the renin angiotensin aldosterone system on the natriuretic and diuretic actions of an intravenous dose of frusemide 40 mg in patients with chronic cardiac failure maintained on oral diuretics were studied in the supine and erect positions. In the patients studied in the supine position the total 4 hour diuresis was decreased from 995 (92) ml to 668 (66) ml and the total 4 hour natriuresis fell from 105 (14) mmol to 67 (14) mmol following the administration of captopril. Creatinine clearance fell from 87 (8) ml/minute to 52 (15) ml/minute. In the patients studied in the erect position the total 4 hour diuresis was 596 (87) ml without captopril and 562 (83) ml with captopril. Total 4 hour natriuresis was 71 (13) mmol without captopril and 65 (9) mmol with captopril. Creatinine clearance was reduced by captopril from 82 (7) ml/minute to 47 (12) ml/minute. The reduction in the diuretic and natriuretic response to frusemide caused by captopril in the supine position is mediated through a fall in glomerular filtration rate. However, in the erect position, which is associated with even further increases in activity of the renin angiotensin aldosterone system, the reduction in diuresis and natriuresis that a fall in glomerular filtration rate would cause is offset by abolition of the rise in sodium retaining hormones, angiotensin II and aldosterone that mediate the antinatriuretic effect of the erect position.

Acute administration of captopril lowers the natriuretic and diuretic response to a loop diuretic in patients with chronic cardiac failure

Angiotensin-converting enzyme inhibitors suppress plasma concentrations of the sodium retaining hormones angiotensin II and aldosterone. This action should potentiate the natriuretic and diuretic effects of loop diuretics. Some studies indicate, however, that the introduction of angiotensin-converting enzyme inhibitors for the treatment of cardiac failure is associated with transient weight gain and the development of oedema. We have compared the natriuretic and diuretic response to intravenous frusemide 40 mg alone with the natriuretic and diuretic response to intravenous frusemide 40 mg following the administration of a single dose of captopril in 12 supine male patients with stable chronic cardiac failure. Captopril lowered the 4 h diuretic response to frusemide from 1160 (60) to 685 (77) ml (P less than 0.05) and the natriuretic response from 120 (9.6) to 68 (11.7) mmol (P less than 0.05). Creatinine clearance fell after captopril from 91 (7.2) to 57 (7.7) ml min-1 (P less than 0.05). Systolic and diastolic blood pressures were lower after the administration of captopril but these changes were not significant. Plasma renin activity rose from 3.8 (1.04) to 12.34 (2.94) ng ml h-1 (P less than 0.05) and plasma angiotensin II was reduced from 24.9 (5.05) to 8.14 (1.8) pg ml-1 (P less than 0.05). Plasma aldosterone concentrations were not significantly lower following captopril. Angiotensin-converting enzyme inhibitors cause an acute fall in creatinine clearance which may reduce the effects of loop diuretics and attention must be paid to diuretic dosage when initiating angiotensin-converting enzyme inhibitors for the treatment of cardiac failure.