CBETA: First Multipass Superconducting Linear Accelerator with Energy Recovery.

Energy recovery has been achieved in a multipass linear accelerator, demonstrating a technology for more compact particle accelerators operating at higher currents and reduced energy consumption. Energy delivered to the beam during the first four passes through the accelerating structure was recovered during four subsequent decelerating passes. High-energy efficiency was achieved by the use of superconducting accelerating cavities and permanent magnets. The fixed-field alternating-gradient optical system used for the return loop successfully transported electron bunches of 42, 78, 114, and 150 MeV in a common vacuum chamber. This new kind of accelerator, an eight-pass energy recovery linac, has the potential to accelerate much higher current than existing linear accelerators while maintaining small beam dimensions and consuming much less energy per electron.

Once-daily, controlled-release tramadol and sustained-release diclofenac relieve chronic pain due to osteoarthritis: a randomized controlled trial.

OBJECTIVE: The present study was a randomized, parallel, double-blind comparison between controlled-release (CR) tramadol and sustained-release (SR) diclofenac in patients with chronic pain due to osteoarthritis of the hips and/or knees. METHODS: Patients with at least moderate pain intensity, and having received analgesics over the past three months, underwent a two- to seven-day washout of current analgesics before initiation of 200 mg CR tramadol or 75 mg SR diclofenac. During the eight-week study, patients returned to the clinic biweekly. CR tramadol doses were titrated to a maximum of 200 mg, 300 mg or 400 mg per day. SR diclofenac doses were titrated to 75 mg or 100 mg once daily, or 75 mg twice a day based on pain relief and the presence of side effects. For rescue analgesic, patients took acetaminophen as needed, up to 650 mg three times a day. RESULTS: Forty-five patients on CR tramadol and 52 patients on SR diclofenac were evaluable. Significant improvements from prestudy treatment were shown for visual analogue scale pain (P=0.0001), stiffness (P<0.0005) and physical function (P=0.0001) scores for both treatments. There were no significant differences between the two treatments in the Western Ontario and McMaster Universities subscales, overall pain, pain and sleep, or the clinical effectiveness evaluation. Overall incidence of adverse events was similar in both groups, with more opioid-related adverse events with CR tramadol, and two serious adverse events occurring with the use of SR diclofenac. CONCLUSIONS: CR tramadol is as effective as SR diclofenac in the treatment of pain due to knee or hip osteoarthritis, with the potential for fewer of the serious side effects that characterize nonsteroidal anti-inflammatory drug administration.

Prospective analysis of possible myocardial damage or hemolysis occurring as a result of prolonged autoperfusion angioplasty in humans.

OBJECTIVES: The purpose of this study was to further explore the procedural safety of prolonged (15-min) dilation using an autoperfusion coronary angioplasty balloon by assessing the degree of myocardial damage or hemolysis, if any, occurring as a result of the procedure. BACKGROUND: Prolonged balloon inflation periods may be beneficial during percutaneous transluminal coronary angioplasty. The duration of standard balloon angioplasty is often limited by the occurrence of myocardial ischemia due to loss of anterograde blood flow. Autoperfusion angioplasty allows continued myocardial perfusion during balloon inflation and has previously been shown to reduce but not totally eliminate acute myocardial ischemia during prolonged (up to 15 min) balloon inflation. The risk of intravascular hemolysis as a result of autoperfusion angioplasty has not yet been fully delineated. METHODS: Sixty-two consecutive patients (76% men; mean age 58 years) undergoing elective percutaneous transluminal coronary angioplasty of a single lesion were studied. Serial electrocardiographic and creatine kinase MB isoenzyme data were examined to detect evidence of myocardial damage. Tests for hemolysis (plasma free hemoglobin, serum haptoglobin and serum lactate dehydrogenase) were obtained in the 1st 24 consecutive patients. RESULTS: Inflation time was 14 +/- 4 min (mean +/- SD) and the procedure was successful (less than or equal to 50% residual lesion stenosis) in 59 patients (95%). Electrocardiographic evidence of myocardial infarction (greater than 1 mm persistent ST segment depression, greater than 1 mm ST segment elevation or new Q waves) was not observed in any patient. Cardiac enzyme assays were within the normal range in all patients. No evidence of hemolysis was found in the 24 consecutive patients studied. CONCLUSIONS: We conclude that prolonged autoperfusion angioplasty can be performed in patients without clinical evidence of myocardial damage or hemolysis.

The conduction of protons in different stereoisomers of dioxolane-linked gramicidin A channels.

Two different stereoisomers of the dioxolane-linked gramicidin A (gA) channels were individually synthesized (the SS and RR dimers;. Science. 244:813-817). The structural differences between these dimers arise from different chiralities within the dioxolane linker. The SS dimer mimics the helicity and the inter- and intramolecular hydrogen bonding of the monomer-monomer association of gA's. In contrast, there is a significant disruption of the helicity and hydrogen bonding pattern of the ion channel in the RR dimer. Single ion channels formed by the SS and RR dimers in planar lipid bilayers have different proton transport properties. The lipid environment in which the different dimers are reconstituted also has significant effects on single-channel proton conductance (g(H)). g(H) in the SS dimer is about 2-4 times as large as in the RR. In phospholipid bilayers with 1 M [H(+)](bulk), the current-voltage (I-V) relationship of the SS dimer is sublinear. Under identical experimental conditions, the I-V plot of the RR dimer is supralinear (S-shaped). In glycerylmonooleate bilayers with 1 M [H(+)](bulk), both the SS and RR dimers have a supralinear I-V plot. Consistent with results previously published (. Biophys. J. 73:2489-2502), the SS dimer is stable in lipid bilayers and has fast closures. In contrast, the open state of the RR channel has closed states that can last a few seconds, and the channel eventually inactivates into a closed state in either phospholipid or glycerylmonooleate bilayers. It is concluded that the water dynamics inside the pore as related to proton wire transfer is significantly different in the RR and SS dimers. Different physical mechanisms that could account for this hypothesis are discussed. The gating of the synthetic gA dimers seems to depend on the conformation of the dioxolane link between gA's. The experimental results provide an important framework for a detailed investigation at the atomic level of proton conduction in different and relatively simple ion channel structures.

Perfusion balloon catheter.

An autoperfusion balloon catheter was developed to allow passive myocardial perfusion during balloon inflation, through a central lumen and multiple side holes in the shaft proximal and distal to the balloon. This report reviews preliminary experimental animal data and initial human clinical experience with this device. In our first study with this device, the duration of inflation in dogs was compared with the maximal duration of inflation using a standard angioplasty catheter. Coronary arteriography was performed to demonstrate distal coronary blood flow through the perfusion balloon catheter. Electrocardiographic recordings and repeated left ventriculograms were performed to detect evidence of ischemia during standard and perfusion and balloon catheter inflations. The average inflation time was 3 +/- 1 minute for the standard catheter and 37 +/- 10 minutes for the perfusion catheter. Each dog had evidence of severe myocardial ischemia during standard inflation, yet none of the animals had ST-segment elevation, ventricular arrhythmia or wall motion abnormality during dilatation with the perfusion catheter. In a second experiment, the effect of prolonged balloon inflations (30 minutes) on intimal hyperplasia was evaluated in the rabbit model. Results of this study showed reduction of intimal and medial hyperplasia after 4 weeks in iliac arteries in rabbits treated with prolonged inflations compared with the contralateral vessel in rabbits treated with standard angioplasty. Initial clinical results from patients treated with this new catheter are presented. The availability of an effective autoperfusion catheter should allow for testing the hypothesis that prolonged inflations could alter the acute angioplasty success rate and long-term restenosis rate.

Doppler echocardiographic evidence of left ventricular diastolic dysfunction in ankylosing spondylitis.

Although cardiac involvement in the form of conduction abnormalities or aortic regurgitation occurs in 5 to 10% of patients with ankylosing spondylitis, few studies have assessed left ventricular (LV) function. This study assesses the prevalence of both systolic and diastolic LV dysfunction and other cardiac abnormalities in patients with ankylosing spondylitis who have no clinical cardiac manifestations. Fifty-nine patients (49 men and 10 women, mean age 42 +/- 10 years) underwent full clinical examination, electrocardiography, 24-hour Holter monitoring and 2-dimensional, M-mode and Doppler echocardiography. Mean disease duration was 17 +/- 9 years (range 1 to 42). Seventeen patients had evidence of noncardiac extraarticular manifestations. Precordial examination was normal in all. An age- and sex-matched control group of 44 healthy subjects was also studied. On echocardiography, abnormal LV diastolic function was detected in 12 patients (20%). Prolonged isovolumic relaxation time, prolonged deceleration time, reduced rate of descent of flow velocity in early diastole (EF slope) and reversal of the early and late peak transmitral diastolic flow velocities (E/A ratio) were noted in 9 patients. In 3 patients there was an increased E/A ratio, reduced deceleration time and increased EF slope. Mild aortic regurgitation and mitral regurgitation was seen in 1 and 3 patients, respectively. No abnormalities of left atrial size, LV systolic or diastolic dimensions or wall thicknesses were noted. There was no correlation between the presence of LV diastolic dysfunction and age, disease severity, disease duration, or the presence of extraarticular manifestations.(ABSTRACT TRUNCATED AT 250 WORDS)

Changes in standard electrocardiographic ST-segment elevation predictive of successful reperfusion in acute myocardial infarction.

The ability of the electrocardiographic ST segment to predict successful reperfusion after thrombolytic therapy remains controversial. To evaluate whether angiographically determined reperfusion could be predicted from changes in ST-segment elevation, the sum of ST-segment elevation in affected leads of the electrocardiogram was compared before and after thrombolytic therapy in 53 patients with acute myocardial infarction (AMI). Reperfusion status of the infarct-related artery was determined angiographically less than 8 hours from onset of symptoms. According to the Thrombolysis in Myocardial Infarction trial (TIMI) criteria, 33 patients had successful reperfusion (TIMI grade 2 to 3 flow) after thrombolytic therapy and 20 patients did not (TIMI grade 0 to 1 flow). Logistic multiple regression analysis showed that the proportional value for the shift in the sum of ST elevation, termed the "% ST change," was more strongly associated with reperfusion than the absolute measured difference in millimeters (chi-square = 11.34 vs 9.22). The entire spectra of sensitivities and specificities were determined to identify a level of the percent ST change with simultaneous high sensitivity and specificity. A 20% decrease in ST elevation provided such a level (88% sensitivity, 80% specificity). The positive and negative predictive values of a 20% decrease in ST elevation were 88 and 80%, respectively. These results suggest that a decrease of only 20% in the sum of ST elevation in the standard electrocardiogram after thrombolytic therapy is a useful noninvasive predictor of reperfusion status in patients with evolving AMI.

Repeat percutaneous transluminal coronary angioplasty and predictors of recurrent restenosis.

One hundred seventeen consecutive patients undergoing repeat percutaneous transluminal coronary angioplasty (PTCA) were studied to assess procedural success and recurrent restenosis rates. Clinical, anatomic and procedural variables were examined as predictors of recurrent restenosis using stepwise logistic regression analysis. Primary success was achieved in 114 patients (97.5%). One patient (0.8%) died after acute occlusion. No other in-hospital complications were encountered. After a mean follow-up interval of 218 +/- 160 days, 72 of 114 successfully dilated patients (63%) remained angina free. There were no late deaths. Three patients (2.6%) experienced a late myocardial infarction. Follow-up arteriography was performed in 100 patients (88%), of whom 32% had recurrent restenosis (greater than 50% luminal diameter narrowing). On univariate analysis, the presence of 3 clinical variables at repeat PTCA was associated with significantly higher recurrent restenosis rates compared with their absence, that is, unstable angina (48 vs 20%, p = 0.003), diabetes (61 vs 26%, p = 0.003) and hypertension (46 vs 18%, p = 0.003). Patients with recurrent restenosis had a shorter interval between first and second PTCA compared with those who remained patent (136 +/- 116 vs 214 +/- 163 days, p = 0.018). Multivariate analysis confirmed unstable angina, diabetes and hypertension as independent predictors of recurrent restenosis. Repeat PTCA may be performed for restenosis with a high likelihood of success and low incidence of complications. The rate of recurrent restenosis is similar to that reported for initial angioplasty. Patients with unstable angina, diabetes and hypertension appear to be at higher risk for recurrent restenosis.

Importance of early and complete reperfusion to achieve myocardial salvage after thrombolysis in acute myocardial infarction.

The importance of the timing and completeness of coronary artery reperfusion for limitation of acute myocardial infarction (AMI) size after intravenous thrombolytic therapy was studied in 39 patients. All had electrocardiographic epicardial injury and acute coronary angiography performed < 8 hours after symptom onset. Acutely jeopardized myocardium was estimated at baseline, and before and after angiography by quantitative ST-segment analysis. The AMI size was estimated on the final electrocardiogram by the Selvester QRS score. Left ventricular ejection fraction was measured at the time of acute angiography and before discharge in 31 of these patients. In the 21 patients with normal flow (Thrombolysis in Myocardial Infarction [TIMI] trial grade 3) in the infarct-related artery, the amount of jeopardized myocardium decreased from baseline to that before and after angiography (17 to 11 and 11%, respectively; p < 0.00005), and the median final AMI size was reduced (17 to 9%; p = 0.0004). In 6 patients with suboptimal flow (TIMI grade 2), the median amount of jeopardized myocardium decreased slightly from baseline to that before to after angiography (15 to 12%); however, the median final AMI size was not reduced (17%). In 12 patients with no reperfusion (TIMI 0 to 1) flow, the median amount of jeopardized myocardium remained unchanged from baseline to that before angiography (21%), and the final AMI size was not significantly reduced. There was a significant inverse correlation between the change in global left ventricular function and the difference between electrocardiographic estimated jeopardized and final AMI size (rs = -0.53; p = 0.008).(ABSTRACT TRUNCATED AT 250 WORDS)

Doppler echocardiographic detection of left ventricular diastolic dysfunction in patients with pulmonary sarcoidosis.

STUDY OBJECTIVE: To determine the prevalence of left ventricular diastolic dysfunction in patients with biopsy specimen-proved pulmonary sarcoidosis without clinical evidence of cardiac disease. DESIGN: A cross-sectional study. SETTING: A large tertiary care university teaching hospital. PATIENTS AND CONTROL SUBJECTS: Fifty consecutive subjects had biopsy specimen-proved pulmonary sarcoidosis without suspected cardiac involvement. Those with other conditions known to affect diastolic function were excluded. The control group comprised 30 healthy hospital workers. INTERVENTIONS: Clinical examination, 12-lead ECG, and combined echocardiographic/phonocardiographic examination. MEASUREMENTS: Indexes of left ventricular diastolic function, including isovolumic relaxation time, peak velocity of early (E) and late (A) ventricular filling, deceleration rate of early diastolic flow, and the sum of the time velocity integrals of E and A were obtained in each patient and control subject. Systolic function was determined using a modification of Simpson's rule. RESULTS: Diastolic dysfunction was present in 7 (14%) patients, 6 of whom had normal systolic function and normal two-dimensional echocardiographic examination. Those with diastolic dysfunction had a longer duration of illness (15 +/- 7 vs 6 +/- 5 years; p = 0.0004), were significantly older (52 +/- 11 vs 38 +/- 9 years; p = 0.0009), and had higher systolic BP (130 +/- 13 vs 117 +/- 12 mm Hg; p = 0.01) than the sarcoid patients with normal diastolic function. CONCLUSIONS: These results demonstrate a significant prevalence of left ventricular diastolic dysfunction in patients with pulmonary sarcoidosis. The cause of this abnormality may be a subclinical sarcoid cardiomyopathy.

The effects of transtracheal gas delivery on central inspiratory neuromuscular drive.

Previous studies have shown transtracheal delivery of low-flow oxygen (TTO) decreases inspired minute ventilation (Veinsp) and have postulated that this would result in a decrease in the work of breathing (WOB). We hypothesized that a fall in central inspiratory neuromuscular drive (CIND) with TTO would reflect a fall in WOB. We measured resting ventilatory parameters (RVP) and CIND by the mouth occlusion pressure technique (MOP) at different gas flow rates through the catheter in 21 subjects (13 men, 8 women; mean age, 60 +/- 10.6 years) with severe COPD with a mature intratracheal oxygen catheter (ITOC). We also constructed a lung/chest wall analog (LCA) to determine if flow through the catheter would alter pressure changes during inspiration. Inspiratory tidal volume (Vtinsp) and minute ventilation (Veinsp) decreased proportionally to the gas flow rate through the catheter. However, with increasing flow through the catheter, P0.1 increased in the LCA, presumably due to the Bernoulli effect. The lack of a similar change in the subject group suggests that CIND does, in fact, fall, and that possibly there is a decrease in WOB. This effect may be of benefit to patients with severe COPD.

The basics of heart failure management: are they being ignored?

BACKGROUND: Advances have been made in the medical management of congestive heart failure. However, there is concern that these changes may not be transmitted to the heart failure population in the community. Other impediments to improved prognosis, such as failure to apply non-pharmacological strategies and poor patient comprehension may also be prevalent in the community. AIMS: The purpose of this study was to assess physician practice and patient knowledge in a heart failure population admitted to a University Hospital in Ireland. METHODS: Patients admitted with a primary diagnosis of heart failure were studied. Estimation of ejection fraction was used to subdivide the population into heart failure with impaired and normal systolic function. Patients' course in hospital was noted with reference to management by cardiology or internal medicine, use of angiotensin-converting enzyme inhibition therapy and digoxin and application of dietary and rehabilitative services. Patient knowledge was assessed by questionnaire. RESULTS: Eighty patients were included in this study. Two-thirds of the population had impaired systolic function. The majority of patients were managed by internal medicine physicians, and this population was older and more likely to have normal systolic function. Prescription of converting enzyme inhibitor therapy was more frequently used in cardiology-managed patients (96 vs. 70%, P<0.05). Neither group applied dietary or rehabilitative advice to a significant level. Patient comprehension was poor, especially with regard to understanding of medicine and the value of weight measurement. CONCLUSION: The above data demonstrate a lack of use of rehabilitative and dietary services and poor patient knowledge. These deficiencies may play a role in determining outlook and may impede the expected improvement in prognosis that has been witnessed in large randomised studies.

Elimination of early rehospitalization in a randomized, controlled trial of multidisciplinary care in a high-risk, elderly heart failure population: the potential contributions of specialist care, clinical stability and optimal angiotensin-converting enzyme inhibitor dose at discharge.

BACKGROUND: Despite a growing body of data demonstrating the benefits of multidisciplinary care in heart failure, persistently high rates of readmission, especially within the first month of discharge, continue to be documented. AIMS: As part of an ongoing randomized study on the value of multidisciplinary care in a high risk (NYHA Class IV), elderly (mean age 69 years) heart failure population, we examined the effects of this intervention on previously high (20%) 1-month readmission rates. METHODS: Unlike previous studies of this approach, both multidisciplinary (MC) and routine care (RC) populations were cared for by the cardiology service, complied with adherence to clinical stability criteria prior to discharge (100% of patients) and received at least target dose angiotensin-converting enzyme (ACE) inhibition with perindopril prior to discharge (94% of indicated patients). We analysed death and unplanned readmission for heart failure at 1 month. RESULTS: This early report from the first 70 patients (67% male, 71% systolic dysfunction with a mean ejection fraction of 31.0+/-6.7%) enrolled in this study demonstrates elimination of 1-month hospital readmission in both RC and MC groups. This unexpected result represents a dramatic improvement both for this patient cohort (20% 30-day readmission rate prior to enrollment reduced to 0% following the index admission in both care groups) and in comparison with available data. CONCLUSIONS: Critical contributors to this improvement appear to be specialist cardiology care, adherence to clinical stability criteria prior to discharge and routine use of target or high-dose ACE inhibitor therapy prior to discharge. Widespread application of this approach may have a dramatic improvement in morbidity of CHF while limiting the escalating costs of this condition.

Xanthogranulomatous pyelonephritis. A comparison of the disease in the cat and man with special reference to the origin of the fat.

The origin of the intracellular fat in human xanthogranulomatous pyelonephritis has been the centre of some discussion in the past. A report of a case in a domestic cat is of interest as normal feline renal epithelium is rich in stainable fat. A comparison of the human and feline varieties of xanthogranulomatous pyelonephritis reveals certain fundamental differences between the two and reinforces the view that the fat concerned in the human disease does not originate in the renal epithelium.

Physiological effects of two FMRFamide-related peptides from the crayfish Procambarus clarkii

The present study examined the effects of two recently identified neuropeptides on crayfish hearts and on neuromuscular junctions of the crayfish deep abdominal extensor muscles. The two peptides, referred to as NF1 (Asn-Arg-Asn-Phe-Leu-Arg-Phe-NH2) and DF2 (Asp-Arg-Asn-Phe-Leu-Arg-Phe-NH2), increased the rate and amplitude of spontaneous cardiac contractions and increased the amplitude of excitatory junctional potentials (EJPs) in the deep extensors. Both effects were dose-dependent, but threshold and EC50 values for the cardiac effects were at least 10 times lower than for the deep extensor effects. The heart responded equally well to three sequential applications of peptide in any given preparation, but the responses of the deep extensors appeared to decline with successive peptide applications. The results support the hypothesis that these two neuropeptides act as neurohormones to modulate the cardiac and neuromuscular systems in crayfish. Quantal synaptic current recordings from the deep extensor muscles indicate that both peptides increase the number of quanta of transmitter released from synaptic terminals. Neither peptide elicited a measurable change in the size of quantal synaptic currents. NF1 caused a small increase in muscle cell input resistance, while DF2 did not alter input resistance. These data suggest that DF2 increases EJP amplitudes primarily by increasing transmitter release, while the increase elicited by NF1 appears to involve presynaptic and postsynaptic mechanisms.

Temperature dependence of synaptic modulation by a FMRFamide-related neuropeptide in crayfish.

The present study examined the temperature dependence of synaptic transmission and peptidergic modulation of chemical synapses on the phasic abdominal extensor muscles of crayfish. Decreasing the temperature from 25 degrees C to 5 degrees C in saline, decreased the EPSP amplitude by 88% and increased the EPSP half-decay time four-fold. The putative neurohormone DRNFLRFamide (DF2) increased EPSP amplitudes, but was more effective at 7-9 degrees C than at 15-17 degrees C. DF2 might play a hormonal role in counteracting low transmitter release at low temperature.

Sunbathing intentions in Irish people travelling to Mediterranean summer holiday destinations.

As exposure to UV light is thought to be the most significant environmental and behavioural risk factor for avoiding skin cancer, we have analysed the sunbathing intentions and attitudes of Irish people travelling to Mediterranean and Iberian holiday destinations. Ninety per cent of respondents planned to get a suntan on their vacation with 44% likely to burn their skin in the process. Although all intended to apply sun cream on holiday only 40% would apply >SPF 15. Sixty-four per cent planned to sunbathe between 11.00 am and 3.00 pm, with 25% intending to spend <5 hours in the sun. One-third of those intending to sunbathe for >6 hours per day were aged between 16 and 24 years. Approximately eight out of 10 people thought suntans made them feel healthier or attractive. Fifty-six per cent regularly checked their moles but men were less likely to check their skin for pigment changes. The results provide baseline information on sunbathing attitudes of Irish people. They show that while most people feel they adopt a careful approach to sunbathing, the experiences and intentions, especially in younger people, are influenced by the desirability of a suntan, and reflect a behaviour that increases their risk of skin cancer.

The effects of bone marrow transplantation on pulmonary function in children.

The effects of current methods of bone marrow transplantation (BMT) on pulmonary function in children have not been extensively studied. We reviewed serial pulmonary function tests (PFTs) in 25 children (median age, 9 yr; range, 4-15) who received allogeneic (n = 14) or autologous (n = 11) BMT for neoplastic diseases at The Johns Hopkins Hospital. The PFTs were obtained before BMT and at 6 months (early) and 15 months (late) after transplant. In all but 6 patients, PFTs were normal before BMT. A mild transient decline in carbon monoxide diffusing capacity (DLCO) was observed early after BMT but returned to baseline levels in the late post-BMT period. A trend towards worsening of PFTs with increasing age of patients was observed. The presence of graft-versus-host disease (GVHD) and pretransplant seropositivity for cytomegalovirus (CMV) were associated with significant decrements in several measurements of pulmonary function in the early post-BMT period. Patients given bulsulfan-containing preparative regimens tended to have less impairment of PFTs than those given other regimens using other combination high-dose chemotherapeutic agents or total body irradiation. These findings suggest that abnormalities in PFTs are common in the first months after BMT in pediatric patients but are not consistently associated with impairment of lung function when studied 15 months post-transplant.

Plasma atrial natriuretic peptide is elevated in patients with hypertrophic cardiomyopathy.

STUDY OBJECTIVES: To determine if plasma levels of atrial natriuretic peptide are elevated in patients with hypertrophic cardiomyopathy and to determine the relationship of atrial natriuretic peptide to symptoms and echocardiographic indices of left ventricular structure and diastolic function in these patients. DESIGN: A prospective study in which atrial natriuretic peptide was measured in peripheral venous plasma in 14 patients (age 44 +/- 14 years) with hypertrophic cardiomyopathy and 17 healthy controls. Echocardiography was performed in all cases and 30 controls to examine indices of left heart structure and function. All patients underwent clinical evaluation. RESULTS: The concentration of atrial natriuretic peptide was significantly higher in patients with hypertrophic cardiomyopathy than controls, (17.86 +/- 8.72 vs. 6.22 +/- 3.26 pmol/l, P = 0.0001). Diastolic dysfunction was observed in 11 of 14 patients with hypertrophic cardiomyopathy. No correlation was demonstrated between atrial natriuretic peptide levels and the degree of diastolic dysfunction, septal or free wall thickness, left atrial size, degree of mitral regurgitation or New York Heart Association functional class. CONCLUSIONS: Plasma levels of atrial natriuretic peptide are elevated in patients with hypertrophic cardiomyopathy but do not correlate with symptoms or echocardiographically-derived indices of left ventricular structure or diastolic function.