[Clinical relevance and indications for cardiac magnetic resonance imaging 2013: an interdisciplinary expert statement]. / Klinischer Stellenwert und Indikationen zur Magnetresonanztomografie des Herzens 2013: Ein interdisziplinäres Expertenstatement.

During the last years the indications of Cardiac Magnetic Resonance Imaging (CMRI) have been continuously expanded. However, the acceptance of the method by cardiologists and radiologists does not correlate with respect to the diagnostic potential. Several factors, such as expensive equipment, relatively long examination times, high technical know how and lack of remuneration, limit the application of CMRI in everyday clinical practice. Furthermore, doctors tend to apply more conventional, well established diagnostic procedures, the access to the method is still limited and there exist difficulties in the interdisciplinary collaboration. The interdisciplinary Austrian approach to Cardiac Imaging is aimed to improve the aforementioned problems and to support the implementation of CMRI in the diagnostic tree of cardiac diseases thus enabling a cost efficient management of patients in cardiology.

Clinical routine implantation of a dual chamber pacemaker system designed for safe use with MRI: a single center, retrospective study on lead performance of Medtronic lead 5086MRI in comparison to Medtronic leads 4592-53 and 4092-58.

AIMS: We report our experience concerning lead performance and re-surgery rate of the Medtronic EnRhythm MRI SureScan pacemaker system (MRI-PM) in comparison to standard pacemaker (PM) systems and leads used at our institution. METHODS: All patients (except patients with transvenous left ventricular leads) with successful PM implantation performed at our institution from 1 March 2009 to 31 October 2009 were included in this analysis and followed until mid January 2010. Lead measurements (assessed at implantation, prehospital discharge interrogation (1st follow-up) and at the first scheduled out-patient follow-up (2nd follow-up) were compared between atrial leads 4592-53 cm and 5086MRI-52 cm (lead group 1), and between ventricular leads 4092-58 cm and 5086MRI-52 cm/-58 cm (lead group 2), respectively. Causes for re-operations were assessed and compared between patients with standard dual chamber PM (DC-PM) and the MRI-PM. RESULTS: A total of 140 patients (VVI-PM: 36 patients; DDD-PM: 102 patients; biventricular PM: 1 patient) were successfully implanted with a PM within the implantation period. Two patients with transvenous left ventricular leads were excluded from further analysis. In an atrial position, lead 4592 was implanted in 51 patients and lead 5086MRI-52 cm was implanted in 40 patients, respectively. Ventricular leads were lead 4092-58 cm (64 patients) and lead 5086MRI (41 patients), respectively. Patients were followed for 26 ± 11 weeks. Comparison of lead measurements of lead group 1 showed significant differences for pacing impedance and pacing threshold at implantation, and for sensing at the 2nd follow-up. Comparison of lead measurements within lead group 2 showed significant differences for pacing impedance at implantation, for pacing threshold at the 1st follow-up, and for sensing, pacing threshold, and impedance at the 2nd follow-up. All assessed mean values were favorable for all leads at any follow-up. The number of re-operations was high in both dual chamber PM groups, but did not differ significantly between the two groups (DC-PM: 5 patients, 8.5%; MRI-PM: 5 patients, 13.2%). CONCLUSION: Our study demonstrates favorable lead measurements of lead model 5086MRI in comparison to lead 4592 and 4092 in a short-term follow-up. The number of re-operations was higher in the MRI-PM group, but not statistically different in comparison with the standard dual chamber PM group.

Forty-slice spiral computed tomography of the coronary arteries: assessment of image quality and diagnostic accuracy in a non-selected patient population.

PURPOSE: To investigate prospectively the image quality and diagnostic accuracy of 40-slice computed tomography (CT) for the detection of hemodynamically significant coronary artery disease (CAD) in a non-selected, consecutive patient cohort. MATERIAL AND METHODS: Forty consecutive patients (28 men, 12 women) underwent both 40-slice CT and conventional invasive coronary angiography (ICA) within 10+/-7 days. The results of both methods were compared on a per-segment and per-patient basis, using ICA as the standard of reference. RESULTS: According to ICA, significant CAD was present in 30/40 patients (75%). Of a total of 545 segments, 43 segments (7.9%) could not be sufficiently evaluated by CT due to motion artifacts in 15 segments (34.9%), small vessel size and suboptimal contrast enhancement in 14 segments (32.6%), severe calcification in 10 segments (23.3%), and opacified adjacent structures such as cardiac veins in four segments (9.3%). Segment-based analysis for detection of significant stenosis >50% yielded an overall sensitivity, specificity, positive predictive value, and negative predictive value of 87%, 99%, 98%, and 95%, respectively. Restricting the assessment to clinically relevant proximal coronary segments led to an increase in sensitivity to 96%, specificity to 99%, and negative predictive value to 99%. Patient-based analysis demonstrated a high negative predictive value (91%) of CT for excluding significant CAD, even when all segments were included in the analysis. CONCLUSION: In a non-selected patient population with a high prevalence of CAD, 40-slice CT demonstrates high diagnostic accuracy in the assessment of significant CAD per patient and per segment.

Afterload reduction in severe aortic regurgitation.

This study was designed to assess the effects of afterload reduction in asymptomatic patients with severe aortic regurgitation (AR) and maintained LV function by cine-MRI. We studied 13 patients at baseline and after 0.2 mg/kg Hydralazine (I.V.). Patients were stratified according to the volumetric LV response to acute afterload reduction: Group I comprised patients with improved LV response; Group II comprised patients with unchanged or deteriorated LV response. Baseline LV function and severity of AR were not significantly different between groups. However, regurgitant fraction decreased (50 +/- 12 vs. 36 +/- 9%; P < 0.03) and cardiac output increased (4.9 +/- 1.4 vs. 7.1 +/- 1.6l/minute; P < 0,001) in Group I and remained unchanged in Group II (54 +/- 10 vs. 55 +/- 10%, P = n.s. and 5.5 +/- 1.4 vs. 6.6 +/- 0.9l/minute; P = n.s.) during maximal vasodilation. Beat-to-beat analysis revealed a decrease of left ventricular endsystolic volume index in group I (48 +/- 13 vs. 37 +/- 9 ml/beat; P < 0.05) and no change in group II (61 +/- 20 vs. 62 +/- 20 ml/beat; P = n.s.). In the natural history of chronic AR, the absence of improved LV performance during acute vasodilation using beat-to-beat analysis by MRI may identify patients with more advanced cardiac adaptation to chronic volume overload.

The effects of ACE inhibitor therapy on left ventricular myocardial mass and diastolic filling in previously untreated hypertensive patients: a cine MRI study.

Cardiac remodeling in case of hypertension induces hypertrophy of myocytes and elevated collagen content and, subsequently, impaired diastolic filling of the left ventricle. The purpose of this prospective study was to evaluate changes of left ventricular (LV) myocardial mass, as well as diastolic filling properties, in hypertensive patients treated with the ACE inhibitor fosinopril. Sixteen hypertensive patients with echocardiographically documented LV hypertrophy and diastolic dysfunction received fosinopril (10-20 mg daily). Measurements of LV myocardial mass and properties of diastolic filling (peak filling fraction (PFF); peak filling rate (PFR)) were performed prior to medication, as well as after 3 and 6 months of therapy using cine magnetic resonance imaging (MRI). Ten healthy subjects served as a control group. LV myocardial mass (g/m2) decreased continuously within 3-6 months of follow-up by 32% (148 +/- 40 vs. 120 +/- 26 vs. 101 +/- 22 g/m2; P < 0.0001/0.005). The extent of regression correlated to the severity of LV hypertrophy at baseline (r = 0.77; P < 0.004). Early diastolic filling increased significantly within 6 months of therapy (PFF (%): 36 +/- 6 vs. 61 +/- 7, P < 0.0001; PFR (mL/second): 211 +/- 48 vs. 282 +/- 48, P < 0.001). Cine MRI can be used to assess the time course of pharmacological effects on cardiac remodeling in the course of hypertension. ACE inhibitor therapy results in a significant reduction of LV mass within 3 months and is accompanied by a normalization of diastolic filling that is completed after 6 months.

Radiological signs of a left atrial aneurysm.

We report a case of an acquired mid-sized extrapericardial aneurysm in the area of the left atrial appendage and demonstrate the diagnostic impact of several imaging methods. Chest radiography gave a hint to the diagnosis with a bulky mass of soft tissue density appearing adjacent to the left atrial appendage. Transthoracic as well as transesophageal echocardiography missed the origin of the aneurysm. Magnetic resonance imaging helped to establish the diagnosis with use of a coronal imaging plane. No contrast agent was necessary. Thus, the combination of chest X-ray and MRI provided excellent support for patient management.

Accuracy of echocardiographic right ventricular parameters in patients with different end-stage lung diseases prior to lung transplantation.

BACKGROUND: Because there are few data available on the accuracy of 2D-echocardiography to assess right ventricular (RV) size and function in patients with far-advanced lung disease, in this prospective study, we compared various echocardiographic RV parameters with RV volumes derived from magnetic resonance imaging (MRI). METHODS: In 32 patients (18 male, 17 female) presenting for lung transplantation, we measured RV end-diastolic and end-systolic area as well as derived RV fractional area change, long-axis diameter, short-axis diameter, tricuspid valve anulus diameter (using 2D apical or sub-costal 4-chamber view), and RV end-diastolic diameter (using M-mode in the parasternal short-axis view). These values were compared with RV end-diastolic and end-systolic volumes derived by MRI, serving as the gold standard. RESULTS: Right ventricular end-diastolic area was the most accurate echocardiographic parameter of RV size (correlation to MRI: r = 0.88, p < 0.001), followed by RV end-diastolic short-axis diameter (r = 0.75, p < 0.001), long axis diameter (r = 0.66, p < 0.001), and tricuspid valve anulus diameter (r = 0.63, p < 0.001). In contrast, M-mode measurement of RV end-diastolic diameter was possible in only 24/35 (68%) patients and showed a weak correlation to MRI-derived RV end-diastolic volume (r = 0.56, p = 0.004). Right ventricular fractional area change correlated well with MRI-derived RV ejection fraction (r = 0.84, p < 0.0001). In a sub-group analysis, patients with vascular lung disease showed best agreement between both methods for RV end-diastolic area and RV fractional area change compared with patients with restrictive or obstructive lung disease. CONCLUSION: This study shows that in patients with far-advanced lung diseases, RV end-diastolic area demonstrated the best correlation with MRI-derived measurement of RV end-diastolic volume, and RV fractional area change compared favorably with MRI-derived ejection fraction. Despite reduced image quality, especially in patients with obstructive lung disease, these parameters can yield clinically valuable information.

Magnetic resonance imaging evaluation of myocardial and pericardial disease.

Magnetic resonance imaging (MRI) has been shown to be an ideal noninvasive tool for imaging and diagnosing myocardial and pericardial diseases. In dilated and hypertrophic cardiomyopathy, MRI is suitable for the diagnosis and quantification of ventricular volume, stroke volume, and myocardial mass. Recent developments in the area of fast imaging techniques and MR contrast agents rapidly are increasing the utility of MRI for studying and assessing myocardial diseases. MRI may become a helpful technique with which to diagnose myocarditis and myocardial involvement in amyloidosis and sarcoidosis. Contrast-enhanced MRI also can be used for patients who have undergone heart transplantation to assess early signs of transplant rejection by improved contrast between normal and pathologic myocardium. For pericardial diseases, MRI provides an exact evaluation of the pericardial thickness, and it is a very sensitive technique for identifying pericardial effusions. Differentiation between hemorrhagic, serous, or chylous pericardial effusions usually can be made by using the typical signal behavior on T1-weighted and T2-weighted sequences. Due to its greater field of view and its ability to evaluate functionally the regional ventricular and atrial motion abnormalities in the typical tissue pattern, MRI has a significant potential in the evaluation of pericardial inflammation and constrictive pericarditis. J. Magn. Reson. Imaging 1999;10:617-626.

Influence of felodipine on left ventricular hypertrophy and systolic function in orthotopic heart transplant recipients: possible interaction with cyclosporine medication.

BACKGROUND: Concentric left ventricular (LV) hypertrophy develops early in orthotopic heart transplant (OHT) recipients. To compare the effects of a calcium channel blocker, felodipine, versus diuretics on LV hypertrophy and LV systolic function repeated magnetic resonance imaging studies were performed in OHT recipients. Cyclosporine levels and neurohormones were also measured to explore potential interactions with treatment. METHODS: Twenty-two patients were randomized at baseline (2 months after OHT) to receive felodipine or diuretic treatment. Before and after 4 months of treatment (n = 19), LV dimensions and LV mass (Simpson's rule) were measured. The relationship between circumferential fiber shortening (two-shell cylindrical model) and end-systolic wall stress was used as a measure of load-independent LV contractility. Neurohormones were measured at the beginning and end of the treatment period, and cyclosporine levels and blood pressures were additionally measured during treatment. RESULTS: At baseline, the felodipine and diuretic groups did not differ in LV mass, wall stress, and fiber shortening. During felodipine treatment LV mass decreased (p < 0.01) and tended to increase during diuretics treatment (p = 0.06). Afterload-corrected fiber shortening did not change during felodipine treatment, but decreased (p < 0.01) with diuretics. Changes in LV mass were positively correlated with cyclosporine levels (r = 0.70) in the diuretics group, but not in the felodipine group. CONCLUSIONS: In OHT recipients during diuretic treatment, progression of LV hypertrophy occurs in relation to cyclosporine plasma levels and is accompanied by impairment of systolic contractile function. Felodipine induces regression of LV hypertrophy, while systolic contractile function is preserved. During felodipine treatment, regression of LV hypertrophy is unrelated to cyclosporine levels. Thus, felodipine seems to attenuate the hypertrophic effect of cyclosporine on transplanted hearts.

Atrial natriuretic peptide release is more dependent on atrial filling volume than on filling pressure in chronic congestive heart failure.

BACKGROUND: The mechanism of atrial natriuretic peptide (ANP) release has been difficult to demonstrate in patient studies because of inaccuracies in measuring atrial volumes using conventional techniques. METHODS: Magnetic resonance imaging was performed in 28 clinically stable patients (New York Heart Association class 3) with chronic heart failure to determine right atrial (RA), left atrial (LA), and ventricular volumes. In addition, right heart catheterization was serially performed and plasma ANP levels (in picograms per milliliter) were drawn from the right atrium. RESULTS: Five patients had to be excluded from data analysis for technical reasons. The remaining 23 patients had the following hemodynamic measurements (mean +/- SD): RA mean pressure 7+/-5 mm Hg, pulmonary artery mean pressure 28+/-10, pulmonary capillary wedge pressure 21+/-8 mm Hg, and cardiac index 2.9+/-1.4 (L/min/m2), respectively. Plasma ANP levels were significantly elevated at 162+/-117 (normal range 20 to 65 pg/ml, p < 0.05), as were LA and RA volumes compared with healthy controls (RA volume 128+/-64 ml vs 82+/-25 ml, p < 0.05; LA volume 157+/-54 ml vs 71+/-24 ml, p < 0.01, respectively). ANP showed a stronger relation with atrial volumes (RA volume, r = 0.91, p = 0.0001; LA volume, r = 0.80, p = 0.001) than with atrial pressures (RA mean pressure, r = 0.45, p = 0.03; pulmonary capillary wedge pressure, r = 0.67, p = 0.001). A subgroup analysis of patients with increased RA or LA volumes (>1 SD of mean of controls) revealed a stronger relation between ANP and RA volumes than between ANP and LA volumes. CONCLUSIONS: These data suggest that increased right heart volume with subsequent increased atrial stretch is the major determinant for ANP release in patients with stable CHF.

Significance of morphological abnormalities detected by MRI in patients undergoing successful ablation of right ventricular outflow tract tachycardia.

BACKGROUND: MRI can demonstrate subtle morphological changes of the right ventricle in patients with idiopathic right ventricular outflow tract tachycardia (RVOT). The present study examines the incidence and significance of right ventricular (RV) abnormalities detected by MRI with respect to the site of successful radiofrequency catheter ablation of the clinical tachycardia. METHODS AND RESULTS: The study population comprised 20 patients (mean age, 40+/-12 years) undergoing elimination of recurrent RVOT by radiofrequency catheter ablation. MRI studies were performed before ablation to assess RV volumes and function, as well as structural abnormalities of the RV myocardium. Ten healthy age- and sex-matched subjects served as control subjects. The successful ablation sites, as documented by radiographs of the catheter position, were compared with MRI findings. Patients with RVOT showed no difference in respect to RV volumes and ejection fractions compared with control subjects. Whereas RV abnormalities were limited to prominent fatty deposits of the right atrioventricular groove extending into the inlet portion of the RV wall in 2 of 10 control subjects, MRI studies demonstrated morphological changes of the RV free wall in 13 (65%) of 20 patients with RVOT, including presence of fatty tissue (n=5), wall thinning (n=9), and dyskinetic wall segments (n=4). Eight of these patients had additional fat deposits, thinning, or a saccular aneurysm in the RV outflow tract, corresponding with the ablation site in 6 patients. CONCLUSIONS: In RVOT, structural abnormalities of the right ventricle can be detected in a substantial number of patients despite normal RV volumes and global function. MRI abnormalities within the RV outflow tract are significantly associated with the origin of tachycardia.

Assessment of early left ventricular remodeling in orthotopic heart transplant recipients with cine magnetic resonance imaging: potential mechanisms.

We performed short axis cine magnetic resonance imaging studies in 11 patients 2 months after they underwent orthotopic heart transplantation (OHT), and in 10 control subjects, to measure left ventricular (LV) volumes, mass, and end-systolic wall stress to assess ventricular remodeling after OHT. Although there were no significant differences in ventricular volumes and ejection fractions between heart transplant recipients and control subjects, heart transplant recipients had significantly higher LV mass (198 +/- 61 vs 132 +/- 27 gm, p = 0.001). As a consequence of myocardial hypertrophy, end-systolic wall stress was significantly reduced in heart transplant recipients compared with control subjects (34 +/- 16 vs 57 +/- 10 kdyne/cm2, p = 0.001). Moreover, heart transplant recipients had significantly reduced end-systolic wall stress/volume ratio when compared with control subjects (0.89 +/- 0.3 vs 1.26 +/- 0.3 kdyne/cm2/ml, p < 0.01), indicating an already reduced LV contractility 2 months after heart transplantation. Univariate regression analysis revealed a significant correlation between LV mass and averaged cyclosporine levels, but no correlation between LV mass and blood pressure, cold ischemic time, acute rejection, age, body mass, blood pressure, plasma catecholamine levels, or plasma renin activity. Magnetic resonance imaging demonstrates early LV remodeling after OHT with reduced myocardial contractility. Cyclosporine may be contributing to these changes.

[Heart valve diseases]. / Klappenerkrankungen.

Although valvular stenosis may be evaluated adequately by measuring transvalvular pressure gradients with Doppler echocardiography and cardiac catheterization, these methods have failed to provide reliable and accurate quantification of valvular regurgitation. In recent years the development of magnetic resonance imaging has broadened the diagnostic spectrum in cardiology, since it allows assessment of ventricular volumes without geometrical assumptions and the non-invasive quantification of blood flow within the heart and great vessels. The purpose of this overview is to evaluate "established" diagnostic tools and to show the capabilities of magnetic resonance imaging in the assessment of valvular heart disease.

Measurement of coronary blood flow velocity during handgrip exercise using breath-hold velocity encoded cine magnetic resonance imaging.

Coronary blood flow velocity was measured during handgrip exercise using breath-hold velocity encoded cine magnetic resonance imaging. Peak diastolic coronary flow velocity in the left anterior descending artery was 20.6 +/- 9.3 cm/s (mean +/- SD) at baseline and increased significantly to 31.1 +/- 16.4 cm/s after exercise (50.7 +/- 31.3% increase, p <0.01).

Plasma exchange for treatment of thrombotic thrombocytopenic purpura in critically ill patients.

OBJECTIVE: Description of diagnostic procedures, treatment modalities and intensive care management of patients with thrombotic thrombocytopenic purpura (TTP). DESIGN: Descriptive study. SETTING: Internal medicine Intensive Care Unit (University Hospital of Vienna). PATIENTS: Six patients (two after allogeneic bone marrow transplantation), treated for 12 episodes of TTP. INTERVENTIONS: Treatment with plasma exchange (fresh frozen plasma, 50-80 ml/kg per day), prednisone (0.75 mg/kg b.i.d.) and, in some cases, vincristine. Supportive therapy as needed. MEASUREMENTS AND RESULTS: Patients were admitted to the ICU because of neurological symptoms with acute onset (42% mild, 58% severe), hemolysis and thrombocytopenia. Additional symptoms were fever (50%), bleeding tendency (50%), acute renal failure (42%) and metabolic derangement (8%). Initial laboratory values showed thrombocytopenia (median 17 G/l), hemolysis (median hemoglobin 10.0 g/dl, lactate dehydrogenase 635 U/l, reticulocyte count 175 G/l) with red cell fragmentation. Coagulation tests were normal. Respiratory assist was needed in six episodes (severe seizures, cardiopulmonary resuscitation). In patients without preexisting hematological abnormality the platelet counts exceeded 100 G/l after 3-8 cycles of plasma exchange. In patients after bone marrow transplantation, the platelet counts never exceeded 40 G/l, but the lactate dehydrogenase levels dropped significantly. The neurological symptoms disappeared in all patients and renal function normalized. One patient died before the initiation of therapy. Three patients relapsed 1-3 times between 2 weeks and 5 months after the last episode. The relapses were associated with symptoms similar to the first episode and responded promptly to plasma therapy. CONCLUSIONS: TTP is a rare, but life-threatening disorder. It needs immediate diagnosis and has a good prognosis after adequate treatment with plasma exchange.

Cardiac abnormalities in patients with primary hyperparathyroidism: implications for follow-up.

Patients with primary hyperparathyroidism (PHPT) show a high incidence of left ventricular hypertrophy, cardiac calcific deposits in the myocardium, and/or aortic and mitral valve calcification and thus may carry an increased risk of death from circulatory diseases. This prospective study was designed to assess an effect of parathyroidectomy on cardiac abnormalities of patients with PHPT. Echocardiography was used to evaluate the mechanical performance of the heart muscle, the thickness of the left ventricular wall, myocardial calcific deposits, and valvular calcifications within 12 and 41 months after parathyroidectomy. In a blinded fashion, aortic and mitral value calcifications were determined in 46% and 39% of patients with PHPT. Calcific deposits in the myocardium were found in 74% of patients. Follow-up studies after parathyroidectomy disclosed no evidence of progression of these calcifications. Before operation left ventricular hypertrophy was detected in 82%. After parathyroidectomy and 41 months of normocalcemia and normal PTH concentrations, a regression of hypertrophy of the interventricular septum and the posterior wall by -6% and -19% (P < 0.05) was observed. Subgroup analysis disclosed the most impressive long-term reduction of left ventricular hypertrophy in patients without a history of hypertension (-11% and -21%; P < 0.05 and P < 0.005); no changes were determined in 9 patients who developed secondary hyperparathyroidism after operation. The present data show a high incidence of left ventricular hypertrophy and aortic and/or mitral valve calcifications in patients with PHPT. Follow-up at 1 year and at 41 months after successful parathyroidectomy disclose regression of hypertrophy. Our results give evidence that parathyroid hormone per se plays an important role in the maintainance of myocardial hypertrophy. Post-surgical restoration of normocalcemia and normalization of parathyroid hormone valvular sclerosis persists without evidence of progression. We further conclude that patients with PHPT and parathyroidectomy are at low risk for the development of severe aortic and mitral valve stenosis within this period of time.

Quantification of the extent of area at risk with fast contrast-enhanced magnetic resonance imaging in experimental coronary artery stenosis.

Fast magnetic resonance (MR) imaging techniques have the capability of demonstrating regions of ischemia caused by stenosis. The size of the potentially ischemic area determines the importance of the stenosis. The purpose of this study was to determine the relative values of relaxivity-enhancing and magnetic-susceptibility MR contrast media in detecting and sizing the area at risk in dogs. Eight dogs were subjected to critical left circumflex coronary artery (LCX) stenosis. Sixty sequential inversion-recovery- and driven-equilibrium-prepared fast gradient recalled echo images were acquired during bolus administration of 0.03 mmol/kg gadodiamide or 0.4 mmol/kg sprodiamide in basal and vasodilated (dipyridamole-stress) states. The size of the area at risk was measured and compared with that measured post mortem. In the basal state, gadodiamide and sprodiamide equivalently altered the signal intensities of nonischemic myocardium and the territory of stenosed coronary artery. Dipyridamole produced a significant increase in left anterior descending coronary artery flow with a decrease in LCX flow. The hypoperfused region was observed as a low-and high-signal intensity region after administration of gadodiamide and sprodiamide, respectively. The size of the hypoperfused region was slightly smaller with gadodiamide (37.4% +/- 2.8%) and sprodiamide (34.0% +/- 2.2%) than the true area at risk measured post mortem (41.8% +/- 2.2%; p < 0.05). Dipyridamole perfusion MR imaging with relaxivity or susceptibility contrast media is a noninvasive method to identify and quantify the area at risk in the territory of a stenotic coronary artery. Changes in myocardial signal intensity on fast gradient recalled echo images reflect the augmentation of flow and volume induced with dipyridamole and are consistent with the "steal phenomenon."

Effects of two different enalapril dosages on clinical, haemodynamic and neurohumoral response of patients with severe congestive heart failure.

Angiotensin converting enzyme inhibitors improve symptoms and prolong life in congestive heart failure, but the dose in the individual patient is uncertain. A randomized, 48-week, double-blind study was performed to investigate the safety and efficacy of 'high' in comparison to continued 'low' angiotensin converting enzyme inhibitor therapy in severe heart failure. Eighty-three patients (56 +/- 1.1 years; 69 men, 14 women) in New York Heart Association functional class III/IV on digoxin, furosemide and 'low' angiotensin converting enzyme inhibitors (captopril < or = 50 mg.day-1 or enalapril < or = 10 mg.day-1) were included. After a > or = 14 day run-in on 10 mg.day-1 enalapril, digitalis and furosemide, right heart catheterization at rest and exercise was performed. All patients presented with atrial pressure > 10 mmHg and/or pulmonary artery pressure > 35 mmHg, and/or cardiac index < 2.5 l.min-1.m-2 at rest. Patients then received enalapril 5 mg twice daily (n = 42), or 20 mg twice daily (n = 41) in random order. Thus, patients randomized to low doses of enalapril actually had no change in therapy from baseline to 48 weeks. Forty-three patients (52%) completed the study, 19 patients on the low dose and 24 patients on the high dose. Both dosages equally influenced survival with 15 (18%) deaths, eight on low dose and seven on high dose. After 48 weeks, functional capacity by New York Heart Association class improved more on the high dose than on the low dose (P = 0.04). In contrast, alterations in invasive haemodynamic variables at rest and exercise as well as maximal exercise capacity were comparable in both groups. Diastolic blood pressure decreased and the change between both groups was statistically significant (P = 0.01). Changes in plasma creatinine levels did not differ between high and low dose treatment and no patients had to be withdrawn because of deterioration in kidney function. With regard to neurohumoral activity, a tendency to a discrepant response to both treatments was observed with a blunted increase in noradrenaline on high versus low enalapril dose. Thus, high-dose enalapril treatment proved superior to low dose as regards symptomatology in severe heart failure after long-term treatment, despite similar effects on haemodynamics and on maximal exercise capacity.