[Clinical relevance and indications for cardiac magnetic resonance imaging 2013: an interdisciplinary expert statement]

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.

[Heart valve diseases]

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.

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.

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).

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.

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.

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.

Value of three-dimensional echocardiography as an adjunct to conventional transesophageal echocardiography

Three-dimensional imaging of cardiac structures could enhance the functional understanding and the interpretation of pathologies. Limited processing capabilities, relocation problems and inadequate two-dimensional image quality have previously limited its applicability. Recently, an integrated echocardiographic computerized tomography unit (echo-CT) which uses a transesophageal approach has been developed. This system is capable of sampling and processing multiple echocardiographic images and, thus, provides three-dimensional views. To evaluate the feasibility and potential of this technique, we studied 69 patients with various cardiac disorders. All but 3 patients (96%) tolerated the procedure well allowing at least one scan to be performed. No complications were encountered. The indication for echo-CT included coronary artery disease (n = 4), mitral valve disease (n = 18), suspected arterial embolism (n = 19), masses (n = 8), congenital malformation (n = 10), postcardiac surgery (n = 8), aortic aneurysm (n = 1) and suspected left-to-right shunt (n = 1). Conventional transesophageal echocardiography revealed a pathology in 45 patients. Of these pathologies, 37 (82%) could be reconstructed and displayed in three-dimensional views. Three-dimensional imaging provided an improved spatial understanding of the pathology in 21 cases (39%). Echo-CT was especially valuable in diseases of the mitral value (i.e. mitral valve prolapse, flail leaflets, mitral stenosis) where it had the potential to delineate the location, type and morphology of defects. In conclusion, three-dimensional transesophageal imaging enhances image interpretation and understanding. This could be of value in complex morphologies and cardiac disorders in which surgical repair is attempted.

Three-dimensional echocardiography using a transoesophageal imaging probe. Potentials and technical considerations

Appreciation of three-dimensional relationships could be useful in cardiac diagnosis, decision making and planning of surgery. However, current ultrasound techniques provide only two-dimensional views. A recently developed echocardiographic computerized tomography unit allows reconstruction of three-dimensional images from a series of transoesophageal slices. To evaluate the potentials and limitations of this technique we performed echo computer tomographic examinations in 104 patients with a total number of 227 scans. All but two patients tolerated the procedure well and no serious complications were encountered. Indications for echo computer tomography included coronary artery disease, valvular heart disease, atrial masses, myocardial infarction, mitral and aortic valve replacement, aortic aneurysm and congenital defects. Most of the anatomical structures could be visualized with the best results obtained for the left atrium, the left ventricular outflow tract and the aortic and mitral valve apparatus. However, a variety of technical factors must be considered to achieve optimal results and to avoid misinterpretation. In 86% of patients the underlying pathology could be visualised by echo-computed tomography, particularly congenital defects such as those of the atrial or ventricular septa, but mitral valve pathologies provided the best results. In these cases three-dimensional imaging led to a better perception and understanding of structural relationships. In conclusion, despite current limitations in data acquisition, processing and computing power, echo computer tomography has the potential to provide relevant information in selected clinical settings.

Assessment of hemodynamic effects of angiotensin-converting enzyme inhibitor therapy in chronic aortic regurgitation by using velocity-encoded cine magnetic resonance imaging

Long-term treatment with angiotensin-converting enzyme (ACE) inhibitors has beneficial effects in patients with chronic aortic regurgitation by reducing left ventricular volumes and regurgitant fraction. Velocity-encoded cine magnetic resonance imaging can directly measure antegrade (forward stroke volume) and retrograde blood flow (regurgitant volume) in the ascending aorta. Velocity-encoded cine magnetic resonance imaging was used in 9 patients with moderate to severe aortic regurgitation (regurgitant fraction 49% +/- 17%) to measure regurgitant fraction, regurgitant volume, and forward stroke volume at baseline and 3 months after therapy with enalapril (mean dose 29 +/- 13 mg). Ten additional patients with aortic regurgitation without any drug therapy served as a control group. In the treatment group, systolic blood pressure slightly decreased from 132 +/- 20 mm Hg to 121 +/- 14 mm Hg (p = not significant), whereas diastolic blood pressure and heart rate (beats per minute) remained unchanged. Regurgitant fraction decreased in 6 patients (responders) from 49% +/- 19% to 39% +/- 20% (percentage change 24% +/- 14%, p = 0.002) and was unchanged in 3 patients (nonresponder, 49% +/- 19% vs 51% +/- 16%; p = not significant). In the responder group, forward stroke volume increased from 128 +/- 32 ml to 148 +/- 57 ml, whereas regurgitant volume remained unchanged (67 +/- 40 ml vs 65 +/- 51 ml). At baseline, the responder group had a significant higher total vascular resistance than the nonresponder group (998 +/- 538 dyne.sec.cm-5 vs 625 +/- 214 dyne.sec.cm-5; p < 0.05). With enalapril treatment, total vascular resistance in the responder group tended to decrease (891 +/- 576 dyne.sec.cm-5), but slightly increased in the nonresponder group (679 +/- 276 dyne.sec.cm-5). The control group showed no changes in regurgitant fraction, regurgitant volume, forward stroke volume, and total vascular resistance at follow-up.

Improved reproducibility in measuring LV volumes and mass using multicoil breath-hold cine MR imaging

There is a generally recognized need for improvement in quality of fast cardiac MR images. Consequently, breath-hold cine MR images were obtained with multiple surface coils connected to phased array receivers, and C/N, intra-observer and inter-observer variabilities for LV volumes and mass were evaluated. Two sets of short-axis images of the LV, one with multiple surface coils and another with a body coil, were acquired in eight subjects with a fast cine MR sequence using k-space segmentation (TR/TE = 7/2.2 msec, temporal resolution = 56 msec). C/N with multicoil imaging was 32.2 +/- 7.6 (mean +/- SD), significantly higher than that with a body coil (11.0 +/- 3.3, P < .01). The mean percentage differences in intra-observer and inter-observer measurements with multicoil imaging were significantly better than those with a body coil. In conclusion, multicoil imaging provides significant gain in C/N on breath-hold cine MRI of the heart. In addition, intra-observer and inter-observer reproducibilities are improved with multicoil imaging.

Breath-hold MR measurements of blood flow velocity in internal mammary arteries and coronary artery bypass grafts

Breath-hold velocity-encoded cine MR (VENC-MR) imaging is a feasible method for measuring phasic blood flow velocity in small vessels that move during respiration. The purposes of the current study are to compare breathhold VENC-MR measurements of flow velocities in the internal mammary arteries (IMA) with nonbreath-hold measurements and to characterize the systolic and diastolic flow velocity curves in a cardiac cycle in native IMA and IMA grafts. Flow velocity in 30 native IMA and 8 IMA grafts were evaluated with a breath-hold VENC-MR sequence with K-space segmentation and view-sharing reconstruction (TR/TE = 16/9 msec, VENC = 100 cm/s). In 10 native IMA, nonbreath-hold VENC-MR images were acquired as well for comparison. Breath-hold VENC-MR imaging showed significantly higher systolic and diastolic peak velocities in native IMA (43.1 cm/second +/- 15.0 and 10.0 cm/second +/- 4.8), in comparison to those of nonbreath-hold VENC-MR imaging (27.6 cm/second +/- 10.2 and 7.3 cm/second +/- 3.9, P < .05). The diastolic/systolic peak velocity ratio in the IMA grafts (.88 +/- .41) was significantly higher than that in native IMA (.24 +/- .08, P < .01). Interobserver variability in the flow velocity measurement was less than 4%. Breath-hold VENC-MR imaging demonstrated higher peak flow velocity in the IMA than nonbreath-hold VENC-MR imaging. This technique is a rapid and effective method for the noninvasive assessment of blood flow velocity in IMA grafts.

Phase I/II trial of dexverapamil, epirubicin, and granulocyte-macrophage-colony stimulating factor in patients with advanced pancreatic adenocarcinoma

BACKGROUND

The purpose of this study was to determine the maximum tolerated dose (MTD) of a cytotoxic regimen consisting of the second-generation chemosensitizer dexverapamil (DVPM), high dose epirubicin, and recombinant human granulocyte-macrophage-colony stimulating factor (GM-CSF) in pancreatic carcinoma.

PATIENTS AND METHODS

Twenty-eight previously untreated patients with locally advanced or metastatic adenocarcinoma of the pancreas were studied. Treatment consisted of oral DVPM at a dose of 1000-1200 mg/day for 3 days, epirubicin administered as an intravenous bolus injection on Day 2 with an initial dose of 90 mg/m2, and a dose of GM-CSF of 400 micrograms administered subcutaneously from Day 5s through 14. Epirubicin dose escalation levels were 90, 105, 120 and 135 mg/m2. Consecutive cohorts of four to eight patients were planned at each dose level. Treatment cycles were repeated every 3 weeks.

RESULTS

Hematologic toxicity, specifically granulocytopenia, constituted the dose-limiting toxicity with an MTD of 120 mg/m2 for epirubicin. Despite routine supportive therapy with GM-CSF, four, two, and five patients experienced Grade 4 granulocytopenia during their first two treatment courses at levels 105, 120, and 135 mg/m2, respectively. Grade 4 granulocytopenia was observed in two, three, and one additional patients during subsequent courses with these levels. Nonhematologic toxicity was uncommon, generally modest, and did not correlate clearly with the anthracycline dose. Dexverapamil-related cardiovascular symptoms occurred frequently, but they never resulted in serious toxicity requiring active medical intervention or permanent discontinuation of therapy. Nine of 28 patients achieved partial responses to this therapy. Stable disease was observed in nine patients, and tumor progress occurred in 10.

CONCLUSION

The MTD of epirubicin for this regimen with DVPM and GM-CSF was 120 mg/m2 every 3 weeks. Though it remains uncertain whether the encouraging response activity observed in this disease-oriented Phase I study was, in fact, due to successful modulation of multidrug resistance, these results suggest that this regimen is likely to be an effective and tolerable treatment strategy for patients with pancreatic cancer, which should be evaluated further.

Assessment of valvular heart disease by magnetic resonance imaging

MRI has developed very rapidly and now provides anatomic and functional information in cases of valvular heart disease. MRI has several important attributes that make it advantageous for the evaluation of valvular heart disease. First, the natural contrast between flowing blood and surrounding cardiovascular structures provides sharp delineation of endocardial and epicardial borders without the need for contrast media. This feature in combination with the essential three-dimensional nature of this imaging technique allows precise quantification of cardiac volumes, function, and mass without the use of any assumed formulas or geometric models. Second, blood flow-sensitive GRE techniques are able to identify areas of turbulent flow caused by stenotic or regurgitant valves. With this technique regurgitant jets can be visualized and semiquantitative grading can be performed as with color Doppler. Third, recently developed velocity-encoded techniques permit measurements of blood flow velocities across stenotic native and prosthetic heart valves and retrograde flow caused by regurgitation. Moreover, the close interstudy reproducibility of measurements of cardiac dimensions and valvular regurgitation suggests a role in assessing the effect of therapeutic interventions.

Comparative assessment of right ventricular volumes and ejection fraction by thermodilution and magnetic resonance imaging in dilated cardiomyopathy

Measurements of right ventricular (RV) ejection fraction (EF) and volumes using a new thermodilution technique were compared to serially performed magnetic resonance imaging (MRI) in 21 patients with dilated cardiomyopathy. For RVEF (%) and RV volume indices (ml/m2) the following correlation coefficients were found: RVEF r = 0.82; end-diastolic volume index (EDVI) r = 0.45; end-systolic volume index (ESVI) r = 0.65; stroke volume index (SVI) r = 0.61; all p < 0.05. However, RVEF by thermodilution was significantly lower (RVEF thermo = 31 +/- 14 vs. RVEF MRI = 50 +/- 14, p < 0.01) and RV EDV and ESVI were significantly higher compared to MRI, while SVI showed no significant difference. Exclusion of patients with atrial fibrillation (n = 8) improved the correlations (RVEF r = 0.94, EDVI r = 0.77, ESVI r = 0.87, SVI r = 0.65, all p < 0.05), but did not reduce the mean difference between both methods.

Beneficial hemodynamic effects of prostaglandin E1 infusion in catecholamine-dependent heart failure: results of a prospective, randomized, controlled study

OBJECTIVE

To study the hemodynamic effects of prostaglandin E1 (PGE1) administered in addition to a standard catecholamine infusion in patients with severe chronic heart failure.

DESIGN

Prospective, placebo-controlled, randomized, single-blind study.

SETTING

Intensive care unit at a university hospital.

PATIENTS

Thirty patients with severe chronic heart failure, New York Heart Association functional class IV (28 men, two women, with a mean age of 54 +/- 2 yrs, mean left ventricular ejection fraction 10 +/- 0.6%). All patients received oral therapy with digitalis, furosemide (mean dose 300 +/- 46 mg/day), and enalapril (20 +/- 2.7 mg/day).

INTERVENTIONS

Hemodynamic measurements using pulmonary artery flotation catheters were performed at baseline, > or = 24 hrs after standardized catecholamine infusion with dopamine (3 micrograms/kg/min) and dobutamine (5 micrograms/kg/min), as well as 48 hrs after randomization to infusion therapy with PGE1 (30 ng/kg/min) or a placebo.

MEASUREMENTS AND MAIN RESULTS

The addition of PGE1 to an ongoing catecholamine infusion in 20 patients caused a 16 +/- 4% decrease in mean pulmonary arterial pressure (p < .001), a 22 +/- 5% decrease in pulmonary artery occlusion pressure (p < .0001), a 24 +/- 8% decrease in pulmonary vascular resistance index (p < .001), a 20 +/- 9% decrease in right atrial pressure (p < .01), a 14 +/- 3% decrease in mean arterial pressure (p < .001), and a 29 +/- 4% decrease in systemic vascular resistance index (p < .0001). These PGE1-induced decreases occurred without a change in heart rate. Stroke volume index increased with PGE1 therapy by 34 +/- 7% (p < .0001), and cardiac index increased by 34 +/- 6% (p < .0001). No hemodynamic changes were observed during combined infusion with catecholamines and placebo in ten patients.

CONCLUSION

PGE1 improves the hemodynamic state in end-stage chronic heart failure patients already receiving a standard dose dopamine/dobutamine infusion.

Effect of lung transplantation on right and left ventricular volumes and function measured by magnetic resonance imaging

To evaluate the effect of lung transplantation on right ventricular (RV) and left ventricular (LV) volumes and function, magnetic resonance imaging (MRI) was performed in 11 patients before and 6 to 24 months after single (n = 7) or double (n = 4) lung transplantation as well as in 15 healthy control subjects. Prior to transplantation, RV end-diastolic (RVEDVI, ml/m2) and end-systolic (RVESVI, ml/m2) volume indices were significantly increased in patients compared with those in control subjects. RV ejection fraction (RVEF, %), although within the lower normal range, was significantly reduced. In contrast, LV volume indices (ml/m2) were significantly smaller in patients than in control subjects, whereas LV ejection fraction (LVEF, %) was not different from that in normal subjects. After lung transplantation, MRI revealed a significant reduction in RVEDVI from 73 +/- 29 to 54 +/- 14 (p = 0.03) and RVESVI from 38 +/- 23 to 20 +/- 6 (p = 0.01) with a concomitant significant increase in RVEF from 48 +/- 14 to 63 +/- 6 (p = 0.01). Consecutively, the LV expanded to normal (LVEDVI from 49 +/- 12 to 65 +/- 14, p = 0.01; LVESVI from 23 +/- 9 to 28 +/- 7, p = 0.05), whereas LVEF remained unchanged (55 +/- 9 versus 56 +/- 8).

Magnetic resonance imaging of the heart during positive end-expiratory pressure ventilation in normal subjects

OBJECTIVES

Magnetic resonance imaging was used to assess the effects of ventilation with positive end-expiratory pressure (PEEP) on cardiac volumes, especially on atrial volumes as well as to determine semiquantitative measurements of spatial interactions between heart, lungs and chest.

DESIGN

Prospective study with healthy volunteers undergoing mechanical ventilation with different levels of PEEP during magnetic resonance imaging.

SETTING

Magnetic resonance unit, Institute of Diagnostic Imaging, Rudolfinerhaus Hospital.

SUBJECTS

Twelve healthy volunteers.

INTERVENTIONS

Volunteers were imaged, using a multislice-multiphase technique during spontaneous breathing and with PEEP values of 0, 7, and 15 cm H2O.

MEASUREMENTS AND MAIN RESULTS

Atrial as well as ventricular volumes, chest diameters, and midventricular contact between the heart and anterior chest wall were determined on transverse-oblique sections. Atrial volumes showed a progressive decline beginning at a PEEP of 7 cm H2O. Diastolic filling of both ventricles was reduced. A PEEP level of 15 cm H2O induced a significant increase in the sagittal-oblique but not in the transverse-oblique chest diameter. PEEP values of 7 and 15 cm H2O shortened the length of the midventricular contact between the heart and anterior chest wall.

CONCLUSIONS

Left and right ventricular end-diastolic volumes and stroke volumes decreased significantly during ventilation with PEEP at 15 cm H2O, as did end-systolic atrial volumes. Volume changes in association with changes of chest and heart configuration suggest external cardiac compression by the expanding lungs. Furthermore, this study illustrates the feasibility of magnetic resonance imaging in mechanically ventilated patients.

Magnetic resonance imaging in the diagnosis of acute Lyme carditis

Lyme disease is a multisystem disease, which can involve the heart causing myopericarditis. We describe 1 patient with serological and histological evidence of Lyme borreliosis and demonstration of pathologic myocardial signal enhancement in magnetic resonance imaging.

Indium 111-monoclonal antimyosin antibody and magnetic resonance imaging in the diagnosis of acute Lyme myopericarditis

BACKGROUND

Lyme borreliosis is a tick-borne multisystem disorder that may present as self-limiting early or persistent chronic diseases of the skin, nervous system, joints, heart, and other organs. Cardiac involvement has mainly been reported as acute atrioventricular conduction disturbances or transient ventricular dysfunction.

METHODS AND RESULTS

We treated a patient with clinical signs of acute myopericarditis and serologic evidence of Lyme borreliosis confirmed by silver staining of endomyocardial biopsy specimens and indium 111-monoclonal antimyosin antibody scan, which we believe has not been reported previously. Additionally, magnetic resonance imaging revealed epicardial and myocardial areas of increased intensity.

CONCLUSION

Indium 111-monoclonal antimyosin antibody scanning and magnetic resonance imaging might play an additional important role in assessing and confirming the diagnosis of Lyme carditis in the presence of clinical symptoms and positive serologic findings.

Doppler sonographic evaluation of the Duromedics-Edwards bileaflet valve at five-year follow up

In order to define normal flow characteristics at mid-term follow up, prospective Doppler echocardiographic studies were performed in 145 patients (mean age 49.3 years) with Duromedics-Edwards bileaflet valve prostheses (76 aortic, 55 mitral and 14 double aortic and mitral) at a mean interval of 5.2 years following operation. All patients had clinically normal prosthetic valve function and no clinical or radiographic signs of heart failure. None of the patients had severely impaired left ventricular function as assessed by cross sectional 2D echocardiography. Mean peak velocity across prostheses in the aortic position was 2.8 +/- 0.5 m/sec, corresponding to a calculated instantaneous peak pressure gradient of 31.4 +/- 10.2 mmHg. Gradients varied inversely to valve size, although differences were significant only when comparing the 19mm and 21mm versus the 27mm valve (p < 0.05). In the mitral position the mean of peak velocity was 1.8 +/- 0.3 m/sec and pressure half time was 102 +/- 14 msec, representing a calculated mean orifice size of 2.2 +/- 0.5 cm2, with no significant difference between valves of different sizes. Paravalvular regurgitation was more common in the aortic than in mitral position (39% vs. 4%, p < 0.05), although in all cases it was mild (range less than one centimeter from prosthesis ring) and clinically insignificant. We conclude that normally functioning DE valve prostheses have a predictable range of Doppler echocardiographic parameters, although the individual variability of pressure gradients and effective valve area (in mitral valves) has to be emphasized. Nevertheless, the Duromedics Edwards valve shows good hemodynamic properties at mid-term follow up.

Primary hyperparathyroidism: incidence of cardiac abnormalities and partial reversibility after successful parathyroidectomy

PURPOSE

This prospective study was designed to assess the effect of primary hyperparathyroidism on heart muscle, valves, and myocardial function. Echocardiography was used to evaluate changes in mechanical performance, the thickness of the left ventricular wall, myocardial calcific deposits, and valvular calcifications in patients with primary hyperparathyroidism.

METHODS

Echocardiography was performed in 54 patients with hyperparathyroidism prior to surgery and 12 +/- 2 months after successful parathyroidectomy. A matched control group was followed for comparison.

RESULTS

In a blinded fashion, aortic and mitral valve calcifications were detected in 63% and 49% of patients with primary hyperparathyroidism (controls: 12% and 15%, respectively). Calcific deposits in the myocardium were found in 69% of patients with hyperparathyroidism and 17% of the control subjects. After parathyroidectomy and 12 months of normocalcemia, a significant regression of left ventricular hypertrophy (p < 0.001) was observed.

CONCLUSIONS

The present data show a high incidence of left ventricular hypertrophy, calcific deposits in the myocardium, and/or aortic and mitral valve calcification in patients with primary hyperparathyroidism. A 1-year follow-up after parathyroidectomy (and restoration of normocalcemia) discloses regression of hypertrophy, while calcifications persist without evidence of progression.

Detection and quantification of pulmonary artery hypertension with MR imaging: results in 23 patients

OBJECTIVE

A study was performed to determine the value of MR imaging in detecting pulmonary artery hypertension and in determining pulmonary artery pressure semiquantitatively.

SUBJECTS AND METHODS

MR studies were performed in 23 patients with pulmonary artery hypertension to measure right ventricular function (right ventricular ejection fraction, end-diastolic and end-systolic volumes, stroke volume), right ventricular wall thickness, and the diameters of the great vessels. The findings were compared with similar MR measurements made in eight control subjects. The cause of the pulmonary hypertension was primary pulmonary hypertension (eight patients), combined mitral valve disease (five patients), dilative cardiomyopathy (four patients), chronic pulmonary embolism (four patients), atrial septal defect (one patient), and pulmonary fibrosis (one patient). MR studies were done on a 0.5-T magnet using a double-angulation projection (equivalent to a four-chamber view) with a multislice-multiphase spin-echo technique and a blood flow-sensitive fast gradient-echo sequence. Pulmonary artery pressures were verified by catheterization of the pulmonary artery.

RESULTS

In patients with pulmonary artery hypertension, MR imaging showed right ventricular enlargement with hypertrophy, right atrial enlargement, and abnormal septal motion. Fast gradient-echo images showed tricuspid regurgitation in all cases. In cases in which the mean pressures in the pulmonary artery were greater than 70 mm Hg, systolic slow-flow phenomena were detected. Linear correlations were seen between the mean pressure in the pulmonary artery and the end-diastolic thickness of the right ventricular wall (r = .83, p < or = .0001), the diameter of the inferior vena cava (r = .73, p < or = .0001), and the diameter of the main pulmonary artery (r = .48, p < or = .02).

CONCLUSION

Our results show that MR imaging is a useful noninvasive technique for the detection of pulmonary artery hypertension and for the semiquantitative assessment of pulmonary artery pressure.

Plasma big endothelin-1 concentrations in congestive heart failure patients with or without systemic hypertension

Plasma endothelin concentrations were evaluated in 53 chronic, congestive heart failure (CHF) patients with or without history of systemic hypertension, as well as in 9 with hypertension only and in 22 healthy control subjects. Plasma renin, aldosterone and atrial natriuretic peptide, as well as clinical and hemodynamic data were determined. In patients with CHF, big endothelin-1 was, independent of hypertension history, significantly greater than in hypertensive patients with normal cardiac function and in control subjects (both p < 0.0001). Patients with severe CHF had significantly greater big endothelin-1 values than did those with moderate CHF. During 12-month follow-up, 11 patients with CHF underwent heart transplantation, and 9 died; these patients had significantly greater big endothelin-1 concentrations than did the 33 clinically stable patients (p < 0.001). Big endothelin-1 and atrial natriuretic peptide correlated with right atrial pressure, pulmonary capillary wedge pressure, left ventricular ejection fraction, effort capacity and severity of CHF (New York Heart Association functional class).

Clinical and neurohumoral response of patients with severe congestive heart failure treated with two different captopril dosages

Although angiotensin converting enzyme inhibitor therapy is an established approach in the treatment of chronic heart failure, the required dosage remains unclear. This open 6 month study investigated the influence of different captopril dosages on the clinical course and neurohumoral activity of patients with severe heart failure (left ventricular ejection fraction < or = 20%). Eighty-five patients in New York Heart Association class II-IV despite treatment with digitalis, diuretics, and captopril (mean dose +/- SEM 28 +/- 2 mg.day-1 at baseline) for > or = 3 months received either 'low dose' captopril (< 75 mg.day-1, mean 32 +/- 2 mg.day-1; n = 46) or 'high dose' captopril (> or = 75 mg.day-1, mean 99 +/- 4 mg.day-1; n = 39) during the follow-up period. Both groups were comparable in clinical, haemodynamic and neurohumoral parameters at baseline. Functional state improved significantly only in the high dose group (P < 0.0001). Of 31 low dose and 20 high dose patients considered as heart transplantation candidates at baseline, 21 low dose and only six high dose patients remained on the waiting list (P < 0.0001). In patients in the low dose group, eight deaths were observed (P < 0.001). Seven patients remained on low dose captopril due to adverse effects. The initially elevated plasma levels of aldosterone and atrial natriuretic peptide decreased significantly only in high dose patients (P < 0.01). Renin increased significantly in both groups. These observations underline the necessity of suppressing neurohumoral overactivation with adequate doses of captopril reflected by sequential humoral plasma determination.

[Pimobendan (UDCG 115 BS) in long-term therapy of chronic heart failure]

Pimobendan is a positive inotropic agent with additional calcium-sensitizing effects of the phosphodiesterase III-inhibitor group. In short-term studies, beneficial hemodynamic effects have been demonstrated in patients with congestive heart failure. The aim of this prospective study was to examine the long-term effect of pimobendan (during at least 6 months) on subjective state, hemodynamic parameters, and arrhythmias in patients with congestive heart failure NYHA classes II and III. After double-blind randomization, 24 patients received pimobendan 5 mg bid or placebo orally in addition to a basic therapy (diuretics, digitalis). After 3 months, pimobendan-treated patients showed a significant clinical improvement (p < 0.03). In the placebo group, one patient underwent acute cardiac transplantation due to rapid clinical deterioration; another patient died suddenly after 5 months. No cardiac events occurred in the pimobendan group. In comparison to placebo, no proarrhythmogenic effect of pimobendan was detected. Clinical stabilization of patients in the pimobendan group was not paralleled by improvement of the hemodynamic parameters of left-ventricular performance.

[Magnetic resonance tomography in pulmonary hypertension]

We examined 23 patients with pulmonary hypertension of varying aetiology by MRI and compared the results with those of right heart catheterisation. The best correlation was obtained between right ventricular mural thickness and mean pulmonary pressure (R = 0.91, p = 0.001). There was significant correlation (R = 0.85, p = 0.001) for the diameter of the inferior vena cava, which was dilated in all patients with pulmonary hypertension. There was no significant correlation between mean pulmonary pressure and the diameters of the superior vena cava or the main pulmonary artery branches (R = 0.55 and 0.75 respectively, p less than 0.05). Amongst functional measurements there was a correlation between right ventricular ejection fraction and mean pulmonary artery pressure (R = 0.71, p = 0.001). There was no correlation between right ventricular end-systolic and end-diastolic volume. In all patients with pulmonary hypertension, dynamic flow sensitive gradient echo sequences showed the presence of tricuspid insufficiency. A further semiquantitative criterion for the presence of pulmonary hypertension in 4 patients (17%) was an abnormal signal from the main pulmonary artery in early to mid-systole shown on T1-weighted transverse sections.

Heart rate behaviour at different stages of congestive heart failure

Depressed heart rate variation has been shown to predict a high mortality rate in patients with severe congestive heart failure. To determine whether the degree of altered heart rate correlates with the clinical state, 24-h Holter monitoring was performed in 21 patients (mean ejection fraction: 18 +/- 11%) at baseline and after 6 months of oral therapy. At baseline, the overall 24-h heart rate variation and night/day heart rate ratio was reduced, depending on the NYHA functional class. The typical morphology of R-R interval histograms was a sensitive marker of the clinical state at baseline: the higher the NYHA class, the smaller the R-R interval variability and standard deviation of R-R intervals (total variability NYHA III versus II: P less than 0.05). Clinical deterioration after 6 months (n = 8) was accompanied by a tendency to further shortening of the mean total R-R interval variability (676 +/- 34 to 586 +/- 25 ms). This was shown in three patients, who were reclassified to NYHA class IV. In stable patients (n = 5) and those with clinical improvement (n = 8) no significant change in R-R variability was observed. It is concluded that variations in R-R interval histogram shapes correspond to different NYHA functional classes. While severe clinical disease progression may be associated with further reductions in the heart rate variability, improvement in the clinical state of congestive heart failure is not necessarily associated with changes in heart rate behaviour.

Doppler sonographic evaluation of the CarboMedics bileaflet valve prosthesis: one-year experience

Between April 1989 and March 1991, 237 CarboMedics bileaflet valve prosthesis carriers (165 aortic and 72 mitral valves, mean age 54.4 years) were studied prospectively with pulsed- and continuous-wave Doppler at a mean interval of 11.4 months following surgery in order to establish ranges of normal flow velocities and pressure gradients. Physical examination revealed no signs of prosthetic dysfunction or heart failure. Postoperative left ventricular function as measured by fractional shortening was 37% for aortic valve carriers and 30% for mitral valve carriers (p = NS). Mean peak velocity (+/- SD) across the aortic valve was 2.6 m/sec (+/- 0.4) and calculated instantaneous peak pressure gradient ranged from 11 to 58 mmHg (mean 28.1 +/- 10.3). It has to be emphasized that occasional patients with normally functioning valve prostheses can show unusual high gradients. Ring diameters between 21 and 27 mm showed no significant difference with regard to flow velocities and pressure gradients, whereas in 19-mm valves, significantly higher values could be demonstrated. The 123 aortic valve carriers with normal left ventricular function (fractional shortening greater than 25%) showed significantly higher pressure gradients than the 19 patients with reduced left ventricular function (28.6 +/- 11.6 mmHg vs 16.2 +/- 5.1 mmHg, p less than 0.05). In the mitral position, the mean of peak velocity (+/- SD) was 1.7 +/- 0.4 m/sec and pressure half-time was 108 +/- 26 msec, representing a calculated valve area between 1.4 to 3.1 cm2 (mean orifice size 2.1 +/- 0.5 cm2). No significant difference between valves of different sizes was found.(ABSTRACT TRUNCATED AT 250 WORDS)

Quantitative assessment of aortic regurgitation by magnetic resonance imaging

Thirty patients with aortic regurgitation and 10 controls were examined using an 0.5 T superconducting magnet with ECG gating. In each case a multislice-multiphase spinecho study in sagittal-coronal double angulated projection (four-chamber equivalent) was performed to assess left and right ventricular volumes, ejection fraction and regurgitation fraction. Additionally, a blood-flow sensitive cine-study (gradient echo, FAME) was performed to visualize direction and area of regurgitant jet. Magnetic resonance imaging (MRI) data were compared with quantitative and qualitative assessment of aortic regurgitation by angiography, Doppler and colour flow mapping. Using the FAME mode MRI, we were able to detect the regurgitant jet as an area of signal loss within the left ventricle in all patients; moderate correlation to jet area was determined by colour flow mapping (R = 0.60, P less than 0.001). Determination of left and right ventricular end-diastolic, end-systolic and stroke volumes by MRI revealed excellent correlation with invasive data (R = 0.94, P = 0.0001). With MRI regurgitant fraction (RF) could be calculated from the difference between right and left ventricular stroke volumes, which showed good correlation with invasively determined RF (R = 0.91, P = 0.001) and with qualitative Sellers' scoring (R = 0.70, P less than 0.001), respectively. Thus MRI provides the basis for noninvasive detection and quantification of aortic regurgitation.

[Myocardial calcinosis in a juvenile patient with Wermer syndrome (multiple endocrine neoplasia type I)]

We describe the rare case of a 19 year-old patient with multiple endocrine neoplasia (Wermer syndrome), presenting with insulinomas as well as primary hyperparathyroidism. Echocardiography revealed evidence of calcific deposits in the interventricular septum. The latter may be explained by long-standing hypercalcemia.

Constrictive pericarditis without typical haemodynamic changes as a cause of oedema formation due to protein-losing enteropathy

A 41-year-old man presented with physical signs of leg oedema and a laboratory value of decreased serum albumin of 2.4 g.dl-1. Loss of protein via the gastrointestinal tract was demonstrated by an increased faecal excretion of 51-chromium-labelled-albumin and by elevated stool clearance of alpha 1-antitrypsin. No anatomical lesions or intestinal disease were found to explain this protein loss. Constrictive pericarditis was suspected as the cause of protein-losing enteropathy but could not be confirmed by right heart catheterization, in which normal filling pressures and no sign of 'dip and plateau' pressure pattern were found. However, magnetic resonance imaging clearly demonstrated a thickening of the pericardium over the right heart and a tubular-shaped right ventricle as signs of constrictive pericarditis. Peripheral oedema disappeared and serum protein concentration returned to normal after pericardectomy. This demonstrates that moderate pericardial constriction not resulting in discernible pressure abnormalities in the right heart can be associated with protein-losing enteropathy and thus result in hypoproteinaemic peripheral oedema. In this condition a morphological investigation by magnetic resonance imaging is of importance in order not to miss the diagnosis of a potentially treatable disease.

[Diagnosis of arrhythmogenic right ventricular disease using magnetic resonance tomography]

In our study, 12 patients with ventricular arrhythmias, but without any documented cardiac disease, and 10 healthy volunteers were investigated by spin echo magnetic resonance tomography (MRT) using a 0.5 Tesla magnet. Axial T1-weighted spin-echo sequences, as well as double angulated, multislice-multiphase sequences were acquired. Left- and right-ventricular volumes were then evaluated by outlining the endocardium in an end-systolic and an end-diastolic frame. The right-ventricular free wall and the right-ventricular outflow tract were investigated for myocardial thickness and intramural fat.

Evaluation of congenital diseases of the heart

Three different new developments have taken place in the evaluation of congenital heart diseases. First, in the fetal period, intravaginal echocardiography allows earlier diagnosis of significant cardiac abnormalities that could lead to a wanted termination of pregnancy. Second, in adults and children, MR imaging has become a standard imaging modality in complex congenital heart diseases. Moreover MR imaging has become the best noninvasive imaging method in visualization of the great vessels. Finally, in surgery, the intraoperative epicardial echocardiography could improve operation results in the future (solving the regurgitation problem). Postoperatively, MR imaging has become an important diagnostic tool that helps to reduce repeated catheterization and angiography.