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Biomedical subjects

R Erbel

Publications and source records attributed to R Erbel.

At least 343 records · Page 19Linked to original sources
PubMed1994

Intravascular ultrasound imaging of angiographically normal coronary arteries: a prospective study in vivo.

Intravascular ultrasound imaging (IVUS) was performed to elucidate the discrepancy between clinical history and angiographic findings and to measure the diameter and area of the lumen of the normal left coronary artery in 55 patients who presented with chest pain but had normal coronary angiograms. The left coronary artery (LCA) was scanned with a 4.8F, 20 MHz mechanically rotated ultrasound catheter at 413 sites. Atherosclerotic lesions were identified at 72 (17%) sites in 25 patients. The mean (SD) (range) plaque area was 5.55 (3.56) mm2 (2-26 mm2) and it occupied 28.8 (9.6)% (13-70%) of the coronary cross sectional area. Calcification was detected at 24 (33%) atherosclerotic sites in nine patients. The correlation coefficients for the lumen dimensions measured at normal sites by IVUS and by angiography were r = 0.93 (SEE = 0.43) mm for lumen diameter and r = 0.89 (SEE = 4.27) mm2 for lumen area (both p < 0.001). 16 of the 30 patients in whom no atherosclerotic plaques were detected in the LCA lumen by IVUS had no risk factors of coronary artery disease. The cross sectional area of 90 consecutive images of left main coronary artery (LMCA), proximal left anterior descending coronary artery (proximal LAD), and mid LAD was measured in these 16 subjects. The mean (SEM) areas at end diastole were LMCA 17.33 (7.98) mm2; proximal LAD 13.56 (5.85) mm2; mid LAD 9.75 (4.67) mm2. During the cardiac cycle the cross sectional area changed by 10.2 (4.0)% in the LMCA, by 8.3 (4.7)% in the proximal LAD, and by 9.8 (4.0)% in the mid LAD. In 11 patients with plagues the change in cross sectional area in plague segments (5.8(3.1)%) was significantly lower than in the segments from patients without plagues (p < 0.001). Lumen area reached a maximum in early diastole rather than in late diastole. IVUS can imagine atherosclerotic lesions that are angiographically silent; it also provides detailed information about plague characteristics. The variation in coronary cross sectional area during the cardiac cycle should not be ignored during quantitative analysis. Maximum dimensions in normal segments are reached in early diastole. Further studies are needed to clarify the clinical significance of atherosclerosis detected by IVUS in patients presenting with chest pain but normal coronary angiography.

Adult↗
PubMed1994

Comparison of intravascular ultrasound and angiography in the assessment of myocardial bridging.

BACKGROUND: In autopsy, myocardial bridging is a common finding. With coronary angiography, a systolic compression, mainly of the left anterior descending coronary artery, is observed in 1% to 3% of the patients. Controversy exists concerning the functional importance of this finding. To obtain a functional insight into the myocardial bridging, intravascular ultrasound and intracoronary Doppler were performed. METHODS AND RESULTS: Intracoronary ultrasound and Doppler were performed in 14 patients with angiographic evidence of systolic vessel compression ("milking effect") in the left anterior descending coronary artery. The 4.8F, 20-MHz ultrasound catheter could not be advanced through the entire myocardial bridge segment in 6 of the 14 patients studied because the lumen was < 1.6 mm. In these patients, only the proximal parts of the bridge segment were scanned. The changes in cross-sectional shape during the cardiac cycle were determined for both the normal proximal segment and the bridge segment by use of a semiautomatic computer program. Intracoronary Doppler (20 MHz) was performed in 7 patients with a 3F catheter. A highly characteristic systolic eccentric or concentric compression with delayed relaxation in diastole of the myocardial bridging segment was clearly visualized in all patients. The cross-sectional lumen area variation was 40 +/- 25% in the bridging segments and 9 +/- 7% in the normal segments (P < .01). No atherosclerotic lesions were detected in the bridge or the distal segment in the 8 patients in whom the IVUS catheter was successfully advanced through the entire myocardial bridge. However, atherosclerotic plaques were found in the segments proximal to the bridge in 12 of 14 patients (86%). The resting mean flow velocity was 6.4 +/- 1.2 cm/s; the maximal mean flow velocity after intracoronary administration of 10 mg papaverine was 14.1 +/- 3.4 cm/s. The coronary flow velocity reserve was 2.2 +/- 0.7. A highly characteristic pattern showing a prominent peak in coronary velocity in early diastole was observed in 86% of patients, and this pattern was enhanced after injection of intracoronary papaverine. CONCLUSION: Intravascular ultrasound demonstrated a characteristic systolic compression of the bridge segments. The delayed compression release may explain the characteristic sharp early diastolic peak in coronary flow velocity found with intracoronary Doppler in vessels with myocardial bridging. Reduced coronary flow reserve may be related to this phenomenon, possibly explaining signs of ischemia detected in some of the patients, but may alternatively be a result of the presence of atherosclerosis in the segment proximal to the bridge in these patients.

Blood Flow Velocity↗
PubMed1994

Randomized comparison of rescue angioplasty with conservative management of patients with early failure of thrombolysis for acute anterior myocardial infarction.

BACKGROUND: When used in the setting of acute myocardial infarction, intravenous thrombolytic agents fail to achieve early infarct artery patency in 15% to 50% of patients. We tested the hypothesis that immediate balloon angioplasty applied to patients with failed early reperfusion would improve left ventricular function and clinical outcome at 30 days compared with conservative management alone. METHODS AND RESULTS: One hundred fifty-one patients with first anterior wall infarction treated with any accepted intravenous thrombolytic regimen and angiographically demonstrated to have an occluded infarct vessel within 8 hours of chest pain onset were randomized to aspirin, heparin, and coronary vasodilators (conservative therapy) or to this therapy and balloon angioplasty supplemented by further thrombolytic therapy as needed. Left ventricular function was assessed using multiple-gated equilibrium radionuclide technique to determine ejection fraction, and adverse clinical outcome was assessed evaluating death, ventricular tachycardia, and class III or IV heart failure at 30 days. Seventy-three patients were randomized to conservative therapy and 78 to angioplasty. The two groups were well balanced for patient age (59 +/- 11 years), sex (82% were male), and time to randomization (4.5 +/- 1.9 hours). Angioplasty was technically successful in 72 of 78 randomized patients (92%). Two patients randomized to conservative therapy crossed over to angioplasty within 72 hours. Resting 30-day ejection fraction was 40 +/- 11% in the angioplasty group and 39 +/- 12% in the conservative group (P = .49), but ejection fraction with exercise was 43 +/- 15% and 38 +/- 13% for the angioplasty and conservatively treated groups, respectively (P = .04). Adverse clinical outcomes included death in 5% and 10% (P = .18), severe heart failure in 1% and 7% (P = .11), and either death or severe heart failure in 6% and 17% (P = .05) of the angioplasty and conservatively managed groups, respectively. CONCLUSIONS: When applied to patients with first anterior infarction, rescue angioplasty appears to be useful in the prevention of death or severe heart failure, with improvement in exercise, but not resting, ejection fraction. This strategy deserves further study and highlights the potential advantage of early mechanical restoration of infarct vessel patency when thrombolytic therapy has failed.

Aged↗
PubMed1994

[Echocardiographic on-line volumetry using acoustic quantification--comparison with manual echocardiographic analysis and cineventriculography].

Acoustic quantification (AQ) represents an ultrasound imaging system which provides detection and tracking of endocardial blood boundaries based on quantitative assessment of acoustic properties of tissue in real time. To assess on-line quantitation of left ventricular enddiastolic (EDV), endsystolic (ESV) volumes and ejection fractions (EF) AQ measurements were compared with off-line measurements obtained by manual analysis of video-taped images (MAN) and with cineventriculographic data (CV). Calculations by the AQ system were based on an algorithm using the monoplane disc method. One day before undergoing CV, 88 unselected patients were studied with echocardiography in the apical four-chamber view. Seventy (79.5%) patients could be studied by AQ. The regression equations for determination of EDV were y = 0.7x + 25.2; r = 0.87 (AQ vs. MAN) and y = 0.5x + 22.8; r = 0.80 (AQ vs. CV), for determination of ESV they were y = 0.8x + 11.4; r = 0.78 (AQ vs. MAN) and y = 0.7x + 6.9; r = 0.71 (AQ vs. CV), and for determination of EF they were y = 0.7x + 9.5; r = 0.77 (AQ vs. MAN) and y = 0.6x + 15.0; r = 0.71 (AQ vs. CV). Calculations of left ventricular volumes by AQ or MAN led to a systematic underestimation, compared to CV. EF was also underestimated by AQ, whereas no significant difference between the mean values of MAN and CV exists. In a heterogenous population, acoustic quantification based on quantitative assessment of tissue acoustic properties mostly permits on-line quantitation of left ventricular volumes and ejection fractions in real-time.

Adult↗
PubMed1994

[Incidence of myocardial bridges after adrenergic stimulation and decreasing afterload in patients with angina pectoris, but normal coronary arteries].

The prevalence of myocardial bridging in patients with angina pectoris but normal coronary arteries was evaluated in 1780 patients who consecutively underwent coronary angiography. 62 patients (3.5%) were free of coronary atherosclerosis or other organic heart disease. In four of these patients systolic narrowing of the LAD was present. The other 58 patients received 0.2 mg nitroglycerin (NTG) intracoronarily and 30 micrograms/ml orciprenalin (ORC) intravenously up to a heart rate of 130/min. Repeated angiography revealed systolic compression of the LAD due to myocardial bridging (MB) in 40% (25 of 62). The length of MB raised from 1.4 +/- 0.9 cm to 2.1 +/- 1.1 cm (p < 0.001) after NTG and to 2.8 +/- 1.1 cm (p < 0.001) after ORC. Coronary luminal stenosis increased from 48 +/- 29% to 67 +/- 25% after NTG (p < 0.001) and to 83 +/- 18% (p < 0.001) after ORC. The prevalence of myocardial bridging in 40% of patients with stress-induced angina pectoris but normal coronary arteries is high. Nearly always coronary compression by myocardial bridging is only evident after adrenergic stimulation or after afterload reduction. Therefore, NTG and ORC are useful drugs to facilitate diagnosis of myocardial bridging by increasing coronary compression.

Adult↗
PubMed1994

[Significance of coronary perfusion for therapeutic success in myocardial infarct].

Survival in acute myocardial infarction is dependent on several parameters. Some of them act by limiting the infarct size, others improve the prognosis independent of the final infarct size. Determinants of infarct size are time of vessel occlusion, degree of collaterals and area at risk. The latter two determinants do not offer a therapeutic approach in acute myocardial infarction. The most important therapeutic intervention remains the restoration of blood flow in the area at risk by either thrombolysis or PTCA. Reperfusion within 60 to 120 minutes significantly reduces mortality and infarct size. Within this time frame, changes in left ventricular function correlate with the survival rate. If reperfusion occurs later, the correlation between changes in left ventricular function and survival is poor or absent in some studies, despite a persistent survival benefit. After 4 bis 6 hours reperfusion is no longer able to limit infarct size significantly. However, this time frame is variable since there are wide variations in the degree of collaterals. With increasing occlusion time of the infarct related coronary artery, mechanisms independent of the limitation of infarct size will determine the prognosis. Late reperfusion has a beneficial effect on survival and on left ventricular function in certain cases. Left ventricular re-modeling and the incidence of severe ventricular arrhythmias can be reduced by delayed reperfusion. Reactivation of hibernating myocardium following reperfusion therapy may improve global left ventricular function. We analysed the importance of the infarct artery perfusion grade (TIMI flow) in 156 consecutive patients treated with infarct-PTCA. The most frequent indications for infarct-PTCA were failed thrombolysis and cardiogenic shock (Table 1).(ABSTRACT TRUNCATED AT 250 WORDS)

Angioplasty, Balloon, Coronary↗
PubMed1994

[Therapy of cardiogenic shock in acute myocardial infarct].

Cardiogenic shock in acute myocardial infarction patients is the most common cause of in-hospital death. Various studies showed, that 60 to 100% of patients in cardiogenic shock will die, if no early reperfusion of their coronary artery could be established. The incidence of cardiogenic shock has decreased during the last years, most likely due to early thrombolytic therapy and administration of nitroglycerin. Reasons for cardiogenic shock are either necrosis of 40% or more of the left ventricular wall, right heart infarction, or complications which can be treated by the surgeon, like papillary muscle rupture, ventricular septal defect or rupture of the free ventricular wall. Diagnosis is based on clinical criteria, echocardiography, and on hemodynamic monitoring. The hemodynamic criteria for cardiogenic shock are a cardiac index of < 2.2/l, and an increased wedge pressure of > 18 mm Hg; additionally, diuresis is usually < 20 ml/h. Therapy can be divided into the following categories: a) pharmaceutical interventions to increase cardiac output like vasodilators or positive inotrope drugs; b) mechanical support systems; c) acute interventions with the aim of reperfusion; d) acute surgical interventions addressing complications like papillary muscle rupture, ventricular septal defect or rupture of the free ventricular wall. While steps a) and b) are able to stabilize the hemodynamical situation in patients with cardiogenic shock, they are rarely the definitive treatment. Point c), reperfusion of the coronary artery, can be divided in thrombolysis or acute PTCA. Thrombolysis failed to show a beneficial effect in most studies, either after intravenous or intracoronary application. On contrast, acute PTCA showed to be of great benefit in various studies with a technical success rate of 54 to 100% and a survival rate of patients from 58 to 100%. Thus, emergency PTCA is the treatment of choice in cardiogenic shock. Point d), surgical interventions can be divided in acute bypass grafting, which should be reserved for patients with severe multivessel disease, left main involvement, or failed PTCA. Furthermore, acute heart transplantation is effective, but will be possible in a minority of patients only. The last part of surgically manageable complications are surgery of papillary muscle rupture and ventricular septal defect. Results of early surgery in papillary muscle rupture or ventricular septal defects are much better than delayed interventions. Rupture of the free wall is usually a fatal event. In summary, the most successful therapy of cardiogenic shock is early emergency PTCA.(ABSTRACT TRUNCATED AT 400 WORDS)

Angioplasty, Balloon, Coronary↗
PubMed1994

[Atrial fibrillation--the value of transesophageal echocardiography].

Transesophageal echocardiography is superior to transthoracic echocardiography in detection of superior to transthoracic echocardiography in detection of left atrial thrombi and spontaneous echocardiographic contrast, particularly in patients with atrial fibrillation and spontaneous echocardiographic contrast, thrombus formation is likely. In addition to the morphology, Doppler-echocardiography can be used to access left atrial appendage function. In patients with lone atrial fibrillation, reduced velocity was found in 60%, and no flow was detected in the left atrial appendage in 40%. These patients had a higher risk for spontaneous echocardiographic contrast and thrombus formation. As left atrial thrombi are found in 12% of patients, transesophageal echocardiography can be used to avoid cardioversion in these patients, which may lead to cerebral or peripheral emboli. Despite ruling out left atrial thrombi, embolism occurred after cardioversion when anticoagulation was insufficient or not performed. Current investigations are undertaken in order to demonstrate the clinical benefit of transesophageal echocardiography in patients with left atrial fibrillation.

Atrial Fibrillation↗
PubMed1994

[Quality management in the heart catheterization laboratory].

Quality management within the catheterization laboratory includes the quality control, the heart catheterization technique and the policy. Quality management is critical in the heart catheterization laboratory. Dedication of all members of the lab and computer personnel ensures high patient satisfaction. A continued quality improvement program is patient-orientated and requires good planning. One of the main emphasis in the catheterization lab is standardization which includes the patient preparation, the procedure itself, and the management. It is supported by teamwork including the economic aspect of prompt delivery of material and avoidance of complications. A continuous circle of treatment planes, performance, and check is regarded as the Deming cycle and leads to continuous improvement of quality. Important are both the avoidance and detection of complications. The reasons for any such have to be evaluated. It is recommended to follow the zero mistake hypothesis of Crosby, which means quality control by the lab supervisor, a quality consciousness, a quality measurement and quality improvement, as well as using a day to day quality improvement and to teach quality control. In Germany a quality control questionnaire was administered in an analysis of the current structure, function, and results of catheterization labs. Most important was the analysis of complications. The data were based on diagnostic catheterization in 1992, which included 140668 catheterizations in 83 laboratories. Thus, a mean of 1030 heart catheterizations was performed in each lab. In the mean, 200 catheterizations were performed by each doctor. In 19% of the labs digital imaging was exclusively performed. Major complications occurred with ventricular fibrillation in 0.36% (range 0.75%), resuscitation 0.18% (0.43%), persistent cerebrovascular accident 0.08% (0.24%), myocardial infarcts 0.19% (0.59%), aortic dissection 0.05% (0.22%). Mortality was 0.03% (0.08%). In heart catheterization laboratories quality management is one of the major goals for the future work. Only the continued improvement of quality and very good quality management ensure patient safety. Quality is the sum of technique and consciousness.

Cardiac Catheterization↗
PubMed1994

[Transthoracic and transesophageal follow-up in patients with left atrial thrombosis].

The embolic risk and changes of thrombus location and size were investigated in 29 consecutive patients with echocardiographically proven thrombi in the left atrium. Inclusion criteria were the visualization of a left atrial thrombus using transesophageal echocardiography. Transesophageal follow-up echocardiograms were performed at a mean period of 18 months. In this period 6 cases of embolism were observed at an interval of 20 days to 26 months after the detection of thrombus. Thus, the embolic rate was 14% per patient year. All patients received phenprocoumon (n = 4) or aspirin at the time of embolism. Furthermore, in two patients after cardiac thrombectomy left atrial thrombi were seen again although patients were treated with anticoagulants. On the other hand, in 12 patients (5 received oral anticoagulation, 2 received aspirin) thrombi completely resolved. It can be concluded from these data, that the majority of patients receiving anticoagulation profit from this therapy, however, a complete protection against arterial embolism or reoccurrence of thrombi cannot be reached. Left atrial spontaneous echo contrast was the only risk factor significantly associated with thromboembolism in patients with left atrial thrombi.

Aged↗
PubMed1994

Enoximon-echocardiography. A new diagnostic approach for the detection of viable myocardium comparison to dobutamin-echocardiography.

UNLABELLED: Hypo- or akinetic myocardial regions can be identified as viable myocardium through recruitment of inotropic reserve. Both, dobutamine (D) as well as enoximone (E) mediate their inotropic action via an increase in intracellular c-AMP concentration based on a different action. In 10 patients with documented myocardial infarction either D (5 to 40 micrograms/kg/min, increments of 5 micrograms/kg/min every 3 min) or E (1 to 9 micrograms/kg/min, increments of 1 microgram/kg/min every 2 min) was administered intravenously on two consecutive days. Heart rate (HR), systolic and diastolic blood pressure (BP), as well as a wall motion score in 16 segment (WMS) and ejection fraction (EF) with 2D-echocardiography were determined at rest and during each increment. Viability of myocardial regions was assessed with 201thallium-SPECT (Table 1). RESULTS: *p < 0.05 vs. rest, data: mean +/- SD. While E did not cause any side effects, patients complained about rash (n = 10), headache (n = 8), angina pectoris (n = 5), and anxiety (n = 2) during the administration of D. D and E are both able to recruit a potential inotropic reserve in infarcted myocardium, and thus, identify viable myocardium. In contrast to E, D caused an increase in HR and systolic BP. Enoximone-echocardiography seems to be a new, promising tool for the identification of viable myocardium.

Adult↗
PubMed1994

[Follow-up and characteristics of restenoses after coronary stent implantation in asymptomatic patients and patients with few symptoms].

Following coronary Palmaz-Schatz single stent implantation 50 patients had an angiographic follow-up after 4-6 and after 12 months. Quantitative angiography revealed that the restenosis process has finished 4-6 months after stent implantation in the majority of patients. In the present study, 6% had, however, developed symptomatic restenosis at 1-year follow-up. Detailed assessment of 15 patients revealed that the residual stenosis after stent implantation is most prominent at the stent edges, however, restenosis did occur in all segments in about the same amount. Analysis of several clinical and morphologic variables did not reveal any particular risk factor for the development of restenosis. The results of the present study do suggest that follow-up angiography should be performed 4-6 months after stent placement.

Adult↗
PubMed1993

[Restenosis after the implantation of Palmaz-Schatz vascular stents in the coronary arteries].

Restenosis rate after successful intracoronary implantation of Palmaz-Schatz stents in 100 patients (92 men, 8 women; mean age 57 +/- 11 years) was quantitatively assessed by angiography performed on average 5.3 +/- 0.3 months after the procedure. Restenosis was defined as a more than 50% decrease in lumen. Data from patients with acute or subacute thrombotic complications were excluded from the analysis. The restenosis rate of the total group was 22%. After placement of only one stent (n = 87) it was 17%, of multiple stents per lesion (n = 13) 54%. Restenosis rate after emergency implantation of a single stent (n = 23) was 17.4%, after elective single stent implantation (n = 64) 17.2%. There was no significant difference regarding treatment of new stenoses (n = 16), and recurrent stenosis (n = 48), namely 12.5% vs 18.8%. The following were risk factors for chronic restenosis after stent implantation: multiple stents (odds ratio [OR] 5.6; 95% confidence interval [CI]: 1.6-19.1); implantation in a small vessel, reference diameter < or = 3.0 mm (OR 6.7, CI 2.4-18.7); and residual stenosis after stent implantation of > 8% (OR 3.1, CI 1.2-8.1).

Aged↗
PubMed1993

Variations in acoustical beam properties of intracoronary Doppler catheters.

The limitations of coronary angiography in assessing the functional significance of coronary obstructions is well known. While the critical variable of coronary blood flow cannot be readily measured, intraluminal Doppler sonography offers useful related functional information on blood flow velocity. In order to fully evaluate Doppler signals it is essential to have exact knowledge of the transducer transmission characteristics and of the ultrasound beam topology. In an experimental set-up, the transmitter-receiver characteristics of five commonly used Doppler catheters were investigated. In comparing the beam characteristics we found inhomogeneities in the lateral beam spread. At a penetration depth of 3.0 mm the beam shape varied from a minimum of 1.25 mm up to a maximum of 3.5 mm. The mean was 2.25 mm. The different beam profiles of the investigated Doppler transducers cause an error in measuring the blood flow velocity. The blood flow velocity tends to be underestimated the more the vessel diameter and the blood flow velocity increase. Contrary to transducer design optimized for imaging, for spectral analysis of the Doppler signal it would be advantageous to have as broad a beam as possible in order to illuminate the entire vessel lumen.

Angioplasty, Balloon, Coronary↗
PubMed1993

Miniaturized pressure-guide-wire: evaluation in vitro and in isolated hearts.

UNLABELLED: The present study focused on the accuracy and reproducability of measurements performed with a miniaturized pressure guidewire system (PGWS) under standardized in vitro conditions and in an isolated pig heart model. We used a pressure guide wire system provided by Pressure Guide, Radi Medical Systems, Uppsala, Sweden. Pressures were recorded by a fiber optic pressure sensor located laterally and 3 cm from the distal end. The basic principle is that the element modulates an optical reflection by pressure induced elastic movements. The light source is an emitting diode in the control unit. The PGWS replaces a standard 0.018 in. guidewire. The PGWS was introduced through a Y-adapter in a recirculating perfusion model, consisting of tubing with internal diameters from 1.00 to 4.00 mm. Different perfusion pressures (range 20-140 mm Hg) were generated by a pressure controlled roller pump. RESULTS: Different lumen sizes from 1 to 4 mm had no influence on the measurements. a) In a range from 20 to 140 mm Hg no significant differences were found between the perfusion pressure and the pressures obtained by the PGWS, resulting in an r-value of 0.99 and an equation of y = 1.04x + 1.9. b) In pressure measurements proximal and distal of an artificial stenoses resulting in gradients from 0 to 100 mm Hg, the PGWS correctly identified the pressure difference with an equally high accuracy, 1, 2, and 3 cm behind the stenoses.(ABSTRACT TRUNCATED AT 250 WORDS)

Angioplasty, Balloon, Coronary↗
PubMed1993

Diagnosis of papillary muscle rupture after acute myocardial infarction by transthoracic and transesophageal echocardiography.

The sensitivity of transthoracic echocardiography to visualize the structural abnormality of papillary muscle rupture (PMR) after acute myocardial infarction can be anticipated to average about 50%; therefore, we evaluated five patients exhibiting the condition with both transthoracic and transesophageal echocardiography. The use of the two imaging techniques resulted in the fact that no instance of PMR was missed. Using transthoracic echocardiography in two patients and transesophageal echocardiography in four, the ruptured papillary muscle was visualized directly. Mitral insufficiency as an indirect sign was observed in all patients. In one patient the papillary muscle rupture developed in a mitral valve previously affected by endocarditis. All patients underwent mitral valve replacement and coronary artery bypass grafting. The diagnosis was confirmed at surgery in all patients. Four patients died in hospital, the fifth 5 months later. We recommended that transesophageal echocardiography be performed in patients with suspected PMR if transthoracic echocardiography does not provide an unequivocal diagnosis.

Aged↗