A.M. Beek

Magnetic resonance imaging-defined areas of microvascular obstruction after acute myocardial infarction represent microvascular destruction and haemorrhage

AIMSnLack of gadolinium-contrast wash-in on first-pass perfusion imaging, early gadolinium-enhanced imaging, or late gadolinium-enhanced (LGE) cardiovascular magnetic resonance (CMR) imaging after revascularized ST-elevation myocardial infarction (STEMI) is commonly referred to as microvascular obstruction (MVO). Additionally, T2-weighted imaging allows for the visualization of infarct-related oedema and intramyocardial haemorrhage (IMH) within the infarction. However, the exact histopathological correlate of the contrast-devoid core and its relation to IMH is unknown.nnnMETHODS AND RESULTSnIn eight Yorkshire swine, the circumflex coronary artery was occluded for 75 min by a balloon catheter. After 7 days, CMR with cine imaging, T2-weighted turbospinecho, and LGE was performed. Cardiovascular magnetic resonance images were compared with histological findings after phosphotungstic acid-haematoxylin and anti-CD31/haematoxylin staining. These findings were compared with CMR findings in 27 consecutive PCI-treated STEMI patients, using the same scanning protocol. In the porcine model, the infarct core contained extensive necrosis and erythrocyte extravasation, without intact vasculature and hence, no MVO. The surrounding-gadolinium-enhanced-area contained granulation tissue, leucocyte infiltration, and necrosis with morphological intact microvessels containing microthrombi, without erythrocyte extravasation. Areas with IMH (median size 1.92 [0.36-5.25] cm(3)) and MVO (median size 2.19 [0.40-4.58] cm(3)) showed close anatomic correlation [intraclass correlation coefficient (ICC) 0.85, r = 0.85, P = 0.03]. Of the 27 STEMI patients, 15 had IMH (median size 6.60 [2.49-9.79] cm(3)) and 16 had MVO (median size 4.31 [1.05-7.57] cm(3)). Again, IMH and MVO showed close anatomic correlation (ICC 0.87, r = 0.93, P < 0.001).nnnCONCLUSIONnThe contrast-devoid core of revascularized STEMI contains extensive erythrocyte extravasation with microvascular damage. Attenuating the reperfusion-induced haemorrhage may be a novel target in future adjunctive STEMI treatment.

‘No-reflow’ after acute myocardial infarction: direct visualisation of microvascular obstruction by gadolinium-enhanced CMR

Cardiovascular magnetic resonance is considered the standard imaging modality in clinical trials to monitor patients after acute myocardial infarction. However, limited data are available with respect to infarct size, presence and extent of microvascular injury (MVO) and changes over time, in relation to cardiac function in optimally treated patients. In the current study we prospectively investigate the change of infarct size over time, and the incidence and significance of MVO in a uniform, optimally treated patient group after AMI. (Neth Heart J 2008;16:179-81.)

The role of cardiac magnetic resonance imaging in differentiating the underlying causes of left ventricular hypertrophy

The onset of sudden cardiac death and large inter- and intra-familial clinical variability of hypertrophic cardiomyopathy pose an important clinical challenge. Cardiac magnetic resonance imaging is a high-resolution imaging modality that has become increasingly available in the past decade and has the unique possibility to demonstrate the presence of fibrosis or scar using late gadolinium enhancement imaging. As a result, the diagnostic and prognostic potential of cardiac magnetic resonance imaging has been extensively explored in acute and chronic ischaemic cardiomyopathy, as well as in several nonischaemic cardiomyopathies.This review aims to provide a critical overview of recently published studies on hypertrophic cardiomyopathy and discusses the role of cardiac magnetic resonance imaging in differentiating underlying causes of hypertrophic cardiomyopathy, such as familial hypertrophic cardiomyopathy, cardiac involvement in systemic disease and left ventricular hypertrophy due to endurance sports. Also, it demonstrates the use of cardiac magnetic resonance in risk stratification for the onset of sudden cardiac death, and early identification of asymptomatic family members of hypertrophic cardiomyopathy patients who are at risk for the development of hypertrophic cardiomyopathy. (Neth Heart J 2010;18:135-43.)

Towards a noninvasive anatomical and functional diagnostic work-up of patients with suspected coronary artery disease

Combining multidetector computed tomography and cardiovascular magnetic resonance imaging provides the clinician a strategy to comprehensively evaluate coronary morphology and function noninvasively. In the MARCC trial (Magnetic Resonance and CT in suspected CAD) a new noninvasive diagnostic work-up for patients with suspected coronary artery disease will be developed, involving the sequential use of both imaging techniques. (Neth Heart J 2010;18:270-3.)

Use of cardiovascular magnetic resonance imaging in the assessment of left ventricular function, scar and viability in patients with ischaemic cardiomyopathy and chronic myocardial infarction

In the previous article in this series, we discussed the cardiovascular magnetic resonance (CMR) techniques used in the assessment of ischaemic heart disease and their clinical application in patients with acute myocardial infarction. In this article we address the use of CMR in the chronic phase of infarction, focusing on the assessment of function and viability in patients with ischaemic cardiomyopathy or (suspected) prior infarction.nnA basic imaging protocol in patients with ischaemic cardiomyopathy or (suspected) old myocardial infarction includes cine imaging for the assessment of ventricular and valvular function, and delayed contrast enhanced (DE) imaging for the assessment of regional scar and viability. Total (maximum) examination time for the assessment of ventricular function and viability will be 30u2005min, which can be reduced to around 20u2005min if contrast is given before the examination. If the presence and distribution of scar is the only clinical concern, DE imaging may provide the answer within 5u2005min. Low dose dobutamine stress cine is a good alternative method for assessing viability in patients with (relative) contraindications to gadolinium based contrast agents—for example, in advanced renal failure. Depending on the clinical situation, adenosine first-pass imaging or high dose dobutamine stress cine can be added to detect ischaemia related perfusion defects or wall motion abnormalities, respectively. An extensive description of these techniques is beyond the scope of this article.nn### Global ventricular functionnnGlobal left ventricular function strongly influences prognosis and management and its assessment is an essential part of the work-up in a patient with prior myocardial infarction. As in acute infarction, the selection of candidates for implantable cardioverter defibrillator (ICD) or cardiac resynchronisation devices relies heavily on left ventricular ejection fraction (LVEF). Cine imaging ensures the quantification of global function with the highest …

Quadricuspid pulmonary valve and left pulmonary artery aneurysm in an asymptomatic patient assessed by cardiovascular MRI

We present a coincidental finding of quadricuspid pulmonary valve and left pulmonary artery aneurysm. As both the pulmonary valve and the pulmonary trunk with its main branches are hard to visualise with cardiac ultrasound, most abnormalities described so far are from autopsy series. With the increasing use of CMR and its excellent potential for visualising both pulmonary valve and pulmonary arteries, we believe more cases will be discovered in the near future. Although pulmonary artery aneurysm are rare, timely detection may prevent lethal bleeding.

Changes in remote myocardial tissue after acute myocardial infarction and its relation to cardiac remodeling: A CMR T1 mapping study

Objectives To characterize the temporal alterations in native T1 and extracellular volume (ECV) of remote myocardium after acute myocardial infarction (AMI), and to explore their relation to left ventricular (LV) remodeling. Methods Forty-two patients with AMI successfully treated with primary PCI underwent cardiovascular magnetic resonance after 4–6 days and 3 months. Cine imaging, late gadolinium enhancement, and T1-mapping (MOLLI) was performed at 1.5T. T1 values were measured in the myocardial tissue opposite of the infarct area. Myocardial ECV was calculated from native- and post-contrast T1 values in 35 patients, using a correction for synthetic hematocrit. Results Native T1 of remote myocardium significantly decreased between baseline and follow-up (1002 ± 39 to 985 ± 30ms, p<0.01). High remote native T1 at baseline was independently associated with a high C-reactive protein level (standardized Beta 0.32, p = 0.04) and the presence of microvascular injury (standardized Beta 0.34, p = 0.03). ECV of remote myocardium significantly decreased over time in patients with no LV dilatation (29 ± 3.8 to 27 ± 2.3%, p<0.01). In patients with LV dilatation, remote ECV remained similar over time, and was significantly higher at follow-up compared to patients without LV dilatation (30 ± 2.0 versus 27 ± 2.3%, p = 0.03). Conclusions In reperfused first-time AMI patients, native T1 of remote myocardium decreased from baseline to follow-up. ECV of remote myocardium decreased over time in patients with no LV dilatation, but remained elevated at follow-up in those who developed LV dilatation. Findings from this study may add to an increased understanding of the pathophysiological mechanisms of cardiac remodeling after AMI.

T1-mapping in a case of acute biopsy-proven myocarditis with an apparently normal CMR: ‘times are a-changing’

A 51-year-old male presented with acute chest pain several days after an episode of acute tonsillitis. Physical examination revealed hypotension (95/60 mmHg) but no fever. The electrocardiogram showed sinus tachycardia (110 bpm) with regional ST-segment elevation in inferolateral ECG leads (see Supplementary material online, Figure S1 ). Troponin-T (0.735 μg/L) and CK-MB (25.7 μg/L) levels were elevated. Furthermore, CRP (277 mg/L) and leukocyte count (16.1 × 109/L) were raised. Invasive coronary angiography showed normal coronary arteries. Transthoracic echocardiogram displayed severely impaired left ventricular function (LVF) with global wall motion abnormalities (see Supplementary material online, Video S1 ). Myocarditis was suspected and the patient was …

Double aortic arch

SamenvattingA 58-year-old male was referred to our outpatient cardiology clinic for evaluation of atrial fibrillation, fatigue, dizziness and exertional dyspnoea. He had suffered recurrent pneumonia in childhood. Beside an irregular pulse, the physical examination was normal. Electrocardiography showed atrial fibrillation (ventricular response of 60 to 70 beats/min), a right bundle branch block and nonspecific repolarisation abnormalities. Pulmonary vascular redistribution was visible on chest X-ray (figure 1).

Prediction of functional recovery after revascularization in patients with chronic ischemic myocardial dysfunction: perfusable tissue index by positron emission tomography and contrast-enhanced MRI comparison study

ObjectivesIn patients with chronic ischemic myocardial dysfunction, perfusable tissue index (PTI) obtained with positron emission tomography using oxygen-15-labeled water and carbon monoxide as tracers is inversely related to the extent of myocardial scar (nonperfusable tissue). Delayed contrast-enhanced (DCE) magnetic resonance imaging (MRI) accurately depicts the regional extent of myocardial fibrosis and predicts functional recovery after revascularization in patients with ischemic cardiomyopathy. Our aim was to compare PTI as a viability marker with DCE MRI. MethodsFourteen patients with ischemic left ventricular dysfunction were studied with positron emission tomography, using oxygen-15-labeled water and carbon monoxide as tracers, and with contrast-enhanced MRI. ResultsFunctional improvement occurred in 38 of initially dysfunctional, revascularized segments (56%). Mean PTI was 1.04±0.20 in the improved segments versus 0.85±0.21 in the group without functional improvement (P<0.001). The areas under the receiver operator characteristics curves of PTI and DCE MRI were 0.7 and 0.74, respectively (P=not significant). Cutoff value of 25% DCE allowed correct identification of 82% segments with reversible dysfunction and 64% segments without reversible dysfunction. A threshold of 0.89 for PTI yielded the best diagnostic accuracy with sensitivity and specificity values of 76 and 54%, respectively. ConclusionPTI can identify viable myocardium and predict improvement in regional function after revascularization in patients with chronic ischemic left ventricular dysfunction. Its diagnostic accuracy is comparable with that of DCE MRI.