Matthias Grothoff

Diagnostic Performance of CMR Imaging Compared With EMB in Patients With Suspected Myocarditis

OBJECTIVES The goal of this study was to assess the diagnostic performance of cardiac magnetic resonance (CMR) compared with endomyocardial biopsy in patients with suspected acute myocarditis (AMC) and chronic myocarditis (CMC). BACKGROUND Several studies have reported an encouraging diagnostic performance of CMR in myocarditis. However, the comparison of CMR with clinical data only and the use of preselected patient populations are important limitations of the majority of these reports. METHODS One hundred thirty-two consecutive patients with suspected AMC (defined by symptoms ≤ 14 days; n = 70) and CMC (defined by symptoms >14 days; n = 62) were included. Patients underwent cardiac catheterization with left ventricular endomyocardial biopsy and CMR, including T(2)-weighted imaging for assessment of edema, T(1)-weighted imaging before and after contrast administration for evaluation of hyperemia, and assessment of late gadolinium enhancement. CMR results were considered to be consistent with the diagnosis of myocarditis if 2 of 3 CMR techniques were positive. RESULTS Within the total population, myocarditis was the most common diagnosis on endomyocardial biopsy analysis (62.9%). Viral genomes were detected in 30.3% (40 of 132) of patients within the total patient population and significantly more often in patients with AMC than CMC (40.0% vs. 19.4%; p = 0.013). For the overall cohort of patients with either suspected AMC or CMC, the diagnostic sensitivity, specificity, and accuracy of CMR were 76%, 54%, and 68%, respectively. The best diagnostic performance was observed in patients with suspected AMC (sensitivity, 81%; specificity, 71%; and accuracy, 79%). In contrast, diagnostic performance of CMR in suspected CMC was found to be unsatisfactory (sensitivity, 63%; specificity, 40%; and accuracy, 52%). CONCLUSIONS The results of this study underline the usefulness of CMR in patients with suspected AMC. In contrast, the diagnostic performance of CMR in patients with suspected CMC might not be sufficient to guide clinical management.

Comprehensive Cardiac Magnetic Resonance Imaging in Patients With Suspected Myocarditis: The MyoRacer-Trial.

BACKGROUND Data suggest that T1 and T2 mapping have excellent diagnostic accuracy in patients with suspected myocarditis. However, the true diagnostic performance of comprehensive cardiac magnetic resonance (CMR) mapping versus endomyocardial biopsy (EMB) has not been determined. OBJECTIVES This study assessed the performance of CMR imaging, including T1 and T2 mapping, compared with EMB in an unselected, consecutive patient cohort with suspected myocarditis. It also examined the potential role of CMR field strength by comparing 1.5-T versus 3.0-T imaging. METHODS Patients underwent biventricular EMB, cardiac catheterization (for exclusion of coronary artery disease), and CMR imaging on 1.5- and 3-T scanners. The CMR protocol included current standard Lake Louise criteria (LLC) for myocarditis as well as native T1, calculation of extracellular volume fraction (ECV), and T2 mapping (only on 1.5-T). Patients were divided into 2 groups according to symptom duration (acute: ≤14 days vs. chronic: >14 days). RESULTS A total of 129 patients underwent 1.5-T imaging. In patients with acute symptoms, native T1 yielded the best diagnostic performance as defined by the area under the curve (AUC) of receiver-operating curves (0.82) followed by T2 (0.81), ECV (0.75), and LLC (0.56). In patients with chronic symptoms, only T2 mapping yielded an acceptable AUC (0.77). On 3.0-T, AUCs of native T1, ECV, and LLC were comparable to 1.5-T with no significant differences. CONCLUSIONS In patients with acute symptoms, mapping techniques provide a useful tool for confirming or rejecting the diagnosis of myocarditis and are superior to the LLC. However, only T2 mapping has acceptable diagnostic performance in patients with chronic symptoms. (Magnetic Resonance Imaging in Myocarditis [MyoRacer]; NCT02177630).

Feasibility of real-time magnetic resonance imaging-guided electrophysiology studies in humans.

AIMS Magnetic resonance imaging (MRI) in the context of electrophysiology (EP) studies facilitates visualization of complex three-dimensional anatomy and the underlying arrhythmogenic substrate, real-time passive visualization of catheters, atrial and ventricular function and complications, as well as lesion visualization during the ablation without radiation. In the following we report on our first experience of a real-time MRI-guided EP study demonstrating current possibilities and drawbacks. METHODS AND RESULTS Five consecutive patients (one male, four female; mean age 66 ± 11 years) with symptomatic arrhythmias, three patients with highly symptomatic typical atrial flutter, presented to our hospital for isthmus ablation, one patient for an EP study and one for slow pathway ablation in atrioventricular node re-entry tachychardia. The four ablations were performed successfully in a conventional EP laboratory and complete bidirectional isthmus block was confirmed in three patients with atrial flutter. After the procedure in the EP laboratory all five patients were transferred to a 1.5 T whole-body MRI scanner (Intera) for a diagnostic EP procedure. Two MRI compatible steerable diagnostic/ablation catheters (Vision) were inserted via the femoral sheaths and manipulated by an experienced electrophysiologist using a commercially available interactive real-time steady-state free precession sequence (repetition time = 3 ms, echo time = 1 ms, flip angle = 35°, slice thickness = 10 mm, frame rate = 8/s). All catheters could be placed successfully in the right atrium and ventricle, confirmed by intracardiac electrograms, using passive catheter tracking. Furthermore, simple programmed stimulation maneuvers were performed. During and after the procedure, no adverse effects were observed in any patients. CONCLUSION To our knowledge, this is the first series of patients with real-time MRI-guided placement of multiple catheters with subsequent performance of stimulation maneuvers. Besides the mentioned benefits, this technology still encounters several limitations, which have to be solved before application in a routine clinical setting. Challenges arise from delineation of precise surface electrocardiogram recordings in the MRI setting along with intracardiac electrograms, easier handling and visualization of catheters, facilitation of immediate defibrillation in the MRI setting and implementation of an active catheter tracking system.

Right ventricular injury in ST-elevation myocardial infarction: risk stratification by visualization of wall motion, edema, and delayed-enhancement cardiac magnetic resonance.

Background— Patients with right ventricular injury (RVI) complicating ST-elevation myocardial infarction (STEMI) have impaired prognosis, but it is unclear which patients are at risk of developing RVI. Cardiac magnetic resonance can identify these patients and might add important information on risk stratification, prognosis, and treatment. Aims were to determine the predictors and the prognostic significance of RVI assessed by wall motion abnormalities, edema, myocardial salvage index, and delayed enhancement in acute reperfused STEMI. Methods and Results— We studied 450 patients 1–4 days after primary angioplasty in STEMI. T2-weighted and delayed-enhancement cardiac magnetic resonance was used for visualizing edema and scar to calculate myocardial salvage index. Cine-imaging was performed to assess wall motion abnormalities, which, in combination with edema, were considered diagnostic for RVI. Patients with RVI were compared with matched patients with isolated left ventricular infarction. The primary end point was the occurrence of a major adverse cardiac event: a composite of death, reinfarction, and congestive heart failure after a median follow-up period of 20.9 months. RVI was present in 69 patients, and 41 of 69 showed myocardial necrosis. In a multivariable stepwise forward logistic regression analysis, a high RV myocardial mass (odds ratio, 2.06; 95% confidence interval, 1.18–3.58; P =0.012) and a low Thrombolysis In Myocardial Infarction flow before angioplasty (odds ratio, 0.50; 95% confidence interval, 0.32–0.76; P =0.011) were associated with RVI. Cox regression analysis revealed RVI as the most statistically significant predictor of time to major adverse cardiac events (hazard-ratio, 3.36; 95% confidence interval, 1.99–5.66; P <0.001). Conclusions— RVI detected by cardiac magnetic resonance is a strong and independent predictor of clinical outcome after acute reperfused STEMI. Clinical Trial Registration— URL: . Unique identifier: [NCT01359306][1]. [1]: /lookup/external-ref?link_type=CLINTRIALGOV&access_num=NCT01359306&atom=%2Fcirccvim%2F5%2F1%2F60.atomBackground— Patients with right ventricular injury (RVI) complicating ST-elevation myocardial infarction (STEMI) have impaired prognosis, but it is unclear which patients are at risk of developing RVI. Cardiac magnetic resonance can identify these patients and might add important information on risk stratification, prognosis, and treatment. Aims were to determine the predictors and the prognostic significance of RVI assessed by wall motion abnormalities, edema, myocardial salvage index, and delayed enhancement in acute reperfused STEMI. Methods and Results— We studied 450 patients 1–4 days after primary angioplasty in STEMI. T2-weighted and delayed-enhancement cardiac magnetic resonance was used for visualizing edema and scar to calculate myocardial salvage index. Cine-imaging was performed to assess wall motion abnormalities, which, in combination with edema, were considered diagnostic for RVI. Patients with RVI were compared with matched patients with isolated left ventricular infarction. The primary end point was the occurrence of a major adverse cardiac event: a composite of death, reinfarction, and congestive heart failure after a median follow-up period of 20.9 months. RVI was present in 69 patients, and 41 of 69 showed myocardial necrosis. In a multivariable stepwise forward logistic regression analysis, a high RV myocardial mass (odds ratio, 2.06; 95% confidence interval, 1.18–3.58; P=0.012) and a low Thrombolysis In Myocardial Infarction flow before angioplasty (odds ratio, 0.50; 95% confidence interval, 0.32–0.76; P=0.011) were associated with RVI. Cox regression analysis revealed RVI as the most statistically significant predictor of time to major adverse cardiac events (hazard-ratio, 3.36; 95% confidence interval, 1.99–5.66; P<0.001). Conclusions— RVI detected by cardiac magnetic resonance is a strong and independent predictor of clinical outcome after acute reperfused STEMI. Clinical Trial Registration— URL: http://www.clinicaltrials.gov. Unique identifier: NCT01359306.

MR Imaging–guided Electrophysiological Ablation Studies in Humans with Passive Catheter Tracking: Initial Results

PURPOSE To assess if real-time magnetic resonance (MR) imaging-guided radiofrequency (RF) ablation for atrial flutter is feasible in patients. MATERIALS AND METHODS The study complied with the Declaration of Helsinki and was approved by the local ethics committee. All patients were informed about the investigational nature of the procedures and provided written informed consent. Ten patients (six men; mean age ± standard deviation, 68 years ± 10) with symptomatic atrial flutter underwent isthmus ablation. In all patients, two MR imaging conditional steerable diagnostic and ablation catheters were inserted into the coronary sinus via femoral sheaths and into the right atrium with fluoroscopic guidance. The patients were then transferred to a 1.5-T whole-body MR imager for an ablation procedure, in which the catheters were manipulated by an electrophysiologist by using a commercially available interactive real-time steady-state free precession MR imaging sequence. RESULTS All catheters were placed in standard positions successfully. Furthermore, simple programmed stimulation maneuvers were performed. In one of 10 patients, a complete conduction block was performed with MR imaging guidance. In nine of 10 patients, creating only a small number of additional touch-up lesions was necessary to complete the isthmus block with conventional fluoroscopy (median, three lesions; interquartile range, two to four lesions). CONCLUSION Real-time MR imaging-guided placement of multiple catheters is feasible in patients, with subsequent performance of stimulation maneuvers and occasional complete isthmus ablation.

Dynamic CT Angiography after Abdominal Aortic Endovascular Aneurysm Repair: Influence of Enhancement Patterns and Optimal Bolus Timing on Endoleak Detection

PURPOSE To determine the time course of enhancement patterns in the aorta and endoleaks at dynamic computed tomographic (CT) angiography as well as their effect on the endoleak detection rate in patients who have undergone abdominal aortic endovascular aneurysm repair (EVAR). MATERIALS AND METHODS This retrospective study was approved by the local ethics committee and compliant with the Declaration of Helsinki. All patients gave written informed consent for the scientific analysis of their data. Seventy-one patients (mean age, 72 years ± 8 [standard deviation]) were retrospectively included after EVAR of the abdominal aorta. All patients underwent dynamic CT angiography with 10 unidirectional scan phases, followed by a venous phase. Endoleaks were detected visually in all scan phases; the magnitude of enhancement was assessed by using region-of-interest measurements in the aorta and the detectable endoleaks. Statistical analysis was performed with the χ(2) test, the paired t test, and analysis of variance with repeated measurements. RESULTS The highest mean aortic enhancement was achieved 12 seconds after the bolus-tracking threshold, and the highest mean endoleak enhancement was achieved 22 seconds after the bolus-tracking threshold. In total, 44 endoleaks were detected. The detection rates differed significantly in between the dynamic CT angiography phases (minimum, seven endoleaks at 2 seconds after the bolus-tracking threshold; maximum, 44 endoleaks at 27 seconds after the bolus-tracking threshold; P = .001). The highest detection rate was achieved when the contrast between aortic and endoleak enhancement reached its maximum. CONCLUSION Dynamic CT angiography revealed that the peak enhancement of endoleaks is significantly different than that of the aorta and that endoleaks may not be adequately evaluated with conventional biphasic CT protocols. The use of dynamic CT angiography is associated with a significantly increased detection rate of endoleaks compared with the detection rates at the time points of conventional biphasic CT.

Cavotricuspid Isthmus Ablation Guided by Real-Time Magnetic Resonance Imaging

Magnetic resonance imaging (MRI) has evolved as a standard cardiac imaging technique. Interventional procedures guided by real-time MRI may derive potential benefit from a fluoroscopy-free working environment, more detailed insights into the target anatomy, and additional information on organ tissue properties relevant for pathomorphology as well as therapy delivery. Electrophysiological (EP) procedures in a magnetic resonance (MR) scanner require new workflows with different, MR safe, interventional materials and hardware setup, different approaches to intracardiac orientation and catheter tracking, and an adapted patient management. Recently, invasive diagnostic EP procedures have been described in animal studies and in a clinical setting.1,2 Actual catheter ablation has so far only been reported in a limited number of animal series.3 Hereby, we report on a MRI-guided cavotricuspid isthmus ablation. A 74-year-old man without structural heart disease was admitted with documented episodes of paroxysmal symptomatic typical right atrial flutter. At the ablation procedure the patient presented in sinus rhythm. The patient was enrolled into a clinical study approved by the local ethics committee and by the German Federal Institute for Drugs and Medical Devices (BfArM). He provided written and verbal informed consent. In this study, we used MR conditional catheters (Vision, Imricor Medical Systems, Burnsville, MN) and an MR conditional EP recording system (Bridge MR EP Recording System, Imricor Medical Systems, Burnsville, MN). The material is designed for use in 1.5 T closed bore scanners and imposes no limitations on the catheter trajectory, scanner landmark, or patient position. The catheter allows for all clinical scan protocols and is safe for use in normal and first level controlled operating modes. ### MR Conditional Catheters Although the appearance and functionality are similar to conventional ablation catheters, the design of the MR conditional catheter differs substantially. All ferromagnetic materials are removed to eliminate the potential for force and torque …

Real-time magnetic resonance-guided ablation of typical right atrial flutter using a combination of active catheter tracking and passive catheter visualization in man: initial results from a consecutive patient series

AIMS Recently cardiac magnetic resonance (CMR) imaging has been found feasible for the visualization of the underlying substrate for cardiac arrhythmias as well as for the visualization of cardiac catheters for diagnostic and ablation procedures. Real-time CMR-guided cavotricuspid isthmus ablation was performed in a series of six patients using a combination of active catheter tracking and catheter visualization using real-time MR imaging. METHODS AND RESULTS Cardiac magnetic resonance utilizing a 1.5 T system was performed in patients under deep propofol sedation. A three-dimensional-whole-heart sequence with navigator technique and a fast automated segmentation algorithm was used for online segmentation of all cardiac chambers, which were thereafter displayed on a dedicated image guidance platform. In three out of six patients complete isthmus block could be achieved in the MR scanner, two of these patients did not need any additional fluoroscopy. In the first patient technical issues called for a completion of the procedure in a conventional laboratory, in another two patients the isthmus was partially blocked by magnetic resonance imaging (MRI)-guided ablation. The mean procedural time for the MR procedure was 109 ± 58 min. The intubation of the CS was performed within a mean time of 2.75 ± 2.21 min. Total fluoroscopy time for completion of the isthmus block ranged from 0 to 7.5 min. CONCLUSION The combination of active catheter tracking and passive real-time visualization in CMR-guided electrophysiologic (EP) studies using advanced interventional hardware and software was safe and enabled efficient navigation, mapping, and ablation. These cases demonstrate significant progress in the development of MR-guided EP procedures.

Role of Preprocedural Computed Tomography in Transcatheter Aortic Valve Implantation

UNLABELLED Transcatheter aortic valve implantation (TAVI) is currently considered an acceptable alternative for the treatment of patients with severe aortic stenosis and a high perioperative risk or a contraindication for open surgery. The benefit of TAVI significantly outweighs the risk of the procedure in patients requiring treatment that are not suitable for open surgery, and leads to a lower mortality in the one-year follow-up. The absence of a direct view of the aortic root and valve remains a challenge for the transcatheter approach. While direct inspection of the aortic valve during open surgery allows an adequate prosthesis choice, it is crucial for TAVI to know the individual anatomical details prior to the procedure in order to assure adequate planning of the procedure and proper prosthesis choice and patient selection. Among the imaging modalities available for the evaluation of patients prior to TAVI, computed tomography (CT) plays a central role in patient selection. CT reliably visualizes the dimensions of the aortic root and allows a proper choice of the prosthesis size. The morphology of the access path and relevant comorbidities can be assessed. The present review summarizes the current state of knowledge regarding the value of CT in the evaluation of patients prior to TAVI. KEY POINTS CT plays a central role in patient selection and planning prior to TAVI. ▶ CT reliably detects the dimensions of the aortic root including the size of the aortic annulus, the degree of valve calcification and the morphology of the access routes. ▶ CT provides a more accurate measurement of the aortic annulus than 2D TEE and CT is the only imaging modality that allows a risk assessment for paravalvular leakages based on the calcification of the aortic valve.

The potential additional diagnostic value of assessing for pericardial effusion on cardiac magnetic resonance imaging in patients with suspected myocarditis

BACKGROUND The presence of pericardial effusion (PE) is considered to be suggestive of inflammation in suspected myocarditis. However, the incremental value of assessing for PE in addition to comprehensive cardiac magnetic resonance (CMR) imaging remains unclear. METHODS In total, 132 patients with suspected acute (AMC) or chronic myocarditis (CMC) were included. All patients underwent endomyocardial biopsy (EMB) and CMR. Imaging protocols included T2 imaging for the assessment of myocardial oedema (oedema ratio [ER]), T1 imaging before and after contrast agent administration for global relative enhancement (gRE) calculation, and late enhancement (LE). Furthermore, the presence and extent of PE were determined. The potential incremental diagnostic value of PE was determined by applying a two, three, or four out of four criteria approach including ER, gRE, LE, and PE. RESULTS PE was present in 84 of the 132 patients (63.6%) and was more common in suspected AMC vs. CMC (56 of 70 vs. 28 of 62; P < 0.001). According to EMB results, PE was found in 86% of patients with AMC, 67% with chronic myocarditis, and 56% without evidence of myocardial inflammation. Implementing PE into a three out of four approach did not result in improved accuracy compared with the established two out of three approach using ER, gRE, and LE (59 vs. 68% for the total population, 69 vs. 79% for suspected AMC, and 48 vs. 52% for suspected CMC). CONCLUSION The finding of PE in unselected patients with suspected AMC or CMC is not specific to myocarditis. Therefore, with the currently applied criteria and methods, assessment of PE does not improve the diagnostic performance of CMR in this patient cohort.