Direct cooling of the catheter tip increases safety for CMR-guided electrophysiological procedures

<p>Abstract</p> <p>Background</p> <p>One of the safety concerns when performing electrophysiological (EP) procedures under magnetic resonance (MR) guidance is the risk of passive tissue heating due to the EP catheter being exposed to the radiofrequency (RF) field of the RF transmitting body coil. Ablation procedures that use catheters with irrigated tips are well established therapeutic options for the treatment of cardiac arrhythmias and when used in a modified mode might offer an additional system for suppressing passive catheter heating.</p> <p>Methods</p> <p>A two-step approach was chosen. Firstly, tests on passive catheter heating were performed in a 1.5 T Avanto system (Siemens Healthcare Sector, Erlangen, Germany) using a ASTM Phantom in order to determine a possible maximum temperature rise. Secondly, a phantom was designed for simulation of the interface between blood and the vascular wall. The MR-RF induced temperature rise was simulated by catheter tip heating via a standard ablation generator. Power levels from 1 to 6 W were selected. Ablation duration was 120 s with no tip irrigation during the first 60 s and irrigation at rates from 2 ml/min to 35 ml/min for the remaining 60 s (Biotronik Qiona Pump, Berlin, Germany). The temperature was measured with fluoroscopic sensors (Luxtron, Santa Barbara, CA, USA) at a distance of 0 mm, 2 mm, 4 mm, and 6 mm from the catheter tip.</p> <p>Results</p> <p>A maximum temperature rise of 22.4°C at the catheter tip was documented in the MR scanner. This temperature rise is equivalent to the heating effect of an ablator's power output of 6 W at a contact force of the weight of 90 g (0.883 N). The catheter tip irrigation was able to limit the temperature rise to less than 2°C for the majority of examined power levels, and for all examined power levels the residual temperature rise was less than 8°C.</p> <p>Conclusion</p> <p>Up to a maximum of 22.4°C, the temperature rise at the tissue surface can be entirely suppressed by using the catheter's own irrigation system. The irrigated tip system can be used to increase MR safety of EP catheters by suppressing the effects of unwanted passive catheter heating due to RF exposure from the MR scanner.</p

Imaging Predictors of Left Ventricular Functional Recovery after Reperfusion Therapy of ST-Elevation Myocardial Infarction Assessed by Cardiac Magnetic Resonance

Background: Left ventricular global longitudinal strain (LV GLS) is a superior predictor of adverse cardiac events in patients with myocardial infarction and heart failure. We investigated the ability of morphological features of infarcted myocardium to detect acute left ventricular (LV) dysfunction and predict LV functional recovery after three months in patients with acute ST-segment elevation myocardial infarction (STEMI). Methods: Sixty-six STEMI patients were included in the C-reactive protein (CRP) apheresis in Acute Myocardial Infarction Study (CAMI-1). LV ejection fraction (LVEF), LV GLS, LV global circumferential strain (LV GCS), infarct size (IS), area-at-risk (AAR), and myocardial salvage index (MSI) were assessed by CMR 5 ± 3 days (baseline) and 12 ± 2 weeks after (follow-up) the diagnosis of first acute STEMI. Results: Significant changes in myocardial injury parameters were identified after 12 weeks of STEMI diagnosis. IS decreased from 23.59 ± 11.69% at baseline to 18.29 ± 8.32% at follow-up (p < 0.001). AAR and MVO also significantly reduced after 12 weeks. At baseline, there were reasonably moderate correlations between IS and LVEF (r = −0.479, p < 0.001), LV GLS (r = 0.441, p < 0.001) and LV GCS (r = 0.396, p = 0.001) as well as between AAR and LVEF (r = −0.430, p = 0.003), LV GLS (r = 0.501, p < 0.001) and weak with LV GCS (r = 0.342, p = 0.020). At follow-up, only MSI and change in LV GCS over time showed a weak but significant correlation (r = −0.347, p = 0.021). Patients with larger AAR at baseline improved more in LVEF (p = 0.019) and LV GLS (p = 0.020) but not in LV GCS. Conclusion: The CMR tissue characteristics of myocardial injury correlate with the magnitude of LV dysfunction during the acute stage of STEMI. AAR predicts improvement in LVEF and LV GLS, while MSI is a sensitive marker of LV GCS recovery at three months follow-up after STEMI

Rationale and design of the MULTISTARS AMI Trial: a randomized comparison of immediate versus staged complete revascularization in patients with ST-segment elevation myocardial infarction and multivessel disease

Background: About half of patients with acute ST-segment elevation myocardial infarction (STEMI) present with multivessel coronary artery disease (MVD). Recent evidence supports complete revascularization in these patients. However, optimal timing of non-culprit lesion revascularization in STEMI patients is unknown because dedicated randomized trials on this topic are lacking. Study design: The MULTISTARS AMI trial is a prospective, international, multicenter, randomized, two-arm, open-label study planning to enroll at least 840 patients. It is designed to investigate whether immediate complete revascularization is non-inferior to staged (within 19-45 days) complete revascularization in patients in stable hemodynamic conditions presenting with STEMI and MVD and undergoing primary percutaneous coronary intervention (PCI). After successful primary PCI of the culprit artery, patients are randomized in a 1:1 ratio to immediate or staged complete revascularization. The primary endpoint is a composite of all-cause death, non-fatal myocardial infarction, ischemia-driven revascularization, hospitalization for heart failure, and stroke at 1 year. Conclusions: The MULTISTARS AMI trial tests the hypothesis that immediate complete revascularization is non-inferior to staged complete revascularization in stable patients with STEMI and MVD

Impact of gender in patients with device-related thrombosis after left atrial appendage closure - A sub-analysis from the multicenter EUROC-DRT-registry.

BACKGROUND Device-related thrombosis (DRT) is a common finding after left atrial appendage closure (LAAC) and is associated with worse outcomes. As women are underrepresented in clinical studies, further understanding of sex differences in DRT patients is warranted. METHODS AND RESULTS This sub-analysis from the EUROC-DRT-registry compromises 176 patients with diagnosis of DRT after LAAC. Women, who accounted for 34.7% (61/176) of patients, were older (78.0 ± 6.7 vs. 74.9 ± 9.1 years, p = .06) with lower rates of comorbidities. While DRT was detected significantly later in women (173 ± 267 vs. 127 ± 192 days, p = .01), anticoagulation therapy was escalated similarly, mainly with initiation of novel oral anticoagulant (NOAC), vitamin K antagonist (VKA) or heparin. DRT resolution was achieved in 67.5% (27/40) of women and in 75.0% (54/72) of men (p = .40). In the remaining cases, an intensification/switch of anticoagulation was conducted in 50.% (9/18) of men and in 41.7% (5/12) of women. Final resolution was achieved in 72.5% (29/40) cases in women, and in 81.9% (59/72) cases in men (p = .24). Women were followed-up for a similar time as men (779 ± 520 vs. 908 ± 687 days, p = .51). Kaplan-Meier analysis revealed no difference in mortality rates in women (Hazard Ratio [HR]: 1.73, 95%-Confidence interval [95%-CI]: .68-4.37, p = .25) and no differences in stroke (HR: .83, 95%-CI: .30-2.32, p = .72) within 2 years after LAAC. CONCLUSION Evaluation of risk factors and outcome revealed no differences between men and women, with DRT in women being diagnosed significantly later. Women should be monitored closely to assess for DRT formation/resolution. Treatment strategies appear to be equally effective

Investigations in creatine kinase knockout mice using MRI: Cardiac phenotype and remodeling after myocardial infarction following creatine kinase-deficiency

Transgene Tiermodelle ermöglichen seit einigen Jahren eine gezielte Untersuchung des Einflusses einzelner Gene, und damit auch ihrer entsprechenden Produkte und deren Substrate, auf die Integrität des Organismus. In der vorliegenden Arbeit wurde die Bedeutung der verschiedenen Isoenzyme der Kreatinkinase im Herzen untersucht, indem die kardiale Morphologie und Funktion dreier verschiedener Stämme von Kreatinkinase-Knockout-Mäusen mit der von Wildtyp-Mäusen verglichen wurde. Der Kreatinkinase wird eine wichtige Rolle im intrazellulären System zur Aufrechterhaltung der Energiehomöostase zugeschrieben, beim Menschen gehen verschiedene kardiale Erkrankungen mit Veränderungen des Kreatinkinase-Systems einher. Neben der Bestimmung verschiedener kardialer Parameter von Mäusen mit Knockout der kardialen Isoenzyme der Kreatinkinase wurde geprüft, inwieweit sich ein durch permanente Koronarligatur induzierter chronischer Myokardinfarkt auf die Morphologie und Funktion des Herzens bei Kreatinkinase-Knockout auswirkt. Als Methode kam hierzu die Cine-Fast Low Angle Shot (FLASH)-Magnetresonanzbildgebung zur Anwendung, die eine nicht invasive, präzise Erfassung verschiedener kardialer Parameter in vivo ermöglicht. Myokardmasse, links- und rechtsventrikuläre Volumina, Ejektionsfraktion, Herzzeitvolumina, Wanddicken sowie die Infarktgröße bei den infarzierten Kreatinkinase-Knockout-Mäusen konnten erstmalig in vivo bestimmt und mit Wildtyp-Mäusen verglichen werden. Es konnte gezeigt werden, dass im Alter von durchschnittlich 41 Wochen ein Knockout des mitochondrialen Isoenzyms der Kreatinkinase eine deutliche linksventrikuläre Hypertrophie sowie leichtgradige biventrikuläre Dilatation verursacht. Bei Knockout der M-Untereinheit der zytosolischen Isoenzyme und dadurch bedingtem Fehlen von CK-MM und CK-MB resultiert lediglich eine geringgradige konzentrische linksventrikuläre Hypertrophie. Der rechte Ventrikel zeigte bei allen Knockout-Mäusen lediglich geringe Veränderungen im Vergleich mit den Wildtypen. Die Herzfunktion war bei allen Tieren unter Normalbedingungen voll erhalten, Zeichen einer Herzinsuffizienz fanden sich nicht. Vier Wochen nach Infarzierung zeigten sich bei Knockout- und Wildtyp-Mäusen keine signifikanten Unterschiede in Herzmorphologie und Funktion. Die Mortalität nach Infarkt war in beiden Gruppen identisch. Die aus einem Fehlen der mitochondrialen Kreatinkinase resultierenden Defizite des Herzens können somit durch Ausbildung einer Hypertrophie kompensiert werden. Im Vergleich mit der mitochondrialen Form kommt den zytosolischen Isoenzymen der Kreatinkinase eine geringere Bedeutung bei der Aufrechterhaltung des Metabolismus und damit auch der Funktion des Herzens zu. Ein kombinierter Knockout sowohl der M-Untereinheit der zytosolischen CK als auch der mitochondrialen CK führt bezüglich der Morphologie und Funktion des Herzens zu keiner stärkeren Pathologie als bei selektiv mitochondrialem Knockout.For several years, transgenic animal models have offered the possibility to determine the influence of specific genes, as well as their products and substrates, on the integrity of an organism. This study investigates the role of different creatine kinase-isoenzymes in the heart by comparing cardiac morphology and function of three different creatine kinase knockout mice with wild types. Creatine kinase is thought to play an important role in intracellular energy homeostasis and there are several human cardiac diseases which are coupled with changes in the creatine kinase system. In addition to assessing cardiac characteristics in creatine kinase-deficient mice, this work also focuses on the effects of chronic myocardial infarction in these animals. This was done by using cine-FLASH magnetic resonance imaging, which allows a non-invasive, precise in vivo-analysis of cardiac characteristics. This work marks the first time myocardial mass, volumes, ejection fraction, cardiac output and wall thickness, as well as infarction extent, were measured in vivo in creatine kinase-deficient mice and compared to wild types. The findings show that a knockout of mitochondrial creatine kinase is followed by distinct left ventricular hypertrophy and moderate biventricular dilatation in mice 41 weeks old. In contrast to these findings, a knockout of the main cytosolic creatine kinase isoenzymes only triggered slight left ventricular hypertrophy, but no dilatation was found. Changes in right ventricular parameters were minor, and there was no sign of diminished cardiac function at rest. Furthermore, no significant differences between creatine kinase knockout and wild type mice hearts were found four weeks after myocardial infarction. Mortality following infarction also did not differ. In conclusion, cardiac shortcomings that accompany a knockout of mitochondrial creatine kinase can be compensated by developing cardiac hypertrophy. Compared to mitochondrial creatine kinase, cytosolic isoenzymes play an inferior role in the upkeep of cardiac metabolism and function. Combined knockout of both mitochondrial and cytosolic creatine kinase does not cause increased pathological effects compared to selective mitochondrial creatine kinase knockout

Personal Papers (MS 80-0002)

Letter from Peter Pyn and Fritz Nordbeck to Harris and Ruth Kempner expressing their condolences for the death of the Kempner's son Sandy who was killed serving in the Vietnam War

Response to “Oral Chaperone Therapy Migalastat for the Treatment of Fabry Disease: Potentials and Pitfalls of Real‐World Data”

No abstract availabl

MRI-guided ablation of wide complex tachycardia in a univentricular heart

Magnetic resonance imaging can be used for preprocedural assessment of complex anatomy for radiofrequency (RF) ablations, e.g., in a univentricular heart. This case report features the treatment of a young patient with a functionally univentricular heart who suffered from persistent sudden onset tachycardia with wide complexes that required RF ablation as treatment