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Background: Cardiovascular Magnetic Resonance (CMR) imaging with adenosine stress is an important diagnostic tool in patients with known or suspected coronary artery disease (CAD). However, the method is not yet established for CAD patients with pacemakers (PM) in clinical practice. A possible reason is that no recommendations exist for PM setting (paused pacing or asynchronous mode) during adenosine stress. We elaborated a protocol for rhythm management in clinical routine for PM patients that considers heart rate changes under adenosine using a test infusion of adenosine in selected patients., Methods: 47 consecutive patients (mean age 72.3 ± 10,0 years) with MR conditional PM and known or suspected CAD who underwent CMR in clinical routine were studied in this prospective observational study. PM indications were sinus node dysfunction (SND, n = 19; 40,4%), atrioventricular (AV) block (n = 26; 55.3%) and bradyarrhythmia in permanent atrial fibrillation (AF, n = 2; 4.3%). In patients with SND, normal AV-conduction and resting HR >45 bpm at the time of CMR and in AF the PM was deactivated for the scan. In intermittent AV-block a test infusion of adenosine was given prior to the scan. All patients with permanent higher degree sinuatrial or AV-block or deterioration of AV-conduction in the adenosine test were paced asynchronously during CMR, in patients with preserved AV-conduction under adenosine the pacemaker was deactivated. CMR protocol included cine imaging, adenosine stress perfusion and late gadolinium enhancement., Results: The adenosine test was able to differentiate between mandatory PM stimulation during CMR and safe deactivation of the device. In patients with permanent sinuatrial or AV-block (n = 11; 23.4%) or deterioration of AV conduction in the adenosine test (n = 5, 10.6%) asynchronous pacing above resting heart rate did not interfere with intrinsic rhythm, no competitive stimulation was seen during the scan. 10 of 15 (66,7%) patients with intermittent AV-block showed preserved AV-conduction under adenosine. As in SND and AF deactivation of the PM showed to be safe during CMR, no bradycardia was observed., Conclusion: Our protocol for rhythm management during adenosine stress CMR showed to be feasible and safe and may be recommended for pacemaker patients undergoing routine CMR. more...

There are only limited data on the impact of device-related artifacts on image quality in cardiovascular magnetic resonance imaging (CMR) in patients with pacemakers (PM). Adenosine stress perfusion, T1-weighted imaging and flow measurement as well as valve characterization have not been evaluated previously concerning artifact burden. We aimed to assess image quality in all routinely used CMR sequences. We analyzed 2623 myocardial segments in CMR scans of 61 patients with MR conditional PM (mean age 72.1 ± 11.5 years), 23 (37.7%) with right sided, 38 (62.3%) with left-sided devices. There were no relevant artifacts in patients with right-sided devices irrespective of the imaging sequence. In left-sided implants no PM-induced artifacts were found in first pass perfusion sequence, flow analysis and T1 weighted imaging. Only few patients with left-sided devices showed significant PM-artifacts in aortic (3/38, 7.9%)/mitral (n = 2/38, 5.3%) valve imaging and STIR (n = 3/35, 8.6%). In STIR only 14/805 (1.7%) segments were involved. In left-sided PM SSFP cine sequences had more artifact burden than LGE with 377/1505 (25.0%) vs. 162/1505 (10.8%) myocardial segments involved by relevant artifacts respectively (p < 0.001). Apart from cine and LGE imaging in anterior myocardial segments with left-sided implants presence of MRI conditional pacemakers does not affect CMR image quality in multimodal CMR examinations to a significant extent. Our data supports evidence that reduced image quality does not need to be a major concern in PM patients undergoing CMR. more...

Background: Patient-activated event recorders (ER) can facilitate diagnosis in unclear palpi-tations, however impact of ER screening on further treatment in clinical routine is unknown. We investigated the feasibility and clinical value of a network-based telemetric monitoring using a patient activated ER., Methods: The network consisted of 12 general practitioners (GP) and a department of car-diology (DC). GP-patients sent electrocardiograms (ECGs) twice daily and in case of palpitations. ECGs were transferred by email to GP and DC and analyzed independently by both. The therapeutic strategy was discussed between GP and DC. The monitoring period ended after 4 weeks or in case of detected arrhythmia., Results: A group of 184 consecutive patients were retrospectively analyzed. Mean age was 57.5 ± 14.4 years (range 17-82), 104 (56.5%) were female. Significant arrhythmia occurred in 71 (38.5%) patients: Recurrence of known paroxysmal atrial fibrillation (AF; n = 27, 14.7%), de novo AF (n = 19, 10.3%), premature complexes/bigeminus (n = 13, 7.1%), sinus tachycar-dia (n = 7, 3.8%), atrioventricular nodal reentrant tachycardia (n = 3, 1.6%), and ventricular tachycardia (n = 2, 1.1%). A therapeutic consequence resulted in 63 (88.7%) patients with de-tected arrhythmia: new oral anticoagulation (n = 29, 40.8%), new antiarrhythmic medication (n = 27, 38.0%), behavioral intervention (n = 19, 26.8%), electrophysiology-study/catheter ablation (n = 4, 5.6%), cardioversion (n = 2, 2.8%), implantable cardioverter-defibrillator- -implantation (n = 1, 1.4%), and left atrial appendage occluder (n = 1, 1.4%)., Conclusions: The investigated cross-sector telemetric network is a feasible approach to detect arrhythmia in patients with palpitations and may have high impact on further treatment, notably in those at risk for stroke due to AF. more...

Background: Cardiovascular Magnetic Resonance (CMR) with adenosine stress is a valuable diagnostic tool in coronary artery disease (CAD). However, despite the development of MR conditional pacemakers CMR is not yet established in clinical routine for pacemaker patients with known or suspected CAD. A possible reason is that adenosine stress perfusion for ischemia detection in CMR has not been studied in patients with cardiac conduction disease requiring pacemaker therapy. Other than under resting conditions it is unclear whether MR safe pacing modes (paused pacing or asynchronous mode) can be applied safely because the effect of adenosine on heart rate is not precisely known in this entity of patients. We investigate for the first time feasibility and safety of adenosine stress CMR in pacemaker patients in clinical routine and evaluate a pacing protocol that considers heart rate changes under adenosine., Methods: We retrospectively analyzed CMR scans of 24 consecutive patients with MR conditional pacemakers (mean age 72.1 ± 11.0 years) who underwent CMR in clinical routine for the evaluation of known or suspected CAD. MR protocol included cine imaging, adenosine stress perfusion and late gadolinium enhancement., Results: Pacemaker indications were sinus node dysfunction (n = 18) and second or third degree AV block (n = 6). Under a pacing protocol intended to avoid competitive pacing on the one hand and bradycardia due to AV block on the other no arrhythmia occurred. Pacemaker stimulation was paused to prevent competitive pacing in sinus node dysfunction with resting heart rate >45 bpm. Sympatho-excitatory effect of adenosine led to a significant acceleration of heart rate by 12.3 ± 8.3 bpm (p < 0.001), no bradycardia occurred. On the contrary in AV block heart rate remained constant; asynchronous pacing above resting heart rate did not interfere with intrinsic rhythm., Conclusion: Adenosine stress CMR appears to be feasible and safe in patients with MR conditional pacemakers. Heart rate response to adenosine has to be considered for the choice of pacing modes during CMR. more...

Background: Adult stem cells can contribute to myocardial regeneration after ischemic injury. The aim of the study was to determine (1) the amount of mobilized CD34(+)/CD117(+), CD34(+)/KDR(+) cells into peripheral blood (PB) in relation to inflammatory and haematopoietic cytokines, (2) the presence of circulating CD34(+) cells, expressing cell adhesion molecules (CAM), in patients with ST-segment elevation myocardial infarction (STEMI) in comparison to patients with coronary artery disease (CAD)., Materials and Methods: Twenty-three patients with STEMI (<12 h), 24 patients with CAD and 15 control subjects were enrolled in this study. The patients were matched in age, 2-CAD, ejection fraction (45%) and end-diastolic volume index (70 ml/m(2)). The number of stem cells and the expression of adhesion molecules were quantified by use of flow cytometry. Inflammatory cytokines [interleukin-6 (IL-6), granulocyte colony-stimulating factor (G-CSF), vascular endothelial growth factor] and chemotactic factors as stromal cell-derived factor-1 (SDF-1), hepatocyte growth factor (HGF) were determined by ELISA., Results: The amount of circulating progenitor cells including CD34(+)/CD117(+) and CD34(+)/KDR(+) cells was significantly higher in patients with STEMI than in patients with CAD (CD34(+)/CD117(+) 433 +/- 128 vs. 100 +/- 17, P = 0.012; CD34(+)/KDR(+) 253 +/- 41 vs. 128 +/- 24, P = 0.02). The mobilization of CD34(+) progenitor cells expressing CXCR4-receptor, lymphocyte function-associated antigen-1 (LFA-1), very late antigen-4 (VLA-4) and ICAM-1 into PB was significantly higher in patients with STEMI compared to CAD (CD34(+)/CXCR4(+) 740 +/- 327 vs. 136 +/- 23, P = 0.006; CD34(+)/LFA-1 976 +/- 227 vs. 329 +/- 41, P = 0.025; CD34(+)/VLA4(+) 830 +/- 161 vs. 330 +/- 31, P = 0.007; CD34(+)/ICAM(+) 387 +/- 66 vs. 144 +/- 26, P < 0.001). Additionally, the cytokines G-CFS, IL-6 and HGF were upregulated and significantly increase in the STEMI group compared with controls and CAD (G-CSF 50.6 +/- 6.8 vs. 23 +/- 3 vs. 23.8 +/- 2, P (Co vs. STEMI) < 0.001, P (Co vs. CAD) = n.s., P (STEMI vs. CAD) < 0.001; IL-6 8.4 +/- 0.6 vs. 3.8 +/- 1.9 vs. 2.6 +/- 1, P (Co vs. STEMI) < 0.001, P (Co vs. CAD) = n.s., P (STEMI vs. CAD) < 0.001; HGF 4,502 +/- 461 vs. 686 +/- 195 vs. 1,746 +/- 461, P (Co vs. STEMI) < 0.001, P (Co vs. CAD) = n.s., P (STEMI vs. CAD) < 0.001), while the level of SDF-1 was increased in patients with CAD compared to controls and patients with STEMI (3,035 +/- 286 vs. 2,028 +/- 76 vs. 2,154 +/- 234, P (Co vs. STEMI) = n.s., P (Co vs. CAD) = n.s., P (STEMI vs. CAD) = 0.005)., Conclusions: The study demonstrates in patients with STEMI an increased mobilization of progenitor cells like CD34(+)/CD117(+) and CD34(+)/KDR(+) compared to CAD. Furthermore, we could shown that in patients with STEMI the mobilization of CD34(+) progenitor cells with expressed CAM was increased. It is to speculate that an enhanced expression of adhesion molecules may increase the transmigration and implantation of progenitor cells into ischemic myocardium for myocardial repair. more...