Carsten Schneider

Strain rate imaging for functional quantification of the left atrium: atrial deformation predicts the maintenance of sinus rhythm after catheter ablation of atrial fibrillation

AIMS The aim of the study was to investigate the atrial myocardial deformation properties using ultrasound strain rate (SR) imaging in patients after catheter ablation of atrial fibrillation (AF) and to compare its prognostic value in maintaining sinus rhythm. METHODS AND RESULTS A total of 118 patients with AF (74 paroxysmal AF, 44 persistent AF) underwent transthoracic echocardiography with Doppler-derived SR examinations before and after ablation as well as during 3 months of follow-up (FU). Peak SR and strain (S) were measured at each left atrium (LA) segment (septal, lateral, anterior, inferior) during systole (LAs) and at early (LAe) and late diastole (LAa). Clinical and echocardiographic parameters of patients with maintained sinus rhythm during FU were compared with those with recurrent AF and controls (n = 25 patients). Of 118 patients 82 (69%) showed stable sinus rhythm during FU. Atrial myocardial properties after catheter ablation differed significantly in patients with paroxysmal AF (SR-LAs 2.5 s(-1), S-LAs 30%, SR-LAa -2.2 s(-1)) from patients with persistent AF (SR-LAs 2.3 s(-1), S-LAs 25%, SR-LAa -1.9 s(-1)) and controls (SR-LAs 4.1 s(-1), S-LAs 88%, SR-LAa -2.9 s(-1)) (P = 0.011). Best individual predictors of sinus rhythm maintenance were cut-off values of >2.25 s(-1) for septal and inferior SR-LAs and of >19.5% for inferior S-LAs (P < 0.001). LA deformation properties increased in patients with maintained sinus rhythm during FU in contrast to patients with recurrent AF (P = 0.001). CONCLUSION SR imaging enables the quantitative assessment of the LA function and can be considered as a potential marker of atrial reverse remodelling. Patients with higher atrial S and SR after catheter ablation appear to have a greater likelihood of maintenance of sinus rhythm. This may have further implications for the anticoagulation regime and the risk of cardioembolic complications.

Percutaneous intramyocardial stem cell injection in patients with acute myocardial infarction: first-in-man study

Background: Clinical studies on intracoronary stem cell infusion in patients with acute myocardial infarction (AMI) have shown promising results for left ventricular ejection fraction (LVEF). However, preclinical studies have shown that intramyocardial cell injection is better than the intracoronary approach. Objective: To test safety and feasibility of intramyocardial cell injection and left ventricular electromechanical mapping (EMM) early after AMI. Design: On day 10.5 (5) (mean (SD)) after AMI and percutaneous coronary intervention with stent implantation (culprit lesion: 15 LAD, 3 circumflex and 2 right coronary arteries) 20 patients (mean (SD) 60.4 (11.4) years) received bone marrow derived mononuclear cells in the low-voltage area using EMM-guided percutaneous intramyocardial injection. EMM and coronary angiography were performed in 15 patients at 6-months’ follow-up. Echocardiography, recording of laboratory data and clinical assessment (6-month and 12-month follow-up) were carried out in all 20 patients. Results: None of the patients showed periprocedural complications. Three patients received an implantable cardioverter-defibrillator for primary prevention of sudden cardiac death and 6 (30%) patients showed in-stent restenosis. One patient underwent bypass surgery owing to chronic stent occlusion after 6 months. 2.0 (0.6)×108 cells, including 1.0 (0.3)×106 CD45dim/CD34hi stem cells, were injected in each patient. EMM showed a mean (SD) improvement from a baseline unipolar voltage of 45.5 (14.3)% to 59.3 (19.8)% of normal voltage (p = 0.002) and reduction of the low-voltage area from 28.7 (12.1)% to 20.3 (13.5)%; (p = 0.016). During the 12-month follow-up, the left ventricular ejection fraction (LVEF) improved from 40.8 (6.9)% to 47.1 (10.6)%; (p = 0.037). Conclusion: Left ventricular EMM and percutaneous intramyocardial cell injection in patients with AMI was shown to be a safe procedure. It is associated with improved LVEF and electromechanical parameters after 12-months’ follow-up. Trial registration number: Eudra-CT-No 2005-003629-19.

Electromechanical mapping for determination of myocardial contractility and viability: A comparison with echocardiography, myocardial single-photon emission computed tomography, and positron emission tomography☆

OBJECTIVE The purpose of this study was to validate electromechanical viability parameters with combined myocardial perfusion and metabolic imaging and echocardiography. BACKGROUND The NOGA System is a catheter-based, non-fluoroscopic, three-dimensional endocardial mapping system. This unique technique allows accurate simultaneous assessment of both local electrical activity and regional contractility. METHODS The results of NOGA, myocardial single-photon emission computed tomography (SPECT), positron emission tomography, and echocardiography in 51 patients with coronary artery disease and a pathologic SPECT study were transcribed in a nine-segment bulls-eye projection and compared. The local shortening of normally contracting segments, as shown by echocardiography, was 9.2 +/- 5.1%, which decreased to 6.6 +/- 5.0% and 4.1 +/- 5.2% in hypokinetic and akinetic segments. The highest unipolar voltage (11.2 +/- 5.0 mV) and local shortening (8.2 +/- 5.0%) characterized normally perfused segments. Fixed perfusion defects with normal or limited 18-fluoro-2-deoxy-D-glucose uptake indicating viability had a significantly higher unipolar voltage than did scar tissue (7.25 +/- 2.7 vs. 5.0 +/- 3.1 mV, p = 0.029). CONCLUSION Electromechanical parameters sufficiently defined the viability state of the myocardium and showed good concordance with the findings by nuclear perfusion and metabolism imaging and echocardiography. The NOGA technique provides all the relevant information immediately after coronary angiography and enables the physician to proceed with therapy in the same setting.

A prospective study on ultrasound-guided percutaneous thrombin injection for treatment of iatrogenic post-catheterisation femoral pseudoaneurysms

BACKGROUND The purpose of this study was to evaluate prospectively the safety and efficacy of bovine thrombin injection for the treatment of iatrogenic post-catheterisation pseudoaneurysms. METHODS AND RESULTS A total of 274 patients (90 women, 184 men, 69.8+/-7 years) with iatrogenic femoral pseudoaneurysms were treated by ultrasound-guided thrombin injection (UGTI). The deepest pseudoaneurysm chamber was entered with a 0.90x40 mm or 90 mm needle and bovine thrombin (solution of 1000 U/ml) was injected. Pseudoaneurysms were associated with diagnostic cardiac catheterisation, percutaneous coronary intervention or invasive electrophysiologic investigation. The majority of the patients were under antiplatelet therapy with aspirin or clopidogrel or both, and additional low dose heparin therapy. A total of 52 patients were treated with either phenprocoumon or enoxaparine body weight adjusted. UGTI was primary successful in 267 of 274 patients (97%). In 3 of 7 patients with a remaining pseudoaneurysm a second injection was required. Three patients were treated by ultrasound-guided compression. One patient was treated by surgical repair of the pseudoaneurysm 1 day after UGTI because a further pseudoaneurysm developed under phenprocoumon therapy. UGTI-related complications such as significant arterial thrombotic events or allergic reactions did not occur. 75 patients (27%) were evaluated by an additional sonography after 3 months to assess the long-term effect. CONCLUSION UGTI was well tolerated, safe and primarily effective in 97% of patients with iatrogenic femoral pseudoaneurysms. Anticoagulant use did not hinder successful thrombosis. UGTI should be considered as first-line therapy for the treatment of post-catheterisation pseudoaneurysms.

Drug-eluting stents for the treatment of pulmonary vein stenosis after atrial fibrillation ablation

AIMS Pulmonary vein (PV) stenosis (PVS) is a complication of radiofrequency PV isolation (PVI). Reported restenosis rates after balloon dilatation and bare-metal stent implantation are high. Drug-eluting stent implantation (DES) has not been reported in the setting of PVS. METHODS AND RESULTS Patients suspected of having PVS after PVI based on clinical symptoms and transesophageal echocardiography (TEE) follow-up (FU) were referred for PV DES. One or more branches of the affected PV as documented by angiography were stented (paclitaxel or zotarolimus DES). Follow-up consisted of repeat PV angiography and TEE. Over a period of 2 years, five patients were treated with a total of eight DES. A paclitaxel DES was used in seven of eight implants. Mean FU was 12 ± 14 months during which all patients remained asymptomatic. Transesophageal echocardiography Doppler maximal flow velocity (V(max)) of the affected PVs rose from 58 ± 6 cm/s pre-PVI to 207 ± 20 cm/s pre-DES (+358%, P < 0.0001). After DES, V(max) decreased acutely with 86 ± 15 cm/s (-58%, P < 0.01). During FU, V(max) remained stable in three patients and increased moderately in one. Angiography at 3 months confirmed absence of restenosis in the first three patients and moderate (40%) restenosis in one patient. In one patient, an increase of V(max) back to pre-DES values correlated with a 65% peri-stent stenosis, treated with a redo DES. In total, after seven primary DES only one (asymptomatic) proximal margin restenosis required re-stenting. CONCLUSION Initial experience with DES for PV stenosis suggests an excellent stent patency rate. Transesophageal echocardiography Doppler measurements provide a viable way of monitoring stent patency.

Percutaneous endocardial injection of erythropoietin: Assessment of cardioprotection by electromechanical mapping

Apart from its well‐known stimulation of erythropoiesis, erythropoietin (EPO) exhibits angiogenic and anti‐apoptotic effects. These cellular protective effects have also been described in experimental acute myocardial infarction models. We investigated the effects of EPO in a porcine model of chronic progressive myocardial ischaemia.

Transplantation of Bone Marrow-Derived Stem Cells Improves Myocardial Diastolic Function: Strain Rate Imaging in a Model of Hibernating Myocardium

BACKGROUND The aim of this study was to evaluate the cardioprotective effects of bone marrow-derived stem cells on myocardial compliance in a chronic ischemia model regarding strain rate (SR) parameters during dobutamine stress echocardiography (DSE). METHODS Ameroid constrictors were placed around the circumflex arteries of 23 domestic pigs to induce chronic vessel occlusions. Fifteen pigs received transendocardially bone marrow derived stem cells, and 8 received placebo injections (a 0.9% solution of NaCl) into the ischemic region. At week 6, the animals were evaluated regarding myocardial fibrosis, neovascularization, apoptosis, and diastolic function during DSE. RESULTS Stem cell-injected hearts showed significantly less fibrosis, higher ejection fractions, significant neovascularization, and less ventricular dilatation than controls (P < .05). Strain rate imaging revealed improved diastolic function, with higher early diastolic SR values and lower E/Ea ratios compared with controls (P < .05). Early diastolic SR during DSE identifies viable myocardium (extent of fibrosis, r = 0.86, P = .0001). CONCLUSION The endocardial injection of stem cells improves diastolic function in chronic ischemic myocardium and helps attenuate postinfarction remodeling.

Transesophageal echocardiography: a follow-up tool after catheter ablation of atrial fibrillation and interventional therapy of pulmonary vein stenosis and occlusion.

BackgroundPulmonary vein stenosis (PVS) has been described as a complication after primary catheter ablation of atrial fibrillation (Afib). The purpose of this study was to evaluate the utility of transesophageal echocardiography (TEE) as follow-up tool after catheter ablation of Afib and interventional therapy of PVS and pulmonary vein occlusion (PVO).MethodsWe report on 28 patients with stenosis (PVS) of 33 pulmonary veins (PVs) and total PVO of 4 veins complicating ablation of Afib assessed by angiography and/or magnetic resonance imaging (MRI). Subsequently, transseptal PV angiograms were performed, followed by recanalization of three totally occluded PVs and balloon dilatation of seven severe PVS (in four cases combined with PV stenting). PVs were analyzed by multiplane TEE in an intraindividual comparison of preablation/preintervention and follow-up measurements of mean and peak flow velocity, velocity time integrals, and diameters.ResultsOf a total of 28 patients, 14 had mild PVS (n = 14), 9 had moderate PVS (n = 10), 6 had severe PVS (n = 8), and 4 patients showed totally occluded PVs (n = 4). In multivariate analysis flow velocities and vessel diameters showed significant differences (mild, moderate, and severe PVS and PVO; p = 0.001). Interventional benefits of balloon dilatation (n = 10) and stent implantation (n = 4), as well as in-stent restenosis could be detected (p = 0.014). In all recanalized vessels TEE showed reestablished flow. In occluded PVs no flow was detectable. The TEE vessel diameters correlated with angiography data (r = 0.87) and computed tomography/MRI (r = 0.90).ConclusionsTEE can be used as a follow-up tool after interventional therapy in patients after catheter ablation and acquired PVS/PVO. Restenosis/in-stent restenosis can be identified by analyzing the vessel diameters and blood flow characteristics.

Intramyocardial Transplantation of Bone Marrow-Derived Stem Cells: Ultrasonic Strain Rate Imaging in a Model of Hibernating Myocardium

BACKGROUND The aim of this study was to evaluate potential cardioprotective effects of bone marrow-derived stem cells in chronic ischemic myocardium regarding strain rate parameters during dobutamine stress echocardiography. METHODS An ameroid constrictor was placed around the circumflex artery in 23 pigs to induce hibernating myocardium. Pigs received autologous mesenchymal stem cells (auto MSCs), allogeneic MSC (allo MSC), autologous mononuclear cells (auto MNCs), or placebo injections into the ischemic region. During dobutamine stress echocardiography, peak systolic strain rates (SR(sys)) and systolic and postsystolic strain values (epsilon(sys), epsilon(ps)) were determined. The animals were evaluated regarding myocardial fibrosis, neovascularization, apoptosis, and myocardial beta-adrenergic receptor density. RESULTS The median ejection fraction was reduced in the control group compared with the auto MSC-, allo MSC-, and auto MNC-treated pigs (36.5% vs 46.0% vs 46.0% vs 41.5%; P = .001, respectively). Histopathology revealed a decreased myocardial fibrosis in auto MSC- (16.3%), allo MSC- (11.3%), and auto MNC- (16.7%) treated pigs compared with controls (31.0%; P = .004). The fibrosis and echocardiographic deformation data correlated in the posterior walls: rest peak SR(sys)r = -0.92; epsilon(sys)r = -0.86; 10 microg dobutamine stimulation peak SR(sys)r = -0.88, epsilon(sys), r = -0.87 (P = .0001). CONCLUSION Endocardial injection of stem cells may induce cardioprotective effects in chronic ischemic myocardium and helps to keep the ischemic myocardium viable.

Percutaneous, transendocardial injection of bone marrow-derived mononuclear cells in heart failure patients following acute ST-elevation myocardial infarction: ALSTER-Stem Cell trial.

AIMS Patients with symptomatic heart failure following acute ST-elevation myocardial infarction (STEMI) received transendocardial application of bone marrow-derived mononuclear cells (BMC) to improve left ventricular (LV) function and clinical outcome. METHODS AND RESULTS Patients (n=12) with LV ejection fraction (EF) <45% and NYHA Class ≥II received NOGA-guided transendocardial injection of BMC into the infarction border zone 17.5±0.8 days following successful interventional revascularisation after STEMI. A matched control group (n=11) was generated from the source data of the previously published LIPSIAbciximab-STEMI trial. Primary and secondary endpoints were derived from comparisons of baseline vs. six-month follow-up cardiac magnetic resonance imaging (CMR) measurements and clinical assessments. Following cell therapy we observed a significant increase of EF (+7.9±1.5%, p=0.001) while the control group showed no change. This effect was driven by a reduction of LV end-systolic volume (ESV) by -27.5±6.5 ml (p=0.001); LV end-diastolic volume (EDV) and scar volu-me remained unchanged. A significant decrease of NYHA Class was found only in the cell therapy group (-0.75 vs. -0.18, p=0.04). Findings were also translated into enhancement of clinical assessments (rehospitalisation for decompensated heart failure, six-minute walk test, NT-proBNP levels). CONCLUSION The data suggest transendocardial injection of BMC can be used safely in patients with sympto-matic heart failure following acute STEMI. These prospective, preliminary data of a well-characterised, small cohort suggest efficiency compared to routine treatment.