Validation of QwikStar Catheter for left ventricular electromechanical mapping with NOGA XP system.

Left ventricular electromechanical mapping (LVEM) is a method for mapping the left ventricular cavity in 3 dimensions by use of a catheter that samples points on the endocardial surface. These points provide data on unipolar voltage and linear local shortening, which can then be used to evaluate myocardial ischemia and viability. The new QwikStar multi-electrode catheter, which acquires data from multiple points simultaneously, potentially improves map quality and decreases mapping time in comparison with the single-point NogaStar catheter. Our study sought to validate the QwikStar catheter's LVEM capabilities in a porcine model of chronic ischemia.Eight pigs underwent ameroid placement over the proximal left circumflex artery, to induce chronic ischemia. In 60 days, LVEM was performed on each animal with the NogaStar and QwikStar catheters. Unipolar voltage and linear local shortening results were displayed in 9-segment polar maps. The unipolar voltage data from both maps were then correlated by means of linear regression.There were no adverse events during LVEM. Mapping time was similar for both groups (QwikStar, 44.6 +/- 25.62 min; NogaStar, 65.75 +/- 25.33 min; P = 0.13). Results of mean unipolar voltage maps acquired with the 2 catheters showed a moderate correlation (r =0.59, P <0.001). Selecting segments with more than 6 point samples increased the Pearson coefficient to 0.69 (P <0.001).Our findings show that the QwikStar catheter enables the reproducible performance of LVEM by sampling fewer points, which shortens procedure time, decreases manipulation of the left ventricular cavity, and might increase procedural safety.

Mesenchymal stem cells differentiate into an endothelial phenotype, enhance vascular density, and improve heart function in a canine chronic ischemia model.

BACKGROUND: Bone marrow-derived stem cells are under investigation as a treatment for ischemic heart disease. Mesenchymal stem cells (MSCs) have been used preferentially in the acute ischemia model; data in the chronic ischemia model are lacking. METHODS AND RESULTS: Twelve dogs underwent ameroid constrictor placement. Thirty days later, they received intramyocardial injections of either MSCs (100x10(6) MSCs/10 mL saline) (n=6) or saline only (10 mL) (controls) (n=6). All were euthanized at 60 days. Resting and stress 2D echocardiography was performed at 30 and 60 days after ameroid placement. White blood cell count (WBC), C-reactive protein (CRP), creatine kinase MB (CK-MB), and troponin I levels were measured. Histopathological and immunohistochemical analyses were performed. Mean left ventricular ejection fraction was similar in both groups at baseline but significantly higher in treated dogs at 60 days. WBC and CRP levels were similar over time in both groups. CK-MB and troponin I increased from baseline to 48 hours, eventually returning to baseline. There was a trend toward reduced fibrosis and greater vascular density in the treated group. MSCs colocalized with endothelial and smooth muscle cells but not with myocytes. CONCLUSIONS: In a canine chronic ischemia model, MSCs differentiated into smooth muscle cells and endothelial cells, resulting in increased vascularity and improved cardiac function.

A dosing study of bone marrow mononuclear cells for transendocardial injection in a pig model of chronic ischemic heart disease.

We studied the effect of the dose of bone marrow mononuclear cells, delivered via transendocardial injection, upon capillary density and fibrosis in pigs with chronic ischemic heart disease.Pigs (n = 16) that had undergone ameroid constrictor placement (left circumflex coronary artery) to induce chronic ischemia were divided equally into 4 groups on the basis of bone marrow mononuclear cell dose: control (saline injection) and 50, 100, or 200 × 10(6) bone marrow mononuclear cells. Thirty days after ameroid placement, each pig received 13 transendocardial NOGA-guided injections. An implantable loop recorder monitored possible arrhythmias caused by cell transplantation. Thirty days later, the pigs were killed, and their hearts were evaluated histopathologically for fibrosis and capillary density; the number of cells per segment was correlated with fibrosis and capillary density. No adverse events, arrhythmias, or cardiac inflammatory reactions were associated with cell therapy. Less fibrosis was seen in pigs that received 100 × 10(6) cells than in control pigs. A trend toward higher capillary density was seen with higher cell concentrations. Segments injected with more than 20 × 10(6) million cells had the highest capillary density and the least amount of fibrosis (P < 0.05 vs controls).In conclusion, transendocardial injections (up to 200 × 10(6) bone marrow mononuclear cells) were safe. Analyses of individual injected segments suggest potential benefit from higher cell concentrations per segment.

[Diabetic and nondiabetic patients respond differently to transendocardial injection of bone marrow mononuclear cells: findings from prospective clinical trials in "no-option" patients]. / El efecto de la inyección transendocárdica de células mononucleadas de médula ósea es diferente en pacientes diabéticos y en no diabéticos: hallazgos derivados de estudios clínicos prospectivos en pacientes "sin opción".

Whether stem cell treatment has the same effect in diabetics and nondiabetics is unknown. To compare outcomes in these two groups, we analyzed data from 26 consecutive patients with chronic ischemic cardiomyopathy who were taking part in two clinical trials. Revascularization was not an option for these patients and they were treated with bone marrow mononuclear cells (BMMNCs). Patients underwent NOGA electromechanical mapping to identify viable myocardium (i.e., with a unipolar voltage > or = 6.9 mV), after which they received a mean of 28.5+/-4.7 x 10(6) BMMNCs. Patients were followed up at 6 months. In nondiabetics, there was a significant decrease in endsystolic volume between baseline and 6-month follow-up. In addition, New York Heart Association (NYHA) functional class decreased significantly (P=.04) from 3.0 (1.75-3.0) to 1.0 (1.0-2.0), the Canadian Cardiovascular Society angina score (CCSAS) improved significantly (P=.04) from 3.0 (2.0-4.0) to 1.0 (1.0-1.5), and oxygen uptake increased significantly (P=.04) from 16.4 (13.1-21.5) to 24.5 (17.3-29.2) ml/kg/min. These changes were not observed in diabetic patients. This is the first clinical study to show that BMMNC injection could have a smaller effect in diabetics.

First experience with remote left ventricular mapping and transendocardial cell injection with a novel integrated magnetic navigation-guided electromechanical mapping system.

AIMS: The purpose of this preclinical feasibility study was to evaluate a novel integrated platform in which magnetic navigation is used to remotely guide electromechanical mapping of the left ventricle (LV) and transendocardial cell injections. Using an integrated remote system would greatly facilitate intramyocardial delivery of stem cells for treating ischaemic heart disease. METHODS AND RESULTS: We used the computer-controlled Stereotaxis magnetic navigation system to guide the NOGA electromechanical mapping system in mapping viable myocardium in the LV of seven pigs. We then tested the feasibility of this system to perform transendocardial injections in three of the pigs and to deliver mesenchymal precursor cells (MPCs) to targeted myocardial segments in four of the pigs. The success or failure of each injection was determined by myocardial contrast staining in the first group and by histopathologic analysis in the last group. The mean time (+/-SD) spent mapping the LV for each pig was 49.3+/-10.6 min. The success rate for transendocardial injections was 94.4%, as indicated by myocardial contrast staining. There was a 95.8% success rate for targeted injections of MPCs, and 4',6-diamidino-2-phenylindole-labeled MPCs were detected in all but one segment of one pig. No epicardial haemorrhage or injury was observed, although there was some venous drainage. CONCLUSIONS: The integrated Stereotaxis/NOGA system has excellent remote navigability inside the LV cavity while sparing the operator from radiation exposure. This system also allows transendocardial cell injections to be performed with a high success rate. Further studies are needed to define the safety profile of this system for clinical use.

El efecto de la inyección transendocárdica de células mononucleadas de médula ósea es diferente en pacientes diabéticos y en no diabéticos: hallazgos derivados de estudios clínicos prospectivos en pacientes «sin opción» / Diabetic and Nondiabetic Patients Respond Differently to Transendocardial Injection of Bone Marrow Mononuclear Cells: Findings From Prospective Clinical Trials in “No-Option” Patients

Se desconoce si la administración de células madre tieneel mismo efecto en pacientes diabéticos y en no diabéticos. Para ello se estudió a 26 pacientes consecutivos, incluidos en dos estudios, tratados con células mononucleadas de médula ósea (CMNMO), con miocardiopatía isquémica crónica y sin opción a revascularización. Se les realizó un mapeo electromecánico con NOGA para identificar miocardio viable (voltaje unipolar ≥ 6,9 mV)y se les inyectó una media de 28,5 ± 4,7 millones deCMNMO. Se realizó un seguimiento a los 6 meses. Enlos pacientes no diabéticos, se observó una reducciónsignificativa del volumen telesistólico a los 6 meses encomparación con el basal, una disminución significativade la clase NYHA (de 3 [1,75-3] a 1 [1-2]; p = 0,04), de la puntuación de angina de la clasificación canadiense (de 3 [2-4] a 1 [1-1,5]; p = 0,04) y un aumento del consumo de oxígeno (de 16,4 [13,1-21,5] a 24,5 [17,3-29,2] ml/kg/min; p = 0,04). Estas diferencias no se observaron en los pacientes diabéticos. Éste es el primer estudio clínico que observa que la inyección de CMNMO podría tener un menor efecto en los diabéticos

Whether stem cell treatment has the same effect indiabetics and nondiabetics is unknown. To compareoutcomes in these two groups, we analyzed data from 26consecutive patients with chronic ischemic cardiomyopathywho were taking part in two clinical trials. Revascularization was not an option for these patients and they were treated with bone marrow mononuclear cells (BMMNCs). Patients underwent NOGA electromechanical mapping to identify viable myocardium (i.e., with a unipolar voltage . 6.9 mV), after which they received a mean of 28.5}4.7~106 BMMNCs. Patients were followed up at 6 months. In nondiabetics, there was a significant decrease in endsystolic volume between baseline and 6-month follow-up. In addition, New York Heart Association (NYHA) functional class decreased significantly (P=.04) from 3.0 (1.75-3.0) to 1.0 (1.0-2.0), the Canadian Cardiovascular Society angina score (CCSAS) improved significantly (P=.04) from 3.0 (2.0-4.0) to 1.0 (1.0-1.5), and oxygen uptake increased significantly (P=.04) from 16.4 (13.1-21.5) to 24.5 (17.3- 29.2) ml/kg/min. These changes were not observed in diabetic patients. This is the first clinical study to show that BMMNC injection could have a smaller effect in diabetics