Abstract 2892: Electrophysiological and Arrhythmogenic Effects of Intramyocardial Bone Marrow Cell Injection in Patients with Chronic Ischemic Heart Disease
Introduction Autologous bone marrow cell injection has recently been introduced to treat patients with chronic ischemic heart disease. However, inadequate incorporation of transplanted cells in the host myocardium may generate arrhythmogenic substrates. We assessed whether intramyocardial bone marrow cell injection alters the electrophysiological properties of the injected myocardium, and increases the occurrence of ventricular arrhythmias.
Methods In 20 patients (65±11 yrs, 19 male) with refractory angina (CCS class III or IV) and myocardial ischemia, bone marrow was aspirated from the iliac crest. During mononuclear cell isolation, electroanatomic mapping of the left ventricle was performed with the NOGA system (Biosense Webster). Areas for cell injection were selected based on the localization of ischemia on Tc-99m tetrofosmin SPECT. These areas were mapped in detail to evaluate the following local bipolar electrogram characteristics: duration (first to last peak distance), amplitude and the degree of fragmentation (number of positive deflections). Then, 100x106 mononuclear cells were injected in the ischemic areas with the Myostar catheter (Biosense Webster). Anginal symptoms (CCS class) and the occurrence of ventricular arrhythmias (Holter monitoring) were evaluated at 3 and 6 months. Electroanatomical mapping was repeated at 3 months.
Results CCS class improved from 3.4±0.5 to 2.5±0.6 at 3 months, and 2.7±0.7 at 6 months (both P<0.01 vs. baseline). Holter monitoring demonstrated no increase in the incidence of premature ventricular contractions (44±100/hr at baseline vs. 33±95/hr at 3 months and 51±130/hr at 6 months (both P=NS vs. baseline)) or complex ventricular arrhythmias according to the Lown and Wolf classification. Repeat electroanatomical mapping of the ischemic region showed that bone marrow cell injection did not prolong electrogram duration (15.9±4.6 ms vs. 15.6±4.0 ms at 3 months; P=NS), decrease electrogram amplitude (3.7±1.5 mV vs. 3.8±1.5 mV at 3 months; P=NS), or increase the degree of fragmentation (2.0±0.5 vs. 1.9±0.4 at 3 months; P=NS)
Conclusion Intramyocardial injection of autologous bone marrow cells is not arrhythmogenic and does not alter the electrophysiological properties of the injected myocardium.