agar and Myocardial-Infarction

Post infarct ventricular tachycardia (VT) often involves the interventricular septum (IVS) and requires transmural septal ablation. The purpose of this study was to compare the efficacy of bipolar ablation (BIA) versus sequential unipolar ablation (SUA) in creating a transmural ablation line along the IVS scar border.. Both ablation strategies were compared in a phantom agar model first and then in 10 post infarct sheep. In the phantom agar model BIA lesions were larger, transmural, and less dependent on catheter alignment and contact compared with SUA. Noncontact mapping was used in the animals to identify the septal scar border and create a 30-mm ablation line. In five animals BIA (50 W) was performed between two irrigated catheters on either side of the IVS, and in five control animals SUA (50 W) was performed, first on the left ventricle (LV) septal scar border and then on the opposing right ventricle (RV) septal surface. Electrical block along ablation lines was confirmed with noncontact mapping. BIA required significantly less ablations (12 + or - 1 vs 29 + or - 7, P = 0.001), ablation time (22 + or - 3 vs 48 + or - 6 minutes, P < 0.001), and energy (58 + or - 7 vs 124 + or - 21 kJ, P < 0.001). At pathological examination all ablation lines in both groups were transmural at the IVS border. BIA endocardial ablation lines (LV + RV) were significantly longer than SUA lines (76 + or - 10 vs 49 + or - 11 mm, P = 0.003).. BIA of the IVS is highly effective at creating a transmural ablation line, requiring less ablation and creating longer lesions than SUA. BIA ablation may have a role for post infarct VT involving the IVS.

Topics: Ablation Techniques; Agar; Animals; Heart Septum; Humans; Models, Structural; Myocardial Infarction; Sheep; Time Factors

Difficulty is frequently experienced in producing a large homogeneous myocardial infarct in the dog heart because of the extensive network of coronary anastomoses. This problem may be overcome by combining the ligation of the left anterior descending coronary artery with agar injection into the distal coronary vasculature to obliterate anastomotic channels. All infarcts produced in this manner occupied a constant area in the anterior wall of the left ventricle. From our results in 25 dogs, the individual infarct averaged 12.3 Gm. in weight (range 9.4 to 13.5), representing 25 to 30 per cent of the total left ventricular muscle mass. The homogeneity of the infarct was verified by a simple, macroscopic enzyme-mapping technique based on the inability of the ischemic (dehydrogenase-deficient) myocardium to reduce triphenyl tetrazolium chloride and by detailed histologic studies. Apart from providing ample raw material for comprehensive morphologic, chemical, histochemical, and radioisotopic analyses, a large myocardial infarct also serves as a useful experimental model for various physiological and hemodynamic studies of cardiogenic shock and left ventricular akinesis.

Topics: Agar; Animals; Arteries; Coronary Vessels; Disease Models, Animal; Dogs; Electrocardiography; Hemodynamics; Injections, Intra-Arterial; Ligation; Myocardial Infarction; Myocardium; Oxidoreductases; Shock, Cardiogenic; Tetrazolium Salts

Topics: Adolescent; Adult; Agar; Cerebrovascular Disorders; Creatine Kinase; Electrophoresis; Female; Humans; Hypothyroidism; Isoenzymes; Male; Middle Aged; Myocardial Infarction; Seizures; Shock

Topics: Agar; Animals; Arteries; Coronary Vessels; Disease Models, Animal; Dogs; Heart Failure; Heart Ventricles; Hemodynamics; Ligation; Methods; Myocardial Infarction; Myocardium; Radiography, Thoracic; Time Factors; Ventricular Fibrillation

Topics: Agar; Electrophoresis; Gels; Hepatitis A; Humans; Isoenzymes; L-Lactate Dehydrogenase; Liver Neoplasms; Myocardial Infarction

Topics: Acute Disease; Adult; Agar; Aged; Female; Fibrin; Fibrinolysis; Humans; Male; Middle Aged; Myocardial Infarction; Racial Groups

Topics: Agar; Angina Pectoris; Clinical Enzyme Tests; Electrophoresis; Gels; Humans; Isoenzymes; L-Lactate Dehydrogenase; Myocardial Infarction; Transaminases

Topics: Agar; Aspartate Aminotransferases; Clinical Enzyme Tests; Creatine Kinase; Densitometry; Electrocardiography; Electrophoresis; Estrogens; Female; Gels; Glucocorticoids; Humans; Isoenzymes; L-Lactate Dehydrogenase; Male; Middle Aged; Myocardial Infarction; Pulmonary Embolism

Topics: Adult; Agar; Aged; Angina Pectoris; Autoantibodies; Female; Hemagglutination Tests; Humans; Latex Fixation Tests; Male; Middle Aged; Myocardial Infarction; Myocardium; Precipitin Tests

Topics: Agar; Anemia, Hemolytic; Diagnosis, Differential; Electrophoresis; Gels; Humans; Isoenzymes; Kidney Diseases; L-Lactate Dehydrogenase; Liver Diseases; Myocardial Infarction; Neoplasms; Prognosis

Topics: Agar; Electrophoresis; Gels; Humans; Lipoproteins; Methods; Myocardial Infarction

Topics: Adult; Agar; Aged; Electrophoresis; Gels; Hepatitis A; Humans; L-Lactate Dehydrogenase; Middle Aged; Myocardial Infarction

Topics: Agar; Antigens; Brain; Chemical Precipitation; Immunoelectrophoresis; Liver; Methods; Myocardial Infarction; Myocardium

Topics: Agar; Anemia, Hemolytic; Blood; Clinical Enzyme Tests; Electrophoresis; Histocytochemistry; Humans; In Vitro Techniques; Kidney Diseases; L-Lactate Dehydrogenase; Liver Diseases; Myocardial Infarction; Neoplasms; Pleural Effusion