title: Experimental atrioventricular block without thoracotomy: a new instrument.
mesh_terms: D000818:Animals; D006328:Cardiac Catheterization / Q000295:instrumentation*; D004285:Dogs; D004562:Electrocardiography; D005557:Formaldehyde / Q000008:administration & dosage; D006327:Heart Block; D006329:Heart Conduction System; D013902:Radiography, Thoracic; D013903:Thoracic Surgery; D013909:Thorax / Q000601:surgery
chemical_list: D005557:Formaldehyde