Animal model system for artificially inducing a heart arrhythmia

Abstract

A method is described for increasing the likelihood of the occurrence of an arrhythmia in a heart, particularly a ventricular arrhythmia of the type leading to Sudden Cardiac Death. The method includes the steps of creating an atrioventricular block in the heart of an animal test subject, inducing a myocardial infarction in the heart of the test subject, and then stimulating myocardial hyperinnervation the test subject. In a specific example described herein, the atrioventricular block is created by ablating the atrioventricular node of the heart using an ablation catheter. The myocardial infarction is induced by ligating the left anterior descending portion of the coronary artery. Myocardial hyperinnervation is stimulated by application of Nerve Growth Factor or other neurotrophic vectors to the left stellate ganglion. The test subject is an adult canine. By creating an atrioventricular block and a myocardial infarction within the heart of an adult canine test subject, then stimulating nerve growth within the left stellate ganglion of the subject using Nerve Growth Factor, it has been found that there is a significant increase in the likelihood of Sudden Cardiac Death arising from ventricular arrhythmias. It is believed that the Sudden Cardiac Death of the test subject arises in a manner very similar to circumstances wherein Sudden Cardiac Death occurs in human patients subject to a previous myocardial infarction. Thus, the method facilitates the collection of data pertinent to conditions within the heart arising prior to Sudden Cardiac Death and for developing and testing therapies intended to prevent Sudden Cardiac Death.

What is claimed:  
     
         1 . An animal model system for artificially inducing a heart arrhythmia, comprising: 
 an animal test subject having an artificially induced atrioventricular block in the heart of the animal test subject, the anterior descending portion of the coronary artery of the heart of the animal test subject being surgically and/or chemically blocked for inducing a myocardial infarction, said animal test subject having, coupled to a myocardial nerve conduction pathway leading to the left ventricle of the heart, means for stimulating myocardial hyperinnervation in the left ventricle and thereby inducing a heart arrhythmia; said animal test subject further having, coupled to its heart via electrical leads, means for detecting electrical heart signals representative of the induced heart arrhythmia.    
     
     
         2 . The animal model system of  claim 1 , wherein the means for stimulating myocardial hyperinnervation in the left ventricle comprises an osmotic pump for pumping a neurotrophic vector into the myocardial nerve conduction pathway leading to the left ventricle.  
     
     
         3 . The animal model system of  claim 1 , wherein the means for stimulating myocardial hyperinnervation in the left ventricle comprises an electrical lead for administering an electrical current to the myocardial nerve conduction pathway leading to the left ventricle.  
     
     
         4 . The animal model system of  claim 1 , wherein the means for detecting electrical heart signals representative of the induced heart arrhythmia further comprises means for pacing the heart in response to the induced heart arrhythmia.  
     
     
         5 . The animal model system of  claim 4 , wherein the means for detecting electrical heart signals representative of the induced heart arrhythmia comprises an implantable cardioverter-defibrillator (ICD).  
     
     
         6 . The animal model system of  claim 5 , wherein the cardioverter-defibrillator (ICD) further applies techniques to prevent the occurrence of further arrhythmias of the heart of the animal test subject.  
     
     
         7 . The animal model system of  claim 5 , wherein the cardioverter-defibrillator (ICD) applies techniques to prevent the occurrence of ventricular fibrillation of the heart of the animal test subject.  
     
     
         8 . The animal model system of  claim 5 , further comprising a telemetry system for downloading signals from the cardioverter-defibrillator (ICD) representative of detected heart signals and any response applied by the ICD; and a test analysis system for processing the signals received from the ICD to verify the efficacy of any response applied by the ICD to the heart of the animal test subject.  
     
     
         9 . The animal model system of  claim 1 , wherein the anterior descending portion of the coronary artery of the heart of the animal test subject is surgically blocked by a ligation of the coronary artery or by wires positioned in the artery through a catheter.  
     
     
         10 . The animal model system of  claim 1 , wherein the animal test subject is a canine.