Biomaterial Database

Pronounced increase in defibrillation threshold associated with pacing-induced cardiomyopathy in the dog. 1994

S D Lucy, and D L Jones, and G J Klein

Department of Physiology, University of Western Ontario, London, Canada.

Progressive changes in myopathology after implantation of an automatic defibrillator could compromise device efficacy. The influence of heart failure development on the defibrillation threshold was evaluated by means of a rapid ventricular pacing model of heart failure in dogs. After transvenous pacemaker lead implantation, adult mongrel dogs were randomly assigned to either the control (n = 7) or rapidly paced group (240 beats/min, n = 6). Seventeen days after implantation, triplicate determinations of the defibrillation threshold were made with three epicardial electrodes. The average defibrillation threshold was four times higher in the rapidly paced group, 13.3 +/- 2.0 joules (mean +/- SEM), than in the control group, 3.3 +/- 0.7 joules (p < 0.01), and was significantly correlated with ventricular weight (r = 0.70, p < 0.01). Both defibrillation threshold energy per gram of ventricle and ventricular weight corrected for body weight were significantly higher in rapidly paced dogs compared with control dogs. It was concluded that myocardial hypertrophy and heart failure may profoundly increase defibrillation energy requirements.

UI	MeSH Term	Description	Entries
D009202	Cardiomyopathies	A group of diseases in which the dominant feature is the involvement of the CARDIAC MUSCLE itself. Cardiomyopathies are classified according to their predominant pathophysiological features (DILATED CARDIOMYOPATHY; HYPERTROPHIC CARDIOMYOPATHY; RESTRICTIVE CARDIOMYOPATHY) or their etiological/pathological factors (CARDIOMYOPATHY, ALCOHOLIC; ENDOCARDIAL FIBROELASTOSIS).	Myocardial Disease,Myocardial Diseases,Myocardial Diseases, Primary,Myocardial Diseases, Secondary,Myocardiopathies,Primary Myocardial Disease,Cardiomyopathies, Primary,Cardiomyopathies, Secondary,Primary Myocardial Diseases,Secondary Myocardial Diseases,Cardiomyopathy,Cardiomyopathy, Primary,Cardiomyopathy, Secondary,Disease, Myocardial,Disease, Primary Myocardial,Disease, Secondary Myocardial,Diseases, Myocardial,Diseases, Primary Myocardial,Diseases, Secondary Myocardial,Myocardial Disease, Primary,Myocardial Disease, Secondary,Myocardiopathy,Primary Cardiomyopathies,Primary Cardiomyopathy,Secondary Cardiomyopathies,Secondary Cardiomyopathy,Secondary Myocardial Disease
D009638	Norepinephrine	Precursor of epinephrine that is secreted by the ADRENAL MEDULLA and is a widespread central and autonomic neurotransmitter. Norepinephrine is the principal transmitter of most postganglionic sympathetic fibers, and of the diffuse projection system in the brain that arises from the LOCUS CERULEUS. It is also found in plants and is used pharmacologically as a sympathomimetic.	Levarterenol,Levonorepinephrine,Noradrenaline,Arterenol,Levonor,Levophed,Levophed Bitartrate,Noradrenaline Bitartrate,Noradrénaline tartrate renaudin,Norepinephrin d-Tartrate (1:1),Norepinephrine Bitartrate,Norepinephrine Hydrochloride,Norepinephrine Hydrochloride, (+)-Isomer,Norepinephrine Hydrochloride, (+,-)-Isomer,Norepinephrine d-Tartrate (1:1),Norepinephrine l-Tartrate (1:1),Norepinephrine l-Tartrate (1:1), (+,-)-Isomer,Norepinephrine l-Tartrate (1:1), Monohydrate,Norepinephrine l-Tartrate (1:1), Monohydrate, (+)-Isomer,Norepinephrine l-Tartrate (1:2),Norepinephrine l-Tartrate, (+)-Isomer,Norepinephrine, (+)-Isomer,Norepinephrine, (+,-)-Isomer
D009929	Organ Size	The measurement of an organ in volume, mass, or heaviness.	Organ Volume,Organ Weight,Size, Organ,Weight, Organ
D010138	Pacemaker, Artificial	A device designed to stimulate, by electric impulses, contraction of the heart muscles. It may be temporary (external) or permanent (internal or internal-external).	Cardiac Pacemaker, Artificial,Artificial Cardiac Pacemaker,Artificial Cardiac Pacemakers,Artificial Pacemaker,Artificial Pacemakers,Cardiac Pacemakers, Artificial,Pacemaker, Artificial Cardiac,Pacemakers, Artificial,Pacemakers, Artificial Cardiac
D001835	Body Weight	The mass or quantity of heaviness of an individual. It is expressed by units of pounds or kilograms.	Body Weights,Weight, Body,Weights, Body
D002302	Cardiac Output	The volume of BLOOD passing through the HEART per unit of time. It is usually expressed as liters (volume) per minute so as not to be confused with STROKE VOLUME (volume per beat).	Cardiac Outputs,Output, Cardiac,Outputs, Cardiac
D002303	Cardiac Output, Low	A state of subnormal or depressed cardiac output at rest or during stress. It is a characteristic of CARDIOVASCULAR DISEASES, including congenital, valvular, rheumatic, hypertensive, coronary, and cardiomyopathic. The serious form of low cardiac output is characterized by marked reduction in STROKE VOLUME, and systemic vasoconstriction resulting in cold, pale, and sometimes cyanotic extremities.	Low Cardiac Output,Low Cardiac Output Syndrome,Output, Low Cardiac
D002304	Cardiac Pacing, Artificial	Regulation of the rate of contraction of the heart muscles by an artificial pacemaker.	Pacing, Cardiac, Artificial,Artificial Cardiac Pacing,Artificial Cardiac Pacings,Cardiac Pacings, Artificial,Pacing, Artificial Cardiac,Pacings, Artificial Cardiac
D004285	Dogs	The domestic dog, Canis familiaris, comprising about 400 breeds, of the carnivore family CANIDAE. They are worldwide in distribution and live in association with people. (Walker's Mammals of the World, 5th ed, p1065)	Canis familiaris,Dog
D004554	Electric Countershock	An electrical current applied to the HEART to terminate a CARDIAC ARRHYTHMIA.	Cardiac Electroversion,Cardioversion,Defibrillation, Electric,Electroversion, Cardiac,Electrical Cardioversion,Electroversion Therapy,Therapy, Electroversion,Cardiac Electroversions,Cardioversion, Electrical,Cardioversions,Cardioversions, Electrical,Countershock, Electric,Countershocks, Electric,Defibrillations, Electric,Electric Countershocks,Electric Defibrillation,Electric Defibrillations,Electrical Cardioversions,Electroversion Therapies,Electroversions, Cardiac,Therapies, Electroversion