---start---- avian dr miller - avian cardiology NB: radiology lecturer isn't here. hopefully, radiology stuff won't be on the quiz. cardiology in veterinary medicine has traditionally focused on the cat and dog, with some horse stuff. avian cardiology is in its infancy. canine and feline cardiology isn't that old either, but avian is really new. in any species: anatomy and embryology, physiology, contractility, electrophysiology are all separate. with cardiac ultrasound, we can now see the antomy in live patients. types of heart disease: congenital (VSD, ASD, PDA) valvular (degenerative, infective) - degenerative in dogs, valvular endocarditis seen in birds myocardial (inflammatory, denegerative, nutritional, fibrosis, other) - both types of cardiomyopathy are seen in birds (dilated and hypertrophic - associated with pathognomonic EKG changes) pericardial disease- very common in birds b/c no diaphragm. vascular disease - (cor pulmonale [RV disease secondary to lung dz], arteritis) - in birds, systemic hypertension. disorders of rate, rhythm, conduction - all the types of arrhythmias in other animals also occur in birds other types of heart disease -remember heart disease affects other organs. remember disease of other organs secondarily affects the heart. think about electrophysiology - heart cells themselves, nodal tissue, muscle, etc - consider the electrolytes' role. consider the autonomic NS. all this interacts in very complex manner. systemic dz affecting the heart: hyper/hypothyroidism addison's dz drugs - chemo, anesthetics, tranquilizers pheochromocytoma, hypertension hypo/hypercalcemia, mgemia,kalemia etc. infections, bacterial, viral, protozoal, mycotic complications of heart disease: -asymptomatic: not all heart disease results in clinical signs or will progress -congestive heart failure -arrhythmias, conduction disorders -cardiogenic shock like after massive heart attack or w/severe myopathy -syncope (huge ddx - bradyarrhythmia, tachyarrhythmia, poor contractility, poor venous return, reflex from pressing on carotid sinus, etc) -thromboembolism (pulmonary thromboembolism is underdiagnosed in vet med; LA thromboembolism in cats occurs with cardiomyopathy) -sudden death: try to avoid and prevent this. :) slide: Dr Robert Altman talking to a green parrot. CHF signs: dyspnea, coughing weakness, syncope cachexia (if heart isn't pumping enough blood, blood is shunted away from muscle to kidneys) exercise intolerance/reduction sudden death arrhythmia signs: asymptomatic dyspnea, coughing weakness syncope sudden death so it may be very hard to tell these apart, clinically. diagnostic workup: history: travel, breeder, other birds, prior signs, etc. observe and inspect bird before attempting to handle. watch at rest. feel heartbeat. exam w/auscultation - listen to heart sounds in pectoralis region; air sounds over dorsal thoracic region radiograph: to detect cardiomegaly, see angle b/w liver and heart. EKG echocardiogram affected birds may be cyanotic, in respiratory distress with head extended, beak opened. a lot of respiratory disease is found in turkeys and chickens with signs of dyspnea and coughing, so people sometimes overlook possible heart disease in birds. don't do that. area around beak and eyes may show cyanosis. PE: visual inspection, auscultation, palpation (precordial), percussion, and smell of the bird... what sense is missing? taste. the father of european cardiology was a french guy, Napoleon's physician. he was renowned throughout europe for PE. first guy to do clinicopathologic correlation and correlate the heart with antemortem symptoms. a paper was published in 1776, on percussion by someone who worked before for a brewery and had to percuss beer kegs. it was ignored. but when Corversoir read the paper he translated it to french and it became a prominent part of the PE at that time. so think about that - percussion wasn't used prior to that. so, taste - drinking beer. okaaaay. auscultation - dorsal thorax for air sounds, ventral thorax for heart sounds. don't hear lub-dub, lub-dub...you hear lubdublubdublubdublubdub really rapidly. normal HR 100-700 per minute. chest rads - often use eihter plexiglass restraint board, or tape bird to film (eh? maybe to the cassette). take a "whole body thoracic radiograph" VD view - normal cardiac silhouette should take about 1/3 the space within the thorax. (?) the enlarged heart may be enlarged from fluid in the sac, chamber enlargment, whatever. you have to work this up further. what about EKG in birds? the conduction tissue is different - purkinje system penetrates from endocardium to epicardium before jumping into myocardial tissue - soyou get a different axis. the different types of tissue, though, nodal tissue, fibers, etc are all the same. EKG definition: record of avg heart muscle electrical activity graphed in terms of voltage and time in different phases of the cardiac cycle, measured from the body surface (unlike His bundle electrogram measured internally) restraint for avian EKG - tape bird down in dorsal recumbency. could use plexiglass restraint board as for rads - in psittacines, make sure wires do not get near the beak!! electrodes are placed on the cranial wing webs, about 1 inch from the body (because respiratory rate is so fast, causes artifacts.) so you have to spread wings out, and use webs. rear limb electrodes go on cranial tibiotarsal area. bird EKG doesn't look like dog/cat one. can apply alcohol or electrode jelly to electrodes. again, the conduction tissue fibers are the same - P wave, atrial activity; QRS activity - you know that has nothing to do with conductive system. P wave is spread in atrial myocardial fibers, Q wave is spread in ventricular myocardial fibers. in dogs, HR speeds up with inspiration, slows with expiration. we don't see sinus arrhythmia in cats or birds. avian: P wave is positive, QRS negative in lead 2 and 3; in lead 1, QRS is small and isoelectric. normal axis is straight up. if you do lead 2 EKG and QRS is positive, that's abnormal. normal axis is -85 to -160 degrees. parakeet to ostrich, no difference. the reason the axis is so different is that the penetration of purkinje fibers doesn't stop at endocardium, goes all the way to epicardium. cardiac arrhytmias in burds. this one shows early QRS, looks funky. this is a VPC in a bird with myocarditis. bird with myocarditis and frequent VPCs P wave not followed by QRS --> AV block. this is a bird in CHF who got too much digitalis. was lethargic, not eating, regurgitating. digitalis toxicity. avian dilated cardiomyopathy - most important heart dz in birds: QRS complex is positive in leads II and III in these birds: classic, pathognomonic change in EKG with this disease. this is round heart dz of turkeys and chickens - they get round, dilated hearts. axis also shifts to look more typical of dog, cat. in parrots, when we find positive QRS complexes in lead II and III, those birds have poorly contracting LV and dilated cardiomyopathy. so this is something you see in psittacines in your practice. other diseases might cause a similar finding butthis should be you main ddx until proven otherwise via echo. CHF: getting away from electrical activity... birds that are given high doses of abx like furazolin may develop a QRS that changes from negative to positive. on echo show poorly contracting hearts. this is a toxic cardiomyopathy, as seen with adriamycin in other animals. essentials of electrocardiography: have system to read it. heart rate, rhythm, analysis of complexes, relate EKG to the clinical data. another nice thing about EKG - use of it in birds under anesthesia - birds temperatures can drop 10-15 degrees and cause life threatening hypothermia under anesthesia. a drop in HR may be an early sign of this. HR going from 500 to 140 as body temp drops over 30 minutes on this graph. heating pads are important during surgery on birds! use of cardiac ultrasound, echocardiography, is a great thing. it's noninvasive, requires no anesthesia, gives good info. slide: parrot with murmur - has mitral valvular regurgitation on color flow doppler. turbulent flow is seen. in birds, you have to image through liver so you get four chambered, long axis view. not right parasternal view like dog. this view, you get in dog by taking left parasternal view. but it's a four chambered view. with mitral regurg, you get progressive LA dilation, pulmonary edema, CHF over time. slide: huge cardiac silhouette blending into abdominal cavity -t his is all fluid, so you don't know if it is heart or not. could tap this. could do an echo. CHF: chronically symptomatic animals; often irreversible; multiple medications; high mortality rate. we don't do cardiac surgery very much; we have to be much bettre than MD at fixing this medically. although, mitral valve replacements are being done at some academic institutions in dogs; one private practicioner in Texas also does it working with someone at the DeBakey institute. in small animals, H/L bypass doesn't work either - they die when you try to put them on bypass. once a dog goes into heart failure - lives a year. bird - under six months. person - under five years. tx methods - restrict exercise, digitalis, vasodilators, inotropic agents, low salt diet, diuretics, special methods. in birds, cut back flying time, restrict activity, use digitalis .02 mg/kg/day, use lasix at diuretic doses. sometimes vasodilators in birds with continued congestion, pulmonary edema, not responding. nitroglycerin could be tried. if there is a lot of thoracoabdominal effusion, could drain that. carefully. in summary - put all parts together. history, PE, labwork. slide: huge amount of fluid in body cavity, heart very poor contractility, dilated cardiomyopathy. slide: an example of a bird with aortic valvular endocarditis, severe aortic murmur. lived with CHF about a year! this is your final court of appeals - the necropsy. you have to try to do them. slide: goose died suddenly - myocardial infarction bird with hypertrophic, thickwalled heart ferret - don't forget other species! ferret with pleural effusion - generally dialted cardiomyopathy or LSA. ferret EKG doesn't look like dog or cat type - like cat P wave with dog QRS complex. ----end----