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Practical Cardiology Case Studies Wendy Blount, DVM Nacogdoches TX Jake Signalment • 9 year old male Boxer Chief Complaint • Deep cough when walking in the morning, for about one week • Appetite is good Jake Exam • Weight 81.9 – has lost 5 pounds in 3 months (BCS 5/9) • Temp 101.4 • Mucous membranes pink, CRT 3.5 seconds • Subtle dependent edema on the lower legs • Jugular veins distended • Harsh lung sounds • 3/6 pansystolic murmur, PMI left apex (link) • Heart rate 160 per minute • Respirations 55 per minute • Femoral pulses somewhat weak Jake Differential Diagnosis - Cough • Respiratory Disease • Cardiovascular Disease • Both Diagnostic Plan (B Client) • Blood Pressure – 150 mm Hg systolic (Doppler) • Chest x-rays Jake Jake Jake Diagnostic Plan (B Client) • Chest X-rays – – – – – – Massively enlarged heart (VHS 12.5) Enlarged LA, LV (dorsally elevated trachea) Enlarged pulmonary arteries and veins Perihilar pulmonary edema Left congestive heart failure Right congestive heart failure (biventricular failure) Jake Immediate Therapeutic Plan (10 am) • Furosemide – 80 mg IM • 4 hours later – Respiratory rate is 36 per minute Jake Diagnostic Plan – 2nd Wave (2 pm) • EKG Jake Diagnostic Plan – 2nd Wave (2 pm) • EKG • Rate – 140 bpm • Rhythm – sinus rhythm – P wave abnormal – – – – – Early and upside down Followed by a normal QRS Occurring 5 times a minute APC – Atrial Premature Contractions Supraventricular premature contractions Jake Diagnostic Plan – 2nd Wave (2 pm) • EKG • Echocardiogram (video 1) (video 2) Jake - Echo Transverse - LV Apex • LV Looks Big Transverse - LV Papillary Muscles • LV looks REALLY big • Myocardium is hardly moving • Flat papillary muscles Jake - Echo Transverse - LV Papillary Muscles • • • • • • IVSTD – 9.7 mm (n 10.8-12.3) LVIDD – 72.1 mm (n 43-48) LVPWD – 15.1 mm (n 8.7-10) IVSTS – 11.9 mm (n 16.5-18.1) LVIDS – 67.1 mm (n 27.4-30.4) LVPWS – 13.0 mm (n 14-15.6) FS = LVIDD – LVIDS LVIDD (72.1-67.1)/72.1 = 7% (n 30-46%) EF = 15% (n >70%) Jake - Echo Transverse - Mitral Valve • No increased thickness of MV • No vegetations on the MV • EPSS – 12 mm (n <6 mm) – myocardial failure Transverse – Aortic Valve/RVOT • LA at least Double Big Jake - Echo Transverse - Aortic Valve/RVOT • AoS – 23.1 mm (n 27.4-30.4) • LAD – 44.7 mm (n 25.8-28.4) • LA:Ao = 44.7/23.1 = 1.9 (n 0.8-1.3) Transverse – Pulmonary Artery • No abnormalities noted Jake - Echo Long – 4 Chamber • LV massively enlarged • Poor systolic function • LA 2x enlarged • IVS is bowed toward the right, due to LV dilation Long – LVOT • No abnormalities in LVOT Jake – Dx & Tx Recommendations • Congestive Heart Failure – – – – – CBC, serum panel and electrolytes Furosemide 80 mg PO BID Enalapril 20 mg PO BID Recheck mini-panel and electrolytes in 3-5 days Recheck chest rads and BP 3-5 days • Dilated Cardiomyopathy – – – – Thyroid panel (TSH, T4, FreeT4) Pimobendan 10 mg PO BID (declined) Carnitine 2 g PO BID Recheck echo, chest rads, BP, EKG, mini-panel/lytes 60 days (sooner if respiratory rate >40 at rest) Jake - Bloodwork Carnitine for DCM – Boxers with genetic defect need extra carnitine – Plasma levels have low sensitivity – Myocardial biopsy is usually required CBC, Mini-panel - BUN, creat, glucose, TP, SAP, ALT • Normal Electrolytes, Thyroid panel • Not done Jake – Follow-Up Recheck – 6 days • BUN 30 (n 10-29) • Creat normal • Electrolytes not done • Chest x-rays not done No additional rechecks were done, owner did not monitor respiratory rate at home Jake – Follow-Up 4 months later… • Chief complaint – – Doing *very* well until last week – poor energy, coughing again, not eating • Heart sounds (audio file) – Chaotic heart sounds with pulse deficits on auscultation – “tennis shoes in a dryer” – Called “Delirium cordis” Jake – Follow-Up 25 mm/sec •Heart Rate •200 bpm (tachycardia) •Rhythm (NSR, RSA or arrhythmia) •irregularly irregular - arrhythmia Jake – Follow-Up • P wave (normal 1 box wide x 4 boxes tall) • not present • PR interval (normal 1.5-3.25 boxes) • no P wave – can’t measure • QRS (normal 1.5 boxes wide x 30 boxes tall) • 2 boxes wide x 26 boxes tall • Wide QRS = LV enlargement Diagnosis – Atrial Fibrillation 25 mm/sec Jake – Treatment • Recommended treatment • Digitalis or Diltiazem for Afib • Treatment was declined, and Jake was euthanatized 1 week later • Most dogs with DCM are gone within 3 months of becoming symptomatic, if treated with furosemide & ACE. • Survival is likely much shorter – days to weeks – if untreated. • Adding Pimobendan increases mean survival to 130 days. • Median survival for dogs with DCM and Afib is 3 weeks, without Pimobendan Dilated Cardiomyopathy Common Signalment • Breed – – – – – – – Doberman Great Dane Boxer Newfoundland Portuguese Water Dog Dalmatian Cocker Spaniel • www.VetGen.com and NCState offer a DNA panel for Dobermans to screen for DCM Dilated Cardiomyopathy Common Historical and PE findings • Onset seems rather acute – signs of LHF – Coughing, dyspnea, exercise intolerance, weak pulses, poor appetite and energy • Sometimes RHF also – Ascites, pleural rubs, jugular vein distension, peripheral edema, diarrhea • Syncope • Mitral murmur – Holosystolic, PMI left apex • Chaotic heart sounds with pulse deficits if A-fib • Vegetarian diet (historical) Dilated Cardiomyopathy Common Historical and PE findings • Chemotherapy – doxorubicin • DCM in a puppy – Parvovirus at 2-4 weeks of age (historical) – Chaga’s Disease – mostly right sided, with VPCs • Trypanosoma cruzi Dilated Cardiomyopathy Common Radiographic Findings • Generalized cardiomegaly - Increased VHS • Enlarged LV – elevated trachea • Enlarged LA – compressed left bronchus • + RA/RV enlargement • + Left Heart Failure – lobar veins > arteries, pulmonary edema • + Right Heart Failure – enlarged caudal vena cava, ascites, pleural effusion, hepatosplenomegaly Dilated Cardiomyopathy Common ECG Findings • Wide P wave – LA enlargement • Tall R wave – LV enlargement • Atrial fibrillation • VPCs • Ventricular arrhythmias Dilated Cardiomyopathy Common Echocardiographic Lesions • Dilation of all 4 heart chambers • Large LVIDD (eventually large LVIDS also) • Hypokinesis of LV wall and IVS • Markedly Reduced FS & EF • Paradoxical septal motion • Increased EPSS • Normal looking MV and TV leaflets • Papillary muscle flattening (Client Handout) Dilated Cardiomyopathy Treatment • Pimobendan 0.2-0.3 mg/kg PO BID – Inodilator – positive inotrope and vasodilator • Treat left heart failure if present – Diuretics – ACE inhibitor if tolerated • 0.5 mg/kg PO SID-BID – Nitroprusside CRI if critical – Dopamine or dobutamine CRI if critical – Thoracocentesis if pleural effusion in cats – Oxygen, of course Dilated Cardiomyopathy Treatment • Furosemide boluses for fulminant LHF – – – – – – 80% effective 6-8 mg/kg IV Q1-2 HR UNTIL RR<50 4 mg/kg IV q1-2h until RR<40 4 mg/kg PO q4-6 hr until RR<30 Then PO q6-12 hrs to maintain RR<30 Give IM if placing IV cath might be fatal • Furosemide CRI may be more effective – 0.5 to 1.0 mg/kg/hr Dilated Cardiomyopathy Torsemide • *much* stronger diuretic than furosemide and spironolactone • Potassium sparing, like spironolactone • 0.2-0.3 mg/kg PO BID • For rescue – too powerful for routine use • Will make ‘em a raisin, and create a swimming pool in the living room • Consider when >4mg/b/day furosemide is not enough Dilated Cardiomyopathy Treatment • Monitoring fulminant LHF – Lactate (return to normal) – blood gases (resolution of acidosis and hypoxemia) – Respiratory rate – PROVIDE WATER & WATCH URINE PRODUCTION – Check BUN & electrolytes at least daily – Central line can make blood draws easy Dilated Cardiomyopathy Treatment • Taurine – if whole blood taurine levels low – – – – – – 250-500 mg PO BID Cats fed low taurine diets, or with genetic defect American cocker spaniels, Newfoundlands Dogs fed vegetarian diets (Large and giant breed dogs fed lamb and rice diet) Almost never Great Danes and Dobermans • Carnitine – 500-1000mg PO BID – Boxers with genetic defect – Plasma levels have low sensitivity – Myocardial biopsy is usually required • Thyroxine – if hypothyroid Dilated Cardiomyopathy Beta Blocker Therapy • Seems counterintuitive for DCM – Negative inotrope • In people, chronic stimulation of B1 receptors is cardiotoxic – Improved survival when people with myocardial failure are put on beta blockers (carvedilol) • No similar success with canine DCM – Pharmacokinetics of carvedilol in dogs have been studied, and are unpredictable Dilated Cardiomyopathy Monitoring patients in chronic LHF • Chest x-rays and exam every 6 months • Echocardiogram when chest x-rays change – Every 6 months with cardiomyopathies • ECG when arrhythmia ausculted, syncope, or if disease which predisposed to arrhythmia – Boxer cardiomyopathy – Dilated cardiomyopathy • Recheck sooner if RR at rest is >35-40 per minute Dilated Cardiomyopathy Monitoring patients in chronic LHF • BUN, creat – 3-4 days after starting or increasing ACE inhibitor – Every 6 months when doing well – Sooner if things get worse • Electrolytes and blood gases – – – – Every 6 months when doing well Sooner if things get worse Potassium supplementation is often necessary Untreated hypokalemia can predispose to arrhythmia, especially if on digitalis Dilated Cardiomyopathy Screening • Predisposed dog breeds show decreased fractional shortening for many years prior to onset of clinical signs and/or murmur – FS has to fall <15% to cause CHF • Screening by echocardiogram at young adult to middle age is effective. – Interpretation of echo in mildly effected dogs can be challenging • Some think a Holter monitor is more effective screening – Especially for Boxers • No one knows whether early intervention changes outcome. Atrial Fibrillation What is it? – Disorganized contraction of the atria – Absence of effective atrial contractions – AV node is bombarded • Impulse makes it through to ventricles irregularly • “irregularly irregular” rhythm – Irregular ventricular rhythm • More obvious at lower heart rates – Irregular intensity of heart sounds due to erratic filling time and volume • More obvious at higher heart rates • Pulse strength irregular with deficits Atrial Fibrillation What causes it? – Anything that can cause enlarged LA • Most common cause is DCM in dogs • Also end stage MR progressing to myocardial failure – Occasionally can be primary in very large dogs • Very rare without underlying heart disease – Less common in cats • Advanced HCM with huge LA Frequent APCs are a harbinger of Afib Atrial Fibrillation In people Afib comes in 4 flavors – First detected episode – Paroxysmal - terminates spontaneously in 2-7 days (2550%) – Persistent - > 7 days, usually requires cardioversion to stop (25%) – Permanent - Fails to cardiovert or reverts within 24 hours of cardioversion Canine Afib is almost exclusively the permanent type “Lone” Afib occurs in giant dogs with no cardiac defects --12-30% of all, 20-45% of young dogs --most go on to develop DCM Atrial Fibrillation – 30-35% of dogs with DCM and CHF have Afib at the time of diagnosis – Median survival for giant dogs with Afib on diagnosis of DCM and CHF is 29 days • Large breed dogs 36 days • Spaniels 62 days • Dobermans 9 days – CHF + DCM with no Afib • • • • Giant – 64 days Large – 164 days Spaniels – 2 years Dobermans – 56 days Atrial Fibrillation Treatment – Afib in unhealthy hearts – Slow the heart rate at the AV node (goal 150 bpm) – Digoxin • Weak positive inotrope – Beta blockers • Negative inotrope • Propranolol 0.1-0.2 mg/kg PO TID • Titrate up to effect to 0.5 mg/kg PO TID – Calcium channel blockers • Diltiazem 0.5 mg/kg PO TID (titrate up to 1.5 mg/kg) – Growing body of evidence that angiotensin II may promote development of AFib DON’T USE BETA BLOCKER AND CALCIUM CHANNEL BLOCKER TOGETHER!! Atrial Fibrillation Why Treat?? • Heart rate around 250 beats per minute – Myocardial failure will result within 3-6 weeks – Ventricles can not fill properly – forward heart failure Treatment • Conversion would be ideal • But this is not easy to accomplish in very sick hearts • Can attempt in big dogs with normal hearts and primary Afib, not dogs with DCM – Can try medical conversion with quinidine – Or Anesthesia and conversion with electric shock Atrial Fibrillation Atrial Fibrillation Atrial Fibrillation Boxer Cardiomyopathy • Can be primarily ventricular arrhythmia – VPCs or bursts of Vtach • Can be primarily DCM • Can have both • If arrhythmia is primary, treatment of choice: – Sotalol 1-3 mg/kg PO BID – Beta blocker and class III antiarrhythmic • Holter Monitor is more likely to diagnose than echocardiogram (Client Handout) Jasper Signalment: • Middle Aged Adult Norwegian Forest Cat • Male Castrated • 13 pounds Chief Complaint: • Acute Dyspnea 1 day after sedation with ketamine and Rompun for grooming • Cannot auscult heart sounds well – muffled (audio) • RR 75 per minute Jasper Immediate Diagnostic Plan: • Lasix 25 mg IM – then in oxygen cage • When RR <40, lateral thoracic radiograph 2 hrs later: • RR 55 with oxygen off • Put water and gel on hair over thorax, and applied ultrasound probe • Cat sternal on the table (video) • Tapped 100ml pleural effusion (pink, opaque); stopped when cat got stressed Jasper • Lasix 25 mg IM – back in oxygen cage • Plan: When RR <40, lateral thoracic radiograph, or tap more if we can’t get RR that low with Lasix 4 hrs after intake (2 hrs later): • RR 45 with oxygen off • Tapped 100 ml more pleural fluid • More stress – Jasper is angry • Lasix 12.5 mg IM – back in oxygen Jasper 6 hrs after intake (2 hrs later): • RR 35 with oxygen off • Quick lateral chest x-ray allowed without too much stress • Regular vet tells me, “Oh, that cat is really mean. We usually can’t touch him without sedation.” • I am glad we took an x-ray before I knew that Jasper 6 hrs after intake (2 hrs later): • RR 35 with oxygen off • Quick lateral chest x-ray allowed without too much stress • Regular vet tells me, “Oh, that cat is really mean. We usually can’t touch him without sedation.” • I am glad we took an x-ray before I knew that Jasper Differential Diagnosis – Pleural effusion • Modified Transudate – Neoplasia, CHF • Exudate – Blood, Pyothorax, FIP • Chylothorax (chart) Jasper Initial Therapeutic Plan: • Thoracocentesis • Tapped both right and left thoraces • Removed 400 ml of pink opaque fluid that resembled Pepto bismol • Fluid had no “chunks” in it Differential Diagnosis – updated • Pyothorax • Chylothorax Jasper Initial Diagnostic Plan: • Fluid analysis – – – – – – – Total solids 5.1 SG 1.033 Color- pink before spun, white after Clarity – opaque, even after spun Nucleated cells 8500/ml RBC 130,000/ml HCT 0.7% Jasper Initial Diagnostic Plan: • Fluid analysis – – – – – – Lymphocytes 5600/ml Monocytes 600/ml Granulocytes 2300/ml No bacteria seen Triglycerides 1596 mg/dl Cholesterol 59 mg/dl chart Likely Chylothorax (need to run serum TG/chol) Jasper DDx Chylothorax • Trauma – was chewed by a dog 2-3 mos ago • Right Heart Failure • Pericardial Disease • Heartworm Disease • Neoplasia – Lymphoma – Thymoma • Idiopathic Jasper Diagnostic Plan - Updated • PE & Cardiovascular exam • CBC, general health profile, electrolytes • Occult heartworm test • Post-tap chest x-rays • Echocardiogram Jasper Exam • Temp 100, P 180, R 48, BCS 3, BP 115 • 2/6 late systolic murmur (audio) • Anterior mediastinum compressible • Some pleural rubs still present • No jugular pulses, no hepatojugular reflux • Peripheral pulses slightly weak • Mucous membranes pink, CRT 3 sec Jasper Bloodwork • Occult Heartworm Test - negative • CBC – normal • GHP, T4 – normal except – Glucose 134 (n 70-125) – Cholesterol 193 & TG 137 (both normal) Chest X-rays • Post-tap chest x-rays Jasper Bloodwork • Occult Heartworm Test - negative • CBC – normal • GHP – – Glucose 134 (n 70-125) – Cholesterol 193 & TG 137 (both normal) Chest X-rays • Post-tap chest x-rays Jasper Chest X-rays • Minimal pleural effusion • No cranial mediastinal masses • Normal cardiac silhouette (VHS 7.5) • Normal pulmonary vasculature • Lungs remain scalloped Jasper – Echo Short Axis – LV apex • No abnormalities noted Short Axis – LV PM Jasper – Echo Short Axis – LV apex • No abnormalities noted Short Axis – LV PM Jasper – Echo Short Axis – LV apex • No abnormalities noted Short Axis – LV PM • • • • • • • • No abnormalities noted IVSTD – 8.8 mm (n 3-6) LVIDD – 16.2 mm (normal) LVPWD – 7.2 mm (n 3-6) IVSTS – 9.8 mm (n 4-9) LVIDS – 10.5 mm (normal) LVPWS – 10.1 mm (n 4-10) FS – 35% Jasper – Echo Short Axis – MV • No abnormalities noted Short Axis – Ao/RVOT Jasper – Echo Short Axis – MV • No abnormalities noted Short Axis – Ao/RVOT Jasper – Echo Short Axis – MV • No abnormalities noted Short Axis – Ao/RVOT • Smoke in the LA • AoS – 11.7 mm ( normal) • LAD – 10.5 (normal) • LA/Ao – 0.9 (normal) Jasper – Echo Short Axis – PA • Difficult to evaluate due to acoustic shadows Long Axis – 4 Chamber Jasper – Echo Short Axis – PA • Difficult to evaluate due to acoustic shadows Long Axis – 4 Chamber Jasper – Echo Short Axis – PA • Difficult to evaluate due to “rib shadows” Long Axis – 4 Chamber Jasper – Echo Short Axis – PA • Difficult to evaluate due to “rib shadows” Long Axis – 4 Chamber Jasper – Echo Short Axis – PA • Difficult to evaluate due to “rib shadows” Long Axis – 4 Chamber Jasper – Echo Short Axis – PA • Difficult to evaluate due to “rib shadows” Long Axis – 4 Chamber Jasper – Echo Short Axis – PA • Difficult to evaluate due to “rib shadows” Long Axis – 4 Chamber Jasper – Echo Short Axis – PA • Difficult to evaluate due to “rib shadows” Long Axis – 4 Chamber • Hyperechoic “thingy” in the LA, with smoke Long Axis – LVOT • Aortic valve seems hyperechoic, but not nodular • 2-3 cm thrombus free in the LA Jasper – Echo Short Axis – Ao/RVOT - repeated • LA 2-3x normal size, with Smoke • AoS – 11.7 mm ( normal) • LAD – 29 mm (n 7-17) • LA/Ao – 2.5 (n 0.8-1.3) Jasper – Echo Therapeutic Plan - Updated • Furosemide 12.5 mg PO BID • Enalapril 2.5 mg PO BID • Rutin 250 mg PO BID • Low fat diet • Plavix 18.75 mg PO SID • Lovenox 1 mg/kg BID • Fragmin 1 mg/kg BID • Clot busters may only send the clot sailing Jasper – Echo Recheck – 1 week • Jasper doing exceptionally well –back to normal. • Lateral chest radiograph Jasper – Echo Recheck – 1 week • Jasper doing exceptionally well –back to normal. • Lateral chest radiograph Jasper – Echo Recheck – 1 week • Jasper doing exceptionally well –back to normal. • Lateral chest radiograph • Jasper declined all other diagnostics, without deep sedation/anesthesia • Will do BUN, Electrolytes, BP, recheck echo to assess thrombus in one month Jasper – Echo Recheck – 1 month • Jasper doing exceptionally well • Lateral chest radiograph – no change • Jasper declined all other diagnostics, without deep sedation/anesthesia • Will do BUN, Electrolytes, BP, recheck echo to assess thrombus at 6 month check-up. Jasper – Echo Recheck – 6 months • Jasper doing exceptionally well • BP – 140, chest x-rays no change • Jasper declined all other diagnostics, without deep sedation/anesthesia • May never do BUN, Electrolytes, recheck echo • Jasper hates my guts, forever • He wants to kill me in my sleep Jasper – Echo Long Term Follow-up • Jasper still doing well 18 months later • On lasix & enalapril only • At 2 years, owners decided Jasper didn’t need heart meds anymore, so they stopped giving them • Jasper was asymptomatic for one year after that • Attacked and killed by dogs 3 years after initial diagnosis • On necropsy, Jasper’s heart weighed 31g – The normal adult cat heart should be <20g Hypertrophic Cardiomyopathy Clinical Characteristics • Diastolic dysfunction – heart does not fill well • Poor cardiac perfusion • Most severe disease in young to middle aged male cats • Can present as – – – – Murmur on physical exam Heart failure (often advanced at first sign) Acute death Saddle thrombus Hypertrophic Cardiomyopathy Radiographic Findings • + LV enlargement – Elevated trachea, increased VHS • LA + RA enlargement seen on VD in cats • + LHF – Pleural effusion – Pulmonary edema – Lobar veins >> arteries Hypertrophic Cardiomyopathy Echocardiographic Abnormalities • Echo required in order to make diagnosis • LV and/or IVS thicker than 8-10 mm in diastole • LVOT view (video) – early HCM no LA enl • Symmetrical or asymmetrical – only a thick IVS (video) – primarily very thick papillary muscles (video) – Primarily apical Hypertrophic Cardiomyopathy Echocardiographic Abnormalities • Echo required in order to make diagnosis • LV and/or IVS thicker than 8-10 mm in diastole • Symmetrical or asymmetrical – only a thick IVS (video) – primarily very thick papillary muscles (video) – Primarily apical Hypertrophic Cardiomyopathy Echocardiographic Abnormalities • Echo required in order to make diagnosis • LV and/or IVS thicker than 8-10 mm in diastole • Symmetrical or asymmetrical – only a thick IVS (video) – primarily very thick papillary muscles (video) – Primarily apical Hypertrophic Cardiomyopathy Echocardiographic Abnormalities • Echo required in order to make diagnosis • LV and/or IVS thicker than 9-10 mm in diastole • Symmetrical or asymmetrical – only a thick IVS (video) (M-mode) – primarily very thick papillary muscles (video) – Primarily apical • LVIDD usually normal to slightly reduced • FS normal to increased, unless myocardial failure developing (Jasper), or unclassified CM (UCM) • LVIDS sometimes 0 mm Hypertrophic Cardiomyopathy Echocardiographic Abnormalities • LA often enlarged • RA sometimes also enlarged • “Smoke” may be seen in the LA • Rarely a thrombus in the LA • Transesophageal US more sensitive at detecting LA thrombi • Borderline thickened LV should not be diagnosed as HCM without LA enlargement Hypertrophic Cardiomyopathy Echocardiographic Abnormalities • HOCM with SAM – Hypertrophic Obstructive CardioMyopathy with Systolic Anterior Motion – Septal leaflet of the MV get sucked up into the LVOT during systole rather than closing the MV caudally – Results in two compounded systolic murmurs • Aortic turbulence due to functional SAS • Mitral regurgitation – SAM and its murmur can be intermittent (video B mode) (video Doppler) Hypertrophic Cardiomyopathy DDx LV thickening • Hypertension • Hyperthyroidism • (Chronic renal failure) • Only HCM causes severe thickening of LV • HCM due to hyperT4 resolves with treatment – CHF is rare, treat with atenolol until resolved Dogs can rarely have HCM • Cocker spaniels Hypertrophic Cardiomyopathy Treatment • Manage heart failure – Therapeutic thoracocentesis in a crisis – Diuretics – ACE inhibitors • Beta blockers – if persistent tachycardia • Calcium channel blockers – if thickening significant • Treat hypertension if present Hypertrophic Cardiomyopathy Follow-Up • Q6month rechecks – – – – Chest x-rays CBC, GHP, electrolytes, blood gases ECG if arrhythmia ausculted or syncope BP • Sooner if RR >40 at rest • Sooner if any open mouth breathing ever Hypertrophic Cardiomyopathy Screening • Genetic test is available at NCSU • Auscultation not always sensitive • Echocardiogram can detect early in breeds predisposed • No evidence that early intervention changes outcome (Client Handout) Hypertrophic Cardiomyopathy HCM and Pimobendan • It seems counterintuitive to treat HCM cats with pimobendan • Positive inotrope *should* increase myocardial oxygen demand, and is not necessary • Case-control study of the effects of pimobendan on survival time in cats with hypertrophic cardiomyopathy and congestive heart failure. J Am Vet Med Assoc. September 1, 2014;245(5):534-9. Yamir et al. NCSU. Hypertrophic Cardiomyopathy HCM and Pimobendan • All cats had HCM and CHF - retrospective • Those treated with pimobendan had significantly longer survival than those treated with other drugs • Median survival for pimobendan cats 635 days • Median survival for other cats 103 days Hypertrophic Cardiomyopathy HCM and Pimobendan Mark Rishniw, DACVIM cardiology • There are several major flaws with this paper -that's the consequence of a retrospective study. • I would be very cautious about adopting this as "standard of care" for cats with CHF. Hypertrophic Cardiomyopathy HCM and Pimobendan Mark Kittleson, DACVIM cardiology • as soon as pimobendan came on the market, veterinary cardiologists started administering it to cats in heart failure. • Some avoided using it in cats with HCM while others did not. • Instead, when they found out it didn't kill these cats and they perceived some benefit they initially tried to publish data to show the drug was beneficial. Hypertrophic Cardiomyopathy HCM and Pimobendan Mark Kittleson, DACVIM cardiology • This latest paper is an attempt to do a clinical trial but in a retrospective fashion, one that brings in all sorts of potential bias. • Layered on top of this is a pharmacokinetic paper that shows that when you give a dog dose to a cat the serum concentration of the parent compound (pimobendan) is 10 times as high as that seen in dogs and the active metabolite (desmethylpimobendan) may not be present. Hypertrophic Cardiomyopathy HCM and Pimobendan Mark Kittleson, DACVIM cardiology • Pimobendan is a calcium sensitizer while desmethylpimobendan is primarily a PDEIII inhibitor. • A 10X dose of a calcium sensitizer should turn the heart to stone (constant state of systole). • Since the drug doesn't kill cats that it's reasonably clear that pimobendan does something very different in cats when compared to dogs. Hypertrophic Cardiomyopathy HCM and Pimobendan Mark Kittleson, DACVIM cardiology • In an ideal world we would go back to square one - do the pharmacokinetic and pharmacodynamic studies in cats that should have been done years ago and then do a proper prospective clinical trial. • Instead we're all sneaking in through the back door that's been left open by the drug company and regulatory agencies. • The front door is closed because the drug company has no incentive to fund a prospective clinical trial. Pleural Effusion • Usually caused by biventricular failure in the dog – Parietal pleura veins drain into the R heart like the systemic veins – Visceral pleura veins drain into the L heart with the pulmonary veins • RHF alone can cause pleural effusion in dogs • LHF alone almost never causes pleural effusion in dogs, but often does in cats – Cats in LHF will often have pleural effusion but no ascites – Dogs in RHF will often have pleural effusion and ascites Summary • PowerPoint – Cases – Cardiomyopathies • .pdf of PowerPoint – Cases Cardiomyopathies • Fluid Analysis Chart • Client Handouts – Feline Cardiomyopathy – Dilated Cardiomyopathy – Boxer Cardiomyopathy