1. Practical Cardiology Case Studies Wendy Blount, DVM Nacogdoches TX Wendy Blount, DVM Nacogdoches TX

2. Jake Signalment 9 year old male Boxer Chief Complaint Deep cough when walking in the morning, for about one week Appetite is good

3. Jake Exam Weight 81.9 – has lost 5 pounds in 3 months (BCS 3) 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 holosystolic murmur, PMI left apex Heart rate 160 per minute Respirations 55 per minute Femoral pulses somewhat weak

4. Jake Differential Diagnosis - Cough Respiratory Disease Cardiovascular Disease Both Diagnostic Plan (B Client) Blood Pressure –150 mm Hg systolic (Doppler) Chest x-rays

5. Jake

7. Diagnostic Plan (B Client) Chest X-rays –Massively enlarged heart (VHS 12.5) –Enlarged LA, LV (dorsally elevated trachea) –Enlarged pulmonary veins –Perihilar pulmonary edema –Left congestive heart failure

8. Jake Immediate Therapeutic Plan (10 am) Furosemide –80 mg IM 4 hours later –Respiratory rate is 36 per minute

9. Jake Diagnostic Plan – 2 nd Wave (2 pm) EKG

10. Jake Diagnostic Plan – 2 nd 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

11. Jake Diagnostic Plan – 2 nd Wave (2 pm) EKG Echocardiogram (video)video (another video)another video

12. Jake - Echo Transverse - LV Apex LV Looks Big Transverse - LV Papillary Muscles LV looks REALLY big Myocardium is hardly moving Flat papillary muscles

13. 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%)

14. Jake - Echo Transverse - Mitral Valve No increased thickness of MV No vegetations on the MV EPSS – 12 mm (n <6 mm) Transverse – Aortic Valve/RVOT LA at least Double Big

15. 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

16. 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

17. 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)

18. 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

19. 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

20. Jake – Follow-Up 4 months later… Chief complaint – –Doing well until last week –poor energy, coughing again, not eating Heart sounds (audio file)audio file –Chaotic heart sounds with pulse deficits on auscultation –“tennis shoes in a dryer” –Called “Delirium cordis”

21. Jake – Follow-Up Heart Rate 200 bpm (tachycardia) Rhythm (NSR, RSA or arrhythmia) irregularly irregular - arrhythmia 25 mm/sec

22. 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 25 mm/sec Diagnosis – Atrial Fibrillation

23. Jake – Treatment Recommended treatment Pimobendan for DCM (declined before) Digitalis 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

24. Dilated Cardiomyopathy Common Signalment Breed –Doberman –Great Dane –Boxer –Newfoundland –Portuguese Water Dog –Dalmatian –Cocker Spaniel No genetic test at this time

25. 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)

26. Dilated Cardiomyopathy Common Historical and PE findings Chemotherapy –doxorubicin DCM in a puppy –Parvovirus at 2-4 weesk of age (historical) –Chaga’s Disease Trypanosoma cruzi

27. 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

28. Dilated Cardiomyopathy Common ECG Findings Wide P wave –LA enlargement Tall R wave –LV enlargement Atrial fibrillation VPCs Ventricular arrhythmias

29. Dilated Cardiomyopathy Common Echocardiographic Lesions Dilation of all 4 heart chambers Large LVIDD (eventually large LVIDS also) Hypokinesis of LV wall and IVS Reduced FS Paradoxical septal motion Increased EPSS Normal looking MV and TV leaflets Papillary muscle flattening

30. 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

31. 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

32. 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 electrolytes at least daily –Central line can make blood draws easy

33. 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

34. 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 mycoardial failure are put on beta blockers (carvedilol) No similar success with canine DCM –Pharmakokinetics of carvedilol in dogs have been studied, and are unpredictable

35. 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 >40 per minute

36. 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

37. 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. (handout)handout

38. 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

39. 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

40. 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) DON’T USE BETA BLOCKER AND CALCIUM CHANNEL BLOCKER TOGETHER!!

41. 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

42. Atrial Fibrillation

45. 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

46. Ventricular Arrhythmias When do you treat? Class I antiarrhythmics –Procainamide, quinidine –Do not prevent sudden death in people –In some cases increase risk of sudden death Beta Blockers –High doses required to prevent sudden death –Not tolerated by dogs with severe DCM Calcium channel blockers not effective for ventricular tachyarrhythmias Sotolol is often the drug of choice, as long as myocardial failure not severe

47. Ventricular Arrhythmias When do you treat? Amioderone –Another class III antiarrhythmic –Unpredictable pharmacokinetics –Significant toxicity –Been around since 1961

48. Pockets Signalment 11 year old spayed female yorkie (5 pounds) Chief Complaint Harsh cough several times daily for 2 months History of chronic inflammatory liver disease, luxating patellas, severe chronic periodontal disease and multiple allergies; these problems clinically well managed at this time. Mammary carcinoma removed one year previously, at the time of OHE.

49. Pockets Exam Temp 100.3, P 110, R 26, BP 110, BCS 3.5 BAR, well hydrated, in good body condition (auscultation)auscultation Crackles in the small airways, especially at peak inspiration Pronounced respiratory sinus arrhythmia 2/6 systolic murmur PMI left apex Pulses normal, CRT < 2 sec Mature cataract right eye

50. Pockets Differential Diagnoses - Cough Chronic Bronchitis Collapsing trachea Diagnostic Plan - initial Chest and cervical x-rays Inspiratory - VD and right lateral Expiratory - left lateral

51. Pockets Differential Diagnoses - Cough Chronic Bronchitis Collapsing trachea Diagnostic Plan - initial Chest and cervical x-rays Inspiratory - VD and right lateral Expiratory - left lateral

52. Pockets Differential Diagnoses - Cough Chronic Bronchitis Collapsing trachea Diagnostic Plan - initial Chest and cervical x-rays Inspiratory - VD and right lateral Expiratory - left lateral

53. Pockets Thoracic and cervical radiographs No collapse of the trachea Vertebral heart score 10 Normal cardiac silhouette and pulmonary vasculature Pronounced peribronchiolar pattern Shoulder arthritis Vertebral arthritis Normal sized liver

54. Pockets Diagnostics – 2 nd round Transtracheal wash Cytology – suppurative inflammation (mature neutrophils) Culture negative Treatment – Diagnosis Chronic Bronchitis Hydrocodone as needed for cough suppression Inhaled steroids PRN for cough Not tolerated – Temaril P instead

55. Pockets Long term outcome – 4 years (handout)handout Monitoring – chest rads every 6 months Dental cleaning every 4-6 months 1 episode of bacterial bronchpneumonia after dental, despite treatment with metronidazole Amoxicillin 1 week before and after dental Increase cough suppressants for 3 days after dental Hydrocodone almost every day Temaril P for flare-ups –Repeat transtracheal wash when severe Coughs once or twice almost every day

56. Chronic Bronchitis Crackles in the lungs do not always mean pulmonary edema If there is no murmur, CHF is very unlikely If there is RSA, CHF is very unlikely Always take a chest x-ray Can lead to airway collapse over time If not doing well, never hesitate to repeat chest x-rays Mainstay of therapy is corticosteroids and cough suppressants Antibiotics periodically for secondary infection –Can be seeded by periodontal infection Guided by TTW/BAL and culture & sensitivity –This procedure can decompensate a dog with collapsing trachea –As can intubation for dental cleaning

57. Chronic Bronchitis CB dogs are well dogs that cough –CHF dogs are sick dogs that cough Weight loss can improve quality of life tremendously if overweight There is the rare dog that needs to live on rotating antibiotics to avoid bronchopneumonia –Pick three, rotate and do C&S when efficacy wanes Don’t forget about hyperadrenocorticism Deworm Consider allergy testing and hyposensitization If all else fails, bronchoscopy might help

58. Chronic Bronchitis Treatment Corticosteroids and cough suppressants to reduce cough by 80% Bronchodilators – beta agonists if no heart failure, methylxanthines Inhaled steroids and/or bronchodilators minimize side effects Monitor blood pressure to make sure bronchodilators tolerated Mucolytics can help if phlegm is thick and copious If patient becomes refractory to treatment without collapsing airways, consider referring for doppler echo –Pulmonary hypertension due to chronic COPD –Sildenafil can sometimes give short term relief

59. Chronic Bronchitis Cough suppressants Hydrocodone guaifenasin + dextromethorphan tabs promethazine (Phenergen) Maropitant (Cerenia) Tramadol

60. NTproBNP ELISA N-terminal pro-B type Natriuretic Peptide In clinic test to distinguish cardiac from respiratory dyspnea Validated in dogs JACVIM January 2008 <210 pmol/L – more likely respiratory disease >210 pmol/L – more likely cardiac disease Falsely elevated by increased creatinine Helpful in distinguishing cardiac from respiratory dyspnea when creatinine is not elevated Most helpful in dogs with airway disease and a murmur Often more helpful in cats whose thoracic rads can be more ambiguous

61. Tom 5 year old neutered male DSH Chief Complaint Outdoor cat, owners think he was hit by a car Tom is laterally recumbent, and breathing hard Exam T 96.5, P- 100, R – 66 No evidence of trauma

62. ECG 1 Heart Rate - 120 Rhythm – regular no P waves QRS – deep S wave, wide, bizarre QRS Tom Dx – atrial standstill, L ventricular escape rhythm

63. Tom Electrolyte panel K 10.9 mEq/L, iCa ++ 0.96 mmol/L pH 7.08, HCO 3 11 mEq/L Grapefruit sized very firm bladder

64. Tom Treatment Place indwelling urinary catheter & IV catheter Begin 0.9% NaCl at 15 ml/hr 1 unit regular insulin IV 5cc 50% dextrose diluted in 15 cc fluids, given over 1 hour; added 5%dextrose to fluids ECG 2 – 6 minutes later

65. Tom

66. ECG 2 – 6 minutes later Heart rate 140 No P waves QRS less abnormal T wave not as tall

67. Tom ECG 3 – 1 hour after presentation Heart rate 120 No change for the past 45 minutes Treatment Ca-gluconate 2cc IV slowly over 20 minutes

68. Tom ECG 4 – 2 hours after presentation – T 98.9 Heart rate 120, normal sinus rhythm P waves have returned, but wide and inverted QRS and T normal

69. Tom ECG 5 – 5 hours after presentation Heart rate 130 Normal sinus rhythm P waves have returned to normal

70. Tom Follow-up electrolytes iCa ++ normal, K 6.6 mEq/L HCO 3 -- 16.3 mEq/L, pH 7.29 Tom began eating the next day, the urinary catheter was removed, and he was discharged 2 days later. He was azotemic on presentation, but this resolved with treatment

71. Treatment by Arrhythmia Antiarrhythmic Drug Classes and DosesAntiarrhythmic Drug Classes and Doses Arrhythmia Description and ClassificationArrhythmia Description and Classification