1 Surgical Meeting Cardiorespiratory focus Carlos F. Agudelo VFU – Brno Cardiac arrhythmias Carlos F. Agudelo VFU – Brno The arrhythmia Importance -Decrease in cardiac output: hypotension a decreased tissue and coronary perfusion -Sign of extra-cardiac disease (trauma, inflammation, cancer) -Sudden death The arrhythmia - Signalement -Breed: WHWT, Springer Spaniel, Boxer, Doberman, etc. -Colour - History Exercise intolerance Dyspnoea Palpitations Fanting episodes Long term cardiac disease (drugs) Trauma Inflammation Cancer (therapy) - Clinical Hypotension Pale MM Irregular heart beats Pulse deficit Sudden death The arrhythmia Ventricular arrhythmia -Cardiomyopathy -Myocarditis / endocarditis -Myocardial hypoxia -Congenital heart disease -Digitalis intoxication -Electrolytic abnormalities -Hypothermia -Systemic disease Supraventricular arrhythmia -Enlargement of the atria -Myocarditis / endocarditis -Ongoing heart disease -Ischemic foci in the atria -Drugs (digitalis, anesthetics) -Abnormal AV pathways -Systemic disease The arrhythmia Diagnosis ECG Holter–event recorders
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Transcript
1
Surgical Meeting
Cardiorespiratory focus
Carlos F. Agudelo
VFU – Brno
Cardiac arrhythmias
Carlos F. Agudelo
VFU – Brno
The arrhythmia
Importance
-Decrease in cardiac output: hypotension a decreased tissue and coronary perfusion
-Sign of extra-cardiac disease (trauma, inflammation, cancer)
-Based on the history, clinical findings (auscultation, pulse palpation), blood pressure, laboratory findings, and others
-Each antiarrhythmic drug has also pro-arryhthmic effects
5
Therapy
Supraventricular arrhythmias
-Physiologic or compensatory…be aware
-Vagal manoeuvre or thump
-Pharmacological intervention
Therapy
Supraventricular arrhythmias: APC, SVT, AF
-Acute onset of congestive heart failure
-Goal at home: dogs 120-150 beats/min; cats 200 beats/min.
-Some cases of pre-clinical DCM: β-blockers? Cardioversion?
Therapy
Supraventricular arrhythmias – acute management
-Diltiazem 0.25 mg/kg IV bolus over 2 minutes. Repeat bolus at 15 minute intervals until conversion (max. dose of 0.75 mg/kg).
-Verapamil 0.05 mg/kg slow IV bolus. Repeat boluses up to a total dose of 0.15 mg/kg.
-Esmolol (incremental doses of 0.05 to 0.1 mg/kg q 5 min up to a maximum dose of 0.5 mg/kg).
Therapy
AF – chronic therapy
- Digoxin – Dogs: 0,005-0,01mg/kg PO. SID-BID (dogs >20kg: 0,22 mg/m2). Maximal dose in Dobermans is 0.25 mg BID.
- Digoxin – Cats 0.0035 to 0.0055 mg/kg SID PO. ¼ tablet 0.125 mg (0.0312 mg/cat) PO in a 2-3 kg = ¼ q48h; 4-5 kg = ¼ SID; 6 kg or > = ¼ BID.
Levels are measured after 1 week of therapy (0.5-2 ng/ml). Watch out digoxin toxicity (about 15% of cases) and renal disease (decrease dose by 30-50%).