Cardiac Dysrhythmias Flashcards
Pathway of electrical conductivity
Sinoatrial Node –> Atrioventricular (AV) node –> AV Bundle or Bundle of His –> Right and left bundle branches–> Purkinje Fibers –>inner surface –> wave of depolarization over outer surface –> ventricles contract
Four properties of heart cells,
Automaticity Ability to initiate an impulse spontaneously and continuously
Excitability Ability to be electrically stimulated
Conductivity Ability to transmit an impulse along a membrane in an orderly manner
Contractility Ability to respond mechanically to an impulse
Evaluation of Dysrythmias
Holter monitoring Event recorder monitoring Exercise treadmill testing Signal-averaged ECG Electrophysiological study
Sinus Bradycardia Occurs in response to
Carotid sinus massage Valsalva’s manoeuvre Hypothermia Increased intraocular pressure Increased vagal tone Administration of parasympathomimetic drugs
Occurs in disease states Hypothyroidism Increased intracranial pressure Obstructive jaundice Inferior wall MI
Sinus Bradycardia symptoms
Hypotension Pale, cool skin Weakness Angina Dizziness or syncope Confusion or disorientation Shortness of breath
Sinus Tachycardia Occurs in response to
Exercise Fever, Pain Hypotension Hypovolemia Anemia Hypoxia Hypoglycemia MI Heart failure Hyperthyroidism Anxiety, fear
Sinus Tachycardia symptoms
Dizziness, dyspnea. and hypotension due to decreased CO
Increased myocardial oxygen consumption may lead to angina.
Atrial Flutter Occurs in response to
CAD Hypertension Mitral valve disorders Pulmonary embolus Chronic lung disease Cor pulmonale Cardiomyopathy Hyperthyroidism Drugs: digoxin, quinidine, epinephrine
Atrial Flutter symptoms
Heart Palpitations
SOB
Dizziness
Pain
Atrial Flutter Treatment
Drugs to slow HR: calcium channel blockers, -adrenergic blockers
Electrical cardioversion may be used to convert the atrial flutter to sinus rhythm emergently and electively.
Antidysrhythmic drugs (e.g., amiodarone, propafenone) to convert atrial flutter to sinus rhythm or to maintain sinus rhythm
Radiofrequency catheter ablation can be curative therapy for atrial flutter.
Atrial Fibrillation Occurs in response to
Rheumatic heart disease CAD Cardiomyopathy Hypertensive heart disease HF Pericarditis
Often acutely caused by Thyrotoxicosis Alcohol intoxication Caffeine use Electrolyte disturbances Stress Cardiac surgery
Atrial Fibrillation Treatment
- Drugs for rate control: calcium channel blockers (e.g., diltiazem) and β-adrenergic blockers (e.g., metoprolol)
- Long-term anticoagulation therapy
- For some clients, conversion to sinus rhythm may be considered.
- Antidysrhythmic drugs used for conversion: amiodarone, propafenone
- The nurse must determine that the client has had atrial fibrillation or atrial flutter for less than 48 hours.
- Radiofrequency catheter ablation
Premature Ventricular Contractions Occurs in response to
Stimulants: caffeine, alcohol, nicotine, aminophylline, epinephrine, isoproterenol and digoxin
Electrolyte imbalances
Hypoxia
Fever
Disease states: MI, mitral valve prolapse, HF, CAD
Ventricular Tachycardia
Occurs in response to
MI CAD Electrolyte imbalances Cardiomyopathy Mitral valve prolapse Long QT syndrome Digitalis toxicity Central nervous system disorders
Syncope Cardiovascular causes / Noncardiovascular causes
Cardiovascular causes Neurocardiogenic syncope or “vasovagal” syncope (e.g., carotid sinus sensitivity)
Primary cardiac dysrhythmias (e.g., tachycardias, bradycardias)
Noncardiovascular causes Hypoglycemia Hysteria Unwitnessed seizure Vertebrobasilar transient ischemic attack
