Tisdale Arrhythmia Flashcards
What is torsades de pointes?
-When the QTc interval is 500 ms or more, there is an increased risk
-Torsades de pointes can cause sudden cardiac death
Types of supraventricular arrhythmias
-Sinus bradycardia
-Atrioventricular (AV) block
-Sinus tachycardia
-Atrial fibrillation
-Supraventricular tachycardia
Types of ventricular arrhythmias
-Premature ventricular complexes (PVCs)
-Ventricular tachycardia
-Ventricular fibrillation
What is sinus bradycardia?
-Heart rate less than 60 beats per minute
-Impulses originating in sinoatrial node
-Decreased automaticity of the SA node
Sinus bradycardia risk factors
-Myocardial infarction or ischemia
-Abnormal sympathetic or parasympathetic tone
-Hyperkalemia
-Hypermagnesemia
-Beta blockers
-CCBs
-Amiodarone
-Idiopathic
Symptoms of sinus bradycardia
-Hypotension
-Dizziness
-Syncope
Treatment of sinus bradycardia
-Only if patient is symptomatic
-Atropine 0.5-1 mg IV, repeat every 5 minutes
-Maximum dose 3 mg
What to do if patient is unresponsive to atropine
-Transcutaneous pacing (pacemaker on the skin)
-Dopamine 5-20 mcg/kg/min
-Epinephrine 2-10 mcg/min or 0.1-0.5 mcg/kg/min
-Isoproterenol 20-60 mcg IV bolus followed by doses of 10-20 mcg or infusion of 1-20 mcg/min
Adverse effects of atropine
-Tachycardia
-Urinary retention
-Blurred vision
-Dry mouth
-Mydriasis
Treatment of sinus bradycardia after heart transplant or spinal cord injury
-Aminophylline 6 mg/kg IV over 20-30 minutes
-Theophylline heart transplant: 300 mg IV followed by oral dose of 5-10 mg/kg/day titrated to effect
-Theophylline spinal cord injury: oral dose of 5-10 mg/kg/day titrated to effect
Long term treatment of sinus bradycardia
-Some patients may require a pacemaker
-For patients unwilling to undergo implantation of a permanent pacemaker: theophylline oral 5-10 mg/kg/day titrated to effect
Features of atrial fibrillation
-Atrial activity: chaotic and disorganized - no atrial depolarizations
-Ventricular rate: 120-180 bpm
-Rhythm: irregularly irregular
-P waves: Absent
Stage 1 atrial fibrillation
Presence of modifiable and nonmodifiable risk factors associated with AF
Stage 2 atrial fibrillation
-Pre-atrial fibrillation
-Evidence of structural or electrical findings that further predispose patients to AF (Atrial enlargement, frequent atrial premature beats, atrial flutter)
Stage 3A atrial fibrillation
Paroxysmal AF: AF that is intermittent and terminates within 7 days of onset
Stage 3B atrial fibrillation
Persistent AF: AF that is continuous and sustains for more than 7 days and requires intervention
Stage 3C atrial fibrillation
Long-standing persistent AF: AF that is continuous for more than 12 months in duration
Stage 3D atrial fibrillation
Successful AF ablation: freedom from AF after percutaneous or surgical intervention to eliminate AF
Stage 4 atrial fibrillation
Permanent trial fibrillation: no further attempts at rhythm control after discussion between the patient and clinician
Mechanisms of atrial fibrillation
-Abnormal atrial/pulmonary vein automaticity
-Atrial reentry
Atrial fibrillation risk factors
-Advancing age
-Cigarette smoking
-Sedentary lifestyle
-Alcohol
-Obesity
-Hypertension
-Diabetes mellitus
-Coronary artery disease
-Heart failure
-Obstructive sleep apnea
-Valvular heart disease
-Chronic kidney disease
-Genetic
-Idiopathic
Etiologies of reversible atrial fibrillation
-Hyperthyroidism
-Thoracic surgery (coronary artery bypass graft, lung resection, esophagectomy)
-Sepsis
Atrial fibrillation symptoms
-May be asymptomatic
-Palpitations
-Dizziness
-Fatigue
-Lightheadedness
-Shortness of breath
-Hypotension
-Syncope
-Angina (in patients with coronary artery disease)
-Exacerbation of heart failure symptoms
Atrial fibrillation morbidity/mortality risks
-Stroke/systemic embolism - risk increased 5x
-Heart failure - risk increased 3x
-Dementia - risk increased 2x
-Mortality - risk increased 2x