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
How to prevent atrial fibrillation
-Lifestyle and risk factor modification
-Physical fitness
-Smoking cessation
-Minimize or eliminate alcohol consumption
-Blood pressure control in patients with hypertension
-Optimal glucose and A1C management in patients with diabetes
Atrial fibrillation goals of therapy
-Prevent stroke/systemic embolism
-Slow ventricular response by inhibiting conduction of impulses to ventricles
-Convert atrial fibrillation to normal sinus rhythm
-Maintain sinus rhythm (reduce frequency of episodes)
When are oral anticoagulants recommended for patients with atrial fibrillation?
-CHADSVASc score of 2 or more in men
-CHADSVASc score of 3 or more in women
When can oral anticoagulants be omitted in patients with atrial fibrillation?
-CHADSVASc score of 0 in men
-CHADSVASc score of 0-1 in women
What anticoagulant is preferred in atrial fibrillation?
-DOACs are preferred
-Warfarin is preferred over DOACs in patients with a mechanical heart valve and patients with atrial fibrillation associated with heart valve disease
-Warfarin or apixaban are preferred in patients with end-stage kidney disease and/or on hemodialysis
Drugs for ventricular rate control
-Diltiazem
-Verapamil
-Esmolol
-Propranolol
-Metoprolol
-Digoxin
-Amiodarone
How to define hemodynamically unstable
One of the following is true:
-Systolic less than 90
-BPM over 150
-Loss of consciousness
-Ischemic chest pain
How do you treat acute ventricular rate control (AFIB) if the patient is not hemodynamically stable?
Direct current cardioversion
How do you treat acute ventricular rate control (AFIB) if the patient is hemodynamically stable and has decompensated heart failure
Amiodarone
How do you treat acute ventricular rate control (AFIB) if the patient is hemodynamically stable and does not have decompensated heart failure?
-Beta-blocker, diltiazem, or verapamil
-Digoxin
-Amiodarone
How do you treat long-term ventricular rate control (AFIB) if the LVEF is 40% or less?
-Beta-blocker
-Digoxin
How do you treat long-term ventricular rate control (AFIB) if the LVEF is over 40%?
-Beta-blocker, diltiazem, or verapamil
-Digoxin
When is it safe to convert to sinus rhythm?
-If AF has been present for 48 hours or less, conversion to sinus rhythm is safe
-If AF has been present for more than 48 hours, conversion to sinus rhythm should not be preformed until patient has been anticoagulated for 3 weeks, or unless a transesophageal echocardiogram (TEE) has been performed to rule out a clot in the atrium
How do you convert hemodynamically stable atrial fibrillation patients to sinus rhythm who have normal LV function?
IV amiodarone, ibutilide
How do you convert hemodynamically stable atrial fibrillation patients to sinus rhythm who have HFrEF (LVEF 40% or less)?
IV amiodarone
How do you convert hemodynamically stable atrial fibrillation patients to sinus rhythm who are not in the hospital and have normal LV function?
Flecainide, propafenone
Oral amiodarone adverse effects
-Blue-grey skin discoloration
-Photosensitivity
-Corneal microdeposits
-Pulmonary fibrosis
-Hepatotoxicity
-Bradycardia
-Hype/hyperthyroidism
Dofetilide adverse effects
Torsades de pointes
How do you dose dofetilide when the creatinine clearance is over 60?
500 mcg orally twice daily
How do you dose dofetilide when the creatinine clearance is 40-60?
250 mcg orally twice daily
How do you dose dofetilide when the creatinine clearance is 20-39?
125 mcg orally twice daily
How do you dose dofetilide when the creatinine clearance is less than 20?
Contraindicated
Amiodarone recommended monitoring
-Hypo- or hyperthyroidism: TSH (T3 and T4 if TSH abnormal)
-Hepatotoxicity: liver function tests (ALT, AST)
-QT interval prolongation: ECG
-Pulmonary fibrosis: chest X-ray
What to give for maintenance therapy of sinus rhythm following conversion to SR or for paroxysmal AF when the patient has normal LV function, and has no history of a prior MI or significant heart disease
-Dofetilide, dronedarone, flecainide, propafenone
-Amiodarone
-Sotalol
What to give for maintenance therapy of sinus rhythm following conversion to SR or for paroxysmal AF when the patient has a history of prior MI or significant structural heart disease, including HFrEF (LVEF 40% or less)
-Amiodarone, dronedarone, dofetilide
-Sotalol
What is dronedarone contraindicated in?
NYHA class III or IV or recent decompensated HF
When would you adjust dofetilide dose?
Adjust 2-3 hours after first dose - check QTc interval
How do you adjust dofetilide dose if QTc increases by 15% or less?
Continue current dose
How do you adjust dofetilide dose if QTc increases by more than 15% or to greater than 500 ms?
Decrease dose by 50%
How do you adjust dofetilide dose if QTc is over 500 ms after the second dose?
Discontinue dofetilide
How do you initiate sotalol therapy?
Place patient on continuous ECG monitoring and proceed only if QTc is 450 ms or less
How do you dose sotalol if the patient has CrCl over 60?
80 mg twice daily
How do you dose sotalol if the patient has CrCl 40-60?
80 mg once daily
When should you check QTc interval after each sotalol/dofetilide dose?
2-4 hours
How do you dose sotalol if the patient has QTc less than 500 ms after 3 days?
-Patient can be discharged
-Dose can be increased to 120 mg twice daily and patient can be followed for 3 days on this dose
How do you dose sotalol if the patient has QTc of 500 ms or more?
Discontinue sotalol
When should catheter ablation be used for rhythm control in atrial fibrillation?
In patients whom antiarrhythmic drugs have been ineffective, contraindicated, not tolerated or not preferred
When can catheter ablation be used as first-line therapy?
In selected patients (generally younger and with fewer comorbidities) with symptomatic paroxysmal atrial fibrillation
What is supraventricular tachycardia?
-Regular rhythm
-Narrow QRS complex
-Heart rate 110 - >250 beats per minute
-Spontaneous initiation and termination
-Prevalence: 225 per 100,000
-Incidence: 35 cases per 100,000 persons per year
What is paroxysmal SVT?
-A subset of SVT
-Intermittent episodes of SVT
-Episodes start suddenly and spontaneously, last for minutes to hours, and terminate suddenly and spontaneously
Risk factors
-Women have 2x higher risk than men
-Age over 65 years have a 5x greater risk than younger people
-Often occurs in individuals with no underlying CVD
Symptoms of supraventricular tachycardia
-“Neck-pounding”
-Palpitations
-Dizziness
-Weakness
-Lightheadedness
-Near-syncope
-Syncope
-Polyuria
How do you treat patients to terminate hemodynamically stable SVT?
-Vagal maneuvers and/or IV adenosine
-If ineffective or not feasible then give IV beta-blockers or IV diltiazem or IV verapamil
-If ineffective or not feasible then give synchronized DCC
How do you treat patients for the prevention of recurrence of SVT when the patient is asymptomatic or minimally symptomatic?
Clinical follow-up without treatment
How do you treat patients for the prevention of recurrence of SVT when the patient is symptomatic and is a candidate for catheter ablation?
Catheter ablation
How do you treat patients for the prevention of recurrence of SVT when the patient is symptomatic, is not a candidate for catheter ablation, and does not have HFrEF?
-Beta-blockers, diltiazem, verapamil
-Flecainide, propafenone (CI in CAD)
-Catheter ablation if all else fails
How do you treat patients for the prevention of recurrence of SVT when the patient is symptomatic, is not a candidate for catheter ablation, and has HFrEF (LVEF less than 40%)?
-Amiodarone, digoxin, dofetilide, sotalol
-Catheter ablation if all else fails
What are the different types of ventricular arrhythmias?
-Premature ventricular complexes (PVCs)
-Ventricular tachycardia
-Ventricular fibrillation
What are premature ventricular complexes?
-Wide QRS complexes
-Low prevalence in healthy population
-Prevalence increases with advancing age
What are simple premature ventricular complexes?
Isolated single PVCs
What are paired premature ventricular complexes?
Couplets, two in a row
What are bigeminy PVCs?
Every second beat
What are trigeminy PVCs?
Every third beat
What are quadrigeminy PVCs?
Every fourth beat
Mechanism of PVCs
Increased automaticity of ventricular muscle cells/Purkinje fibers
Risk factors for PVC
-Ischemic heart disease
-Myocardial infarction
-Anemia
-Hypoxia
-Cardiac surgery
Symptoms of PVC
-Usually asymptomatic
-Frequent/repetitive PVCs can result in palpitations, dizziness, lightheadedness
How to treat asymptomatic PVCs
Asymptomatic PVCs should not be treated
How to treat symptomatic PVCs in patients who do not have CAD or HF
-Beta-blockers, diltiazem, or verapamil
-If unresponsive - antiarrhythmic drugs
How to treat frequent symptomatic PVCs (>15% of beats) in patients who are unresponsive to beta-blockers, CCBs or antiarrhythmic drugs
Catheter ablation
How to treat symptomatic PVCs in patients who have CAD
-Beta-blockers, diltiazem, or verapamil
-If unresponsive - antiarrhythmic drugs
How to treat symptomatic PVCs in patients who have HF
Beta-blockers
What is ventricular tachycardia?
-Regular rhythm
-Wide QRS complexes
-Defined as a series of 3 or more consecutive PVCs at a rate of over 100 bpm
Types of ventricular tachycardia
-Nonsustained
-Sustained
What is nonsustained ventricular tachycardia?
3 or more consecutive VPDs, terminates spontaneously
What is sustained ventricular tachycardia?
-VT lasting more than 30 seconds
-Requires termination because of hemodynamic instability in less than 30 seconds
What is sustained monomorphic VT in patients with no structural heart disease known as?
Idiopathic VT
What is idiopathic VT sometimes responsive to?
Verapamil
Ventricular tachycardia mechanism
-Increased ventricular automaticity
-Reentry
Risk factors of ventricular tachycardia
-Coronary artery disease
-Myocardial infarction
-HFrEF
-Electrolyte abnormalities (hypokalemia, hypomagnesemia)
-Flecainide
-Propafenone
-Digoxin
Symptoms of ventricular tachycardia
-May be asymptomatic (nonsustained VT)
-Palpitations
-Hypotension
-Dizziness
-Lightheadedness
-Syncope
-Angina
What is the class 1 treatment to terminate VT in a patient with structural heart disease?
DCC
What is the class 2a treatment to terminate VT in a patient with structural heart disease?
IV procainamide
What is the class 2b treatment to terminate VT in a patient with structural heart disease?
IV amiodarone or IV sotalol
What do you do when VT is terminated after the first treatment in a patient with structural heart disease?
Give therapy to prevent recurrence guided by underlying heart disease
What do you do when VT is not terminated after the first treatment in a patient with structural heart disease?
DCC
How do you treat verapamil-sensitive VT in a patient who does not have structural heart disease?
Verapamil
How do you treat outflow tract VT in a patient who does not have structural heart disease?
beta-blocker
What do you do when VT is terminated after the first treatment in a patient without structural heart disease?
Therapy to prevent recurrence
What do you do when VT is not terminated after the first treatment in a patient without structural heart disease?
DCC
What therapy is used to prevent recurrence of VT and sudden cardiac death?
-Implantable cardioverter-defibrillator
-Amiodarone
-Sotalol
-Catheter ablation
What is ventricular fibrillation
-Irregular, disorganized, chaotic electrical activity
-No recognizable QRS complexes
Risk factors of ventricular fibrillation
-Myocardial infarction
-HFrEF
-Coronary artery disease
Symptoms of ventricular fibrillation
Syndrome of sudden cardiac death
How do you terminate VT (or VT with no pulse)
-CPR for 2 minutes and obtain IV/IO access
-Defibrillation shock
-CPR for 2 minutes
-Epinephrine 1 mg IV/IO
-Defibrillation shock
-CPR for 2 minutes
-Amiodarone 300 mg IV/IO or lidocaine 1-1.5 mg/kg IV/IO
-After first dose of amio/lidocaine, every subsequent dose should be halved
-CPR should be occurring throughout the entire duration
-Continue pattern of defibrillation, shock, then CPR for 2 minutes, then epinephrine 1 mg IV every 3-5 minutes until patient is resuscitated or resuscitation attempt is terminated
