tachyarrhythmias Flashcards
Paroxysmal tacycardias - what are they? What causes them
Rapid heart beats that come and go in bursts, 3 or more > 100 bpm. Mostly due to reenrty
Causes of Tachyarrhytmias
1.) Reentry 2.) Abnormal Impulse formation (enhanced automaticity or triggered activity)
enhanced automaticity causes
due to increased catecholamines, electrolyte abnormality (hypkalemia), hypoxia/ischemia, mechanical stretch, drugs (digoxin)
Triggered activity
early or delayed depolarization due to increased intracellular calcium, digoxin toxiciy, accelerated idioventricular rhythm in acute myocardial infraction and exercise induced VT
Management of premature atrial contractions
Asymptomatic = no treatment needed treatment of annoying palpations = betablocker (takes away the feeling but you still have the premature beat)
management of AV junctional beats
no treatment needed
management of premature ventricular contractions in the absence of left ventricular dysfunction
no treatment needed
management of symptomatic premature ventricular contractions
Beta blokers
management of symptomatic premature ventricular contractions in presence of heart disease
treat underlying cause - Automatic Implantable Cardiac Defibrillator (AICD) or amiodarone if high risk
Antiarrythmics and premature ventricular contractions
antiarrhythmics increase mortality risk
Causes of sinus tachycardia
fever, hypovolemia, anxiety, exercise, thyrotoxicosi, hypoxia, hypotenion, CHF, acidosis
Most common abnormal arrhythmia
atrial fibrillation (60% of population at some point)
Paroxysmal Atrial fibrillation
duration less than 7 days and terminates spontaneously. Causes - emotional, post op, exercise, alcohol, vasovagal, hypoxia, metabolic)
Persistent Atrial Fibrillation
Duration greater than 7 days and would last indefinitely unless cardioverted. Causes- rheumatic fever, non rheumatic valve disease, hypertensive cardiovascular disease, chronic lung disease
Permanent Atrial fibrillation
duration greater than 7 days and sinus rhythm not possible
management of Paroxysmal A Fib
1.) focus on cause: HTN, hyperthyroidism, pericarditis, alcohol. 2.) Focus on prevention - class IC and/or Class III (amioderone most effective)
management of Persistent A Fib
1.) Termination with electric cardioversion 2.) Prevention - class IC or III drugs
management of Permanent A Fib
Rate control- Digoxin, B-Blocker, Verapamil, Diliazem, anticoagulants
what is the importance of giving and anticoagulant before cardioversion
prevents clot- blood is stagnant in the left atrium
when do we do cardioversion in A fib
when LA <4.5 cm ( if higher it wont sustain the cardioversion)
CHAD2 Score
1 point for each of the following: 1.) Congestive heart failure 2.) Hypertension 3.) Age >75 4.) Diabetes 5.) Stroke/transient ischemic attack - Score >2 = warfarin or diabigatran (Pradaxa) indicated
Heparin
fast action IV or injection for immediate anticoagulation - peaks after 2-4 hours
problems with warfarin
1.) food and drug interations 2.) Genetic variation in metabolism 3.) Narrow theraputic window 4.) slow onset of action (2-3 days to get a person anticoagulated)
Atrial remodeling
if sustained distention and stretch it remains that way and will become permanently enlarged
Is it better to control rate or rhythm in A Fib?
Overall better to control rate but in younger patients its probably better to try and control the rhythm
Atrial flutter causes
oragnic heart disease (pericarditis, respiratory failure, post op)
Management of Atrial flutter
1.) ALWAYS electrocardioversion - DO NOT RESPOND TO MEDS 2.) Ablation is curative
Prevention in Atrial Flutter
Prevention and rate control with beta blockers , calcium channel blockers and digoxin
Treatment of SVT
Vagal stimulation (carotid sinus massage), Adenosine (12 mg IV), pacing, ablation
SVT prevention
beta blockers, calium channel blockers and digoxin
causes of multifocal atrial tachycardia (MAT)
COPD, hypokalemia, or adrenergic drugs
MAT treatment
correct hypoxia and acidosis (a result of lung disease)
treatment of pre-excitation tachyarrythmias (ex: WPW)
localize and ablate tracts
Treatment of nonparoxysmal junctional tachycardia
DO NOT CARDIOVERT (can cause cardiac arrest) - override pacing and treat cause
causes of nonparoxysmal junctional tachycardia
dig toxicity, myocarditis, acute rheumatic fever, catecholamines
causes of ventricular tachycardia
ischemia, prior MI, cardiomyopathy, metabolic abnormality, drug toxicity, prolonged QT
treatment of ventricular tachycardia
cardioversion, beta blockers, verapamil, amiodarone, overdrive pacing (ex: thump on chest)
causes of Torsade de pointe
Hypokalemia, hypomagnesmia, and quinidine
treatment of Torsades de pointe
beta blockers, sympathectomy, magnesium pacing
managemet of accelerated idioventricular tachycardia
DO NOT TREAT THIS!!!
management of Ventricular flutter and fibrillation
defibrillation
Arrythmogenic RV Dysplasia
associated with plantopalmar kerotosis and wooly hair, right ventricle fibrofatty myocardial degeneration, syncope and sudden death
Which cases require Ablative therapy
WPW, A fib, A flutter, AV nodal SVT
