tachyarrhythmias Flashcards
(43 cards)
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
