Arrhythmia management Flashcards
What are some factors that can lead to AFib?
-electrolyte derangements (hypokalemia hypomagnesemia)
-acidosis
-fever
-sepsis
-volume overload
-thyrotoxicosis
-withdrawal
What class of antiarrhythmic medication can be used for AFib rate control?
-class 2 (cardiac beta blocker, metoprolol)
-class 4 (L-type Ca blocker, diltiazem)
What class of antiarrhythmic medication can be used to convert out of AFib?
class 3 (K channel blocker, amiodarone)
What antiarrhythmic drug can be used to help distinguish between SVT and Vtach?
adenosine- temporarily blocks AV node so slows SVTs but doesn’t effect VTach
What clinical factors can lead to VT?
-hypokalemia
-acidosis
-catecholamine surge
-thyrotoxicosis
-ischemia
What is usually the cause of polymorphic VT?
-myocardial ischemia
For the rare patient with stable vitals in VT what antiarrhythmic drugs can be used?
-class 1 (fast Na channel blocker, procainamide)
-class 3 (K channel blocker, amiodarone)
Which arrhythmia is the leading cause of sudden cardiac arrest?
VF
Haloperidol is associated with which dysrhythmia?
VT
Lidocaine and other class 1b antiarrhythmics are associated with which dysrhythmia?
VT
Dobutamine is associated with which dysrhythmias?
arterial and ventricular tachycardias
Fluoroquinolones are associated with which dysrhythmia?
Torsades de pointes
Micafungin is associated with which dysrhythmias?
arterial and ventricular tachycardia
Ondansetron is associated with which dysrhythmia?
Torsades de pointes
What are some clinical factors that can lead to new first degree AV block?
-hypokalemia
-myocardial ischemia
-myocarditis
-medication side effects
Which type of AV block is at risk for progression and cardiac death?
Mobitz 2- nonconducted p-waves at regular intervals
What percent of annual ACS cases are STEMIs vs. NSTEMI?
30% STEMI
70% NSTEMI
What is the 90-day mortality of a patient who had preoperative MI?
30%
What ECG changes are concerning for STEMI?
-ST elevation in 2 contiguous leads
-new LBBB
-anterior ST depression suggesting a posterior MI
What ECG changes suggest NSTEMI?
new ST depression or a horizontal or downsloping ST
What ECG changes can be suggestive of a MI or a PE?
transient ST changes (< 0.5mm) and/or T wave inversion (> 2mm)
What biomarker is the most sensitive and specific for ACS?
troponins
What can cause a chronic troponin elevation?
LV hypertrophy and ventricular dilation
What biomarker should be used to detect new or worsening heart failure?
BNP
What is the goal time period from medical contact to cath lab balloon time for STEMI patients?
90 min
What are recommended initial treatments for STEMIs?
-ASA 162mg or 325mg
-unfractionated heparin or bivalirudin with ACT 200-250s
What is the MOA of clopidogrel or ticagrelor?
P2Y12 inhibitor
Clopidogrel or ticagrelor therapy should be held until what is determined in the cath lab?
coronary anatomy
-if anatomy is not amenable to PCI an emergent CABG is needed and prior P2Y12 inhibitor administration could lead to significant hemorrhage
Overall basic treatment for NSTEMI patients?
-continuous cardiac monitoring
-antianginal
-antiplatelet
-anticoagulation
What antiplatelet therapy should be started for NSTEMIs?
start ASAP
-nonenteric coated chewable 162-325mg followed by maintenance of 81-325mg
-if can’t take ASA us clopidogrel (only 300mg if unsure if pt will need CABG)
-for 12 months post NSTEMI everyone who can should get ASA and P2Y12 inhibitor
What anticoagulation therapy should be started for NSTEMIs?
-enoxaparin
-bivalirudin
-fondaparinux
-unfractionated heparin
What antianginal therapy should be started for NSTEMIs?
-up to 3 doses of sublingual nitroglycerin
-after that switch to IV is still having CP
How long after phosphodiesterase inhibitors before nitrates can be given?
-sildenafil and varsenafil = 24h
-tadalafil = 48h
Beta-blocker therapy should be started in all NSTEMI patients except for those with what?
-heart failure
-low CO state
-increased risk for cardiogenic shock (>70yo HR >110 SBP <120)
-PR interval > 0.24s
-2nd or 3rd degree heart block without a pacemaker
-active asthma or reactive airway disease
Where is atrial activity beat seen on EKG?
P waves in inferior leads (II, III, aVF)
A QRS complex that follows a p-wave in less than what amount of time means they’re not associated?
< 0.1s
Each small box on an EKG is how much time?
0.04s
What can provoke or exacerbate arrhythmias?
-eletrolye disturbances
-mechanical irritation of the heart
-drugs
-ischemia
What lab abnormalities can aggravate arrhythmic tendencies?
-hypo/hyperkalemia
-hypomagnesium
-alkalosis
-anemia
-hypoxemia
What stimuli can provoke arrhythmias that cease once the stimuli is removed?
-intracardiac catheters
-pacemaker malfunctions
-digitalis
-theophylline
-sympathomimetic agents (catecholamines, cocaine)
What drugs can be given in a HD stable patient with a new wide-complex tachycardia of unknown ventricular or atrial origin?
-lidocaine: if it fails to respond this supports a SVT rhythm
-procainamide or amiodarone: will help both SVT and VT but won’t help diagnosis which one
-adenosine: transiently blocks AV node so treats SVT but not VT
What drugs should not be given in a HD stable patient with a new wide-complex tachycardia of unknown ventricular or atrial origin?
Verapamil or diltiazem
-cardiodepressants and vasodilating so lower BP
-can accelerate some SVTs
What is the main treatment of sinus tach?
Treat the underlying cause
Why should beta-blockers be used with caution in patients with obstructive lung disease?
Can precipitate bronchospasm
Which patient populations should beta-blockers be used with caution?
-hypotensive
-acute infarction
-chronic CHF
What is the response of VT to vagal manuevers?
Unresponsive
What is the response of AFib to vagal manuevers?
Transient slowing of ventricular rate
What is the response of AFlutter to vagal manuevers?
Unmasking of underlying flutter waves
What disease processes is multifocal atrial tachycardia most often associated with?
-COPD
-metabolic derangements
In patients with COPD what are risk factors to developing multifocal atrial tachycardia?
-hypoxemia
-hypercapnia
-acidosis
-alkalosis
-pulm HTN
-beta blockers
What is the prevalence of AFib in >70yo?
5%
At what rate does the atria depolarize in AFib? The AV node?
-up to 400/min
-rarely >180-200 per min
What are 3 prominent risks due to AFib?
-hypoperfusion (rapid ventricular rate)
-embolism (clot formation in non-contractile atrium)
-cardiomyopathy (chronic tachycardia)
In AFib what does ventricular rates >200bpm suggest? If rate is <60bpm?
-accelerated conduction due to vagolytic meds (type 1a antiarrhythmic) or accelerated conduction pathway
-drug effect (digitalis beta-blocker Ca-channel blocker) or conduction system disease
An atrial diameter above what signifies conversion from AFib to NSR is unlikely?
4cm
For HD stable AFib who need rate control what is the preferred choice for good ventricular function? Impaired ventricular function?
-Ca channel blockers or beta-blockers
-digoxin
What is the best medication to use for rate control and rhythm conversion in AFib with a sudpected nodal bypass tract?
Amiodarone
What medications can be used for AFib rhythm conversion?
-amiodarone: highly effective but 25% get hypotension and chemical phlebitis is common; don’t give with digoxin (can get significant bradycardia)
-procainamide: effective in 40% poor long term tolerance
-ibutilide: only parental can can as proarrhythmic
What is the annual stroke rate in patients with AFib but without mitral valve disease or HF? With those comorbidities?
-1%
-6%
Where does depolarization usually occur in Aflutter?
Low in the right atrium
What are frequent causes of Aflutter?
-PNA
-exacerbation of COPD
-post thoracic surgery
What are common atrial rates in Aflutter? Ventricular rate?
-260-340bpm
-½ to ¼ of the atrial rate
What is the most effective way to get rhythm conversion in Aflutter?
Electric cardioversion
What does sinus bradycardia in a patient with recent posterior or inferior MI signify?
Ischemia of nodal tissue
When treating sinus bradycardia what medications can be used and their doses?
-atropine 0.5 - 1mg q3 - 5min
-dopamine 5 - 20mcg/kg/min
-epinephrine 2 - 10mcg/min
-isoproterenol 2 - 10mcg/min
What can a new 1st degree AV block signify?
Drug toxicity or progressive conduction system disease
When is pacing indicated for 1st degree AVB?
When accompanied by RBBB and L anterior fasicular block in the setting of myocardial ischemia or infection
What is characteristic of a mobitz 1 AVB?
Weneckebach
-progressive prolongation of PR interval with eventual failure to transmit an atrial impulse
-RR intervals progressively shorten
-often accompanies inferior MI
What is frequently the cause of mobitz 1?
-digitalis toxicity
-intrinsic heart disease
What is the significance of mobitz 1 after an anterior infarct?
Suggests extensive myocardial damage and a guarded prognosis
What is characteristic of a mobitz 2 AVB?
-constant PR intervals but inconsistent conduction of atrial depolarization
-originates below the level of the AV node in the His-Purkinje system
-often progresses to symptomatic type 3 AVB
-generally requires transvenous pacing
What are potential causes of 3rd degree AVB?
-degenerative myocardial disease
-myocarditis
-MI
-infiltration of conducting system
-toxic concentration of digitalis
What are the treatments for symptomatic AFib or AFlutter?
-cardioversion
-amiodarone
-digoxin
-esmolol
-diltiazem
-procainamide
-prevent recurrence with Ca channel blockers or beta blockers
What are the treatments for symptomatic bradycardia?
-correct underlying cause
-atropine/oxygen
-isoproterenol/pacing
-catecholamine infusion
What are the treatments for symptomatic PVCs?
-lidocaine
-procainamide
What are the treatments for monomorphic VT?
-cardioversion
-lidocaine
-procainamide
-sotalol
-amiodarone
What are the treatments for polymorphic VT?
-cardioversion
-isoproterenol
-Mg
-pacing
What are the treatments for VF?
-cardioversion
-lidocaine
What is the MOA and examples of class 1a antiarrhythmic drugs?
Depresses conduction and accelerates repolarization
-procainamide
-quinidine
-disopyramide
What is the MOA and examples of class 1b antiarrhythmic drugs?
Depresses conduction and accelerates repolarization
-lidocaine
-phenytoin
-tocainide
What is the MOA and examples of class 1c antiarrhythmic drugs?
Markedly reduces conduction
-encainide
-flecainide
What is the MOA and examples of class 2 antiarrhythmic drugs?
Beta blockers
-metoprolol
-propranolol
-esmolol
What is the MOA and examples of class 3 antiarrhythmic drugs?
Prolongs repolarization
-amiodarone
-sotalol
-bretylium
What is the MOA and examples of class 4 antiarrhythmic drugs?
Slow Ca channel blockers, decreases automaticity, blocks nodal conduction
-verapamil
-diltiazem
-nicardipine
What is the cardiac arrest, critical ventricular arrhythmia, and less critical ventricular arrhythmia dosing of amiodarone?
-300mg IV push
-150mg IV over 15min
-1mg/min loading dose over 6hrs then 0.5mg/min for another 540mg
What are the most common side effects of amiodarone? The less common more concerning SE?
-GI and neurological
-pulmonary toxicity (esp. with preexisting lung fibrosis), liver injury, thyroid dysfunction
Amiodarone can raise plasma levels of which drugs?
-digoxin
-quinidine
-procainamide
-flecainide
-potentiates anticoagulant effect of warfarin
What is the MOA of propranolol?
-nonspecific beta-blocker
-negative inotrope and chronotrope
-decreases rate of SA node and conduction velocity
Which are the cardioselective beta-blockers?
-metoprolol
-carvedilol
Which beta-blocker ultrashort acting making it good for SVT management without depressing myocardial function?
Esmolol
What are Ca channel blockers good for?
-converting AVNRT and AVRT to NSR
-slows ventricular response of AFib and flutter
What are two of the more serious complications of verapamil?
-can cause high degree AVB or asystole
-decreases contractility and vasodilation to point of hypotension (esp in elderly and volume deplete)
What can be given prior to verapamil for to avoid extreme hypertension?
IV Ca gluconate
What is the major use of digitalis?
Slow AV conduction in AFib and flutter
What is the typical Afib/flutter dosing of digitalis?
0.125 - 0.25mg IV q4-6hr
What does lidocaine do as type 1b antiarrhythmic?
Suppresses ventricular irritability but little effect on SVT
In what scenario is lidocaine good for?
Myocardial ischemia with VT
What attribute of lidocaine causes it to require several loading doses to achieve and maintain effect?
It distributes into multiple compartments
-also means it does not need a taper to stop
What drug class can be exacerbated by lidocaine?
Neuromuscular effects of paralytics
What can procainamide be used for?
SVT and ventricular arrhythmias
-type 1a antiarrhythmic
What consideration must be made when procainamide is to be used in patient with AFib/flutter?
Controlling conduction rate with beta-blockers Ca channel blockers or digitalis
-alone it can accelerate ventricular rate
What is the dosing of procainamide?
-loading 100mg q5min for total of 1gm
-infusion 2 - 6mg/min
What arrhythmia can procainamide precipitate?
Torsades de pointes
What syndrome can be induced in prolonged periods of procainamide use?
Lupus-like syndrome
-in as many as 20%
-50% develop positive ANA
Which analgesic drug class is contraindicated in pts w/ a STEMI due to increased mortality?
NSAIDS
How long after onset of symptoms does it take for the majority of infarct to occur in a MI? For the infarct to be complete?
-4hrs
-6hrs
What is the medication recommendation for pts within 1yr of coronary stent placement who need urgent noncardiac surgery on ASA and plavix?
stop plavix for 5 days but continue ASA
At what CHA2DS2-VASc does a pt need perioperative anticoagulation bridging?
4 or greater
What are the components of CHA2DS2-VASc?
-CHF
-HTN
-age >75 (2 points)
-DM
-stroke (CVA/TIA/TE)
-vascular disease
-age 65-74 (1 point)
-sex category (female gets 1 point)
What is the most common location of a spontaneous ectopic foci in paroxysmal AFib?
in nearly 90% of pts the point of origin is in the pulmonary veins
What type of MI would ST elevations in leads 2, 3, aVF be concerning for?
inferior STEMI
What are the components of the TIMI (thrombolysis in myocardial infarction) score for periop risk stratification?
-age >/= 65
->/= 3 risk factor for CAD
-aspirin use in last 7 days
-recent severe symptoms of angina (>/= 2 in last 24hrs)
-elevated cardiac markers
-ST deviation >/= 5mm
-prior coronary artery stenosis 50%
-measures the risk of death, new/recurrent MI, or need for urgent revascularization w/in 14 days
-each component is worth 1 point, >/= 5 is high risk
For pts w/ drug eluding coronary stents what is the ideal time frame for them to use dual antiplatelet therapy?
1 year
-studies show that for at least 6 months they have an increased risk of stent thrombosis
-stop clopidogrel (or other P2Y12 inhibitor) and continue ASA
How long should surgery be delayed after the placement of coronary stents?
-30 days after bare metal stent
-6 months after drug eluding stent
What medication should be used to treat Wolfe-Parkinson-White? Which should be avoided?
-procainamide (increases refractory period and decreases accessory pathway conduction)
-agents that slow AV node (adenosine, amiodarone, digoxin, verapamil) cause an increased ventricular rate d/t more atrial activity passing through the accessory pathway –> VT
