Nagelhout - Antiarrhythmics - Exam 2 Flashcards
In general, drugs that _ the heart are anti-arrhythmic
depress
T/F People experience arrhythmias more under GA than awake
false.
less under anesthesia than awake
A drug that _ the heart is typically arrhythmogenic
stimulates
Most successful way to treat arrhythmias:
ablations
Class I Antiarrhythmics
Na Channel blockers!! -slow phase 0 depolarization, acts mainly on ventricles
IA-after-prolong AP
-procainamide, quinidine, disopyramide
IB-before-shorten AP repolarization
-lidocaine, mexilitine, phenytoin
IC-depression
-flecainide, propafenide
Class II Antiarrhythmics
Beta Blockers! - inhibit phase 4 depolarization
-esmolol, propranolol, metoprolol, timolol, atenolol, nadolo, carvedilol
Class III Antiarrhythmics
K Channel blockers! - prolongs repolarization
-AMIO, sotalol, ibutilide, dofetilide
Class IV Antiarrhythmics
Ca Channel Blockers! - acts mainly on Atria/ SA/AV node
-Verapamil, Diltiazem
Class Other/V Antiarrhythmics
-Adenosine, Digoxin, Atropine
In the heart, Ca++ channels leak in which areas mainly:
atria, SA + AV node
In the heart, Na+ channels leak in which areas mainly:
ventricles
Which class of antiarrhythmics have a LA effect on heart?
Class I -Na channel blockers
Which antiarrhtyhmic class is preferrable for Afib normally
Class IV, CCB
Most common cause of arrhythmias during anesthesia:
pt not deep enough
Arrhythmias
-general factors
-age
-LA enlargement
-high adrenergic state
-hypoxia
-hypovolemia
-reperfusion arrhythmia
-HTN
-pulm disease
-beta blocker withdraw
Arrhythmias
-structural factros
-CAD
-MI
-valve/congenital heart disease
-cardiomyopathy
-SSS or long QT syndrome
-WPW
-secondary heart disease
-brady
-AV HB
Arrhythmia
-transient imbalances/factors
-lytes
-stress
-laryngoscopy, hypoxia, hypoxemia
-device malfunctions
-diagnostic interventions (interrogations)
-surgical stim
-central venous caths
4 main cardiac risk factors:
-Unstable coronary syndrome
-Decomp. HF
-Significant Arrhythmias
-Severe valve disease
Major cardiac risks
-Unstable Coronary Syndrome
-acute or recent (<6mo) MI
-severe/unstable angina
Major cardiac risks:
-Decomp HF
-NYHA Class IV, new-onset or worsening
Major cardiac risks:
-Significant Arrhythmias
-high grade AV blk
-2’2 blk
-3’ AV Blk
-symptomatic vent. arrhythmias
-supraventricular arrhythmias (afib w uncontrolled rate>100)
-symptomatic brady
-newly recognized VT
Major cardiac risks:
-Severe Valve Disease
-Severe AS w/ mean pressure grad >40mmHg, aortic valve area<1cm^2, or symptomatic
-symptomatic Mitral stenosis, exertional presyncope, dyspnea on exertion, HF
Scariest cardiac risk factor to be on edge about:
HF
-#1 risk for mortality/morbidity for anesthesia
Intermediate cardiac risk factors
-mild angina
-previous MI or pathologic Q waves, but doing ok
-compensated/previous HF
-IDDM
-renal insufficiency
Minor cardiac risk factors:
-age
-abnormal EKG (LBBB, ST abnormalities, LVH)
-not sinus rhythm -but stable
-low METS
-CVA hx
-uncontrolled systemic HTN
Major Surgical Risk for Heart:
->5% risk
-major vasc surgery
-emergent major surgery
-long cases with large fluid shifts or blood loss
Intermediate Surgical Risks for Heart
-1-5% risk
-carotid endarterectomy
-endovasc. AAA repair
-H+N cases
-Intraperitoneal/Intraabdominal cases
-Ortho
-Prostate surgery
Minor Surgical Risks for Heart:
-<1%
-superficial case
-cataracts
-breast
-ambulatory surgery
Effective preventative cardiac measures for surgery:
-Beta blockers (debatable)
-Statins
-Alpha2 blockers
-CABG if they desperately need it (4-5x)
-PAC (not common now)
-EPIDURAL ANESTHESIA
-normothermia intraoperatively!
Afib/ A Flutter
-acute mgmt
-Rate control IV verapamil
-beta blocker or digoxin
-DC cardiovert
OR
-procainamide or amio
Afib/ A flutter
-chronic tx
rate control
-verapamil
-diltiazem
-Bblocker
-digoxin
-amio
-sotalol
Other supraventricular arrhythmia
-acute mgmt
-IV adenosine, verapamil, diltiazem
-esmolol, Bblocker, digoxin
-we won’t terminate this rhythm unless its pathway is thru the AV node, adenosine won’t be effective
Other supraventricular arrhythmia
-chronic tx
Bblocker, verapamil, diltiazem, flecainide, amio, sotalol, dig
Typically, for arrhythmia tx
-atria:
-vent:
A: CCB
V: Amio
If pt develops acute, unexpected arrhythmia during case, what is our goal?
-Try to treat but focus on pt stabilization
-get thru case
-get to PACU
-CONSULT CARDS, let the experts handle it
PVC or nonsustained VT
-acute mgmt
Asymptomatic=nothing
Symptomatic- BBlocker
Sustained VT
-acute mgmt
Amio
-or procainamide/ Lidocaine
Ventricular Fibrillation
-acute mgmt
Amio/ Defib
-lidocaine/procainamide
-prevent recurrence
Cardiac Glycoside-induced VT (Dig-tox!)
-acute mgmt
Digoxin-immune Fab / Digibind
Drug-induced Torsades
-acute mgmt
IV Mag sulfate
-pacing, isoprel, keep K ~4-5
Bradycardia
-acute mgmt
Atropine
Tachycardia
-acute mgmt
BBlocker
Ok to give Adenosine during case?
No, not safe to “stop” heart
-just give Bblocker or CCB
3 (4) pts to avoid BBlockers in:
-Diabetics (low BG + masks s/s)
-Asthmatics (bronchoconstriction)
-Claudication
-HB (duh)
Why avoid adenosine in asthmatics?
in large doses can cause BSpasm
Adenosine interact with
Methylxanthines (caffeine/ theophylline) - antagonize it
Which beta blocker is ideal for asthmatics? (esmolol, labetalol, metoprolol)
Metoprolol
-B1 selective!
Esmolol is metabolized by :
RBCs
-no renal/liver involvement
Esmolol CI:
HF, severe brady, HB >1’, cardiogenic shock
4 main drugs Esmolol interacts with:
-Digoxin (increase blood levels)
-Sux (prolongs)
-Warfarin
-Catecholamine depleting drugs
