Arrhythmias Flashcards
Diagnosis
ECG
-Holter monitor is an ambulatory ECG
-Zio is a wireless patch monitor placed on chest and worn up to 14 days
Sx: dizzy, SOB, fatigue, chest pain, lightheadedness
Conduction Pathway
- SA node
- Right/left atrium
- AV node
- Bundle of His
- Right bundle branch/ventricle
- Left bundle branch/ventricle
- Pukinje fibers
Normal HR
60-100 BPM
SA Node
Pacemaker
-Cells here have automaticity (can initiate their own action potential)
Phases of Cardiac Action Potential
0/QRS: rapid ventricular depolarization (Na influx) - ventricular contraction
1: early rapid repolarization (Na ch close)
2: plateau (Ca influx, K efflux)
3/T: rapid ventricular repolarization (K efflux) - ventricular relaxation
4/P: resting (atrial depolarization)
Arrhythmia Causes
Cardiac: MI or ischemia
Non-cardiac: (TIED)
-Electrolyte imbalance (K/Mg/Na/Ca)
-Hyperthyroidism, infection (sympathetic)
-Illicit drugs and QTc prolonging drugs
Supraventricular vs Ventricular Arrhythmias
Supraventricular (originate above the AV node)
-AFIB, a flutter, sinus tachy, SVT
Ventricular (originate below the AV node)
-premature ventricular contractions (skip beat)
-VT (>100 BPM), VFIB, pulseless VT
QT Prolongation
-QT (QRS to T wave) interval is longer when heart rate is SLOWER
-QT interval used when =<60 BPM, if > 60 BPM then a corrected QT is used (QTc)
-QTc is prolonged when > 440-460 msec (more concerning when > 500)
-Prolonged QT is a risk factor for Torsades (TDP)
Drugs That Prolong QT
-Antiarrhythmics (Ia, Ic, III)
-Anti-infectives (hydroxychloroquine, azoles (except isa), macrolides, quinolones, lefamulin)
-Antidepressants (SSRI, tricyclic, mirtazapine, trazodone, venlafaxine)
-Antiemetics (5HT3 zofran, droperidol, metoclopramide, promethazine)
-Antipsychotics (1st-2nd gen, halo, chlorpromazine, thioridazine, ziprasidone)
-Oncology (leuprolide, nilotinin, arsenic)
AI DOPE
Before Starting Anti-Arrhythmics
-Check electrolytes and toxicology screen
-All have potential for proarrhythmias (new or worsening arrhythmia)
Classification of Anti-Arrhythmics
CLASS 1: Na
-1a: Disopyramide, Quinidine, Procainamide
-1b: Lidocaine, Mexiletine
-1c: Flecainide, Propafenone
CLASS 2: BB
CLASS 3: K
-Dronedarone, Dofetilide, Sotalol, Ibutilide, Amiodarone
CLASS 4: NON DHP CCB (DV)
Remember:
Double Quarter Pounder, Lettuce. Mayo, Fries Please! Because Dieting During Stress Is Always Very Difficult
Amiodarone: BBW/CI/AE
BBW: LIL TABS VPN
-Pulmonary toxicity
-Hepatotoxicity
-Life-threatening arr (pro-arr): continuous ECG monitoring
CI:
-Iodine hypersensitivity
-2-3 AV block, sick sinus, brady = syncope, cardiogenic shock
Warning:
-Hyper or hypo thyroidism (hypo more common - inhibits T4 to T3)
-Visual (optic neuropathy, corneal micro deposit)
-Photosensitivity (blue/gray skin coloration)
-Neurotoxicity (peripheral neuropathy)
AE: hypotension, bradycardia (may require lower infusion rate)
Avoid in pregnancy/breastfeeding
Mon: ECG, BP, HR, elec, LFTS, TSH/Free T4
IV Administration for Amiodarone
-Infusions > 2 hr require non-PVC container (polyolefin or glass) - PVC tubing is okay
-Premixed IV bags have longer stability, non-PVC (Nexterone comes in non-PVC, non-DEHP container)
-Use 0.22 micron filter
-CENTRAL line preferred
-INCOMPATIBLE with heparin (flush line with saline)
222 CPS NaH
Amiodarone: DDI
-Decrease digoxin 50%
-Decrease warfarin 30-50%
-Simvastatin max 20 mg/day
-Lovastatin max 40 mg/day
-Don’t use with sofosbuvir
Disopyramide (Norpace): AE
BBW:
-Reserve use for patients with life-threatening ventricular arrhythmias
Warning:
-AC effects (worsen BPH/UR, glaucoma, myasthenia gravis, dry mouth, constipation)
DIS SO SERIOUS CA
Quinidine: AE
Warning:
-Hemolysis risk (avoid in G6PD def - positive Coombs test)
AE:
-DILE, diarrhea, stomach cramping
-Cinchonism (tinnitus, hearing loss, BV, HA, delirium)
TAKE WITH FOOD or milk
Quine the CHF GoD
Procainamide: BBW/Notes
Active metabolite, N-acetyl procainamide (NAPA) is renally cleared
-Decrease dose when CrCl < 50
-Metabolism of procainamide to NAPA occurs by acetylation: slow acetylators are at drug accumulation and toxicity risk
Thera levels: 4-10 of pro, 15-25 of NAPA
BBW: agranulocytosis, + antinuclear ab (ANA) = DILE
PRO DA STAR #50
DOC for Wolff Parkinson White Syndrome
Procainamide
Lidocaine: CI
-Wolff-Parkinson-White syndrome
-Adam-Stokes syndrome
-Allergy to corn or amide anesthetics
IV lidocaine is used for refractory VT and cardiac arrest
ARA is WAC cus she LIEDO
Mexiletine: CI
Reserve for life-threatening ventricular arrhythmia
Abnormal liver function seen in CHF/ischemia
DRESS, blood dyscrasia
CI: cardiogenic shock
MEX in HI LBD little black dress
Flecainide: CI
-Cardio shock
-SHD (HF, MI)
-Use with ritonavir
-2/3 AVB
-Severe renal/hepatic impairment
SKRAL
Propafenone: CI
-Cardio shock
-SHD (HF, MI)
AE: taste disturbance (metallic), visual disturbance, NV, dizzy
ones with F remember shock/SHD CI
PROP the TV
Dronedarone: AE
CI in decompensated HF (Class 4 or any class with a recent hos) or permanent AF
CI with erythromycin, 3A4 inh and QT-pro drugs
Liver failure/lung toxicity like amio
BUT no iodine and little effect on thyroid
drone’s PD EQ is NOT IT
Dofetilide: BBW/Notes
Must be initiated with continuous ECG monitoring
-Assess CrCl for min 3 days
PREFERRED IN HEART FAILURE
DOFE the CHapter
