Laflamme- Chapter 6 (Arrhythmias) Flashcards
What are the three Arrhythmic mechanisms?
1) Abnormal Automaticity: Increase phase 4 diastolic depolarization
2) Reentry
3) Triggered activity:
- Early Afterdepolarization: Torsades
- Delayed Afterdepolarization: Digoxin posioning, Idiopathic VT, CPVT
What is RP interval cut off?
90 msec
What is definition of POTS?
Orthostatic tolerance with significant increase of HR in the first 10 mins after standing (HR > 120 or increase by 30 bpm)
What is heart block rate in AVNRT ablation? Recurrence rate?
- Heart block: 1%
- Recurrence: 5%
What does left lateral pathway look like on ECG?
+V1, AVF
Left septal/Posterior pathway on ECG?
+V1, AVF
Right Septal pathway on ECG?
-V1, +AVL
Anterior or right lateral pathway on ECG?
- V1, + aVF, + aVL
What are the two properties of a malignant accessory pathway?
- Refractory period < 250 msec
- Able to maintain effective anterograde conduction of possible AF
What is the Mahaim pathway? What does the associated arrhyhthmia look like?
- Accessory pathway in the lateral wall of the RV or to the right branch
- Associated arrhythmia is antidromic AVRT with LBBB
What can you consider in a young patient with Lone AF?
EP Study: To eliminate other SVT degenerating into AFib (can be target for ablation)
Resting and walking HR for Afib rate control?
- Resting < 100 bpm
- Walking < 110 bpm
Efficacy of Class 1C, Sotalol and Amio for Afib rhythm control at one year? What trial?
30%, 50%, 70%
CTAF trial
Name 8 complications of AFib ablation? What is total quoted rate?
- 5%
- Vascular complication, Cardiac perforation/Tamponade, TE, PV stenosis, Atrio esophageal fistula, Phrenic nerve palsy, Atypical flutter, Death
Name all 8 HASBLED risk factors?
HTN, Abnormal LE (ALT > 3x ULN), Cr > 200, Stroke, Bleeding history, Labile INR, Elderly > 65, Drugs associated with bleeding or Alcohol
How does Dabigatran work?
-Direct thrombin inhibitor
When to dose reduce Dabigatran?
- > 75 y.o -> 110 mg BID
How to renally dose Rivaroxaban?
15mg if 15-50 crcl
How to renally dose Edoxaban?
30mg daily if CrCl 15-50
What is the reversal agent for Dabigatran?
-Idarucizumab
How to switch from INR to DOAC?
- If INR < 2 -> switch right away
- If INR 2-3 -> start DOAC following day
How to switch from LMWH to DOAC? What about visa versa?
-Next schedule dose (for both)
How to switch from DOAC to Warfarin?
Stop doac when INR > 2.0
When to stop Apix, Riva and Dabigatran prior to surgery with high bleeding risk?
- Apixaban and Rivaroxaban: 48h prior
- Dabigatran: >48h if CrCl > 80, >72h if CrCl > 50, >96h if CrCl >30
What did the ASSERT Trial show?
Detection of SCAF (HR > 190 and duration > 6min) associated with increased TE risk
Espisodes > 17.7 significantly increased stroke risk (5x)
What did the TRENDS trial show?
SCAF > 5.5h associated with increased TE risk
What are the 4 brugada criteria?
- Structural heart disease
- Precordial concordance, absence of RS complexes
- RS interval > 100msec in 1 of more precordial lead
- AV dissociation
- Morphological criteria V1-V2 and V6
What are the ECG criteria of the Schwartz score?
- QTC > 480 (3), QTC > 460 (2), > 450 (males, 1)
- Tdp (2)
- Alternating T wave (1)
- Notched T wave on 3 leads (1)
What are two clinical criteria of Schwartz score?
- Syncope on exercise
- Syncope without stress
What are other components of Schwartz score?
- QTc ( >480, 460-470, 450)
- TDP
- T wave alternans
- Notched T wave in 3 leads
- Low heart rate for age
- Syncope (With stress or without)
- Congenital deafness
- Family members with LQTs
- Unexplained SCD below age 30
What is Gene mutation in LQT1, LQT2 and 3
- KCNQ1 (Loss of function)
- KCNH2 (Loss of function)
- SCN5a (Gain of function)
What are triggers for LQT1, 2 and 3?
1) Exercise, swimming, stress
2) Alarms, noise
3) Rest or sleep
Describe ECG morophology in LQT1 2 and 3
- Wide based T wave
- Notched or biphasic T wave
- Long isoelectric line with narrow based T wave
What are three RF for SCD in LQT?
- QTc > 500
- Complex ventricular arrhythmia
- Jervell and Lange Nielsen
What is definition of Carotid Sinus Massage?
-Ventricular asystole > 3s
What to monitor for quinidine?
- QRS increase
- Increase QTc
What are 5 adverse effects of Procainamide?
- drug induced Lupus
- Arrhyhtmogenic
- Torsades/increased QTc
- Negative inotropic agent with high doses
- Hypotension
3 adverse effects of Disopyramide?
- Negative inotrope
- Increased HR
- Vagal tone: Urinary retention, constipation
Amiodarone side effects and incidence?
- Pulmonary toxicity (2%): BOOP, COP, ARDS, Restriction
- GI toxicity (30%): Nausea, anorexia. AST, ALT 2x normal
- Hypothyroidism (20%): Continue amiodarone, supplement levothyroxine.
- Hyperthyroid (10%): Iodine load, destruction. Stop amiodarone, consider PTU.Methimazole or Prednisone
- Skin: Photosensitivity (75%), blue discoloration
- CNS: Ataxia
- Opthalmic: Halo, Opti meuropathy
- Cardiac: Bradycardia, increased defibrillation threshold.
11 drugs that interact with Amiodarone?
-Warfarin (need to reduce warfarin by 30-40% when starting Amiodarone)
- Digoxin
- Procainamide
- Disopyramide
- Diltiazem
- Flecaniade
- Phenytoin
- Cyclosporine
- Simvastatin
- Atorvastatin
What is monitoring schedule for Amiodarone?
- Baseline CXR
- TSH and free T3+T4 -> q6 months
- LFT -> q6 months
- CXR -> annual
- Optho exam
- Renal function
- ECG
3 studies that show minimal RV pacing improves results?
- MOST
- DAVID
- CTOPP
What happens if P-P interval is less than upper rate limit?
-Electronic wenckebach
What happens if PP interval is less than Total Atrial Refractory period?
- 2:1 block
- The frequency of 2:1 block = 60 000 / TARP
What is Hysteresis?
Lower rate limit drops after V sense event
What is Dynamic AV delay and what is it used for>
-AV delay decreases at higher HR (Decreased TARP), useful in patients with AV block and 2:1 block on exercise
What is mode switch?
-DDD more switches to DDI mode following atrial tachyarrhythmia to prevent tracking of this tachyarrhythmia
What is ventricular safety pacing ?
-Following atrial pacing -> early ventricular pacing in the presence of a ventricular event detected inside the cross-talk detection window (Prevents asystole in the presence of cross-talk or preventing R on T in the presence of PVC)
What are 8 causes of Capture failure?
Lead migration Exit block Myocardial infarction/CMO/Metabolic (increased threshold) Lead fracture Lead insulation defect Loose set screw Battery depletion Ineffective autocapture algorithm
What are 10 causes of undersensing?
- Inadequate intrinsic signal like PVC or APC
- Signal modification due to same as capture issues
- High sensitivity programming
- Lead migration
- Lead perforation
- Lead fracture
- Insulation defece
- Noise response
- Magnet
- Functional undersensing
What are 6 reasons for oversensing?
- Cross talk
- Far field oversensing (QRS detected as an atrial event)
- Oversensing of T wave
- Electromagnetic interference
- Myopotentials (unipolar only)
- Lead issues
What are 4 risk factors for Pacemaker mediated tachycardia?
- PVC with retrograde conduction
- Atrial capture failure
- Very long programmed AV delay
- Atrial oversensing or undersensing
What are three ways to prevent or terminate PMT?
- Prolong PVARP
- Extension of post-PVC PVARP
- 1 cycle without V pace following A sense during PMT
What is a class 1 and 4 class IIa indications for CRT?
- (1): LVEF M 35% NYHA II-IV + SR + LBBB + QRS > 150 msec
- IIa: As above but QRS 120-149msec, Anything other than LBBB > 150msec, BiV pacing after Afib AV ablation, LVEF <35% with VPace > 40% according to DAVID
What does ECG look like in CRT pacing?
- V1: Dominant R wave
- 1: Negative
What are indications for ICD for primary prevention? (3)
- LVEF < 35% II-III
- LVEF < 30% I
- LVEF < 40% + NSVT + Inducible VT
- 40 days post MI and > 3 months post revascularization
What are 7 reasons for Inappropriate ICD shock?
- Lead issues
- SVT
- T wave oversensing
- Atrial far field
- Myopotentials
- Electromagnetic interference
- R wave double counting
Indications to ablate an asymptomatic patient with WPW?
-High risk job that precludes employment (SVT 2015)
- High risk findings on EPS:
a) Induced Afib with R-R < 250 msec
b) presence of multiple pathways
c) refractory period < 240 msec
d) the ability to provoke sustained AVRT
e) the finding of AVRT precipitating Afib
