Vt And Scd

Front 1

Automatic Mechanisms

Back 1

PVCs
Myocardial Infarction / Ischemia
Acid based disturbances
electrolyte inbalances
hypoxemia

Front 2

Drugs and SCD - VT

Back 2

Beneficial:

a. Beta Blockers are inhibitors - Amiodarone

Harmful:

Flecanide, Sotalol, Proporol

Neutral: Dotefilide

Front 3

MTWA

Back 3

Measures T waves to 1 millionth of a volt

Micro T wave Alternans

SCD Heft: ICDs lowered the risk of SCD by 23 %

Front 4

SAECG

Back 4

Signal Averaged ECG

let's you see late action potentials

Front 5

Long QT Syndrome

Back 5

1. Congenital or
2. Result of drugs
3. Propensity for Syncope or Torsades do Points

Front 6

Reason for VT Ablation Failure

Back 6

Isthmus broader than lesion
Intramural or epicardial location is too deep
Mural Thrombos

Front 7

RVOT

Back 7

Right Ventricular Outflow Tract

deals with mapping

Front 8

Endocardial Activation Mapping

Back 8

Ablation catheter examines area around inside of RVOT. and can possibly determine foci of arrhythmia

Front 9

Non Contact Mapping

Back 9

Used for hemodynamic intolerance of VT and is a catheter which is an electrode array from left ventricle

Front 10

Pace Mapping

Back 10

pace in area arrhythmia originates. ECG same as during Tachycardia - same morphology

Front 11

What Causes VT

Back 11

Premature ventricular depolarization - PVC

Front 12

What causes VT to move to VF

Back 12

unknown mechanism

Front 13

VF Mechanisms

Back 13

1. Multiple wavelets
2. Mother rotors

Front 14

SCD in Young

Back 14

Greater than 1000 die each day in US
HCM - hypertrophic cardiomyopathy is most common

Front 15

Cardiac Arrest

Back 15

1. Electrical Phase - first 4 minutes and best treatment is immediate defib

2. Circulatory Phase - 4-10 minutes, delay defib 1-3 minutes and compress chest and ventilate

3. Metabolic Phase 10 minutes + = tissue injury

Front 16

Commotio Cordis

Back 16

Blunt force to chest:

1. Hockey, lacrosse, baseball
2. survival following collapse is 15% increasing to 46% when in V-fib when difibrillated

Front 17

Electrical Storm

Back 17

Occurrences of 3 or more episodes of VT / VF within 24 hours

6-7 shocks

Front 18

Precordial Thump

Back 18

thump to chest if external ICD not available

Front 19

Seasonal Variation of VT / VF

Back 19

1. Study show circadian variation patterns and season patterns

2. Wintertime peak with January having highest incidence

Front 20

Antiarrhythmic therapy

Back 20

1. Sotalol & Amiodarone - neutral affect on survival

2. Beta Blockers associate with better survival

Front 21

ICD Indications

Back 21

Class I - you get the device
a. Spontaneous sustained VT
b. Cardiac arrest due to VF or VT

Class II -
a. Cardiac arrest presumed to be due to VF when electrophysiologic testing precluded by medical conditions

b. Severe symptoms from sustained VT

c. Recurrent Syncope - undetermined origin

Class III

a. Incessant VT / VF because you would shock them all the time

Front 22

Mechanisms -Automatic

Back 22

1. PVCs
2. VT and VF associated with acute conditions: MI, Ischemia, Hypoxemia
3. Acid base disturbances

Need to treat the underlying cause and they are not inducible

Front 23

Mechanisms - Reentry

Back 23

Pre-entrant Ventricular Arrhythmias
Usually from underlying heart disease
Commonly ischemic heart disease

Can initiate with pacing and can terminate with pacing

Front 24

Mechanisms - Trigger

Back 24

1. Pause dependent
2. Catechol dependent
3. Features - both automatic and reentry
4. Both types develop polymorphic VT

Front 25

Two types of Activation Sequences that maintain fibrillation

Back 25

1. Wandering wavelets of activation due to multiple reentry

2. Stationary mother rotor - pebble in a pond

Front 26

ATP limitations for fast VT

Back 26

1. 70-80 % fast VTs up to 250 bpm
2. may be terminated with a single burst of ATP
3. Medtronic can deliver ATP during charge

Front 27

Shock delivered after ATP termination

Back 27

Patient has ATP but gets shocked

Not unusual if it has a type II break

Front 28

Factors that influence ATP efficacy

Back 28

1. timing of the stimulus
2. coupling interval
3. rate and number of pulses in the stimulus drive train
4. Proximity of the stimulating site to the circuit

Front 29

Asterid

Back 29

Atrial sensing to reduce inappropriate defibrillation:

1. Inappropriate therapy - 20-30 % of patients

Front 30

Pause Dependent

Back 30

Pause dependent caused by after potentials in Phase 3 that reach threshold potential

Related to conditions with prolonged action potential

Front 31

EADs

DADs

Back 31

1. Early After Depolarization

2. Delayed After Depolarization - occurs in settings DIG toxicity

Front 32

Factors for EP Study

Back 32

Factors Increasing Positive Study:
1. Monomorphic VT
2. Sustained
3. Induce single or double stimuli

Factors Decreasing Positive Study

1. Polymorphic
2. Non-sustained
3. Induce triple extrastimuli

Front 33

VT Mapping

Back 33

Looking for earliest signal on left side of the line

Front 34

Upper limit of Vulnerability

Back 34

Lowest energy given during the vulnerable period of the cardiac cycle that DOES NOT induce VF when other lower energies are successful.

If you do not induce your DFT should be less

Front 35

Idiopathic VTs - without heart disease such as CAD or MI

Back 35

1. ARVD - arrhythmogenic RV Displasia - predominately in males - Epsilon waves & family history of arrythmias

2. RVOT - RV Outflow tract - thought to be a harmless condition

3. ILVT - idiopathic LV tachycardia - originates in lower left septum and appears in younger patients. It is usually reentry or triggered

4. BBR - bundle branch reentry tachycardia - reentrant tachycardia found in either right or left bundle branches. May be good to ablate and pace. Patients usually have syncope, palpitations and SCD with rates > 200 bpm

Front 36

Triggered VTs - 2 types

1. Pause dependent

2. Catechol dependent

Back 36

Cardiac Action Potentials

1. Pause dependent associated with EAD's or early after depolarizations - Phase 3

2. Catechol dependent associated with DAD's or delayed after depolarizations - phase 4