Ventricular Rythms + Cardiac Monitor and Defribillator Applications

-SA Node, Intranodal Pathways, AV Node, AV Junction.

-have associated P-waves

-narrow QRS

-less lethal

Supraventricular Conduction

Ventricular Rhythms

-Bundle of His, Left and Right Bundle Branches, Anterior and Posterior Fascicles, Purkinje, Ventricular Myocytes

-No associated P-waves

-wide QRS

-more lethal

Ventricular Rhythms

-Never have an associated P-Wave (they may exist, but wont line up with QRS complex) Ex; Third degree AV Block

-Always have a wide QRS

Automaticity

The ability to generate an electrical impulse independently of stimulation by the nervous system or any other souce

Excitability

The ability of cells to respond to electrical stimulation

Conductivity

The ability to pass or propagate an electrical impulse from cell to cell through the heart

SA Node

normal pacemaker of the hear

Ectopic beat

any beat or rhythm that originates outside of the SA node

Irritability

The normal pacemaker (the Sinoatrial node) is still working, but another area jumps in before it should, which results in an early beat

Ex: PAC’s, PJC’s, PVC’s

Escape

fires because the normal pacemaker is too slow or fails completely, which results in a late beat.

SA node rate

60-100

AV Node

40-60

Purkinje Node

20-40

Premature Ventricular Complexes (PVC’s)

-early heartbeat (iritable) that starts in the ventricles instead of following the normal conduction pathway from the Sinoatrial node.

-wide QRS

-followed by a compensatory pause

-can be unifocal or multifocal

Compensatory Pause

temporary pause in the heart rhythm that occurs after a premature or abnormal beat before the next normal beat appears, heart then returns to norml underlying rhythm.

Bundle Branch Block

The QRS becomes wide because there is a delay in conduction

Non-Compensatory pause

An early beat happens → the heart’s natural pacemaker (the SA node) gets “reset” → the next normal beat comes sooner than expected.

Unifocal

Multiple PVC’s look the same

Multifocal

Multiple PVC’s look different

Bigeminy

Alternating between norml and abnormal beat

Trigeminy

abnormal beat occurs every third beat.

couplet

two ectopic beats in a row.

Run of Vtach

3 sequential PVC’s are called a run of V-tach

increase frequency of PVC’s can turn into what?

V-tach or V-Fib

R-on-T PVCs

dangerous type of Premature Ventricular Contraction where a PVC happens so early that its R wave lands on the T wave of the previous heartbeat.

Relative Refractory period

cardiac cycle where the heart cells are partially recovered and can be stimulated again, but only by a stronger stimulus

Drugs that prolong QT interval

Haloperidal, Odansetron

prolonged QT interval can increase risk of?

PVCs during T wave = R-on-T PVCS, which increase chAnce of V-tach, or V-fib

Ventricular Tachycardia

-ventricular cell becomes irritable and beat faster 150-250 then normal (originates in the ventricles)

-wide/bizzare looking QRS (can be monomorphic or polymoprhic)

-can be short run PVC’s or sustained

-decreases cardiac output

Torsades Des Pointes

-a type of polymoprhic v-tach where QRS complex changes into a twisting pattern

-QRS is wide

Wide Complex tachy

generalized wide QRS

Ventricular Flutter

-extreme V-tach (250-350)

Ventricular Fibrillation

-chaotic (Quiver), all pacemaker sites are depolarizing

-only F-Waves

-will never generate a pulse

-can be course or fine

Commotio Cortis

A perfectly timed impact to the chest causes the heart to go into ventricular fibrillation, leading to sudden cardiac arrest.

The only thing that fixed V-Fib is

Defib (electrical rythmic shocking)

Pacing

control the heart’s rhythm by delivering small electrical impulses that make the heart beat at a set rate.

Course V-fib

form of ventricular fibrillation where the ECG shows large, obvious, high-amplitude chaotic waves

Fine VF

form of ventricular fibrillation where the ECG shows very small, low-amplitude chaotic waves that can be hard to distinguish from asystole.

Idioventricular Rhythm

-backup heart rhythm that comes from the ventricles when higher pacemakers fail or are too slow.

20-40 bpm

-Wide QRS with no P waves

Accelerated Idioventricular

above 40 bpm

agonal idioventricular

below 20 bpm

Treatment for idioventricular rhythms

pulse = Transcitaneous pacing

pullseless (PEA) = CPR, Epi, look for reversible causes

DO NOT DEFRIBRILATE OR GIVE ANTIARRHTHMICS

Ventricular Escape Beat

-Late beat that takes place when normal pacemaker temperarily loses control.

-single isolated beat

Agonl Rhythm

extremely slow, abnormal, and ineffective heart rhythm that occurs near death or during severe cardiac arrest.

asystole

-final rhythm of a dying heart

-no cardiac output (no pulse)

-nearly flat line

Ventricular standstill

Asystole with p waves

PEA (pulsless Electrical Activity)

Any organized rhythm that does not produce a pulse, treat with CPR and epi, try to find H’s and T’s

Shockable rhythms

V-Vib and V-tach

not shockable rhythms

PEA and Asystole

H’s

Hypoxia, hypovolemia, Hydrogen ion, Hypo/hyperkalemia, Hypothermia

T’s

Tension Pnuemothorax

Cardiac Tamponade

Cardiac thrombosis (MI)

Pulmonary Thrombosis

Toxins/ Drug Overdose

Trauma

Cardiac Pacing types

Emergency: TCP

Short term: Transvenous Pacing

Permanent: Pacer machine

Cardiac Pacing

medical technique used to make the heart beat when its own electrical system is too slow or unreliable.

Capture

-Electrical and mechanical (MUST HAVE BOTH)

small spike in ECG and palpable pulse

-evidence that the pacer is working

Ventricular Paces Rhythms

-Pacer Spike precedes the QRS complex immediately

-Wide QRS

AV sequential paced rhythm

is a heart rhythm produced by a pacemaker that stimulates both the atrium and the ventricle in a coordinated sequence to mimic normal cardiac conduction.

Atropine

first dose” 1mg Iv bolus

-repeat every 3-5 min Max 3mg

Dopamine IV infusion

5-20mcg/kg/min

Epi Iv dose

2-10mcg/min

Adenosine

first dose:6mg rapid IVP, followed with NS flush

Second dose: 12mg

Antiarrhythmis medications for Stable-Wide-QRS tachycardia

Procainamide

amiodarone

Sotalol

Procainamide

20-50mg/min, Max 17mg/kg

Amiodarone

first dose: 50 mg over 10 min

Sotalol

100 mg( 1.5 m/kg) over 5 min

CCR (Cardiac Cerebral Resiscitation)

-focuses on continuous, high-quality chest compressions with minimal interruptions

What is Lidocaine

medication that blocks electrical signals in nerves and heart tissue by blocking sodium channels.

why do i give lidocaine in a cardiac arrest?

-treat and prevent dangerous ventricular rhythms (VF and pulseless VT) when the heart is electrically chaotic.

-stabalizes the mycardium after shock resets the rhythm

Lidocaine dosage

first dose: 1-1.5 mg/kg

Second dose: 0.5-0.75mg/kg

Older cardiac models

-3 leads

-monomoprhoic energy

-no vital sign monitoring

Newer models

-four lead w/ 5 limb leads

-biphasic energy

-vital sign monitoring

Defribiliation

-electrical current through pads on chest

-Goal: depolarize the entire myocardium, thus terminating the arrythmia

Monophasic

current delivered in one direction through the heart

Biphasic

Current delivered in two directions

Initial defibrilation energy

120-200

Lifepack shock Sequence

1: 200

2: 300

3: 360

Zoll shock sequence

1:120

2: 150

3: 200

What kind of wavework does Zoll use

Rectilinear Biphasic

what kind of waveform does Lifepak use

Biphasic Truncated Exponential

How do u maximize CPR

-use manual mode instead of AED mode

-Precharge the monitor in anticipation of defibrillation

During typical defibrilliation, what amount of energy is deleivered to the myocardium

4%

Advanced Defibrillation strategies

Vector Strategies

Double Sequential Defibrillation

Vector change

place a new set of pads in the alternate position.

Double Sequential Defibrillation

-uses two monitors and two sets of pads

-does not deliver twice the energy, but depolarizes more of the myocardium

-hit both buttons at the same time

Synchronized Cardioversion

procedure where a defibrillator delivers a timed electrical shock to restore a dangerous fast rhythm back to a normal rhythm. Pt does have a pulse

What rythm do we not treat

Sinus Tachycardia

Supraventricular TachyCardia

Adenosine to slow or breifly block electrical conduction

RVR (Rapid Ventricular Response)

The atria are firing chaotically and very fast

The AV node allows some of those impulses through to the ventricles

Atrial Fibrillation with RVR

Treat with synchronized cardioversion at high dose: 120-200

if A fib or a flut is greater then 48 hours

high risk for Cerebrovscular accident

only consider adenosine in V-Tach if

regular and monomorphic

Use syncrhonized cardioversion if

fast ryhthm w/ a pulse

use defibriilliation if

-pt has no pulse and is in a shockable rythm (v-tac, and v-fib)

-can be polymorphic or monomorphic

use pacing when

its a low pulse

Torsades Des Pointes

-polymorphic V-tac

-treat with magnesium Sulfate

Unsynchronized (defibrillation) vs synchronized

-The shock is delivered immediately, with no regard to the ECG pattern

or

-shock is timed to the R wave (QRS complex) on the ECG.

Transcutaneous Pacing

frequent, timed, small shocks to take over control of the heart

Capture

arrows on the ECG that represent when the pacer is working, the QRS will be immediately