Cardio-Clinical- Ventricular dysrhythmia- Trainer Flashcards
What are some questions to ask with people that arrhythmias?
rate
Sick/ not sick
p waves
regular/ irregular rhythm
wide/narrow QRS
sinus tachycardia- underlying issue
What is the most common tachyarrhythmia and how is it treated?
sinus tachycardia
we don’t treat this with electricity or rate control, use medication or we aim our treatment at the cause of the tachycardia, like shock, hemorrhage, pulmonary embolism, things like that
Unstable patients need electricity immediately to improve perfusion, unless the instability is caused by :
sepsis, blood loss, hypothermia, toxins, etc
What is the difference between cardioversion and defribrillation?
cardioversion is synchronized shock and defribrillation is nonsynchronized shock
Once the ventricular rate gets above about bpm however the cardiac output can actually drop significantly because the heart cannot fill completely during diastole
can we actually get a increase/decrease in stroke volume
140
decrease
Determining the cause of tachycardia can direct how to treat. If underlying condition causing tachycardia (shock) then:
if tachycardia is being caused by abnormal rhythm, then:
treat underlying condition
do something directly on the heart whether it’s electricity or medication
What are the 2 main diagnostic tests in arrhythmia patients?
EKG and rhythm strip
Ventricular tachycardia is often misdiagnosed as:
SVT with aberrancy (ie, SVT or afib or flutter with RBBB/LBBB which causes a WCT).
stable VT can look like the top ECG
— treat like VT
How to be systematic with an ECG:
1. establish a safety net- IV, O2, monitor, crash cart
- stable/unstable (sick/not sick)
- P waves present (are thy uniform)- suptaventricular or ventricular
- regular/irregular ( irregular rhythm is not VT because irregular is coming from above the AV node)
- QRS complex wide (WCT) or narrow (NCT) -narrow would not be VT
axis
intervals
wave morphology
What is a normal PR interval and what does it mean if its less than?
PR interval: 120-200 ms
If PR <120 ms = Ectopic pacemaker = SVT (WPW, preexcitation)
What is a normal QRS interval and what does it mean if wide?
QRS complex: 80-100 (should be less than 120) ms
QRS >120 ms = wide-complex (BBB, ventricular)
What is the normal range of the QTc interval? And what could it mean if over?
QTc interval: <400 ms
QTc >500 ms = Danger (TdP (Torsades), VT, VF); normal is typically <400 ms
How would you treat unstabel v tach or SVT with aberrancy if they can look the same?
Treat the same, with electricity
What are some symptoms of instabiity or decreased perfusion?
chest pain, shortness of breath, or confusion. Signs include hypotension (typically with a systolic blood pressure less than 90 mmHg).
Other signs would include things like pulmonary edema, stroke symptoms, decreased Glasgow coma score, or pallor.
- One strong caveat here is that even if we don’t specifically know what the underlying rhythm is, if the patient is found to be unstable, electricity is still the preferred method and we would deliver that again even without knowing the specific rhythm.
If someone is in sinus tachycardia (most common tachycardia), treat with cardioversion?
No, it will not help
What does it mean if there are not inverted P waves present on aVR lead and upright P waves in 2?
limb lead reversal
One way to help us determine if the patient has P waves and is in sinus tachycardia or if this is an unstable arrhythmia is to:
look for a change in rate when the patient is moving in bed or exerting themselves in any way.
Typically sinus tach will increase or become variable with movement while PSVT or ventricular tachycardia will almost always have a fixed rate regardless of any movement.
What is the typical rate of vtach?
V tach is usually right around a rate of 150 bpm or higher
If a rhythm is irregular, where is it most likely coming from?
an irregular rhythm is not ventricular tachycardia, in other words an irregular rhythm is coming from above the AV node. This is extremely important to recognize and will help you with diagnosis
V tach with rate above 150 bpm
How would you treat an irregular rhythm above the AV node (SVT)?
AV nodal blockade (medication)
Wide complex, regular tachyarrhythmias should always push you toward thinking about?
ventricular tachycardia as the cause in your initial assumption.
typically older, and frequently have some prior history of cardiovascular illness though this is not always the case
Why is it important to recognized V tach right away?
because it has a propensity to deteriorate ventricular fibrillation and cardiac arrest.
treat with cardioversion (has regular rhythm)
What would a wide irregular QRS complex indicate and how to treat?
SVT, like atrial fibrillation with aberrancy, or polymorphic ventricular tachycardia, also known as torsades de pointes can both be irregular and wide complex, but for the most part when you see this you have to start thinking about ventricular fibrillation.
How to distinguish wide irregular QRS complex Torsades de Pointes. SVT with aberrancy, and V fib?
V Fib/V tach- no pulse (cardiac arrest)
Torsades de Pointes and SVT w/ aberrancy- Pulse
same treatment-they will all be defribrillated
How to differentiate Afib with aberrancy and WPW with Afib?
Anytime you see a rate close to 200, wide complex, irregular, you have to think about WPW with atrial fibrillation and aberrant conduction.
- the treatment options and a life-threatening complications if you use the wrong treatment.
- do not use AV nodal blocker on WPW
How to treat narrow QRS complex?
Treat like usual SVT (adenosine, calcium channel blockers, beta blockers, other AVN blockers)
How to treat wide QRS and regular rhythm?
Treat like VT (wide complex and regular is monomorphic V tach and can be treated as such)
Stable- use meds
unstable - cardioversion
How to treat WPW with Wide or Narrow Complex AND Irregular:
Stable and unstable?
If stable use - Procainamide
Cardioversion - unstable
If wide or narrow QRS, irregular, and WPW, how to treat?
-do not use AV node blocker because blocks AV nodal inherent pathway and increases conduction through accessory pathway which can cause V tach and eventual V fib. V fib is refractory because iherent pathway blocked by AV nodal blocker.
Treat- procainamide
Cardiovert! Especially if unstable.
Differences between VT and SVT:
Clinical?
ECG?
QRS?
Clinical: focus on history
VT-50+ ,history of cardiac issues vs. SVT <35, history of SVT
ECG:
VT: QRS >0.14 s vs. SVT <0.14s
VT- LAD vs SVT- normal axis
VT: rate >150 bpm, atria and ventricles independent
AV dissociation: 1. Arrowheads are the P waves in the top EKG: 1. They are pretty regular. 2. Note the QRS’ occur without preceding P wave.
VT
- A fusion beat is specific for V tach and is where there is a fusion of a beat that originates above the AV node and one of the ventricular-origin beats. 1. Short arrow is the fusion beat.
V tach
Capture beat is also specific to V tach (arrow on 3rd ECG)
Capture beats occur when an atrial impulse arrives at the AV node when the node has just recovered from its refractory period.
- Then, conduction proceeds normally through the AV node and “captures” the ventricle, leading to normal, narrow QRS.
- Capture beats are narrower than V tach beat.
- The QRS in capture beats will have different appearance/axis than the V tach beat
Can you use Brugada criteria with an irregular rhythm?
No, the rhythm must be regular
What Brugada criteria must be met to rule out V tach?
all criteria must be met to rule out V tach
What are the Brugada criteria?
Fusion beats - yes= VT
capture beats- yes= VT
AV dissociation- if present, then VT
. Does it look like SVT with a typical RBBB or LBBB? 1. If NOT, then the rhythm is V tach.
Other criteria for V tach:
- Regular
Rate ≥150 (tick marks)- almost always V tach
Almost always V Tach if they meet the following criteria:
Bottom line:
- > 50 age
- underlying heart dz
- Rate 150 bpm
- WCT
How to treat stable V-tach?
• Procainamide > Amiodarone > Lidocaine
First line: Procainamide (class Ia) is preferred and is a “membrane stabilizer,” via Na+ channel blockade.
- It increases the electrical threshold, decreases automaticity, depresses myocardial contractility.
Amiodarone (class III) is an AVN blocker mainly K+ channel but also Na+ and Ca++ channel action
- Found to be more effective in terminating stable, monomorphic V tach and with less side affects
Lidocaine (class Ib) is also a “membrane stabilizer,” increases electrical threshold and suppresses automaticity. 1. It is also a Na+ channel blocker, similar to procainamide.
How do we treat unstable VT?
• Shock Shock Shock • Pick the Right Shock
Treatment of choice =>=>=> electricity
i. IF V tach with a pulse, or other regular or irregular organized rhythm, you must use synchronized cardioversion to treat. -• If you defibrillate you will cause deterioration to V fib, asystole, or PEA which are all incompatible with life and your patient dies.
if no pulse, then defibrillation
TdP or torsades de pointe
What is and how to treat TdP?
. Special type of polymorphic VT
TdP Treatment - Stable
a. Magnesium sulfate
b. “PAS” on or do not use: i. Procainamide ii. Amiodarone iii. Sotalol
TdP Treatment - Unstable
a. Cardioversion b. Overdrive pacing
What type of QT interval?
Long QT= >400ms
Anything that prolongs the QT interval can cause what?
TdP
Which meds do we “PAS” on due to if TdP?
procainamide, amiodarone, sotalol and macrolides like azithromycin which can cause long QT and lead to TdP
Which electrolyte abnormalities can cause long QT and lead to TdP?
Hypokalemia, hypocalcemia, hypomagnesemia
Congenital causes of long QT (not as common):
- History:
a. No prodrome
b. No other symptoms
c. Has occurred twice in 1 month
d. But has noted nightmares/thrashing as child
e. Oldest brother died suddenly at 25-yo; no explanation was found
a. Anytime you hear this, a family history of unexplained SCD be very concerned for your patient.
Brugada syndrome
Afib occurs in about 20% of patient with . 1. If you see a young person with new onset Afib, definitely consider as the cause.
Brugada Syndrome
What is Brugada Syndrome?
. It’s due to a gene mutation.
- We used to think the person’s heart was structurally normal but it’s since been proven that the arrhythmia is caused by mutations to sodium channels in the heart.
c. Unfortunately this is a much more common cause of sudden cardiac death than previously thought and is frequently overlooked.
d. SCD typically occurs around 41 years of age on average but the arrhythmias that cause initial symptoms typically occur at around age 20 but definitely before age 60
What is the best clue to Brugada Syndrome?
Family History of SCD, or even unexplained sudden death not determined to be of cardiac origin alone should make you think of Brugada Syndrome.
- This is because many times patients have no symptoms prior to their arrhythmia and this can be a lethal arrhythmia as their first presentation.
Symptoms of Brugada syndrome?
palpitations, lightheaded, dizziness, fainting, nocturnal dyspnea, and in kids, nightmares.
How to treat Brugada?
Treatment is with an ICD to treat the unexpected V tach and V fib.
How many types to Brugada syndrome?
3
all have elevated ST and T inversion after: look at diagram
What is an idioventricular rhythm?
similar to VT (WCT) but slow (runs at intrinsic rate of ventricle, around 45), <60
What is an accelerated idioventricular rhythm (AIVR)?
similar to V tach but between 60-100bpm
Treat all WCTs as if they are what?
VTs
stable-meds
unstable-cardiovert
