Term
| 2 types of tachyarrythmias and mechanism |
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Definition
• Disorders of impulse propagation. - Re-entrant mechanism.
• Disorders of impulse formulation. - Enhanced automaticity and Triggered activity. |
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Term
| Reentry: Impulse propagation, most common |
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Definition
• Most common mechanism of sustained paroxysmal tachycardias.
• In most re-entrant tachycardia be it supra- ventricular or ventricular there has to be a slow zone of conduction that allows for the tissue to recover. |
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Term
| Enhanced Automaticity: Impulse formulation, pacemakers, occurs due to? |
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Definition
• Enhancement of normal automaticity in latent pacemaker fibers or the development of abnormal automaticity due to partial depolarization of the resting membrane occurs as a consequence of a variety of pathophysiolgic states:
• Increased catecholamines • Electrolyte abnormalities
• Hypoxia or ischemia |
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Term
| Triggered Activity: Impulse formulation |
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Definition
• Events do not occur spontaneously but require a change in cardiac electrical frequency as a trigger.
• Can be caused by early afterdepolarizations, which occur during phase 2 and 3 of the action potential or
• Delayed after depolarization that occur following completion of phase 3 of the action potential.
• Has been observed in atrial, ventricular and His-Purkinje tissue.
• Most commonly seen with digitalis intoxication, accelerate idio-ventricular rhythm after an acute MI, exercised induced VT. |
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Term
| Tachycardia: >100 BPM for 3 or more beats, 2 categories |
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Definition
| • The first branch point is to distinguish if the tachycardia is NARROW QRS Complex tachycardia vs WIDE QRS Complex tachycardia |
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Term
| Narrow QRS Tachycardia, next question |
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Definition
• If Narrow QRS, suggest that it is going through the normal conduction where is if the QRS is wide it suggest either ventricular tachycardia or tachycardia with aberration (more on that later)
• Now once the determination is made that the QRS is narrow, the next question to ask is whether the tachycardia is REGULAR or IRREGULAR. |
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Term
| regular narrow QRS tachycardias |
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Definition
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Term
| irregular narrow QRS tachycardias |
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Definition
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Term
| narrow complex tachycardia treatment algorithm |
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Definition
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Term
| wide complex tachycardia definition |
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Definition
| • Definition: Wide QRS complex tachycardia is a rhythm with a rate of more than 100 BPM and QRS duration of more than 120ms |
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Term
| differential diagnosis of wide complex tachycardia and description, ex's |
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Definition
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Term
| most wide complex tachycardias are? ask? |
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Definition
• 80% of WCT are VT
Ask the patient
• Prior MI
• Heart disease?
• If yes, 95% chance of VT |
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Term
| mechanisms of wide complex tachycardia |
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Definition
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Term
| wide complex tachycardia ekg vs sinus |
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Definition
• WPWa->pre-excited tachycardia
• Preexisting BBB
- Similar BBB during Wide QRS->SVT
- Different BBB during wide QRSa->VT |
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Term
| wide QRS tachycardia algorithm |
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Definition
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Term
| clinical manifestations of wide QRS tachycardia |
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Definition
• Can be quite variable dependent on:
- How rapid the heart rate
- Blood pressure
- Underlying comorbidities
• Can present with variety of symptoms
- Palpitations (most common with NCT)
- Syncope or Presyncope (most common with WCT)
- Lightheadedness or dizziness
- Diaphoresis
- Chest pain
- Dyspnea |
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Term
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Definition
G.L. – AVNRT
Here's an example of a patient with a narrow complex tachycardia. And you could see that this is a patient that I took care of. When you look at the EKG here, you see these little activation in the terminal portion of the QRS. That is what we call the retrograde p-wave. So you can imagine if it's a re-entrant mechanism, it goes antigrade down one pathway and then goes retrograde up the other pathway. You get the activation of the atria. This is what you are seeing. |
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Term
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Definition
| And this was a patient of mine who had AVNRT. And this patient then had determination of the AVNRT might be given adenosine, which, as you could imagine, took effect over here. And you could see the p-wave going. So determination occurred right here, and that patient was at a normal sinus rhythm. |
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Term
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Definition
Once again, this as a patient. So if you pay attention to the terminal portion of the QRS, you see this retrograde p-wave, which you do not see over here. And this is what we classically describe as a retrograde p-wave that you do not see in their normal EKG. And this was the patient's baseline EKG.
LLAP |
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Term
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Definition
This is a patient of mine who has WPW. As you can see, there's a pre-excitation. So the initial portion of QRS is quite slurred, but then the terminal portion is normal, because you have activation by the accessory pathway initially. But then the rest of the activation is via the normal conduction system or the heart.
But one key thing is you could note is that the delta wave-- this is what it's described as-- can be seen in all EKG leads. If you do not see the delta wave in all the 12 leads, then chances are that patient does not have WPW. So the delta wave must be present in all 12 leads. Otherwise, it's not a WPW.
And this patient had a left lateral accessory pathway-- so basically a connection between the left atrium and the left ventricle that was pre-exciting the ventricles.
LLAP |
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Term
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Definition
| This is another patient of mine who has WPW and had a right posterior accessory pathway. So once again, you can appreciate the slurred upstroke and how the p-wave, even before it ends, activates the ventricle. And therefore you're getting this slurred upstroke because, once again, you're pre-exciting the ventricle. Therefore, you get activation of the ventricle even before the p-wave has had a chance to complete its conduction through the AV node. |
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Term
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Definition
| This was the example of the patient having the tachycardia. Now, this ended up being a orthotropic AVRT because you could see the QRS is narrow compared to what we had on her baseline EKG. So this is an example of an orthotropic tachycardia, which means the antigrade conduction was down the AV node, but the retrograde conduction was of the accessory pathway. And so that's an example. |
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Term
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Definition
| Now this is an example of a patient of mine who has Afib with an underlying left bundle branch block. And when they go into a wide complex tachycardia, now the patient has a right bundle branch block morphology and is fairly regular. Remember, Afib, by definition, is an irregular rhythm. So if you see a wide complex tachycardia in a patient with Afib and it's regular and now that the fact that the bundle branch block is right bundle, chances are this is VT. And that's exactly what this was. |
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Term
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Definition
Now, this is an example of atrial flutter. So you could see there's multiple p-waves between each QRS. And this is what an atrial flutter looks like. And this is an atypical flutter. Discussion about atypical versus typical could take another half hour, so I will table that for other time.
But nevertheless, this is an atypical flutter. And you can see the flutter morphology within each QRS complex. This was what I described. If you give adenosine, you don't terminate atrial flutter. What you do is you slow down the conduction through the AV node. Therefore, you can see the flutter waves more clearly. |
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Term
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Definition
| This is an example of what we call typical flutter, which then breaks into sinus rhythm. So the patient's in atrial flutter, atrial flutter, atrial flutter and then terminates in sinus rhythm. Now this, one again, was not due to adenosine. This is spontaneous, which is what we typically see in cardiology is you have patients who go into atrial flutter. and then spontaneously terminate into normal sinus rhythm. |
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Term
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Definition
| This is an example of a patient who had apical LV hypertrophy and has a chronic Afib. So you can see the low amplitude p-waves, the marked irregularity, and also the large amplitudes at the LV, and also the T-wave inversions. This is classic for apical LV hypertorphy. But the key thing I wanted you guys to pay attention to is the small amplitude and the highly irregular rhythm. |
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Term
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Definition
• Flecainide
• Sotalol
• Dofetilide
• Amiodarone
• Dronedarone
• Mexiletine
• Quinidine
• procainamide |
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Term
| ablation treatment based on type |
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Definition
• AVNRT: slow pathway modification
• AVRT: ablation of the accessory pathway
• Afib: pulmonary vein isolation
• Aflutter: most commonly cavotricuspid isthmus ablation
• VT: based on etiology substrate based. |
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