MMT: treating arrhythmia Flashcards
What are sinus arrhythmias?
Arrhythmia originating in the SA node; all the elements of the EKG are present, just at an altered rate.
What is a major way to alter sinus arrhythmia?
Modifying phase 4 via decreasing its slope, modifying threshold potential, increasing maximum diastolic potential, or increasing AP duration/prolonging the refractory period.
Decreasing camp will…
Flatten phase 4 and slow HR.
How can we increase maximum diastolic potential? What is the significance of this?
Making the membrane potential more negative; this means the cell has further to go to reach AP. This can be done via PSNS.
What do we do to treat sinus bradycardia?
Correct the precipitating event or atropine.
What do we do to treat sinus tachycardia?
Correct precipitating event or beta blockers.
What does a premature ventricular contraction look like on EKG?
Wide QRS with no preceding p wave.
How do we treat PVC?
Generally, we don’t. Can reduce the stimulus such as caffeine, stress, sympathomimetic drugs.
Where do atrial arrhythmias originate?
Above the bundle of His.
Give examples of supraventricular arrhythmias.
Afib, atrial flutter, AVNRT, AP mediated reentrant tachycardia.
Describe afib.
Typically caused by reentry and appears as irregular firing on EKG. They can be a result of structural heart diseases such as HTN, MI, ischemia, etc.
How does hypertension lead to afib?
Hypertension causes left ventricular hypertrophy, resulting in increased LA pressure. This increased pressure can cause increased LA stretch, causing afib.
Afib causes a loss of what?
Atrial kick, leading to a small loss of CO. Can also show a loss of p waves on EKG.
What is a significant consequence of afib?
Risk of stroke. The atrial stasis makes thromboembolism a major concern, often leading them to take aspirin.
what kind of drugs do we use for rate control in afib?
drugs that can control rate in the ventricles by slowing conduction from the AV node. these are typically beta blockers or CCB
what do do for acute rhythm control in afib?
drugs to restore sinus rhythm in the SA node (cardioversion). this is typically DC cardioversion, but drugs like ibutilide, dofetilde, and amiodarone can be used.
What drug should we not use for rate control in afib?
Digoxin.
What is the recent data regarding rhythm vs rate control in afib?
Early rhythm control has a lower risk of adverse cardiovascular events.