Cardiology - Arrhythmia Flashcards
What type of arrhythmia is lidocaine used for?
ventricular arrhytmias
What type of anti-arrhythmic should be avoided in patients with atrial fibrillation with pre-excitation
Adenosine, verapamil, Beta-blockers, digoxin
-These agents block the AV node which can cause electrical impulses to preferentially use the accessory pathway - leading to worsening tachycardia and could lead to V-fib.
What is pre-excitation atrial fibrillation?
EKG will look like irregular wide-complex tachycardia. Differentiated from V-tach by very fast rate, irregular cycle lengths, and varying QRS morphology.
What drug should be used in pre-excitation atrial fibrillation?
procainamide
Adverse effects of amiodarone?
thyroid toxicity, hepatotoxicity, lung toxicity, photosensitivity, corneal/lenticular deposits
In which patients should Sotalol and dofetilide be avoided?
CKD patients
Reversible causes of bradycardia?
- elevated intracranial pressure
- hypothyroidism
- hyperkalemia
- lyme disease
- medication (BB, digoxin)
Explain the two types of 2nd degree heart block”
Mobitz Type 1 (Wenkebach). Progressive prolongation of PR intervals until dropped beat.
Mobitz Type 2. PR interval is constant prior to non-conducted P-waves.
Type 2 has higher risk of progression to complete heart block
Indications for permanent pacing?
- symptomatic bradycardia without a reversible cause
- Asymptomatic bradycardia with significant pauses (>3 secs in sinus rhythm) or persistent HR <40
- Afib with 5 second pauses
- Asymptomatic complete heart block or Mobitz Type 2 Second degree heart block
- alternating BBB
How to remember left vs right BBB?
Left BBB:
WiLLiaM
V1: looks like W
V6: looks like M
Right BBB:
MoRRoW
V1: looks like M
V6: looks like W
Medication for an acute episode of SVT in hemodynamically stable patient?
What do you do next if this fails
adenosine
(before adenosine Try bearing down, carotid sinus massage or facial immersion in cold water first)
If adenosine fails - try a synchronized cardioversion
How to treat PAC’s?
extremely common
Can try BB’s or calcium channel blockers
AVNRT is the most common type of SVT.
How to treat AVNRT?
AV blocking drugs or
catheter ablation
AVRT (Atrioventricular re-entrant tachycardia), what is the mechanism behind it?
Accessory pathway between atria and ventricles. Normal what you see is a delta wave because conduction goes from SA to atria to accessory pathway to ventricle. Accessory pathway faster than AV node, so delta wave is from early conduction of ventricle.
You see AVRT when there is a PAC - accessory pathway not conducted initially due to refractory period, but then is conducted retrograde through the accessory pathway, restimulating the AV node and creating a cyclic pathway of tachycardia.
Please explain AVNRT
Slow and fast pathways of the AV. The slow side has a shorter reftractory period, fast track has longer refractory. Works fine until there is a PAC. The PAC then gets the slow track going while the fast is in refractory, then slow will then stimualte the fast in a retrograde manner and the cycle will continue with a tachycardia 100-250bpm.
First line tx for Wolf-Parkinson-White?
Catheter ablation
Patient with newly discovered atrial fibrillation - his symptoms started 36 hours ago. What is your plan for anticoagulation plan for before and after cardioversion? Would your plan be different if his atrial fibrillation had started earlier or later?
If in A-fib less than 48 hours - no need for pre-procedural anticoag.
In A-fib > 48 hours, patient needs 3 weeks of pre-procedural therapeutic anticoagulation prior to cardioversion. OR you could do a TEE and if negative for intracardiac thrombus then cardiovert immediately.
Regardless of length of A-fib - all patients anticoagulated at time of cardioversion and minimum of 4 weeks afterward.
Resting heart rate goal with therapy for patient with atrial fibrillation?
less than 110
How do you calcululate CHADSVASC? what is the cutoff for anticoagulation?
CHF: +1 HTN: +1 Age: <65 0, 65-74 +1, >75 +2 Diabetes: +1 Sex: fem +1 Stroke/TIA/thromboembolism: +2 Vasc (MI, PAD, aortic plaque): +1 0 = low risk 1 = low-mod 2 = moderate high and should be anticoagulated
Patient with A-fib undergoes catheter ablation. At 3 and 6 months after ablation, no evidence of atrial fibrillation and no concerning symptoms. She is curretnly on anticoagulation. How do you decide about anticoagulation disconinuation?
Anticoag discontinuation depends on risk stratification rather than current rhythm status. You should calculated her CHADS2VASc score to decide if discontinuation is appropriate. (people can still have underlying transient a-fib)
60yoM w/ dyspnea on exertion for 1 month. Remains in sinus rhythm after 2nd catheter ablation 1 year ago. No HF sx or hx. On Warf, metop, ramipril, atorva. Vital signs and O2 sat are normal. EKG NSR, PFT’s without obstruction. Echo w/ EF > 55% and mild diastolic dysfunction.
Cause of dyspnea?
Pulmonary vein stenosis
Progressive unexplained dyspnea with history of multiple cather ablations procedures for a-fib. In a catheter ablation, the tissue around the pulm veins is cauterized to achieve electrical isolation and prevent foci from triggering recurrent a-fib
How should cardiac device infection be treated?
complete removal of all hardwar, debridement of pocket, sustained abx therapy, and reimplantation at a new site
