Cardiology - Arrhythmia

Question 1

What type of arrhythmia is lidocaine used for?

Answer 1

ventricular arrhytmias

Question 2

What type of anti-arrhythmic should be avoided in patients with atrial fibrillation with pre-excitation

Answer 2

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.

Question 3

What is pre-excitation atrial fibrillation?

Answer 3

EKG will look like irregular wide-complex tachycardia. Differentiated from V-tach by very fast rate, irregular cycle lengths, and varying QRS morphology.

Question 4

What drug should be used in pre-excitation atrial fibrillation?

Answer 4

procainamide

Question 5

Adverse effects of amiodarone?

Answer 5

thyroid toxicity, hepatotoxicity, lung toxicity, photosensitivity, corneal/lenticular deposits

Question 6

In which patients should Sotalol and dofetilide be avoided?

Answer 6

CKD patients

Question 7

Reversible causes of bradycardia?

Answer 7

• elevated intracranial pressure
• hypothyroidism
• hyperkalemia
• lyme disease
• medication (BB, digoxin)

Question 8

Explain the two types of 2nd degree heart block”

Answer 8

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

Question 9

Indications for permanent pacing?

Answer 9

• 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

Question 10

How to remember left vs right BBB?

Answer 10

Left BBB:
WiLLiaM
V1: looks like W
V6: looks like M

Right BBB:
MoRRoW
V1: looks like M
V6: looks like W

Question 11

Medication for an acute episode of SVT in hemodynamically stable patient?
What do you do next if this fails

Answer 11

adenosine
(before adenosine Try bearing down, carotid sinus massage or facial immersion in cold water first)

If adenosine fails - try a synchronized cardioversion

Question 12

How to treat PAC’s?

Answer 12

extremely common

Can try BB’s or calcium channel blockers

Question 13

AVNRT is the most common type of SVT.

How to treat AVNRT?

Answer 13

AV blocking drugs or

catheter ablation

Question 14

AVRT (Atrioventricular re-entrant tachycardia), what is the mechanism behind it?

Answer 14

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.

Question 15

Please explain AVNRT

Answer 15

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.

Question 16

First line tx for Wolf-Parkinson-White?

Answer 16

Catheter ablation

Question 17

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?

Answer 17

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.

Question 18

Resting heart rate goal with therapy for patient with atrial fibrillation?

Answer 18

less than 110

Question 19

How do you calcululate CHADSVASC? what is the cutoff for anticoagulation?

Answer 19

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

Question 20

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?

Answer 20

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)

Question 21

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?

Answer 21

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

Question 22

How should cardiac device infection be treated?

Answer 22

complete removal of all hardwar, debridement of pocket, sustained abx therapy, and reimplantation at a new site