Cardiology - Arrhythmias

Question 1

reversible causes of bradycardia?

Answer 1

#elevated intracranial pressure
#hypothyroidism
#hyperkalemia
#Lyme disease
#medications (beta-blockers, digoxin)

Question 2

Most common INTRINSIC cause of pathologic sinus bradycardia? Extrinsic?

Answer 2

age-related myocardial fibrosis near the sinus node

medication effect

#R sided ischemia
#intracranial hypertension
#Post-surgical 
#Infiltrative/Inflammatory disease

Question 3

Why is 1st degree AV block a problem?

Answer 3

#increased risk of afib
#increased need for pacemaker
#increased all-cause mortality

Question 4

Heart block with generally benign prognosis?

Answer 4

Mobitz type I (wenckebach)

Question 5

In patients with minimal symptoms, when are the (non-conduction block) indications for a permanent pacemaker?

Answer 5

#HR under 40
#Pauses over 3 seconds
#AFib with 5 second pauses

Question 6

When to place a pacemaker in patients with AV block?

Answer 6

#Asymptomatic complete heart block 
#Mobitz type 2 second-degree atrioventricular block
#Alternating bundle branch block

Question 7

This type of conduction abnormality only has a 1-3% chance of progression to complete AV block and therefore does not need a pacemaker?

Answer 7

Intraventricular conduction delay

Question 8

All ICDs have pacemaker functions except?

Answer 8

subcutaneous ICDs

Question 9

CRT-P vs CRT-D?

Answer 9

pacing only vs pacing/ATP/defibrillating

Question 10

Only devices that can ATP?

Answer 10

non-subcutantous ICD and CRT-D

Question 11

SVT with wide QRS complexes - differential?

Answer 11

#bundle branch block
#aberrancy
#pacing
#anterograde accessory pathway conduction (antidromic trachycardia)

Question 12

Antidromic tachycardia - mechanism?

Answer 12

accessory AV connection is used as the antegrade limb and the AV node or a second pathway serves as the retrograde limb of the circuit.

Question 13

SVT arise from (with examples)?

Answer 13

Atrial - APCs, Afib, flutter, multifocal atrial tachycardia

Question 14

ECG classification of SVTs?

Answer 14

short-RP (RP less than PR; P closely follows QRS) - typical AVNRT, AVRT, and junctional tachycardia

Question 15

Maneuvers that can terminate SVTs?

Answer 15

#valsalva
#carotid massage
#facial immersion in cold water

Question 16

Patient with (true) SVT given adenosine - possible outcomes?

Answer 16

Termination - suggests AV nodal rhythm

Question 17

APCs increase risk for?

Treatment if symptomatic?

Answer 17

Afib

beta-blockers or CCBs

Question 18

Atrial tachycardia - first line treatment? Second line?

Answer 18

β-blocker or nondihydropyridine calcium channel blocker (diltiazem or verapamil)

Question 19

Most common type of SVT?

Answer 19

AVNRT

Question 20

Typical AVNRT - pathway? General ECG findings? Specific ECG finding?

Answer 20

electrical conduction goes down the slow pathway and conducts back up toward the atrium over the fast pathway (slow-fast).

Short RP interval with a retrograde P wave inscribed very close to the QRS complex.

QRS complexes may appear as a pseudo R′ wave in lead V1 and a pseudo S wave in the inferior leads.

Question 21

Atypical AVNRT - pathways? General ECG findings?

Answer 21

Conduction goes down the fast pathway and returns to the atrium via the slow pathway (fast-slow); this leads to a long RP interval.

Rarely, AVNRT can involve conduction over more than one slow pathway (slow-slow AVNRT).

Question 22

Treatment to prevent recurrent AVNRT?

Answer 22

β-blockers or nondihydropyridine CCBs

Question 23

AVRT - ECG findings?

Orthodromic vs antidromic?

Answer 23

shortened PR interval +/- slurred QRS (delta wave)

Anterograde conduction over AV node/His-purkinje system vs accessory pathway

Question 24

Clinical importance in treatment of orthodromic vs antidromic AVRT?

Answer 24

Adenosine vs NO adenosine (can cause VF)

Question 25

WPW is often seen in patients with this anomaly?

Answer 25

Ebstein anomaly (right heart enlargement and severe tricuspid valve regurgitation)

Question 26

Non-invasive risk stratification for patients with preexcitation? Low risk if what findings?

Answer 26

exercise stress testing. Loss of preexcitation with exercise

Question 27

First line therapy for patients with preexcitation with symptoms?

Answer 27

catheter ablation