Cardiology - Non-QT Channelopathies Flashcards

1
Q

Brugada: Who is it more common in?

A

Male > Female
Asian
Peak prevalence of sudden cardiac death in 4th decade (ie: 30’s)

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2
Q

What mutation is most commonly seen in Brugada?

A

10-30% have a LOSS-of-function mutation in SCN5A gene encoding voltage gated Na channel

with AUTOSOMAL DOMINANT inheritance

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3
Q

What other genes (other than the most common type) are seen in Brugada?

A

Alpha-1 and Beta-2 subunits of L-type Calcium Channel
(= CACNA1C and CACNB2)

GPD1-L
SCN1B

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4
Q

When do Brugada patients most commonly present?

A

After syncope or cardiac arrest

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5
Q

When do arrythmias commonly occur in Brugada?

A

Typically in the nighttime with nocturnal nightmares and thrashing

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6
Q

What can unmask a Brugada on an ECG?

A
  • Febrile
  • Hyper or Hypo kalaemia
  • HypERcalcaemia
  • Alcohol or cocaine

The unmasking challenge with Flecainide

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7
Q

What arrythmias is Brugada associated with?

A

AF

Polymorphic VT

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8
Q

ECG features of Brugada?

A
  • Broad P with some PQ prolongation
  • Convex/coved ST segment elevation >2mm in one or more of V1-V3
  • TWI in V1-V3
  • J point elevation

+/- partial RBBB

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9
Q

Which antiarrythmic do we use to ‘unmask’ Brugada?

A

Flecainide

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10
Q

Management of Brugada?

A

ICD if syncope or ventricular arrythmias

Quinidine if recurrent syncope or ICD shocks

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11
Q

Prognosis of Brugada?

A

8% have VF or sudden death within 2 years

Mean age of death 41 years old

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12
Q

What inheritance and genes are involved in Catecholaminergic Polymorphic VT (CPVT)

A

Autosomal DOMINANT (prevalence 1 in 10,000)

RYR2 (ryanodine receptor) in myocardium sarcoplasmic reticulum

Calsequestin-2 is calcium binding protein in sarcoplasmic reticulum

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13
Q

Catecholaminergic Polymorphic VT (CPVT) has what clinical features

A
  • Sudden cardiac death
  • Family history
  • Symptoms begin <20 years old
  • Provokable arrythmias on EXERCISE or when given ADRENALINE
    (–>polymorphic VT or alternating QRS)
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14
Q

In catecholaminergic polymorphic VT (CPVT) what provokes arrythmias and what types of arrythmias?

A

Provoked by: Exercise & adrenaline

Polymorphic VT
Alternating QRS

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15
Q

Management of catecholaminergic polymorphic VT (CPVT)?

A
  • Flecainide or verapamil
  • Betablocker plus ICD
  • Abstain from exercise
  • Sympathectomy (ESPECIALLY if ICD insertion results in MORE VT)
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16
Q

What channelopathy must you think of if a patient is from Italian or Greece (especially VENETO region of Italy)?

A

Arrythmogenic Right Ventricular Cardiomyopathy / Dysplasia (ARVC/D)

17
Q

How common is Arrythmogenic Right Ventricular Cardiomyopathy / Dysplasia (ARVC/D)

A

1 in 1000-2000

18
Q

What is the inheritance of Arrythmogenic Right Ventricular Cardiomyopathy / Dysplasia (ARVC/D)

A

Autosomal DOMINANT with variable penetrance (50%)

19
Q

What is Naxos Disease?

A

A variant of Arrythmogenic Right Ventricular Cardiomyopathy / Dysplasia (ARVC/D)

  • Autosomal RECESSIVE mutation on Ch17q21 with 100% penetrance
  • Associated with:
  • –ARVC/D
  • –Wooly hair
  • –Palmoplantar keratosis
20
Q

The disease characterised by ARVC/D, wooly hair and palmoplantar keratosis is what? And what gene?

A

Naxos disease
Autosomal RECESSIVE
Ch17q21

21
Q

What pathophysiology features are seen in Arrythmogenic Right Ventricular Cardiomyopathy / Dysplasia (ARVC/D)

A

Right ventricle myocardium gets replaced by fatty and fibrofatty tissue
Due to mutations in DESMOSOMAL proteins at CELL-TO-CELL JUNCTIONS

22
Q

What genes are associated with ARVC/D

A
JUP: Plakoglobin
DSP: Desmoplakin
PKP2: Plakophilin-2 (EARLIER ONSET)
DSG2: Desmoglein-2
DSC2: Desmocollin-2
TMEM43
23
Q

Which ARVC/D associated gene is also associated with an earlier onset?

A

PKP2: plakophilin-2

24
Q

How does Arrythmogenic Right Ventricular Cardiomyopathy / Dysplasia (ARVC/D) present clinically?

A

Presents in 2nd-5th decades
Usually Asymptomatic

But present with palpitations / syncope / sudden cardiac death / heart failure

25
Q

What type of arrythmias result from Arrythmogenic Right Ventricular Cardiomyopathy / Dysplasia (ARVC/D)

A

25% get supraventricular arrythmias (AF or flutter)

Ventricular ectopics
MONOMORPHIC VT

26
Q

ECG findings in Arrythmogenic Right Ventricular Cardiomyopathy / Dysplasia (ARVC/D)

A
  • Epsilon wave in V1-V3 in 30%
  • TWI in V1-V3
  • LBBB or VT
  • > 200PVCs in 24 hours
27
Q

Echo findings in Arrythmogenic Right Ventricular Cardiomyopathy / Dysplasia (ARVC/D)

A

Mild global dilation or reduced RV EF but with NORMAL LVEF

Dilatation of RV
Regional RV hypokinesis

28
Q

Which imaging form is best for Arrythmogenic Right Ventricular Cardiomyopathy / Dysplasia (ARVC/D)

A

MRI because you will see the RV fibrofatty changes better

29
Q

Management of Arrythmogenic Right Ventricular Cardiomyopathy / Dysplasia (ARVC/D)

A
  • Abstain from exercise (which accelerates disease progression)
  • ICD if cardiac arrest or VT
  • beta blockers FIRST LINE (most commonly SOTOLOL)
  • amiodarone is alternative to sotolol
  • Catheter ablation if recurrent VT
30
Q

What is the underlying pathophysiological features of Accelerated Idioventricular Rhythm (AIVR / AIVD)

A

Enhanced automaticity of His-Purkinje fibers and/or myocardium
+/- vagal excess
+/- decreased sympathetic activity

31
Q

How is MI associated with Accelerated Idioventricular Rhythm (AIVR / AIVD)

A
  • 15-20% incidence in treated MI with PCI
  • Acts as a marker of coronary reopening
  • Associated with MORE EXTENSIVE myocardial damage
32
Q

Triggers of Accelerated Idioventricular Rhythm (AIVR / AIVD)

A
Myocardial ischaemia (most common)
Buerger Disease
Congenital heart disease
Dilated cardiomyopathy
Myocarditis
Post resuscitaiton
Drugs: cocaine and digoxin
33
Q

Which drugs act as triggers of Accelerated Idioventricular Rhythm (AIVR / AIVD)

A

Cocaine and digoxin

34
Q

What is Buerger’s Disease?

What is it associated with?

A

Also known as Thromboangiitis Obliterans which is small and medium vessel vasculitis

STRONG association with smoking

35
Q

What are the features of Buerger’s Disease?

A
  • Extremity ischaemia (intermittent claudication / ulcers)
  • Raynaud’s Phenomenon
  • Superficial thrombophlebitis
36
Q

ECG seen in Accelerated Idioventricular Rhythm (AIVR / AIVD)

A
  • Wide QRS
  • Starts as long coupled PVCs
  • Terminates once sinus rate surpasses that of the AIVD
37
Q

Management of Accelerated Idioventricular Rhythm (AIVR / AIVD)

A

Usually self limited
Need to assess for MI

If unstable then use atropine to increase the underlying sinus rate so that it can shortcircuit the AIVD