Transcript HCM - Cardiology

Prof. N. Sudhaya Kumar,
AIMS, Cochin
Primary cardiomyopathies
Genetic
HCM
ARVD
LV noncompaction
Mitochondral myopathy
Glyc.storage dis.
channelopathies
Mixed
Acquired
DCM
RCM
Inflammatory
Tachycardiomyopathy
Takotsubo
Infants of IDDM mothers
HCM
Most common of the genetic CVD
Mutation in genes coding proteins of sarcomere
Autosomal dominant pattern of inheritance
Heterogenous manifestation
Unique pathophysiology
Diverse clinical course
HCM
• most common cause of SCD in children
•30 % of SCD in competitive athletes
• LVH is a dynamic process
• occasionally LVH appears at or slightly after birth
• striking increase in LVH during adolescence
HCM .. GENETICS
• autosomal dominant
• usually missense mutations in genes that
encode sarcomere proteins
• HCM mutant proteins are incorporated into cardiac myofilaments
Hypertrophy, remodeling, fibrosis, dysfunction
• 50% of first degree relatives are at risk of inheriting the mutation
HCM .. GENETICS
Mutations
missense, deletions,insertions,nonsense
In
thick filament proteins
thin filament proteins
metabolic genes
lysosomal proteins
HCM .. GENETICS
Protein
chrom
gene
incidence
clinical
BMHC
14
MYH7
40%
MYBPC
11
MYBPC3
Titin
2
TTN
TropT
1
TNNT2I
Trop I
19
TNNI 3
rare
?apical ; restrictive physio
Actin
15
ACTC
rare
? Apical
TPM 1
< 5%
variable degree LVH
good prognosis
> in Finland
Thick filament
40%
rare
classical HCM
?regression with statin
mild LVH, older age,
good prognosis
typical HCM
Thin filament
Tropomyosin
15
5%
modest LVH ; high SCD
? Benefit with losartan/
spirono
HCM .. Classification (Maron’s)
Type 1 ..Hypertrophy confined to anterior IVS …
10%
2 .. Hypertrophy involving ant. & inferior IVS..
20%
3 ..
,,
IVS and lateral free wall
52%
4 ..
,,
regions other than IVS
18%
5 .. Apical HCM
HCM -- Pathophysiology
• LV diastolic dysfunction
pulm. congestion
• LV outflow obstruction
dynamic
SAM , hypercontractile septum
• myocardial ischemia
inadequate capillary density
abnormal microvasculature
myocardial bridging of coronaries
• arrhythmia
ischemia ; LVH ; fibrosis ; cardiac failure
HCM .. Clinical
Asymptomatic / symptomatic .. Dyspnea, angina, SCD..
Pulse .. brisk, spike and dome pattern
JVP .. A +
Apex .. Double / triple
Murmurs .. LVOT / MR
any situation which reduces
LV size increases the
obstruction
Apex cardiogram in HOCM
ACG
ACG
Normal
HOCM
HCM .. hemodynamics
HCM – Natural history
• presentation at any age
• overall mortality - 1% per year ; in children 2%
• SCD --
more in adolescence and young adults
rare < 10 yrs
extremely uncommon in infancy
commonly arrhythmia based - VT / VF
> in early morning hours
sedentary / modest activity
during or just after vigorous activity
HCM .. risk factors for SCD
Major
• prior cardiac arrest / sustained VT
• family h/o HCM related SCD
• syncope
• repetitive nonsustained VT
• massive LVH > 30 mm
• fall in BP during exercise
Possible
• malignant genotype
• LVOT gr > 50 mm Hg
• myocardial ischemia
• AF
• competitive physical exertion
HCM -- Management
• Pharmacologic
betablockers, verapamil , disopyramide
antiarrhythmics .. ? Amiodarone
anticoagulation
antifailure measures
• Pacing
• PTSA
• ICD
• Surgery
HCM …. Pacing
DDD pacing …. ? Benefit
2 randomised studies
• modest reduction in LVOT gr . 25 – 40 mm Hg
• subjective improvement
• treadmill time / max. O2 cons. didn’t improve
? Placebo effect
Pacing In Cardiomyopathy trial …. Similar data
Conclusion : can be an option for severely symptomatic patients
refractory to medical treatment and not planned for
other treatment modalities
HCM -Surgery
• for patients with drug refractory symptoms
and LVOT gradient of > 50 mm Hg
• septal resection (Morrow procedure)
• operative mortality < 1% ; 0% in Mayo series
• in 90%
- abolition / reduction in LVOT gr
• in 85% - symptom relief
• 83 % 10 year survival
HCM -- PTSA
1 – 3 ml of 96 –98 % alcohol is injected into
the septal artery
Necrosis and thinning of IVS
Reduction in LVOT gradient
• scar may enhance arrhythmic death
• high incidence of heart block
• procedure mortality of 2%
Hence surgery is preferred in children
HCM … PTSA Vs surgery
myectomy
PTSA
Procedure mortality
1–2%
1–2%
Gr. reduction (rest)
to < 10mm Hg
to < 25 mm Hg
Symptoms
less
less
PPI for AVB
1–2%
5 – 10 %
Intramyocardial scar
absent
present
Longterm SCD risk
very low
?
HCM … PTSA Vs surgery
CMR after myectomy Vs PTSA
HCM ..Prevention of SCD
• drugs
-- ? Role
• ICD -- for primary and secondary prevention
Primary … > 1 major risk factor
Secondary .. SCD / sustained VT
• study of 128 pts
appropriate shock in 11%
in secondary prevention and
5% in primary prevention
HCM .. management
Asymptomatic
SCD risk high … ICD
HCM
Follow up
AF………cardioversion,rate control
anticoagulation
paroxysmal AF.. ? amiodarone
Progressive symptoms
DRUGS
BB ,verapamil, disopyramide
Refractory
Nonobstructive
Tt of CHF
Heart transplant
obstructive
Surgery … PTSA
?? DDD
HCM - screening
< 12 years – optional unless
family h/o HCM death
competitive athletes
symptomatic
12 – 18 years -- every 12 –18 months
> 18 years -- every 5 years
HCM Vs athletes heart
HCM
Athletes heart
Unusual pattern of LVH
+
_
LV cavity > 55 mm
_
+
LA enlargement
+
_
Bizarre ECG
+
_
Abnormal LV filling
++
±
LVH regression with
deconditioning
_
+
Family h/o
++
_