RT Book, Section
A1 Douglas, Jr., John S.
A2 Samady, Habib
A2 Fearon, William F.
A2 Yeung, Alan C.
A2 King III, Spencer B.
SR Print(0)
ID 1146604306
T1 Alcohol Septal Ablation in Drug-Refractory Obstructive Hypertrophic Cardiomyopathy
T2 Interventional Cardiology, 2e
YR 2017
FD 2017
PB McGraw-Hill Education
PP New York, NY
SN 9780071820363
LK accesscardiology.mhmedical.com/content.aspx?aid=1146604306
RD 2024/04/19
AB Hypertrophic  cardiomyopathy  (HCM),  defined  clinically  by  the  presence  of  hypertrophy  of  a  nondilated  left  ventricle  without  loading  conditions  or  other  recognized  causes  of  hypertrophy,  occurs  in  1  per  500  individuals  in  the  general  population,  with  approximately  700,000  cases  in  the  US  population.1  HCM,  inherited  with  an  autosomal  dominant  Mendelian  pattern,  is  the  most  common  familial  heart  disease  and  the  most  common  cause  of  sudden  death  in  athletes  and  adolescents.  HCM  is  caused  by  1  of  more  than  1500  different  mutations  of  genes  encoding  sarcomeric  proteins.  This  genetic  heterogeneity  and  the  diverse  and  unpredictable  phenotypic  expressions,  clinical  manifestations,  and  prognosis  limit  the  value  of  genetic  testing  or  projections  based  on  affected  family  members.  The  vast  majority  of  individuals  who  are  genotype  positive/phenotype  positive  are  asymptomatic  or  minimally  symptomatic  and  are  undiagnosed.  Heart  failure  is  the  most  common  clinical  presentation  of  HCM  in  adults.  Diagnosis  may  be  difficult  due  to  compensating  adjustments  in  lifestyle  that  minimize  symptoms  and  nonspecific  physical  and  electrocardiogram  (ECG)  findings.  Elevation  of  left  atrial  pressure  results  from  diastolic  dysfunction  and  mitral  regurgitation.  Limitations  of  cardiac  output  in  HCM  resulting  in  fatigue,  dyspnea,  presyncope,  and  syncope  are  commonly  related  to  left  ventricular  outflow  tract  (LVOT)  obstruction  and  low  end-diastolic  volume  because  of  diastolic  dysfunction.  LVOT  obstruction  (LVOT  pressure  gradient  ≥30  mm  Hg)  is  present  in  one-third  of  HCM  patients  at  rest  and  in  an  additional  one-third  with  provocation  with  Valsalva  maneuver,  nitroglycerin,  post-extrasystolic  potentiation,  or  exercise  echocardiography,  a  preferred  method  of  evaluating  patients  with  no  resting  LVOT  gradient  but  marked  exercise  tolerance.  The  presence  of  LVOT  obstruction  is  a  predictor  of  HCM-related  progressive  heart  failure  and  heart  failure  death,2  and  relief  of  obstruction  surgically  results  in  better  survival  than  achieved  by  patients  without  this  treatment.3  Relief  of  LVOT  obstruction  is  a  principle  goal  of  both  medical  and  septal  reduction  therapies.