[Assessing autonomic function in hypertrophic cardiomyopathy].
OBJECTIVE
Assess the autonomic function in hypertrophic cardiomyopathy (HCM) through heart rate variability (HRV) and to correlate it to echocardiographic data.


METHODS
Two groups were studied, and compared for gender, age and HR: A) Ten (10) patients reporting septal HCM (70% non-obstructive); B) Ten (10) healthy volunteers. HRV was analyzed along four successive stages: at rest, under controlled breathing, while bending, and controlled breathing associated to bending. Variables means were compared between groups and intra-groups in the different stages; in Group A, variables means were correlated to echocardiographic measurements (interventricular septum and left atrial diameter).


RESULTS
No HRV difference was reported among groups in the first 3 stages. In the fourth stage vagal activity was shown to be higher in Group A [quadratic mean log between RR intervals (RMSSD) - 1.35+/-0.14 vs 1.17+/-0.16; p=0.019; high frequency component logarithm (LogHF)- 4.89+/-0.22 vs 4.62+/-0.26; p=0.032]. Along the stages, vagal measurements [rate of pairs of consecutive RR intervals whose difference is > or =50 ms (pNN50) and LogHF] also showed lower reduction in the third stage in Group A, while LogHF showed some increase in last stage (p=0.027), thus indicating marked parasympathetic activity in that group. Group A HRV analysis showed no difference among patients reporting larger hypertrophy or atrial diameter.


CONCLUSIONS
1) Parasympathetic prevalence was shown during autonomic stimulation in HCM patients; 2) No correlation was found between HRV and echocardiographic measurements under analysis.
Bittencourt
Marcelo Imbroinise
MI
Universidade do Estado do Rio de Janeiro, Santa Casa de Misericórdia, Rio de Janeiro, RJ. mib@cardiol.br
Benchimol Barbosa
Paulo Roberto
PR
Drumond Neto
Cantídio
C
Bedirian
Ricardo
R
Barbosa
Eduardo Corrêa
EC
Brasil
Flavia
F
Bomfim
Alfredo de Souza
Ade S
Albanesi Filho
Francisco Manes
FM
D000328:Adult; D000465:Algorithms; D001341:Autonomic Nervous System / Q000503:physiopathology*; D002312:Cardiomyopathy, Hypertrophic / Q000503:physiopathology*; D016022:Case-Control Studies; D015150:Echocardiography, Doppler; D015716:Electrocardiography, Ambulatory; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010275:Parasympathetic Nervous System / Q000503:physiopathology; D018709:Statistics, Nonparametric; D013564:Sympathetic Nervous System / Q000503:physiopathology