Assessing autonomic function in hypertrophic cardiomyopathy

• Published in: Arquivos brasileiros de cardiologia Vol. 85; no. 6; pp. 388 - 396
• Main Authors: Bittencourt, Marcelo Imbroinise, Benchimol Barbosa, Paulo Roberto, Drumond Neto, Cantídio, Bedirian, Ricardo, Barbosa, Eduardo Corrêa, Brasil, Flavia, Bomfim, Alfredo de Souza, Albanesi Filho, Francisco Manes
• Format: Journal Article
• Language: English; Portuguese
• Published: Brazil 01-12-2005
• Subjects: Adult; Algorithms; Autonomic Nervous System - physiopathology; Cardiomyopathy, Hypertrophic - physiopathology; Case-Control Studies; Echocardiography, Doppler; Electrocardiography, Ambulatory; Female; Heart Rate - physiology; Humans; Male; Middle Aged; Parasympathetic Nervous System - physiopathology; Statistics, Nonparametric; Sympathetic Nervous System - physiopathology
• DOI: 10.1590/S0066-782X2005001900004
• ISSN: 0066-782X

Assess the autonomic function in hypertrophic cardiomyopathy (HCM) through heart rate variability (HRV) and to correlate it to echocardiographic data.
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).
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.
1) Parasympathetic prevalence was shown during autonomic stimulation in HCM patients; 2) No correlation was found between HRV and echocardiographic measurements under analysis.