Heart Rate Variability Declines with Increasing Age and CTG Repeat Length in Patients with Myotonic Dystrophy Type 1

Abstract

and in the sinoatrial node associated to myocyte hypertrophy 7. Patients with greater skeletal muscle impairment are older and experience heart problems more frequently 8. The autonomic nervous system plays a crucial role in heart rate (HR) modulation. A decrease in its variability is a predictor of morbidity and mortality 9,10. Earlier research found that healthy women showed greater vagal dominance over HR, which seems to account for their enhanced cardioprotection compared to men, although these differences decrease with age 11. The study of heart rate variability (HRV) has therefore been proposed as a simple, inexpensive and non-invasive method that provides information on neurocardial integrity. A number of investigations on the overall function of the autonomic nervous system in patients with MD show that the presence of autonomic neuropathy is highly unlikely 1,12,13. However, studies on autonomic modulation of HR in patients with MD have obtained conflicting results 14-18. The present study aimed to evaluate the possible differences in autonomic modulation of HR between the sexes for patients with MD and healthy individuals in different body positions and the influence of interaction between sex and disease on autonomic modulation of HR in different body positions.

Usefulness of clinical and electrocardiographic data for predicting adverse cardiac events in patients with myotonic dystrophy

“…Although such a correlation between the extent of CTG repeats and the degree of cardiac involvement has been described in some series, others have shown conflicting results (9,17,18,25,(34)(35)(36)(37)(38)(39). Of note is the study by Lazarus et al (17); using precise invasive electrophysiological measurements, the study was unable to show such a relationship between conduction delays and the extent of CTG repeats.…”

Myotonic dystrophy and the heart: A systematic review of evaluation and management

“…The CTG expansion size may increase with age, vary between tissues and correlate with the extent and rate of progression of cardiac disease [2][3][4][5], however, the correlation with clinical cardiac disease has not International Journal of Cardiology 184 (2015) 600-608…”

Variabilidade da frequência cardíaca em pacientes com Distrofia Miotônica tipo 1

“…In contrast to other research [14][15][16][17][18] , this study assesses HRV during short time periods in sitting and supine positions, in addition to analyzing the magnitude of gender differences. Methodological procedures were based on the fact that [24][25][26] .…”

“…In a multicenter study, Hardin et al 16 evaluated 289 MD patients in the supine position during short HRV acquisition periods. They did not include a control group since the study aims were to evaluate ambulatory ECG in a large and diverse population with MD type 1, in which clinical factors were associated to HRV by analyzing low frequency domains LFms 2 , HFms 2 and LF/HF ratio.…”

“…A number of investigations on the overall function of the autonomic nervous system in patients with MD show that the presence of autonomic neuropathy is highly unlikely 1,12,13 . However, studies on autonomic modulation of HR in patients with MD have obtained conflicting results [14][15][16][17][18] . The present study aimed to evaluate the possible differences in autonomic modulation of HR between the sexes for patients with MD and healthy individuals in different body positions and the influence of interaction between sex and disease on autonomic modulation of HR in different body positions.…”