Evaluation of the relation between changes in R-wave amplitude and LV mass and dimensions in a model of “Reversed Hypertrophy”

Electrocardiographic (ECG) diagnosis of left ventricular (LV) hypertrophy, based on the so-called voltage criteria, suffers from low sensitivity, so that the dominant cardiac factors influencing the QRS voltage have not been fully elucidated. Our aim was to evaluate the correlation between changes in R-wave amplitude (R-AMP) and LV mass and size in a model of “reversed hypertrophy”, such as that induced by 5-days head-down (6°) bed rest (HDBR). ECG Holter-24h and echocardiographic imaging were obtained before (PRE) and on the last day (HDT5) of HDBR in 11 male subjects (age 21÷41 years).The R-AMP derived from the vectorcardiogram was correlated with the echo-derived LV mass, end-diastolic (EDV), systolic (ESV) and stroke (SV) volumes. Linear regression between R-AMP and ESV (y=.013R+26, r2=.31) was found significant (p<;.05), while regression with LV mass (y=.195R+83, r2=.19, p=.04) was weaker. Further studies using electrophysiologic models could better elucidate the phenomenon.