Soares-Costa J T, Soares-Costa T J, Santos A J, Monteiro A J
Hospital de Santa Maria.
Rev Port Cardiol. 1991 Dec;10(12):943-51.
To evaluate the influence of age (I) on the left ventricle (VE) systolic time intervals, the S2O interval, the pulse transmission time (TTP) and the relative amplitude of the a wave (Aa%) of the apexcardiogram (ACG) of normal individuals.
202 subjects considered as normal by clinical and electrocardiographic examinations were studied. Their age (I) was 38 +/- 13 years (average +/- 1 SD), being 125 male and 77 female. The electrocardiogram (ECG), phonocardiogram, ACG and carotid arterial pulse tracing (PC) were simultaneously recorded. The following intervals were determined: Electromechanical (IEM)--from the onset of QRS complex of the ECG to the ascending branch of the great wave of the ACG (A point); mechanical systole (SM)--from the A point of the ACG to the beginning of first high frequency vibration of the aortic component of the second heart sound (S2); ejection period (FE)--from the beginning of the anacrotic branch of the PC to the nadir of its dicrotic notch (ID); isovolumic contraction time (FIS)--subtracting FE duration to the SM duration; S2O interval--since S2 to the O point (nadir) of the ACG; Aa%--relation percentage expressed between a wave amplitude and total amplitude of the ACG; pulse transmission time--since S2 to ID. Statistically significant correlations (p less than 0.05) between I (years expressed) and the previously mentioned variables were investigated.
It was possible to verify: a) the IEM and FIS intervals were not significantly correlated with I; b) the FE had a linear, positive and significant correlation with I (r = 0.222); c) the correlations between FE and heart rate (FC) were not significantly different between the considered age groups (14-34, 35-49, 50-69 years); d) the S2O interval had a linear, negative and significant correlation with FC (r = -0.196), and a linear, positive and significant correlation with I (r = 0.392); e) multiple regression equation between S2O, I and FC was: S2O = 70 - 0.36 x FC + 0.55 x I; f) the Aa% had a linear, positive and significant correlation with I (r = 0.252); g) TTP has a linear, negative and significant correlation with I (r = -0.793).
a) The FE increases with I related probably to the afterload increasing that follows aging process; b) the S2O interval increases with I reflecting the elongation of the relaxing time that is associated to the senescence; c) the Aa% increases with I, expressing the reduction of the compliance of the VE associated to the aging; d) the TTP decreases with I related to the increasing of velocity of the pulse wave that follows senescence and is attributed to the increasing of the aortic stiffness.
评估年龄（I）对正常个体左心室（VE）收缩时间间期、S2O间期、脉搏传播时间（TTP）以及心尖搏动图（ACG）a波相对振幅（Aa%）的影响。
对202名经临床和心电图检查判定为正常的受试者进行研究。他们的年龄（I）为38±13岁（平均±1标准差），其中男性125名，女性77名。同时记录心电图（ECG）、心音图、ACG和颈动脉脉搏描记图（PC）。测定以下间期：机电间期（IEM）——从ECG的QRS波群起始点至ACG大波波峰上升支（A点）；机械收缩期（SM）——从ACG的A点至第二心音主动脉成分的首次高频振动起始点（S2）；射血期（FE）——从PC上升支起始点至其重搏波切迹最低点（ID）；等容收缩时间（FIS）——用SM持续时间减去FE持续时间；S2O间期——从S2至ACG的O点（最低点）；Aa%——a波振幅与ACG总振幅的关系百分比；脉搏传播时间——从S2至ID。研究I（以年表示）与上述变量之间具有统计学意义的相关性（p<0.05）。
可以证实：a）IEM和FIS间期与I无显著相关性；b）FE与I呈线性、正性且显著的相关性（r = 0.222）；c）在各考虑的年龄组（14 - 34岁、35 - 49岁、50 - 69岁）中，FE与心率（FC）之间的相关性无显著差异；d）S2O间期与FC呈线性、负性且显著的相关性（r = -0.196），与I呈线性、正性且显著的相关性（r = 0.392）；e）S2O、I和FC之间的多元回归方程为：S2O = 70 - 0.36×FC + 0.55×I；f）Aa%与I呈线性、正性且显著的相关性（r = 0.252）；g）TTP与I呈线性、负性且显著的相关性（r = -0.793）。
a）FE随I增加，可能与衰老过程中后负荷增加有关；b）S2O间期随I增加，反映了与衰老相关的舒张时间延长；c）Aa%随I增加，表明与衰老相关的VE顺应性降低；d）TTP随I降低，与衰老后脉搏波速度增加有关，这归因于主动脉僵硬度增加。
