Kojodjojo Pipin, Kanagaratnam Prapa, Markides Vias, Davies D Wyn, Peters Nicholas
St. Mary's Hospital, National Heart and Lung Institute of Imperial College of Medicine, London, UK.
J Cardiovasc Electrophysiol. 2006 Feb;17(2):120-7. doi: 10.1111/j.1540-8167.2005.00293.x.
Advancing age is an independent risk factor for atrial fibrillation (AF), which is considered to be initiated by ectopic triggers and maintained by an arrhythmogenic substrate. It is not known whether substrate changes produce this age-related increase in propensity toward AF. We addressed the hypothesis that advancing age is associated with changes in biatrial electrophysiology even in patients with no history of atrial arrhythmias.
Patients with left-sided accessory pathways and requiring routine electrophysiological studies were recruited. Electroanatomic mapping was performed in the left and right atria of 23 patients (age ranging from 17 to 75 years) with structurally normal hearts and no history of AF during sinus rhythm and pacing. Unlike previous studies, a trigonometric method was used to quantify wavefront propagation velocities (WPV) precisely in the direction of propagation. Refractoriness was measured at 2 cycle lengths, at three different atrial sites. Both right (r =-0.77, P < 0.0001) and left (r =-0.79, P < 0.001) atrial WPV demonstrated strongly inverse correlation with age. Furthermore, left and right WPVs were highly correlated (r = 0.66, P < 0.01), with velocities being 6.4 +/- 2.2 cm/sec higher in the right atria (P < 0.01). Refractoriness was significantly correlated with increasing age only at the septum (r = 0.53, P < 0.01). Left atrial wavelength was inversely correlated with increasing age (r =-0.56, P = 0.03). P wave duration was associated with age (r = 0.42, P = 0.04) and left atrial size (r = 0.44, P = 0.04) but not atrial WPV.
Aging human atria demonstrate progressive decline in WPV and increase in septal refractoriness. These age-related changes in biatrial electrophysiology are likely to be important factors in the age-related increase in AF prevalence.
年龄增长是心房颤动（AF）的一个独立危险因素，心房颤动被认为由异位触发因素引发，并由致心律失常基质维持。目前尚不清楚基质变化是否会导致与年龄相关的房颤易感性增加。我们探讨了这样一个假设，即即使在没有房性心律失常病史的患者中，年龄增长也与双房电生理变化有关。
招募患有左侧旁路且需要进行常规电生理研究的患者。对23名（年龄在17至75岁之间）心脏结构正常且在窦性心律和起搏期间无房颤病史的患者的左、右心房进行电解剖标测。与以往研究不同，采用三角测量法精确量化波前传播速度（WPV）在传播方向上的数值。在三个不同的心房部位，于两个心动周期长度下测量不应期。右心房（r = -0.77，P < 0.0001）和左心房（r = -0.79，P < 0.001）的WPV均与年龄呈强烈负相关。此外，左、右WPV高度相关（r = 0.66，P < 0.01），右心房的速度比左心房高6.4±2.2 cm/秒（P < 0.01）。仅在房间隔部位，不应期与年龄增长显著相关（r = 0.53，P < 0.01）。左心房波长与年龄增长呈负相关（r = -0.56，P = 0.03）。P波时限与年龄（r = 0.42，P = 0.04）和左心房大小（r = 0.44，P = 0.04）相关，但与心房WPV无关。
老年人心房的WPV逐渐下降，房间隔不应期增加。这些与年龄相关的双房电生理变化可能是房颤患病率随年龄增长而增加的重要因素。
