AIM: To determine the degree to which an extended time to the peak of the aortic forward wave or early wave reflection time enhance associations between aortic backward wave pressure and hence central aortic pulse pressure (PPc) and left ventricular mass index (LVMI). METHODS: In 701 adult participants from a community sample either receiving no antihypertensive therapy or receiving low-dose thiazide diuretic monotherapy for at least a year (the major therapy employed), we assessed aortic haemodynamics (SphygmoCor software and wave separation analysis; AtCor Medical, West Ryder, New South Wales, Australia) and LVMI (echocardiography). RESULTS: An interaction between time to the peak of the aortic forward wave and aortic backward wave pressure was independently associated with aortic augmented pressure (P < 0.01), PPc (P < 0.005), LVMI (P < 0.01), and LV hypertrophy (LVH; P = 0.01). The time to the peak of the aortic forward wave-aortic backward wave pressure interaction translated into a stepwise increase in the independent association between aortic backward wave pressure and aortic augmented pressure or PPc across quartiles of time to the peak of the aortic forward wave (P < 0.05 to < 0.0001 for comparison of slopes of relations). Furthermore, the time to the peak of the aortic forward wave-aortic backward wave pressure interaction translated into an increase in the independent association between PPc or aortic backward wave pressure and LVMI (P < 0.05 to < 0.001 for comparison of slopes and strength of relations) or LVH (P < 0.05 for comparisons of odds ratios), but not between forward wave pressures and LVMI or LVH across quartiles of time to the peak of the aortic forward wave. A markedly better ability of aortic backward wave pressure and PPc, but not forward wave pressures to detect LVH was noted in the highest as compared with the first three quartiles of time to the peak of the aortic forward wave (P < 0.05). In contrast, reflection time failed to influence the impact of aortic backward wave pressure or PPc on LVMI. CONCLUSIONS: Time to the peak of the aortic forward wave, but not early wave reflection markedly influences the impact of aortic backward wave pressure and hence aortic pulse pressure on LVMI and LVH in adults.