Effect of Chronic Afterload Increase on Left Ventricular Myocardial Function in Patients With Congenital Left-Sided Obstructive Lesions

The effect of pressure-overloading distance on left ventricular (LV) function in patients with congenital aortic coarctation and aortic stenosis (AS) was investigated. LV long-axis motions were recorded using M-mode and tissue Doppler imaging (TDI) techniques in 46 consecutive patients with severe LV outflow tract obstruction (23 coarctation and 23 AS), and results were compared with those of 23 controls. TDI lateral and septal long-axis systolic velocities, early diastolic velocities, and M-mode systolic amplitudes were lower in patients with coarctation and AS than controls (lateral site long-axis systolic velocity 7.1 ± 1.7 and 6.4 ± 1.6 vs 9.7 ± 1.7 cm/s, septal site long-axis systolic velocity 6.3 ± 1.3 and 5.4 ± 1.1 vs 7.7 ± 1.3 cm/s; lateral site early diastolic velocity 10.5 ± 2.2 and 8.2 ± 2.6 vs 13.1 ± 2.5 cm/s, septal site early diastolic velocity 7.4 ± 1.9 and 6.0 ± 1.8 vs 10.8 ± 1.6 cm/s, lateral site M-mode systolic amplitude 1.4 ± 0.2 and 1.3 ± 0.2 vs 1.6 ± 0.2 cm, septal site M-mode systolic amplitude 1.2 ± 0.2 and 1.1 ± 0.2 vs 1.4 ± 0.2 cm, p <0.01 for all). Compared with patients with coarctation, those with AS had lower TDI velocities, higher early LV filling velocity/long-axis diastolic velocity ratios, and a higher prevalence of long-axis incoordination (p <0.05 for all) despite similar LV mass index, ejection fraction, and systolic wall stress. In conclusion, LV long-axis function is impaired in patients with a chronic increase in afterload. Worse deterioration in LV function and higher prevalence of long-axis incoordination independent of LV outflow resistance is seen in patients with proximally increased LV afterload (AS) compared with distal disease (aortic coarctation).