Asymmetric Left Ventricular Contraction in Patients with Previous Myocardial Infarction

The possibility was considered that the presence and magnitude of asymmetry of left ventricular (LV) contraction in patients with previous myocardial infarction (MI) could be determined from volume and dimensional characteristics of contraction derived independently from the frontal (AP) and lateral (LAT) views of biplane cineangiograms. Accordingly, regression analyses were determined from biplane cineangiograms in 18 patients without MI to compute end-diastolic (EDV) and end-systolic (ESV) volumes in the AP and LAT views (V biplane = 1.03V calc AP-7.7 ml, r = 0.989, SEE = 8.7 ml; V biplane = 0.85V calc LAT+5.9 ml, r = 0.99, SEE = 8.2 ml). Comparative measurements of EDV, stroke volume (SV), and ejection fraction (EF) in these patients were identical in AP and LAT films, with a small random error (EDV AP = 136.7 ± 13.0 ml; EDV LAT = 136.7 ± 13.4 ml; SEE for SV = ± 13.0 ml ( ± 16%), SEE for EF= ± 0.03 ( ± 5%). In 20 patients with MI EDVs calculated from AP and LAT films were also identical (189.9 ± 18.1 ml and 184.2 ± 17.1 ml, respectively). However, SV exhibited substantial variation between the two views (SV AP = 76.7 ± 5.5 ml and SV LAT = 51.5 ± 4.7 ml, P < 0.001), as did EF (EF AP = 0.45 ± 0.03 and EF LAT = 0.31 ± 0.03, P < 0.001). In addition, directly measured extent of LV minor circumferential shortening was comparable in AP and LAT films in patients without MI (5.15 ± 0.50 cm and 5.25 ± 0.47 cm, respectively), while in patients with MI these measurements differed significantly (4.74 ± 0.41 cm and 2.73 ± 0.31 cm, respectively; P < 0.001). It is concluded that a systematic error will result when estimates of SV and EF, as well as mean circumferential fiber shortening rate, are derived from single plane cineangiograms in patients with MI.