Differences in ventricular septal motion between subgroups of patients with heart failure.

BACKGROUND: Septal systolic motion is determined by the end-diastolic trans-septal pressure gradient, and hence is load dependent.

OBJECTIVE: To explore septal contribution to left ventricular (LV) systolic function in patients with heart failure.

DESIGN: Echocardiograms were identified post hoc from normal subjects and a cohort of patients with heart failure.

PATIENTS: Twelve normal subjects and 69 patients with heart failure and normal conduction or left bundle brance block (LBBB) were studied.

METHODS: Parasternal short axis LV end-diastolic and end-systolic areas were traced. Using a floating centroid, 32 radial chords were constructed, and perecentage shortening from end-diastole to end-systole was calculated for each chord.

MAIN RESULTS: Comparing heart failure with normal conduction and LBBB, LV end-diastolic area was similar (43+/-10 versus 45+/-12 cm(2) not significant), but stroke area was higher in normal conduction (7+/-4 versus 4+/-4cm(2), P<0.05) as was area ejection fraction (0.17+/-0.11 versus 0.10+/- 0.08, P<0.01). In normal subjects, the summed percentage shortening of 10 midseptal chords was similar to that of 10 midfreewall chords (256+/-16% versus 235+/-32%, not significant). In contrast, patients with heart failure and normal conduction had greater midseptal than midfreewall sum med chord shortening (113+/-18% versus 60+/-12%, P<0.05); patients with heart failure and LBBB had paradoxical septal motion (3+/-28, P<0.05 compared with normal conduction).

CONCLUSIONS: Patients with heart failure and normal conduction have an enhanced septal contribution to LV systolic function compared with normal subjects. In heart failure with LBBB, this is lost and the area ejection fraction is lower. Strategies to optimize septal function in heart failure warrant further study.