European Journal of Cardio-Thoracic Surgery, Vol 7, 528-532, Copyright © 1993 by European Association for Cardio-thoracic Surgery
Hemodynamic findings in patients with left bundle branch block after myectomy in hypertrophic obstructive cardiomyopathy (HOCM)
RM Klein, B Schwartzkopff, HD Schulte, B Losse and BE Strauer
Department of Cardiology, Pneumology and Angiology, Heinrich-Heine- University Dusseldorf, Germany.
To determine the hemodynamic effects of postoperative left bundle branch
block (LBBB) in patients with hypertrophic obstructive cardiomyopathy
(HOCM), we investigated 28 patients using Swan-Ganz pulmonary artery
catheterization at rest and on exercise. Fourteen patients had
postoperative LBBB (group A) and 14 had undisturbed intraventricular
conduction (group B). All patients were examined by clinical investigation,
electrocardiogram and bicycle ergometer exercise preoperatively and
postoperatively (mean 6 months). Pulmonary artery pressure and pulmonary
capillary wedge pressure were continuously measured, stroke volume index
and cardiac index were obtained by the thermodilution method. All patients
showed an improvement of their clinical symptoms (NYHA class: 2.8 +/- 0.45
before and 1.7 +/- 0.22 after operation) (P < 0.05). The postoperative
exercise capacity (Watt) increased significantly (P < 0.05) in group A
by 38% and in group B by 30%. The maximum mean pulmonary artery pressure on
physical exercise decreased in group A from 40.7 +/- 9.1 to 32.5 +/- 8.7
mmHg and in group B from 42.8 +/- 12.4 to 32.4 +/- 9.2 mmHg (P < 0.05).
The maximal stroke volume index and cardiac index improved significantly in
9 of 14 patients in each group. Thus, patients with HOCM and LBBB after
myectomy have a marked improvement in postoperative hemodynamics, the
results equaling those of patients with undisturbed intraventricular
conduction.
