Acute decrease of left ventricular mechanical dyssynchrony and improvement of contractile state and energy efficiency after left ventricular restoration.
OBJECTIVE
Surgical left ventricular restoration by means of endoventricular patch aneurysmectomy in patients with postinfarction aneurysm should result in acute improved left ventricular performance by decreasing mechanical dyssynchrony and increasing energy efficiency.


METHODS
Nine patients with left ventricular postinfarction aneurysm were studied intraoperatively before and after ventricular restoration with a conductance volume catheter to analyze pressure-volume relationships, energy efficiency, and mechanical dyssynchrony. The end-systolic elastance was used as a load-independent index of contractile state. Left ventricular energy efficiency was calculated from stroke work and total pressure-volume area. Segmental volume changes perpendicular to the long axis were used to calculate mechanical dyssynchrony. Statistical analysis was performed with the paired t test and least-squares linear regression.


RESULTS
Endoventricular patch aneurysmectomy reduced end-diastolic volume by 37% (P < .001), with unchanged stroke volume. Systolic function improved, as derived from increased +dP/dt(max), by 42% (P < .03), peak ejection rate by 28% (P < .02), and ejection fraction by 16% (P < .0002). Early diastolic function improved, as shown by reduction of -dP/dt(max) by 34% (P < .006) and shortened tau by 30% (P < .001). Left ventricular end-systolic elastance increased from 1.2 +/- 0.6 to 2.2 +/- 1 mm Hg/mL (P < .001). Left ventricular energy efficiency increased by 36% (P < .002). Left ventricular mechanical dyssynchrony decreased during systole by 33% (P < .001) and during diastole by 20% (P < .005).


CONCLUSIONS
Left ventricular restoration induced acute improvements in contractile state, energy efficiency, and relaxation, together with a decrease in left ventricular mechanical dyssynchrony.
Schreuder
Jan J
JJ
Department of Cardiac Surgery, San Raffaele University Hospital, Milan, Italy. schreuder@libero.it
Castiglioni
Alessandro
A
Maisano
Francesco
F
Steendijk
Paul
P
Donelli
Andrea
A
Baan
Jan
J
Alfieri
Ottavio
O
D000368:Aged; D006348:Cardiac Surgical Procedures / Q000379:methods; D005260:Female; D005500:Follow-Up Studies; D006322:Heart Aneurysm / Q000209:etiology / Q000601:surgery*; D006334:Heart Function Tests; D006801:Humans; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D009200:Myocardial Contraction / Q000502:physiology*; D009203:Myocardial Infarction / Q000150:complications* / Q000175:diagnosis; D011336:Probability; D011446:Prospective Studies; D012494:Sampling Studies; D013318:Stroke Volume / Q000502:physiology*; D016896:Treatment Outcome; D016277:Ventricular Function, Left / Q000502:physiology*; D020257:Ventricular Remodeling / Q000502:physiology