Echocardiographic evaluation oftheresponse to afterload stress test inyoungasymptomatic patients withchronic severe aortic regurgitation: sensitivity oftheleft ventricular end-systolic pressure-volume relationship

Thedetection ofmyocardial depression isanimportant goalinthemanagement of patients withchronic severe aortic regurgitation butmaybequite difficult atanearly stage bythe conventional basal measures ofcontractility. Theresponse toafterload stress determined byangioten- sinchallenge andtheend-systolic pressure-volume relationship wasevaluated echocardiographically in 16asymptomatic ormildly symptomatic patients with chronic severe aortic regurgitation, ages15to56 years (mean32± 12). Ninenormal subjects, ages25to41years (mean31± 5),served asacontrol group. Inthegroup withaortic regurgitation, end-systolic dimensions weregreater than55mm infive of16patients andfractional shortening was25%orless intwoof16.Inthecontrol group angiotensin caused adecrease ofstroke volume index insixoutofninepatients (15%atthemost)andamild increase inthree. Inthegroup withaortic regurgitation stroke volume index decreased by15%ormore ofthebasal value innineof16patients andincreased ordecreased byless than15%inseven of16. Ejection fraction decreased inbothgroups, from61± 6%to52± 7%inthecontrol group andfrom56 ± 6%to45± 5%inthegroup withaortic regurgitation. Ventricular function curves werederived by relating end-diastolic volume index tostroke workindex; seven of16patients hadabnormal responses reflecting anafterload mismatch. End-systolic pressure-volume relationships wereconstructed; the slope oftherelationship (Es) ranged from660 to800(740 +50) inthecontrol group andfrom460 to72° (580 ±70) inthegroup withaortic regurgitation. Inthis group Eswasbelowthe95%confidence limits ofthecontrol group in12of16patients. Considering all thetested indexes ofventricular performance, therankorder ofincidence ofabnormal findings inthegroup withaortic regurgitation wasasfollows: basal fractional shortening (13%ofpatients), basal end-systolic dimension (31%),angiotensin-induced decrease ofstroke workindex (41%) andstroke volume index (56%), andEs(75%). Inconclusion, in youngasymptomatic ormildly symptomatic patients withchronic severe aortic regurgitation (1)Es, derived fromnoninvasive measurement ofsystolic pressure andechocardiographic parameters, isthe mostsensitive index ofmyocardial dysfunction amongthose considered inthis study and(2)depression ofcontractility isfrequently present before end-systolic dimension reaches 55mm andfractional shortening decreases below25%. Circulation 70,No.4,561-569, 1984. ITISgenerally agreed that aortic valve replacement for between contractility andloading conditions atrest patients withchronic severe aortic regurgitation should andduring exertion canaccount forthis apparent dis- notalways bedelayed until theappearance ofsevere crepancy.7 8Nevertheless, myocardial dysfunction, symptoms. 1-6 Animpairment ofmyocardial contractil- whether ornotitisassociated withseveresymptoms, itycanbepresent evenintheabsence ofsignificant canbeirreversible, preventing improvement orad- symptomsinthese patients. Thecomplex interplay versely affecting survival after valve replacement. l9-' FromtheIstituto diMalattic dell'Apparato Cardiovascolare. Univer- Thereforeearlydetection of potentially irreversible sita degli Studi, Bologna, Italy. myocardial depression isanimportant goal intheman-