942-42 Is Mitral Valve Prolapse with Significant Mitral Regurgitation a Different Condition from Uncomplicated Mitral Prolapse? Results of Family Studies

Mild instances of mitral valve prolapse (MVP) have been suggested to represent variants of normal, whereas individuals with complicated forms of MVP have a distinct medical condition. This hypothesis would predict different phenotypic features and patterns of inheritance in relatives of index cases with complicated or uncomplicated MVP. Accordingly, we performed clinical and echocardiographic assessment of 16 MVP patients with and 76 without moderate to severe mitral regurgitation (MR+and MR– probands) and 60 and 256, respectively, first-degree relatives (MR+ and MR– relatives). MR+ probands were older (p=0.01), more likely to be male (p=0.002), were more overweight (p=0.004) and had higher systolic blood pressures (p=0.05) and larger aortic roots (p=0.034) after the effects of age and body size were taken into account. MR+ and MR– relatives had similar prevalences (27 and 32%) and age distribution of MVP, but affected MR+ relatives were younger (expected because more children and fewer parents of MR+ probands could be evaluated). and more likely to be male. MR+ and MR- relatives were virtually identical in regard to body habitus, blood pressure, the prevalence of auscultatory findings, thoracic bony abnormalities and palpitations and all echo measurements including anterior mitral leaflet thickness. Four instances of significant MR and two MVP-related complications (infective endocarditis and transient ischemic attack) occurred in the 82 relatives of MR– probands as opposed to none among relatives of MR+ probands. In 20 families, one proband or relative with MVP had severe MR and at least one other with MVP (presumably due to the same gene) was free of MR or complications. Thus, MVP with severe MR does not represent a heritable phenotype and commonly coexists with mild forms of MVP in the same family, making their classification as separate conditions illogical and potentially misleading

763-1 Assessment of Left Ventricular Function by Circumferential Stress-Midwall Shortening Relations in Dilated Cardiomyopathy

Echocardiographic stress endocardial shortening relations provide estimates of LV contractility that do not uniformly detect myocardial dysfunction in dilated cardiomyopathy (DCM). Recently it has become apparent that midwall (mid) fractional shortening and circumferential (c) end-systolic stress (ESS) provide the most appropriate paired afterload and function measures. Both meridional (m) and cESS were related to both endocardial (e) FS and midFS in 42 patients with DCM (98% dead during follow-up; eFS =4% in the survivor) and in 140 normals. Eight patients (19%) fell into the 95% confidence interval of the normal relation of eFS to mESS (top panel), 14% had apparently normal midFS-mESS relations but midFS was depressed in relation to cESS in 100% of patients (lower panel). Thus, (1) use of cESS-shortening relations improves the ability to identify patients with depressed LV function; (2) use of midFS or eFS are equivalent in DCM with LV dilatation and wall thinning

Lack of Reduction of Left Ventricular Mass in Treated Hypertension: The Strong Heart Study

BACKGROUND: Hypertensive left ventricular mass (LVM) is expected to decrease during antihypertensive therapy, based on results of clinical trials. METHODS AND RESULTS: We assessed 4‐year change of echocardiographic LVM in 851 hypertensive free‐living participants of the Strong Heart Study (57% women, 81% treated). Variations of 5% or more of the initial systolic blood pressure (SBP) and LVM were categorized for analysis. At baseline, 23% of men and 36% of women exhibited LV hypertrophy (LVH, P<0.0001). At the follow‐up, 3% of men and 10% of women had regression of LVH (P<0.0001 between genders); 14% of men and 15% of women, free of baseline LVH, developed LVH. There was an increase in LVM over time, more in men than in women (P<0.001). Participants whose LVM did not decrease had similar baseline SBP and diastolic BP, but higher body mass index (BMI), waist/hip ratio, heart rate (all P<0.008), and urinary albumin/creatinine excretion (P<0.001) than those whose LVM decreased. After adjusting for field center, initial LVM index, target BP, and kinship degree, lack of decrease in LVM was predicted by higher baseline BMI and urinary albumin/creatinine excretion, independently of classes of antihypertensive medications, and significant effects of older age, male gender, and percentage increase in BP over time. Similar findings were obtained in the subpopulation (n=526) with normal BP at follow‐up. CONCLUSIONS: In a free‐living population, higher BMI is associated with less reduction of hypertensive LVH; lack of reduction of LVM is independent of BP control and of types of antihypertensive treatment, but is associated with renal damage