Abstract:

Objective

To investigate the correlation between left atrial/ventricular diameter ratio（LAD/LVD） and the degree of left ventricular outflow tract （LVOT） obstruction in patients with obstructive hypertrophic cardiomyopathy （HOCM）.

Methods

A total of 364 HOCM patients in Xijing Hospital were continuously enrolled.The demographic parameters and 24-hour brachial artery blood pressure parameters of the patients were collected.The following parameters were obtained using transthoracic echocardiography：maximum septal thickness （MIVS） at the base of the septum， length of anterior mitral leaflet （AML） and posterior mitral leaflet （PML）， coaptation point of the leaflets and the septum （CS）， left ventricular enddiastolic volume index （LVEDVi）， left ventricular end-systolic volume index （LVESVi）， left ventricular enddiastolic left atrial diameter （LAD） and left ventricular end-diastolic diameter（LVD）， and left atrial/ ventricular diameter ratio （LAD/LVD）.SAM and E/e' were recorded as well.LVOT resting gradient （LVOTPG-r） was measured by continuous Doppler and LVOT provoking gradient （LVOTPG-p） was measured by exercise stress echocardiography.The correlation between LAD/LVD and LVOTPG-r and LVOTPG-p was analyzed.

Results

Pearson correlation analysis showed that natural logarithm LVOTPG-r ［ln（LVOTPG-r）］ was linearly correlated with age （r =0.240， P＜0.001）， MIVS （r =-0.224， P＜0.001）， AML （r =0.135， P =0.010），LAD/LVD ratio （r =0.195， P ＜0.001）， LVESVi （r =0.113， P =0.031）， and E/e' （r =0.195， P ＜0.001）.Spearman's correlation analysis showed that ln（LVOTPG-r） was linearly correlated with gender （r =0.191，P＜0.001） and SAM classification （r =0.343， P＜0.001）.Multivariate linear regression analysis showed that after adjusting for age， gender， MIVS， AML， SAM classification， LVESVi， and E/e'， the LAD/LVD ratio was independently correlated with ln（LVOTPG-r） （P =0.008）.Pearson correlation analysis showed that natural logarithm LVOTPG-p ［ln（LVOTPG-p）］ was linearly correlated with age （r =0.128， P＜0.001）， mean diastolic blood pressure （DBP） （r =-0.127， P =0.015）， heart rate （HR） （r =1.04， P =0.048）， MIVS （r =-0.210，P＜0.001）， AML （r =0.116， P =0.027）， PML （r =0.184， P＜0.001）， LAD/LVD ratio （r =0.195， P＜0.001），and E/e' （r =0.201， P＜0.001）.Spearman's correlation analysis showed that ln（LVOTPG-p） was linearly correlated with gender （r =0.125， P =0.017） and SAM classif ication （r =0.296， P＜0.001）.Multivariate linear regression analysis showed that after adjusting for age， gender， mean DBP， HR， MIVS， AML， PML， and E/e'，the LAD/LVD ratio was independently correlated with ln（LVOTPG-p） （P =0.017）.

Conclusion

There is an independent correlation between the LAD/LVD and the degree of LVOT obstruction in patients with HOCM，whether at rest or under exercise state.This suggests that clinicians need to fully consider the contribution of LAD/LVD ratio to LVOT obstruction in patients with HOCM， in order to develop reasonable treatment plans and prognostic evaluation strategies.

Key words: Hypertrophic obstructive cardiomyopathy, Left ventricular outflow tract obstruction, Cardiac anatomy, Left atrial diameter, Left ventricular diameter