Implication of sleep apnea for cardiac remodeling in patients with hypertrophic cardiomyopathy

OBJECTIVES

Cardiac remodeling is a life-long process in hypertrophic cardiomyopathy (HCM), and if uncontrolled, would cause substantial morbidity and mortality. Sleep apnea (SA) is a common comorbidity in HCM. This study aimed to investigate the relationship between SA and cardiac remodeling in a large series of patients with HCM.

METHODS

A total of 606 patients with HCM who underwent sleep evaluations at Fuwai Hospital were included. Parameters of cardiac remodeling were evaluated by echocardiographic studies.

RESULTS

SA was present in 363 (59.9%) patients. Left ventricular (LV) end-diastolic diameter (P < 0.001), left atrial (LA) diameter (P = 0.024), ascending aortic diameter (P < 0.001) all increased and maximal end-diastolic wall thickness (P < 0.001) decreased with the severity of SA. After adjustment for sex, age, body mass index, hypertension, hyperlipidemia, diabetes, coronary artery disease and cigarette use, log (apnea-hypopnea index+1) was independently correlated with increasing LV end-diastolic diameter (β = 0.729, P = 0.003) and deceasing maximal end-diastolic wall thickness (β = -0.503, P = 0.009). Log (percentage of total sleep time spent with oxygen saturation<90% + 1) was independently correlated with increasing LV end-diastolic diameter (β = 0.609, P = 0.004) and LA diameter (β = 0.695, P = 0.006). Severity of SA (severe SA with odds ratio, 2.38; 95% CI, 1.20-4.70; P = 0.013), log (apnea-hypopnea index+1) (OR, 1.28; 95% CI, 1.01-1.63; P = 0.045) and log (percentage of total sleep time spent with oxygen saturation<90% + 1) (OR, 1.31; 95% CI, 1.08-1.59; P = 0.006) were also independently associated with LV enlargement.

CONCLUSIONS

Severity of SA is independently associated with cardiac remodeling indicating a trend toward enlarged chamber size and thinned wall. Clinical trials are required to determine whether treatment of SA improves cardiac remodeling and long-term outcomes in patients with HCM.

Risk Factors and Heart Rate Variability Associated with Left Ventricular Enlargement in Patients with Frequent Premature Ventricular Contractions

INTRODUCTION

Premature ventricular contractions (PVCs) were now well recognized to carry the risk of inducing left ventricular (LV) enlargement and were closely related to the cardiac autonomic nervous activity quantified by heart rate variability (HRV) analysis. However, the relationship between LV enlargement and HRV in patients with frequent PVCs is still unclear. This study aimed to investigate the risk factors and HRV for LV enlargement in patients with frequent PVCs.

METHODS

Patients with frequent PVCs (n = 571), whose PVC burden counts >10,000/24 h or PVC burden >10%, were recruited. Patients were divided into LV enlargement group (n = 161), defined as female left ventricular end-diastolic diameter (LVEDD) >49.8 mm or male LVEDD >54.2 mm, and LV normal group (n = 410). Two groups were compared on their clinical, electrocardiographic, and HRV parameters. Logistic regression analysis was used to predict the risk factors of LV enlargement in patients with frequent PVCs. The parameters of echocardiography, Holter monitoring, and HRV were collected after ablation.

RESULTS

There were significant differences between the patients with left enlargement and with normal LV structure, in terms of sex, left ventricular ejection fraction (LVEF), level of N-terminal pro-brain natriuretic peptide (NT-proBNP), 24-h PVC burden, with nonsustained ventricular tachycardia, multifocal PVCs, QRS duration of PVC, and values of very low-frequency power of HRV parameter (all p < 0.05). Multivariate analysis showed that female gender (odds ratio [OR] = 2.753, p < 0.001), increased NT-proBNP (OR = 1.011, p = 0.022), increased LVEF (OR = 0.292, p < 0.001), increased 24-h PVC burden (OR = 1.594, p < 0.001), increased standard deviation of all NN intervals (SDNN) (OR = 1.100, p = 0.003), increased the proportion of consecutive NN intervals that differ by more than 50 ms (pNN50) (OR = 0.844, p = 0.026) were predictors for LV enlargement in patients with frequent PVCs. 84.4% (54/64) of patients with LV enlargement at baseline had normalized their LV structure after ablation. The values of SDNN, standard deviation of the averages of NN intervals in all 5-min segments, the square root of the mean of the sum of the squares of differences between adjacent NN intervals, pNN50, low-frequency power (LF), LF/high-frequency power ratio of patients were significantly decreased after ablation (all p < 0.05).

CONCLUSION

Female gender, increased level of NT-proBNP, lower LVEF, higher PVC burden, increased sympathetic parameters SDNN, and reduced parasympathetic parameters pNN50 were the independent risk factors of LV enlargement in patients with frequent PVCs. LV enlargement induced by PVCs can be reversible after PVC elimination by ablation. The activities of sympathetic and parasympathetic were reduced after ablation.

Incidence and predictors of left ventricular remodeling among elderly Asian women: a community-based cohort study

Background

Left ventricular (LV) remodeling is closely linked to the progression of heart failure. There are limited data on the epidemiology of new onset LV remodeling among elderly women, which requires further investigation.

Method

We examined data from a community-based cohort of women aged > 65 years, who had received > 2 echocardiography scans from 2009 to 2014. Exclusion criteria for patients included prior echocardiographic evidence of left ventricular enlargement (LVE) or hypertrophy (LVH). LVE was defined as the index of left ventricular internal diameter at end-diastole to height, and LVH was defined as the left ventricular mass and thickness index which indicate hypertrophy.

Results

Of the 474 subjects (age 71.85 ± 6.47 years), 49 (10.3%) developed LVH, while 55 (11.6%) developed LVE during the mean follow-up period of 5 years. Independent predictors of LVH included: central blood pressure (CBP, per 10 mmHg) [HR 1.094, 95% CI 1.011–1.202], BMI˃25(kg/m ²)[HR 1.306, 95% CI 1.175–1.434], B-type natriuretic peptide (BNP) ≥ 100 (pg/mL) [HR 1.635, 95% CI 1.107–3.311] and brachial-ankle pulse wave velocity (baPWV) ≥16 m/s [HR 1.605, 95% CI 1.474–2.039]. Predictors of LVE were CBP (per 10 mmHg) [HR 1.121, 95% CI 1.027–1.238], BMI˃25(kg/m ²)[HR 1.302, 95% CI 1.173–1.444], Low-density lipoprotein cholesterol (LDL-C) [HR 1.193, 95%CI 1.013–1.405] and E/e’ ratio [HR 1.077, 95% CI 1.017–1.140].

Conclusion

CBP and BMI were demonstrated to be independent and robust predictors of left ventricular remodeling among elderly women, including both LVE and LVH. BNP and baPWV were specifically related to the development of LVH, whereas LDL-C and E/e’ ratio were related to LVE.