Influence of cigarette smoking on biventricular systolic function independent of respiratory function: a cross-sectional study

Simultaneously Assessed Three-Dimensional Speckle-Tracking Echocardiography-Derived Left Ventricular and Left Atrial Volumes Are Associated in Healthy Adults-Findings from the MAGYAR-Healthy Study

INTRODUCTION

The left atrium (LA) has a significant role in regulating blood flow from veins to the left ventricle (LV). LV performance is affected by several factors including preload, which is partly, but highly, dependent on LA volumes. The aim of the present study is to perform simultaneous assessment of LA and LV volume changes during the cardiac cycle in healthy circumstances. Therefore, LA and LV volumes and volume-based functional properties were determined in healthy adults, and the associations of these parameters were examined.

METHODS

The present study consists of 164 healthy adults (age: 33.0 ± 12.3 years, 82 males) being in sinus rhythm. All subjects have undergone complete two-dimensional Doppler echocardiography with three-dimensional speckle-tracking echocardiography (3DSTE).

RESULTS

Increased end-systolic maximum LA volume was associated with higher LV volumes and reduced LV ejection fraction. Very high early pre-atrial contraction and late diastolic LA volumes were associated with increased LV volumes, reduced LV ejection fraction and increased LV mass. Increased LA volumes were associated with increased LV mass. Higher LV volumes were associated with tendentiously higher LA volumes. Higher LV end-diastolic volume was associated with tendentiously higher all LA stroke volumes (SVs) and total and active LA emptying fractions (EFs). Higher LV end-systolic volume was associated with tendentiously higher all LA SVs but preserved all LA EFs.

CONCLUSIONS

3DSTE is capable of simultaneous assessment of LA and LV volumes and volume-based functional properties for (patho)physiologic studies. Moreover, 3DSTE-derived LV and LA volumes and functional properties show strong associations.

Nicotine and novel tobacco products drive adverse cardiac remodeling and dysfunction in preclinical studies

Background

The heart undergoes structural and functional changes in response to injury and hemodynamic stress known as cardiac remodeling. Cardiac remodeling often decompensates causing dysfunction and heart failure (HF). Cardiac remodeling and dysfunction are significantly associated with cigarette smoking. Although cigarette smoking has declined, the roles of nicotine and novel tobacco products (including electronic cigarettes and heat-not-burn tobacco) in cardiac remodeling are unclear. In this perspective, we present evidence demonstrating maladaptive cardiac remodeling in nicotine-exposed mice undergoing hemodynamic stress with angiotensin (Ang)-II infusion and review preclinical literature linking nicotine and novel tobacco products with cardiac remodeling and dysfunction.

Methods

Adult, male C57BL/6J mice were exposed to room air or chronic, inhaled nicotine for 8 weeks. A subset of mice was infused with Ang-II via subcutaneous osmotic mini-pumps during the final 4 weeks of exposure. Left ventricular structure and function were assessed with echocardiography.

Results

Chronic, inhaled nicotine abrogated Ang-II-induced thickening of the left ventricular posterior wall, leading to reduced relative wall thickness. Ang-II infusion was associated with increased left ventricular mass index in both air- and nicotine-exposed mice.

Conclusions

These changes suggest a phenotypic shift from concentric hypertrophy to eccentric hypertrophy in nicotine-exposed, hemodynamically-stressed mice which could drive HF pathogenesis. These findings join a growing body of animal studies demonstrating cardiac remodeling and dysfunction following nicotine and electronic cigarette exposure. Further exploration is necessary; however, clinicians and researchers should not overlook these emerging products as potential risk factors in the pathogenesis of cardiac remodeling and associated diseases including HF.