Changes in Left and Right Ventricular Mechanics During the Mueller Maneuver in Healthy Adults

Abstract

Background— Obstructive sleep apnea is highly prevalent in patients with cardiovascular disease and has detrimental effects on systolic and diastolic function of the ventricles. In this research, the changes in strain (S) and strain rate (SR) during the performance of the Mueller maneuver (MM) in an effort to better understand how negative intrathoracic pressures affect ventricular mechanics. Methods and Results— The MM was performed to maintain a target intrathoracic pressure of −40 mm Hg. Echocardiography was used to measure various parameters of cardiac structure and function. Myocardial deformation measurements were performed using tissue speckle tracking. Twenty-four healthy subjects (9 women; mean age, 30�6 years) were studied. Global left ventricular longitudinal S in systole and SR in early filling were significantly decreased during the MM (S: baseline, −17.0�1.6%; MM, −14.5�2.2%; P <0.0001, SR: baseline, 1.09�0.20 s −1 ; MM, 0.92�0.21 s −1 ; P =0.01). Global right ventricular longitudinal S was also significantly decreased during the MM (baseline, −22.0�3.1%; MM, −17.2�2.5%; P <0.0001), as was global right ventricular longitudinal systolic SR (baseline, −1.34�0.35 s −1 ; MM, −1.02�0.21 s −1 ; P =0.0006). Conclusions— Left ventricular and right ventricular longitudinal deformation are significantly reduced during the MM. These results suggest that negative intrathoracic pressure during apnea may contribute to changes in myocardial mechanics. These results could help explain the observed changes in left ventricular and right ventricular mechanics in patients with obstructive sleep apnea.

Obstructive Sleep Apnea

“…There are multiple mechanisms by which OSA could lead to heart remodeling, including exacerbation of nighttime and daytime hypertension, increased sympathetic tone, increased left ventricular afterload due to increased arterial stiffness, and exaggerated swings in intrathoracic pressure during obstructive episodes, among others (67–69). The impact of OSA on heart remodeling has recently been explored in obese patients.…”

Echocardiographic Findings in Healthy Elderly People with Unrecognized Sleep Disordered Breathing

“…Moreover, the elevated negative intrathoracic pressure 18 due to upper airway collapse and the consequent mechanical stretching of the LA wall, [19][20] the increased transmural cardiac pressure, and ventricular wall tension and afterload 21 may explain LV remodeling and diastolic and systolic cardiac dysfunction.…”

“…Using previously published thresholds, LVH was defined as an LV mass index > 48 g/m 2 for men and > 44 g/m 2 for women. 18 The LV ejection fraction was measured as a LV systolic function parameter with the normal value set at > 55%. Left atrial (LA) mass index, surface, and diameter were also calculated.…”

Sleep-Disordered Breathing and Cardiac Arrhythmias

“…15 Acute distension of the atrium might be an important trigger for the onset of AF in these patients. 16 Furthermore, negative intrathoracic pressure changes were shown to trigger AF episodes by shortening of atrial effective refractory periods, mainly due to enhanced vagal activation.…”

“…11,30,31 A decline in systolic and diastolic left ventricular function was also found during respiratory events in OSA. 15,32 In addition, SDB affects cardiac electrophysiology by modifying conduction velocity and refractoriness. Rossi and coworkers, for instance, demonstrated that OSA is associated with prolongation of the corrected QT interval and corrected Tpeak to Tend interval intervals and TpTe/ QT ratio.…”