Dynamic Changes of Left Ventricular Performance and Left Atrial Volume Induced by the Mueller Maneuver in Healthy Young Adults and Implications for Obstructive Sleep Apnea, Atrial Fibrillation, and Heart Failure

Abstract

Using the Mueller maneuver (MM) to simulate obstructive sleep apnea (OSA), we sought to investigate the acute changes in left sided heart morphology and function that develop with apneas occurring during sleep. Strong evidence supports a relationship between OSA and both atrial fibrillation (AF) and heart failure (HF). However, the acute effects of airway obstruction on cardiac structure and function have not been well defined. In addition, it is unclear how OSA might contribute to the development of AF and HF. We utilized echocardiography in healthy young adults to measure various parameters of cardiac structure and function. Subjects were studied at baseline, during and immediately after performance of the MM, and after a 10 minute recovery. Continuous heart rate, blood pressure and pulse oximetry measurements were made. During the MM, left atrial (LA) volume index markedly decreased. Left ventricular (LV) end systolic dimension increased in association with a decrement in LV ejection fraction. On release of the maneuver, there was a compensatory increase in blood flow to the left side of the heart with stroke volume, ejection fraction and cardiac output exceeding baseline. After 10 minutes of recovery all parameters had returned to baseline. In conclusion, sudden imposition of severe negative intrathoracic pressure leads to an abrupt decrease in LA volume and a decrease in LV systolic performance. These changes reflect an increase in LV afterload. Repeated swings in afterload burden and chamber volumes may have implications for future development of AF and HF.

A Novel Method for Sensitive Determination of Subclinical Left-Ventricular Systolic Dysfunction in Subjects With Obstructive Sleep Apnea

“…However, coordination may be disturbed due to the decrease in arterial oxygen saturation and the high negative intrathoracic pressure imposed by OSA. 10 Two-dimensional speckle tracking is a novel echocardiographic method for obtaining strain and strain rate measurements by tracking speckles in the ultrasonographic image in 2 dimensions. It is not based on tissue Doppler measurements; consequently, it is not angledependent.…”

Effects of obstructive sleep apnoea on heart rhythm

“…During the Mueller manoeuvre, the negative intrathoracic pressure transmitted to the pericardial cavity leads to an increase in the left ventricular afterload, in the pressure developed during the left ventricular isovolumetric phase, and in left ventricular volume [52,53]. In healthy subjects, simulated obstructive apnoea or hypopnoeas were associated with an acute increase in proximal aortic diameter and in left ventricular volume, as assessed by echocardiography, while left atrial volume and left ventricular ejection fraction were reduced [53][54][55]. These findings suggest that repeated intrathoracic pressure changes in OSA might play a role in the onset of cardiac arrhythmias by promoting both mechanical and electrical remodelling of the heart, as evidenced by recent findings [48].…”

Renal Sympathetic Denervation Suppresses Postapneic Blood Pressure Rises and Atrial Fibrillation in a Model for Sleep Apnea

“…9,14 The Mueller maneuver (forced inspiration against airway obstruction after deep expiration generating a negative pressure of Ϸ40 mm Hg) is used in the clinical setting to simulate conditions, particularly negative thoracic pressure, during OSA. 15 As a modification of this maneuver, we applied NTP at Ϫ80 mbar during tracheal occlusion corresponding with NTPs found in patients with OSA. 6,7,15,16 BP was measured by a TIP-catheter (Millar PC 350; Millar Instruments, Houston, TX) in the femoral artery.…”

“…15 As a modification of this maneuver, we applied NTP at Ϫ80 mbar during tracheal occlusion corresponding with NTPs found in patients with OSA. 6,7,15,16 BP was measured by a TIP-catheter (Millar PC 350; Millar Instruments, Houston, TX) in the femoral artery. Bipolar body surface ECG was recorded using subcutaneous needle electrodes in the classic lead II arrangement.…”