Mueller maneuver and LV function in coronary artery disease

Area of Science:

• Cardiology
• Physiology

Background:

• Decreased pleural pressure during the Mueller maneuver increases left ventricular (LV) transmural pressure, potentially affecting LV function.
• Patients with coronary artery disease (CAD) may exhibit LV wall akinesis during this maneuver, possibly due to ischemia or mechanical inhibition from prior myocardial infarction (MI).

Purpose of the Study:

• To differentiate between ischemia and prior MI as causes of regional LV akinesis during the Mueller maneuver in patients with CAD.
• To determine if CAD alone is sufficient to induce regional akinesis or if prior MI is a prerequisite.

Main Methods:

• Utilized first-pass radionuclide ventriculography (RVG) to assess LV ejection fraction (EF), volumes (EDV, ESV), heart rate, and regional wall motion during the Mueller maneuver.
• Compared four groups: normal subjects, patients with CAD without MI, patients with prior nontransmural MI, and patients with prior transmural MI.

Main Results:

• LV ejection fraction decreased significantly in all patient groups but not in normals during the Mueller maneuver.
• LV wall akinesis during the Mueller maneuver was observed only in patients with prior transmural MI (17/36), not in those with CAD alone or prior nontransmural MI.
• Akinetic segments identified during RVG were not always apparent on routine contrast ventriculography.

Conclusions:

• Prior transmural myocardial infarction, not just coronary artery disease, is necessary for the development of left ventricular wall akinesis during the Mueller maneuver.
• The Mueller maneuver can unmask regional LV dysfunction not evident during routine ventriculography in patients with prior transmural MI.