Use of a tantalum-178 generator and a multiwire gamma camera to study the effect of the Mueller maneuver on left ventricular performance: Comparison to hemodynamics and single photon emission computed tomography perfusion patterns

Abstract

During the Mueller maneuver, there is a decrease in intrathoracic pressure and an increase in transmural left ventricular pressure. The changes in loading conditions cause transient left ventricular dysfunction. This study examined the effects of the Mueller maneuver on left ventricular performance using tantalum (Ta)-178 (half-life 9.3 min) and a multiwire gamma camera. First-pass radionuclide angiograms were obtained at baseline and during Mueller maneuver in 41 patients aged 58 ± 10 years. In 34 patients, stress single photon emission computed tomography (SPECT) myocardial perfusion imaging with thallium-201 or sestamibi was also performed. Hemodynamic measurements during the Mueller maneuver ( n = 10) showed a decrease in systemic pressure (139 ± 25 mm Hg vs 123 ± 24 mm Hg, p < 0.001) and pulmonary artery pressure (24 ± 6 mm Hg vs 14 ± 12 mm Hg, p = 0.01) and an increase in heart rate (67 ± 10 bpm vs 75 ± 14 beats/min, p = 0.001). Among the 34 patients who had perfusion imaging, the left ventricular ejection fraction remained unchanged or increased in 17 patients (group 1) (48% ± 19% vs 49% ± 21%, p not significant) and decreased (≥5%) in 17 patients (group 2) (55% ± 13% vs 40% ± 16%, p = 0.001). The stress SPECT images showed no or only fixed defects in 11 (65%) patients in group 1 and 3 (18%) patients in group 2 ( p = 0.02), and reversible defects in 6 (35%) patients in group 1 and 14 (82%) patients in group 2 ( p = 0.04). Group 2 had more regional dysfunction (measured as regional ejection fraction) than group 1 in the anterior wall and inferior walls ( p < 0.05, each). In 31 regions with regional dysfunction the SPECT images showed reversible defects in 18 (58%) segments and fixed defects in 8 (26%) segments. Thus the Mueller maneuver causes transient left ventricular dysfunction in many patients with coronary artery disease, especially those with stress-induced myocardial ischemia.