Noninvasive estimation of impaired hemodynamics for patients with acute myocardial infarction by Tei index.

摘要

BACKGROUND: Tei index, defined as the sum of isovolumic contraction and relaxation times divided by ejection time, has been proposed to express global left ventricular function. For patients with acute myocardial infarction (AMI), left ventricular function can potentially be a major determinant of hemodynamics with limited time for compensation, such as increased brain natriuretic peptide to attenuate congestion, and usually without any intervention to modify cardiac loading on arrival at the hospital during the acute phase. We, therefore, hypothesized that left ventricular function, expressed by the Tei index, allows noninvasive estimation of impaired hemodynamics for patients with AMI. METHODS: We studied 86 consecutive patients with first AMI (34 inferoposterior and 52 anteroseptal). Tei index was obtained as: (a - b)/b, where a is the interval between the cessation and onset of mitral flow and b is the ejection time by aortic flow by pulsed Doppler echocardiography. By using pulmonary capillary wedge pressure (PCWP) >/= 18 mm Hg or <18 mm Hg and cardiac index (CI) 2.2 L/min/m(2) by consecutive catheterization, patients were classified into 4 subsets: subset I with normal hemodynamics; subset II with elevated PCWP; subset III with reduced CI; and subset IV with both elevated PCWP and reduced CI. RESULTS: For patients with inferoposterior AMI, there was no significant correlation between the Tei index and PCWP or CI. For patients with anteroseptal AMI, however, the Tei index showed significant correlation both with PCWP (r = 0.59, P <.0001) and CI (r = -0.42, P <.01). Diagnosis of impaired hemodynamics (subset II-IV) by a Tei index >/= 0.60 showed a sensitivity, specificity, and accuracy of 86%, 82%, and 83%, respectively. CONCLUSIONS: Although the Tei index has limitations to evaluate hemodynamics in patients with inferoposterior AMI, the index allows approximate but quick and practical noninvasive estimation of impaired hemodynamics in patients with anteroseptal AMI.