The isovolumic index: A new noninvasive approach to the assessment of left ventricular function in man

doi:10.1016/0002-9149(82)90482-9

The American Journal of Cardiology

Volume 50, Issue 6, December 1982, Pages 1401-1408

https://doi.org/10.1016/0002-9149(82)90482-9 Get rights and content

Abstract

Both a high ratio of preejection period (PEP) to left ventricular ejection time (LVET) and a prolonged isovolumic relaxation time are associated with left ventricular dysfunction. In pilot studies in instrumented dogs, we measured a combined isovolumic index, defined as (isovolumic contraction + isovolumic relaxation time)/LVET and found an inverse correlation with changes in fractional shortening. To test the utility of this index in human subjects, we used the electrocardiogram, mitral valve (MV) echogram, and indirect carotid arterial tracing to calculate isovolumic index as (time from R wave to MV opening — LVET)/LVET × 100%. Normal subjects had isovolumic index values that averaged 24 ± 7% (standard deviation), in contrast to patients with cardiomyopathy who averaged 5 ±14% (p < 0.001 versus normal values) and patients with coronary artery disease who averaged 40 ±15% (p < 0.001 versus normal values and patients with cardiomyopathy). All normal subjects had an isovolumic index of < 32% and all patients with cardiomyopathy had values >32%. Of patients with coronary artery disease, 72% (21 of 29) had an isovolumic index >32%. An isovolumic index >32% identified 20 of 22 patients (91%) with a reduced ejection fraction and 12 of 14 (86% ) with a segmental wall motion abnormality, and it was a more sensitive marker of these abnormalities than abnormal E point-septal separation. In 6 patients with coronary artery disease who had simultaneous echocardiograms and measurements of left ventricular pressure by micromanometer tip catheter, the time constants of isovolumic pressure decrease were uniformly increased in association with an isovolumic index >32%. In contrast, all had normal PEP/LVET ratios. The isovolumic index is thus a sensitive, potentially useful noninvasive marker of left ventricular dysfunction that is easily obtained from the routine echocardiogram.

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Color Tissue Doppler imaging (TDI) M-mode through the mitral leaflet is a novel method to obtain the cardiac time intervals including the isovolumic contraction time (IVCT), isovolumic relaxation time (IVRT) and ejection time (ET). The myocardial performance index (MPI) is defined as [(IVCT+IVRT)/ET]. Our aim was to investigate if the cardiac time intervals can be used to predict heart failure (HF) in the general population.
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A significant association was found between MPI and HF both in unadjusted and adjusted models (per 0.1 increase: HR 6.93; 95% CI (1.63–29.31), p = 0.009). No associations between the IVRT or ET and HF remained significant after multivariable adjustment.
In the general population the IVCT provides novel and independent prognostic information on the long-term risk of incident HF.
Diagnostic methods for the canine idiopathic dilated cardiomyopathy: A narrative evidence-based rapid review
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Citation Excerpt :
Doppler echocardiography facilitated the assessment of diastolic function by assessing ventricular filling patterns and pulmonary vein flows, as well as isovolumetric times (Werner et al., 1993; Gromadzinski et al., 2014; Butnariu et al., 2016). Efforts to evaluate systolic and diastolic function led to the proposal of a new combined method, known as the index of myocardial performance (Tei Index) proposed for the first time by Mancini (Mancini et al., 1982). The Tei Index is calculated as the sum of the isovolumetric contraction time and the isovolumetric relaxation time, divided by the ejection period ([IVCT + IVRT]/ET).
Idiopathic dilated cardiomyopathy (DCM) is an important etiology of mortality and morbidity in dogs and its diagnosis relies on systolic dysfunction, chambers dilation, electrical instability and congestion. During the last decades veterinary cardiologists have been joining efforts to obtain diagnostic resources to correctly identify canine DCM in the preclinical stage. Unfortunately, most diagnostic resources have been used with the support of research with weak evidence, without high quality methodologies such as systematic reviews or meta-analysis. Therefore, the support of evidence-based medicine is tailored by empiricism and diagnostic criteria lose'out the ability to properly classify dogs suffering DCM. The presentation of the evidence in medicine is established by multiple sources and the most reliable source has been the presentation of evidence-based medicine from systematic reviews and meta-analysis. Rapid reviews can be interpreted as a pragmatic approach to systematic reviews and although a rapid review follows most of the critical steps of a systematic review to provide timely evidence, some components of a systematic review process are either simplified or omitted. The objective of this narrative evidence-based rapid review is twofold. First: To recognize and to stratify the level of evidence offered by rigorous selected papers about the diagnosis of DCM. Second: To classify the degree of clinical recommendation of the diagnostic resources available.
Usefulness of the myocardial performance index determined by tissue doppler imaging m-mode for predicting mortality in the general population
2011, American Journal of Cardiology
The objective of this study was to evaluate the prognostic value of the myocardial performance index (MPI), assessed by color-coded tissue Doppler imaging (TDI) M-mode through the anterior mitral leaflet. Color TDI M-mode through the mitral leaflet is an easy, very fast, and precise method to estimate cardiac intervals and thus obtain the MPI, but the diagnostic and prognostic values of this parameter are unknown. In a large population study, cardiac function was evaluated in 1,100 participants by conventional echocardiography and TDI. MPI was calculated from pulse-wave Doppler analyses of left ventricular in- and outflow using standard procedures (MPI_conv) and by color-coded TDI M-mode through the mitral leaflet in the apical 4-chamber view (MPI_TDI). MPI_TDI was increased in subjects with coronary heart disease (CHD) compared to controls, even after multivariable adjustment (p <0.002). During follow-up (median 5.3 years), 90 participants died. MPI_TDI was significantly associated with overall mortality, and risk of dying increased by 31% per 0.1 increase in MPI_TDI. In contrast to MPI_conv, MPI_TDI provided independent prognostic information in a multivariable Cox proportional hazard model (adjusting for age, gender, body mass index, heart rate, mean arterial blood pressure, and CHD), with a hazard ratio of 1.18 (p = 0.01) per 0.1 increase in MPI_TDI. In conclusion, MPI_TDI is a quick, simple, and reproducible measurement, which is increased in subjects with CHD and provides independent prognostic information in a low-risk population.
The Tei Index as an Expression of Right Ventricular Impairment and Recovery. Investment Grade or Subprime?
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Risk assessment in patients with depressed left ventricular function after myocardial infarction using the myocardial performance index - Survival and Ventricular Enlargement (SAVE) experience
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Myocardial performance index (MPI) is a noninvasive, quantitative Doppler measure of global cardiac function, integrating systolic and diastolic functions. The prognostic significance of MPI is less clear for cardiovascular (CV) events after myocardial infarction (MI) among individuals at high risk with depressed left ventricular (LV) systolic function.
We analyzed echocardiograms from 512 patients with depressed LV function after MI enrolled in the Survival and Ventricular Enlargement (SAVE) echocardiographic substudy. Baseline MPI measures were obtainable in 226 patients. The cohort was separated by median MPI (0.50). MPI was related to baseline clinical and echocardiographic characteristics, ventricular remodeling, and subsequent CV events, including recurrent MI, heart failure, CV death, and a composite of all CV end points.
An MPI of 0.5 or more was associated with larger infarct size and reduced LV systolic function at baseline; other baseline characteristics between the groups were similar. A total of 64 (28.3%) patients experienced CV events. Baseline MPI did not influence ventricular remodeling and did not modify the relationship between ventricular dilatation and CV events. After covariate adjustment, an MPI of 0.50 or higher remained an independent predictor for adverse CV events (hazard ratio [HR], 2.00, 95% confidence interval 1.17-3.43).
An MPI of 0.50 or greater is an independent predictor for CV events after MI in patients with known LV dysfunction.
Measurement of cardiac time intervals by Doppler tissue M-Mode imaging of the anterior mitral leaflet
2005, Journal of the American Society of Echocardiography
We sought to evaluate a new method of measuring cardiac time intervals from Doppler tissue imaging (DTI) of the anterior leaflet of the mitral valve.
For a reliable analysis of the regional cardiac performance by DTI, a reference of time intervals of global cardiac events in the same cardiac cycle and based on the same imaging modality is required to reduce measurement error.
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MethodThe isovolumic index: A new noninvasive approach to the assessment of left ventricular function in man

Abstract

Am J Cardiol

Am Heart J

Am Heart J

Chest

Am J Cardiol

Am Heart J

Am J Cardiol

Am J Cardiol

Am J Cardiol

Am J Cardiol

Am J Cardiol

Am Heart J

Chest

Am Heart J

Method
The isovolumic index: A new noninvasive approach to the assessment of left ventricular function in man