A simultaneous study of Doppler-echo and catheterization in noninvasive assessment of the left ventricular dp/dt

Non-invasive measuring of the acceleration of contraction of the left ventricle with the Doppler echocardiography

BACKGROUND

Echocardiographically measured ejection fraction (EF) of the left ventricle (LV) is the most useful standard of the LV systolic function. Its limitations are poor delineation of the LV endocardium, pronounced regional disorders of contractility, dyssynchrony of the LV and in particular significant mitral regurgitation. The aim of this research is to evaluate the advantage of Doppler indices of left ventricular function such as index of acceleration of contraction of the LV (AccLV) over EF in patients with heart failure.

METHODS

We performed a prospective observational study. We included 45 patients with known chronic heart failure and 76 healthy subjects. We performed standard echocardiographic measurements. AccLV was calculated by the following formula: AccLV = Vmax LVOT/dt × EDV [cm/s(2) ml]. Vmax LVOT represents the maximum velocity during ejection in the left ventricular outflow tract (LVOT), dt stands for the interval from the beginning of the LV contraction to the achieved Vmax LVOT, EDV represents end-diastolic volume of the LV.

RESULTS

Between patients and healthy subjects we observed statistically significant differences in mean EF values (65.4 ± 6.7 % vs. 38.6 ± 18.0 %; p < 0.001) and of AccLV (12.1 ± 2.88 cm/s(2)ml vs. 4.4 ± 2.1 cm/s(2)ml; p < 0.001). Receiver operating characteristic (ROC) curve showed higher area under the curve values for AccLV in comparison to EF (0.996 vs. 0.897). In the patient group we observed more important correlation between AccLV index and the New York Heart Association (NYHA) functional classes (r = - 0.657; p < 0.001), than between EF and the NYHA classes (r = - 0.539; p < 0.001).

CONCLUSIONS

We could distinguish with higher accuracy between healthy subjects and patients with heart failure LV by calculated AccLV in comparison to EF. AccLV values correlated with NYHA functional classes in patients with heart failure better than EF values.

Use of ultrasound in the ICU

Echography has developed as an indispensable tool in diagnosis and subsequent therapy in the critically ill. Although pulmonary and abdominal ultrasounds play a major role in their management, this article will discuss the advantages and indications of echocardiography in the intensive care unit (ICU). The assessment of morphological abnormalities, left or right ventricular malfunction, pulmonary arterial hypertension and valvular dysfunctions is a routine indication of echocardiography. Actually, besides contractility, several preload and even afterload indicators can also be assessed. In short, this bedside tool rapidly provides insight in the haemodynamics without invasive pressure estimations.

A New Echocardiographic Index for Assessing Left Ventricular Function and Mechanism of Mitral Regurgitation and Its Relation to Other Echocardiographic Indices

OBJECTIVE

Mitral regurgitation (MR) is a progressive disease of the mitral valve, which can be primary or functional. The assessment of left ventricular function in MR is still troublesome. In this study, we evaluated the validity of a new parameter, total dt, in patients with MR.

METHODS

Forty patients with severe MR constituted the study group. According to the transesophageal echocardiographic evaluation, the patients were dichotomized into two groups: (1) Primary MR; n = 21, (2) Functional MR; n = 19. The total dt was defined as the sum of time intervals from 1 msto 3 ms (positive dt) and from 3 ms to 1 ms (negative dt) on the CW Doppler recording of MR jet. It was compared to other indices of left ventricular function and left ventricular geometry, including ejection fraction, fractional shortening, myocardial performance index, coaptation distance, left ventricular volume and diameter, sphericity index, and parameters of diastolic function.

RESULT

The total dt correlated with myocardial performance index, coaptation distance, and sphericity index. It could differentiate between primary and functional MR with an area under curve of 0.878, followed by myocardial performance index with 0.860. The total dt > 104 ms was 79% sensitive and 81% specific for discrimination.

CONCLUSION

The total dt is useful for assessing left ventricular function and also for differentiating primary MR from functional MR.

Elongation Index as a New Index Determining the Severity of Left Ventricular Systolic Dysfunction and Mitral Regurgitation in Patients with Congestive Heart Failure

The shape of the left ventricle is an important echocardiographic feature of left ventricular dysfunction. Progression of the mitral regurgitation and consequent left ventricular remodeling is unpredictable in heart failure. Elongation index is an index of left ventricular sphericity. The surface area of the elongated ventricle is larger than that of a spherical one. The objective of this study was to assess the relation between elongation index and the degree of mitral regurgitation along with noninvasive indices of left ventricular function. Thirty-two patients (21 male, 11 female, mean age: 57 +/- 6 yrs) with congestive heart failure and mitral regurgitation were included. Patients were stratified into three groups according to vena contracta width as having mild (n = 11), moderate (n = 11) and severe mitral regurgitation (n = 10). The elongation index (EI) was considered as equal to {[(left ventricular internal area-measured) - (theoretical area of the sphere with measured left ventricular volume)]/(theoretical area of the sphere with measured left ventricular volume)}. Ejection fractions by the modified Simpson rule, dP/dt and sphericity index (SI) were also recorded. The relationship between (EI), ejection fraction, dP/dt and SI reached modest statistical significance (p < 0.05). When the EI and SI were compared, the correlation was also significant (p < 0.01). The areas under the receiver operator curve of EI and SI for discriminating dP/dt < 1000 mm Hg/s were 0.833 and 0.733, respectively. In conclusion, the elongation, which defines the shape of the left ventricle, might be related to the systolic function of the left ventricle and the degree of the mitral regurgitation. Further studies are needed to demonstrate its use in other clinical entities.

Dicoumarol toxicity in cattle associated with ingestion of silage containing sweet vernal grass (Anthoxanthum odoratum)

A diagnosis of dicoumarol toxicity in a herd of Friesian cattle was made following investigation of the deaths of three mature cows and eleven yearling heifers. Affected stock had been fed wrapped, bailed silage containing approximately 90% sweet vernal grass (Anthoxanthum odoratum). Sweet vernal grass contains coumarin, which can be converted to dicoumarol, a vitamin K antagonist, through the action of moulds. Most deaths were preceded by lethargy, severe anaemia and subcutaneous and internal haemorrhage. Dicoumarol toxicosis was suspected based on clinical signs, necropsy findings and prolonged prothrombin and activated partial thromboplastin times. Dicoumarol analysis of blood from affected animals and silage confirmed the diagnosis. Activated partial thromboplastin time Haemoglobin Packed cell volume Prothrombin time Red cell count

Noninvasive estimation of cardiac systolic function using continuous-wave Doppler echocardiography in dogs with experimental mitral regurgitation

OBJECTIVE

To evaluate the feasibility of noninvasive estimation of cardiac systolic function using transthoracic continuous-wave Doppler echocardiography in dogs with mitral regurgitation.

PROCEDURE

Seven mongrel dogs with experimental mitral regurgitation were used. Left ventriculography and measurement of pulmonary capillary wedge pressure were performed under inhalational anaesthesia. A micromanometer-tipped catheter was placed into the left ventricle and transthoracic echocardiography was carried out. The peak rate of left ventricular pressure rise (peak dP/dt) was derived simultaneously by continuous-wave Doppler and manometer measurements. The Doppler-derived dP/dt was compared with the catheter-measured peak dP/dt in the dogs.

RESULTS

Classification of the severity of mitral regurgitation in the dogs was as follows: 1+, 2 dogs; 2+, 1 dog; 3+, 2 dogs; 4+, 1 dog; and not examined, 1 dog. We were able to derive dP/dt from the transthoracic continuous-wave Doppler echocardiography in all dogs. Doppler-derived dP/dt had a significant correlation with the catheter-measured peak dP/dt (r = 0.90, P < 0.0001).

CONCLUSION

It was demonstrated that transthoracic continuous-wave Doppler echocardiography is a feasible method of noninvasive estimation of cardiac systolic function in dogs with experimental mitral regurgitation and may have clinical usefulness in canine patients with spontaneous mitral regurgitation.

Comparison of simultaneous Doppler- and catheter-derived right ventricular dP/dt in hypoplastic left heart syndrome

Doppler estimation of RV dP/dt correlates well with micromanometer catheter-measured values in children with hypoplastic left heart syndrome. Doppler estimation of RV dP/dt is a method of quantifying RV systolic function independent of geometric assumptions, and may be a valuable method for longitudinal analysis of RV function.