Measures Of Ventricular Performance Research Articles

Longitudinal changes in echocardiographic measures of ventricular function after Fontan operation.

While numerous indices have been developed in an attempt to quantify ventricular function in patients with single ventricle heart disease after Fontan, there are little data on how these parameters change over time. A retrospective observational study was performed of individuals who underwent Fontan operation at Children's Hospital of Philadelphia (CHOP) in 2006 and 2007. Measurements of fractional area change (FAC), tricuspid annular planar systolic excursion (TAPSE), myocardial performance index (MPI), systolic to diastolic (s/d) ratio, and myocardial strain and strain rate were made offline. A composite outcome of protein-losing enteropathy (PLE), plastic bronchitis, transplant, or death was created, and change in function was compared between those who did and those who did not meet the outcome. There were 312 echocardiograms from 40 unique patients (75% male, 55% dominant right ventricle). The aggregate mean values for most assessed parameters were worse than what would be expected for a healthy age-matched population. The global longitudinal strain rate increased (worsened) by 0.014 (1/s) per year (P=.02), and the global circumferential strain rate increased (worsened) by 0.011 (1/s) per year (P=.01). There was no difference in the rate of change of ventricular function in the 6 patients who met the composite endpoint vs those who did not. This study demonstrates that global longitudinal strain rate and global circumferential strain rate decrease over 10years following Fontan operation. These measures of ventricular performance may be early signs of cardiac dysfunction that predate more obvious echocardiographic signs of deterioration.

Comparison of Fontan Survivors with and without Pacemakers: A Report from the Pediatric Heart Network Fontan Cross-sectional Study

Although many Fontan patients undergo pacemaker placement, there are few studies characterizing this population. Our purpose was to compare clinical characteristics, functional status and measures of ventricular performance in Fontan patients with and without a pacemaker. The National Heart, Lung, and Blood Institute funded Pediatric Heart Network Fontan Cross-Sectional Study characterized 546 Fontan survivors. Clinical characteristics, medical history and study outcomes (Child Health Questionnaire [CHQ]), echocardiographic evaluation of ventricular function, and exercise testing) were compared between subjects with and without pacemakers. Of 71 subjects with pacemakers (13%), 43/71 (61%) were in a paced rhythm at the time of study enrollment (age 11.9 ± 3.4 years). Pacemaker subjects were older at study enrollment, more likely to have single left ventricles, and taking more medications. There were no differences in age at Fontan or Fontan type between the pacemaker and no pacemaker groups. There were no differences in exercise performance between groups. CHQ physical summary scores were lower in the pacemaker subjects (39.7 ± 14.3 vs. 46.1 ± 11.2, P =.001). Ventricular ejection fraction z-score was also lower (-1.4 ± 1.9 vs. -0.8 ± 2.0, P =.05) in pacemaker subjects. In our cohort of Fontan survivors, those with a pacemaker have poorer functional status and evidence of decreased ventricular systolic function compared to Fontan survivors without a pacemaker.

Late Status of Fontan Patients With Persistent Surgical Fenestration

This study was undertaken to determine the effects of creating a systemic-to-pulmonary venous atrial-level communication (fenestration) at the time of the Fontan procedure on late outcomes. Fenestrations are frequently performed during Fontan procedures, but late consequences are not well described. Patient characteristics were compared between those with and without surgical fenestration among 536 subjects (mean age 11.9 years) enrolled in the Pediatric Heart Network Fontan Cross-Sectional Study. The status of the fenestration and the association of a currently patent fenestration with health status and measures of ventricular performance were investigated. Fenestration was performed in 361 patients (67%), and frequency differed by year and center (p < 0.001 for each). After adjustment for center, age at Fontan, year of Fontan, and prior superior cavopulmonary surgery, the fenestrated group had shorter length of Fontan hospital stay. At the time of cross-sectional testing 8 ± 3 years after Fontan, the fenestration remained open in 19% of subjects. Among those with confirmed fenestration closure, 59% were by catheter intervention and 1% by surgical intervention, and 40% had apparent spontaneous closure. Compared with those without evidence of a fenestration, subjects with a current fenestration were taking more medications (p = 0.02) and had lower resting oxygen saturation (median 89% vs. 95%, p < 0.001). Functional health status, exercise performance, echocardiographic variables, prevalence of post-Fontan stroke or thrombosis, and growth did not differ by current fenestration status. Surgical fenestration is associated with well-demonstrated early post-operative benefits. This cross-sectional study found few associations between a persistent fenestration and deleterious later outcomes.

The catecholamine release-inhibitory peptide catestatin (chromogranin A344-364) modulates myocardial function in fish

Catestatin (CST), the 21-amino acid, cationic and hydrophobic peptide proteolytically derived from the ubiquitous chromogranin A (CgA), is an endogenous inhibitor of catecholamine release, a potent vasodilator in vivo and an anti-hypertensive agent in mammals, including humans. Recently, we discovered that CST also functions as an important negative modulator of heart performance in frog and rat. To gain an evolutionary perspective on CST cardiotropism in fish, we analysed the influence of bovine CST (CgA₃₄₄₋₃₆₄) on the eel heart, as well as the eventual species-specific mechanisms of its myocardial action. Experiments were carried out on fresh-water eels (Anguilla anguilla L.) using an electrically paced isolated working heart preparation. Stroke volume and stroke work were used as measures of ventricular performance. Under basal conditions, CST (from 11 nmol l⁻¹ to 165 nmol l⁻¹) caused a concentration-dependent negative inotropism, which was abolished by inhibitors of either β₁/β₂ (propranolol) or β₃ (SR₅₉₂₃₀) adrenergic receptors, or by G(i/o) protein (PTx) or nitric oxide synthase (L-NMMA), or guanylate cyclase (ODQ) blockers. This suggests a β-adrenergic receptor-G(i/o) protein-NO-cGMP-dependent mechanism. By contrast, the CST-induced cardio-suppression was not influenced by atropine, unspecific muscarinic antagonist, thus excluding cholinergic receptor involvement. CST also counteracted the adrenergic (isoproterenol)-mediated positive inotropism. Under increased preload (i.e. Frank-Starling response) conditions, CST induced a significant increase of the Frank-Starling response, which was blocked by L-NMMA and thapsigargin, but independent from guanylate cyclase. In conclusion, this is the first report in fish that CST modulates myocardial performance under basal, as well as under increased preload, conditions and counteracts the adrenergic-mediated positive inotropism, which strikingly supports the evolutionary significance and establishes the cardioactive role of this peptide.

Automatic detection of left ventricular ejection time from a finger photoplethysmographic pulse oximetry waveform: comparison with Doppler aortic measurement

Left ventricular ejection time (LVET) is a useful measure of ventricular performance and preload. The present study explores a novel method of continuous LVET monitoring using a noninvasive finger photoplethysmographic pulse oximetry waveform (PPG-POW). A method for the automatic beat-to-beat detection of LVET from the finger PPG-POW is presented based on a combination of derivative analysis, waveform averaging and rule-based logic. The performance of the detection method was evaluated on 13 healthy subjects during graded head-up tilt. Overall, the correlation between the PPG-POW derived LVET and the aortic flow derived LVET was high and significant (r = 0.897, p < 0.05). The bias was −14 ± 14 ms (mean ± SD), and the percentage error was 9.7%. Although these results would not be sufficient to satisfy the requirement for clinical evaluation of LVET when absolute accuracy was demanded, the strong correlation between the PPG-POW LVET and the aortic LVET on an intra-subject basis (r = 0.945 ± 0.043, mean ± SD) would support the application of PPG-POW to detect the directional change in LVET of an individual. This could be very useful for the early identification of progressive hypovolaemia or blood loss. The present study has demonstrated a promising approach to extract potentially useful information from a noninvasive, easy-to-obtain signal that could be readily acquired either from existing patient monitoring equipment or from inexpensive instrumentation. More extensive investigation is necessary to evaluate the applicability of the present approach in clinical care monitoring.

Cardiac pump performance in patients who underwent coronary artery bypass grafting

The measure of ventricular performance, as an independent parameter of cardiovascular function, must be performed by a beat-to beat assessment of systolic function independent of load conditions, and is useful both as an index of contractility and as an index of ventricular functional reserve. We analyzed three different parameters of ventricular performance: the preload adjusted peak power (PAPP) [1], as an index of contractility; the cardiac cycle efficiency (CCE) [2], as a measure of ventricular arterial coupling; and the ejection fraction (EF), as an index of global ventricular function.

Noncompressibility of myocardium during systole with freehand three-dimensional echocardiography

Background: Measures of ventricular performance, such as the ejection fraction, assume that myocardium is noncompressible and does not change volume significantly from end diastole to end systole. Although this principle is widely accepted as true, little data exist in the literature to support it. Freehand 3-dimensional (3D) echocardiography has previously been shown to be highly accurate for measurement of myocardial mass and volume. Therefore, we hypothesized that it has sufficient accuracy to test the validity of this assumption. We measured myocardial volume at end diastole and end systole in 2 groups of subjects with hypertrophy. Methods: Forty-one healthy young adult athletes and 17 adult patients with hypertension, hypertrophy, normal ejection fraction, and heart failure symptoms underwent examination with freehand 3D echocardiography. Endocardial and epicardial surfaces at end diastole and end systole were reconstructed, and their volumes were computed. From these surface volumes, myocardial volume at end diastole and end systole and epicardial stroke volume and endocardial stroke volume were calculated. These volumes were compared with the 2 sample paired t test. Results: Myocardial volume was constant from diastole to systole (174.7 ± 45.3 mL versus 174.6 ± 45.8 mL; P = not significant), and endocardial and epicardial stroke volumes were identical (76.0 ± 17.4 mL versus 76.0 ± 17.1 mL; P = not significant). The average absolute difference between the end-diastolic and end-systolic myocardial volumes was 1.9 mL, or less than 1.1% of end-diastolic volume. Conclusion: Myocardial volume measured with freehand 3D echocardiography does not change significantly during systole. Myocardial volume may be considered noncompressible for purposes of measurement of ventricular function with freehand 3D echocardiography. Comparison of end-diastolic and end-systolic myocardial volumes may be used for quality assurance in performing 3D reconstructions. (J Am Soc Echocardiogr 2002;15:1503-6.)

Transthoracic and transesophageal echocardiography in the hemodynamic assessment of patients with congestive heart failure

All methods for estimating the severity of heart failure, such as clinical and radiographic examination, measures of ventricular performance, and exercise capacity, when used independently, have major limitations. Echocardiography can be used, not only to assess left-ventricular ejection fraction but also other determinants of prognosis (i.e., left-ventricular size and shape, estimation of left atrial and pulmonary artery pressures, right side involvement). The availability of continuous-wave Doppler has permitted us to evaluate pulmonary artery systolic pressure from tricuspid regurgitation, and this contributes to additional powerful data. In long-standing heart failure, pulmonary artery wedge pressure is a predictor of survival, and aggressive therapy to reduce wedge pressure improves survival. Noninvasive estimation of left-atrial pressure and left-ventricular filling pressure have been attempted by continuous-wave Doppler echocardiography in patients with heart failure and mitral regurgitation and by tissue Doppler imaging at the mitral annulus level. A significant relation has been reported between profiles of pulmonary venous flow and left-atrial pressure, but pulmonary venous flow indexes can be better assessed by transesophageal echocardiography (TEE) in terms of detection rate. It has recently been recognized that TEE can provide valuable information on intracardiac hemodynamics and ventricular function. Two-dimensional evaluation of ventricular function and pulsed- and continuous-wave Doppler recordings from the pulmonary artery, pulmonary vein, and mitral inflow are combined to provide these data, which are both qualitative and quantitative, and permit estimation of ventricular ejection fraction, left-atrial pressure, and cardiac output. It would be important to be able to stratify patients with congestive heart failure according to groups with the highest risk for early death because heart transplantation or aggressive medical treatment could be specifically applied to this population. Serial echocardiographic evaluations of the classic variables of systolic left-ventricular function as well as Doppler transmitral flow may be useful in monitoring the progression of the disease and the effects of medical treatment. The degree of pulmonary hypertension is independently associated with the restrictive left-ventricular diastolic filling pattern and with the degree of functional mitral regurgitation. Future studies on the impact of these hemodynamic variables on the outcome of patients with left-ventricular dysfunction are desirable.

Chronic nonocclusive coronary artery constriction impairs ventricular function, myocardial structure, and cardiac contractile protein enzyme activity in rats.

To determine the effects of chronic nonocclusive coronary constriction on cardiac hemodynamics, structural integrity, and contractile protein enzyme activity, the left coronary artery was narrowed in rats, and measurements of ventricular performance, magnitude, and distribution of tissue damage and myofibrillar Mg2+ and Ca2+ myosin ATPase activities were evaluated 1 month later. In the presence of coronary artery stenosis averaging 58%, three levels of involvement of global cardiac performance were identified, and the rats were divided accordingly. In the first group, only left ventricular end-diastolic pressure (LVEDP) was increased; in the second group, LVEDP and left ventricular +dP/dt and/or -dP/dt were affected; and in the third group, LVEDP, left ventricular +dP/dt and -dP/dt, and right ventricular end-diastolic pressure were impaired. Thus, left ventricular moderate dysfunction, severe dysfunction, and failure occurred with coronary narrowing. On a structural basis, coronary constriction resulted in an ongoing process characterized by acute myocytolytic necrosis and foci of replacement fibrosis in different stages of healing. The number of these lesion profiles in the left ventricular myocardium increased 4.7-, 4.4-, and 8.3-fold in rats with moderate dysfunction, severe dysfunction, and failure, respectively. Biochemically, Mg(2+)-ATPase activity of myofibrils increased biventricularly when moderate dysfunction was present. However, this parameter decreased with the appearance of severe dysfunction, reaching control values in ventricular failure. Ca2+ myosin ATPase activity was reduced in the left ventricle of rats with severe dysfunction and failure, whereas it was elevated in the right ventricle of rats with severe dysfunction. In conclusion, a fixed lesion of the left main coronary artery with a modest reduction in vessel luminal diameter generates a conditioned state of the heart characterized by a continuous loss of myocytes and replacement scarring, which, in combination with alterations in contractile protein enzyme activity, may be responsible for a number of abnormalities in cardiac dynamics ranging from moderate dysfunction to pump failure.

Systolic time intervals

The systolic time intervals (STI) offer temporal description of the sequential phases of cardiac cycle which are influenced physiologically by the same variables as affect other measures of left ventricular (LV) performance. The STI hence offer a measure of ventricular function which augments other measures of ventricular performance. Because of the extreme sensitivity of this variable and the ease of its measurement the STI are well suited for studying the effect of pharmacologic agents upon the heart.

An Introduction to High-Resolution ECG Recordings of Cardiac Late Potentials

High-resolution electrocardiography utilizes computer processing to record low-levels signals not normally observed on standard electrocardiographs. Cardiac late potentials occur at the end of or after the QRS complex and require these methods to be quantified. A brief overview of the methods used to record late potentials is presented. These include lead placement, computer-implemented signal averaging, high-pass filtering, and feature extraction for characterizing the late potential. The major application of late- potential analysis has been in patients after myocardial infarction. Several of these studies are reviewed that demonstrate the usefulness of this new approach in identifying those patients at greatest risk for developing ventricular tachycardia. The most impressive studies have been those that compare late potentials with measures of ventricular performance and ventricular ectopy.

Reproducibility of Measurements of Ventricular Performance and Oxygen Consumption at Rest and Exercise Using Supine Radionuclide Ventriculography in Coronary Artery Disease

Reproducibility of Measurements of Ventricular Performance and Oxygen Consumption at Rest and Exercise Using Supine Radionuclide Ventriculography in Coronary Artery Disease

Rapid assessment of ventricular function in acute volume overload using opaque myocardial markers.

Radiopaque markers, implanted in the myocardium, have been used to analyze ventricular function. However, the inordinate time involved in measuring marker motion limited widespread use. This work describes the application of a marker recognition system, which provides automatic recording and storage of marker locations. Use of the system was demonstrated by repeated measurements of ventricular performance in a canine model of acute volume overload.

Ventricular Function in Children During Halothane Anesthesia

The effect of halothane on ventricular function in normal children was studied with the aid of echocardiography, which offers a noninvasive method to obtain these measurements safely. Thirteen healthy children ranging in age from 19 months to 12 years (mean=6 years), undergoing elective non-cardiac surgical procedures, were studied. Secobarbital, 4 mg/kg, and morphine, 0.1 mg/ kg, were administered intramuscularly an hour prior to induction of general anesthesia. Echocardiographic measurements were obtained while the patients breathed room air (control) and following nitrous oxide, 60 per cent, and concentrations of halothane ranging from 0.5 to 2 per cent. Increasing inspired concentrations of halothane significantly altered ventricular function in a dosedependent fashion. At halothane, 2 per cent, systolic blood pressure, pulse rate, and cardiac output decreased to 82, 94, and 72 per cent of control values, respectively. Measurements of ventricular performance, ejection fraction (EF), left ventricular enddiaslolic volume (LVEDV), and mean normalized rate of circumferential fiber shortening (Vuf) showed parallel decreases. Following atropine, 0.02 mg/kg, intravenously, improvement in cardiac output and all rate-dependent variables was observed. Although V,.r improved by 18 per cent, other indices of myocardial performance (EF, LVEDV, PEP/LVET) still showed depression. It is concluded that halothane can significantly decrease ventricular function in children undergoing surgical procedures. The accompanying decrease in cardiac output was completely offset by the administration of atropine.

Ventricular function in children during halothane anesthesia: an echocardiographic evaluation.

The effect of halothane on ventricular function in normal children was studied with the aid of echocardiography, which offers a noninvasive method to obtain these measurements safely. Thirteen healthy children ranging in age from 19 months to 12 years (mean=6 years), undergoing elective non-cardiac surgical procedures, were studied. Secobarbital, 4 mg/kg, and morphine, 0.1 mg/ kg, were administered intramuscularly an hour prior to induction of general anesthesia. Echocardiographic measurements were obtained while the patients breathed room air (control) and following nitrous oxide, 60 per cent, and concentrations of halothane ranging from 0.5 to 2 per cent. Increasing inspired concentrations of halothane significantly altered ventricular function in a dosedependent fashion. At halothane, 2 per cent, systolic blood pressure, pulse rate, and cardiac output decreased to 82, 94, and 72 per cent of control values, respectively. Measurements of ventricular performance, ejection fraction (EF), left ventricular enddiaslolic volume (LVEDV), and mean normalized rate of circumferential fiber shortening (Vuf) showed parallel decreases. Following atropine, 0.02 mg/kg, intravenously, improvement in cardiac output and all rate-dependent variables was observed. Although V,.r improved by 18 per cent, other indices of myocardial performance (EF, LVEDV, PEP/LVET) still showed depression. It is concluded that halothane can significantly decrease ventricular function in children undergoing surgical procedures. The accompanying decrease in cardiac output was completely offset by the administration of atropine.