Biomedical subjects

J Gorcsan

Publications and source records attributed to J Gorcsan.

At least 19 recordsLinked to original sources

PubMed2001

Color-coded tissue Doppler assessment of the effects of acute ischemia on regional left ventricular function: comparison with sonomicrometry.

Echocardiographic assessment of regional left ventricular (LV) function usually consists of subjective visual inspection of endocardial movement and wall thickening. Color-coded tissue Doppler (TD) is a potential means to quantify regional LV function more objectively. Accordingly, in this study, color-coded TD was used to assess the regional effects of acute ischemia in an open-chest canine model of coronary occlusion, with implanted sonomicrometry length crystals as a standard of reference. Eight dogs were studied during baseline conditions and during left anterior descending coronary artery occlusion. Midventricular short-axis images were used to guide the color TD M-mode cursor through circumflex (septal) and left anterior descending (anterolateral) perfusion zones. Off-line conversion of endocardial time-velocity maps was performed. Peak systolic endocardial velocity by TD decreased from 4.4 +/- 1.4 cm/s to 1.8 +/- 1.5 cm/s with coronary occlusion (P < .05 versus baseline). Similar significant decreases in calculated systolic velocity by sonomicrometry occurred with ischemia from 11.1 +/- 3.8 mm/s to 8.2 +/- 1.2 mm/s (P < .05 versus baseline). Peak systolic velocity by TD was inversely correlated with end-systolic length by sonomicrometry as a measure of regional function (r = -0.77, P < .001). Time to peak systolic velocity increased with ischemia from 154 +/- 60 ms to 286 +/- 67 ms by TD and 200 +/- 60 ms to 320 +/- 30 ms by sonomicrometry (P < .05 versus baseline). The delay in time to peak systolic velocity by TD and sonomicrometry were correlated (r = 0.75, P < .001). In conclusion, color-coded TD echocardiography has the potential to quantify regional LV function during coronary ischemia.

Animals↗

PubMed2001

Effects of aging on left atrial reservoir, conduit, and booster pump function: a multi-institution acoustic quantification study.

OBJECTIVE: To assess the feasibility of measuring left atrial (LA) function with acoustic quantification (AQ) and then assess the effects of age and sex on LA reservoir, conduit, and booster pump function. PATIENTS AND SETTING: 165 subjects without cardiovascular disease, 3-79 years old, were enrolled by six tertiary hospital centres. INTERVENTIONS: Continuous LA AQ area data were acquired and signal averaged to form composite waveforms which were analysed off-line. MAIN OUTCOME MEASURES: Parameters of LA performance according to age and sex. RESULTS: Signal averaged LA waveforms were sufficiently stable and detailed to allow automated analysis in all cases. An age related increase in LA area was noted. LA reservoir function did not vary with age or sex. All parameters of LA passive and active emptying revealed a significant age dependency. Overall, the passive emptying phase accounted for 66% of total LA emptying ranging from 76% in the youngest to 44% in the oldest decade. LA contraction accounted for 34% of atrial emptying in all subjects combined with the older subjects being more dependent on atrial booster pump function. When adjusted for atrial size, there were no sex related differences in LA function. CONCLUSIONS: LA reservoir, conduit, and booster pump function can be assessed with automated analysis of signal averaged LA area waveforms. As LA performance varies with age, establishment of normal values should enhance the evaluation of pathologic states in which LA function is important.

Acoustics↗

PubMed2001

Dynamic effects of positive-pressure ventilation on canine left ventricular pressure-volume relations.

Positive-pressure ventilation (PPV) may affect left ventricular (LV) performance by altering both LV diastolic compliance and pericardial pressure (Ppc). We measured the effect of PPV on LV intraluminal pressure, Ppc, LV volume, and LV cross-sectional area in 17 acute anesthetized dogs. To account for changes in lung volume independent of changes in Ppc and differences in contractility, measures were made during both open- and closed-chest conditions, during closed chest with and without chest wall binding, and after propranolol-induced acute ventricular failure (AVF). Apneic end-systolic pressure-volume relations (ESPVR) were generated by inferior vena caval occlusions. With the open chest, PPV had no effects. With the chest closed, PPV inspiration decreased LV end-diastolic volume (EDV) along its diastolic compliance curve and decreased end-systolic volume (ESV) such that the end-systolic pressure-volume domain was shifted to a point left of the LV ESPVR, even when referenced to Ppc. The decrease in EDV was greater in control than in AVF conditions, whereas the shift of the ESV to the left of the ESPVR was greater with AVF than in control conditions. We conclude that the hemodynamic effects of PPV inspiration are due primarily to changes in intrathoracic pressure and that the inspiration-induced decreases of LV EDV reflect direct effects of intrathoracic pressure on LV filling. The decreases in LV ESV exceed the amount explained solely by a reduction in LV ejection pressure.

Acute Disease↗

PubMed2000

Tissue Doppler echocardiography.

Tissue Doppler echocardiography (TDE) is a relatively recent addition to the diagnostic ultrasonographic examination. This is similar to routine Doppler ultrasonography to assess blood flow, but technologic features focus on lower velocity frequency shifts. Two techniques are used to assess myocardial function: pulsed TDE and color-coded TDE. A great deal of data has been generated on TDE over the last 5 years, and this review allows for only a small portion of these emerging data to be discussed. One clinical application is to assess peak systolic mitral annular velocity from the apical windows as an index of global ventricular function. The six-site average for peak systolic mitral annular velocity by the color-coded TDE method of greater than 5.4 cm/sec is predictive of an ejection fraction greater than 50% with an 88% sensitivity and a 97% specificity. An emerging application is to use pulsed-TDE to assess ventricular filling pressures. The mitral annular to inflow ratio (E/Ea) greater than 10 is predictive of a mean pulmonary capillary wedge pressure greater than 15 mm Hg with a 92% sensitivity and 80% specificity. Another application is to use peak early diastolic velocity to help differentiate constrictive pericarditis from restrictive cardiomyopathy. Peak early diastolic velocity is blunted with restrictive cardiomyopathy and preserved with constrictive pericarditis. These are just a few of the many evolving clinical applications of this new quantitative diagnostic ultrasonographic method.

Blood Flow Velocity↗

PubMed2000

Normal values of regional left ventricular endocardial motion: multicenter color kinesis study.

Our goal was to establish normal values for quantitative color kinesis indexes of left ventricular (LV) wall motion over a wide range of ages, which are required for objective diagnosis of regional systolic and diastolic dysfunction. Color-encoded images were obtained in 194 normal subjects (95 males, 99 females, age 2 mo to 79 yr) in four standard views. Quantitative indexes of magnitude and timing of systolic and diastolic function were studied for age- and gender-related differences. Normal limits of all ejection and filling indexes were in a narrow range (< or =25% of the mean), with no major gender-related differences. Despite invariable ejection fractions, both peak filling and ejection rates decreased with age (30 and 20%, correspondingly) with a concomitant increase in mean filling and ejection times, resulting in five- and twofold increases in the late to early filling and ejection ratios, correspondingly. Diastolic asynchrony increased with age (from 4.7 +/- 2.0 to 6.4 +/- 3.2 from the 2nd to 7th decade). The normal values of color kinesis indexes should allow objective detection of regional LV systolic and diastolic dysfunction.

Adolescent↗

PubMed1999

Assessment of left internal mammary artery graft patency and flow reserve after minimally invasive direct coronary artery bypass.

Despite its merits, minimally invasive direct coronary artery bypass surgery (MIDCAB) has been criticized for variable left internal mammary artery (LIMA) graft patency rates, prompting the frequent use of postoperative LIMA angiography. Noninvasive transthoracic Doppler interrogation of LIMA grafts has recently been shown to have utility for assessing patency and flow reserve after conventional bypass surgery, but data after MIDCAB has been limited. The objective of this study was to assess LIMA graft anatomy and physiology in 54 patients after MIDCAB using angiography and noninvasive LIMA Doppler imaging. The right internal mammary artery (RIMA) was studied as a control. LIMA flow reserve in response to adenosine was evaluated in a subgroup of 18 randomly chosen patients with patent grafts. LIMA angiographic patency was 93%. Forty-four patients (81%) had obtainable LIMA Doppler data. Patent grafts had a diastolic dominant flow pattern with a peak diastolic/systolic velocity ratio of 1.3 +/- 0.6 and a percent diastolic time-velocity integral (TVI) of 70 +/- 11%. These data were significantly different than the RIMA control values of 0.2 +/- 0.1 and 30 +/- 10%, respectively (p <0.05). Occluded grafts had absent flow or a systolic dominant pattern. Adenosine-induced increases in LIMA peak diastolic velocity from 48 +/- 20 to 105 +/-28 cm/s (p <0.05 vs baseline) and diastolic TVI from 21 +/- 10 to 37 +/- 19 cm (p <0.05 vs baseline), yielding adenosine/baseline ratios of 2.4 +/- 0.9 and 2.0 +/- 0.7, respectively, which was consistent with normal flow reserve. The diastolic flow velocity reserve response was inversely related to baseline diastolic flow (r = -0.69). In conclusion, MIDCAB can be associated with a high rate of LIMA potency and favorable physiologic Doppler flow patterns. Correlation of these findings to long-term patient outcome after MIDCAB is warranted.

Adenosine↗

PubMed1999

Evaluation of the potential role of color-coded tissue Doppler echocardiography in the detection of allograft rejection in heart transplant recipients.

BACKGROUND: Color-coded tissue Doppler (TD) echocardiography can noninvasively quantify alterations in left ventricular (LV) systolic and diastolic function. The objective of this study was to test the hypothesis that TD may play a role in the detection of LV dysfunction associated with allograft rejection in heart transplant recipients. METHODS AND RESULTS: Seventy-eight consecutive transplant recipients underwent 89 TD studies of posterior wall myocardial velocity gradient and mitral annular velocity within 1 hour of endomyocardial biopsy. Color TD echocardiographic images were digitized for semiautomated computer analysis. Histologic analysis revealed no significant rejection in 75 biopsies and significant rejection in 14. TD posterior wall peak systolic and diastolic velocity gradients were reduced significantly with rejection: 3.9 +/- 2.0 s(-1) versus 2.6 +/- 0.9 s(-1) and 5.4 +/- 2. 4 s(-1) versus 3.5 +/- 1.6 s(-1), respectively (P <.05 vs the nonrejecting group). Peak systolic and diastolic mitral annular velocities by TD were also reduced with rejection: 63 +/- 14 mm/s versus 49 +/- 12.4 mm/s and 90 +/- 23 mm/s versus 60 +/- 21 mm/s, respectively (P <.001 vs the nonrejecting group). A TD peak-to-peak mitral annular velocity >135 mm/s had 93% sensitivity, 71% specificity, and 98% negative predictive value for detecting rejection. Although TD was unable to discriminate between rejection and other causes of low velocity values, high TD velocity values were supportive of excluding rejection. CONCLUSIONS: These data suggest that color-coded TD may play a potential role as a screening test to exclude rejection in heart transplant recipients. Although this method has the potential to decrease the number of biopsies, further testing in a larger series of transplant recipients with rejection is warranted.

Biopsy↗

PubMed1999

Determinants of aortic pressure variation during positive-pressure ventilation in man.

STUDY OBJECTIVES: To define the relation between systolic arterial pressure (SAP) changes during ventilation and left ventricular (LV) performance in humans. DESIGN: Prospective repeat-measures series. SETTING: University of Pittsburgh Medical Center Operating Room. PATIENTS: Fifteen anesthetized cardiac surgery patients before and after cardiopulmonary bypass when the mediastinum was either closed or open. INTERVENTIONS: Positive-pressure ventilation. MEASUREMENTS AND RESULTS: SAP and LV midaxis cross-sectional areas were measured during apnea and then were measured for three consecutive breaths. SAP increased during inspiration, this being the greatest during closed chest conditions (p < 0.05). Changes in SAP could not be correlated with changes in either LV end-diastolic areas (EDAs), end-systolic areas, or stroke areas (SAs). If SAP decreased relative to apnea, the decrease occurred during expiration and was often associated with increasing LV EDAs and SAs. SAP often decreased after a positive-pressure breath, but the decrease was unrelated to SA deficits during the breath. Increases in SAP were in phase with increases in airway pressure, whereas decreases in SAP, if present, followed inspiration. No consistent relation between SAP variation and LV area could be identified. CONCLUSIONS: In this patient group, changes in SAP reflect changes in airway pressure and (by inference) intrathoracic pressure (as in a Valsalva maneuver) better than they reflect concomitant changes in LV hemodynamics.

Aorta↗

PubMed1998

Assessment of left ventricular contractile state by preload-adjusted maximal power using echocardiographic automated border detection.

OBJECTIVES: We sought to assess the ability of preload-adjusted maximal power measured by echocardiographic automated border detection (ABD) to quantify left ventricular (LV) contractility by determining the effects of alterations in preload, afterload and contractile state. BACKGROUND: Preload-adjusted maximal power can reflect LV contractile state relatively independent of changes in loading conditions. METHODS: Eight anesthetized dogs had placement of aortic electromagnetic flow probes, LV and arterial pressure catheters and inferior vena caval (IVC) occluders; four had placement of thoracic aortic balloon occluders. Echocardiographic ABD measures of cross-sectional area were used as a surrogate for LV volume, and flow was estimated as the first derivative of area with respect to time. Power was calculated as the product of flow and pressure. RESULTS: Preload independence during vena caval occlusions was achieved by preload adjustment (1/[end-diastolic area]3/2). Afterload independence was demonstrated by preload-adjusted maximal power being unaffected by acute increases in LV systolic pressure induced by aortic occlusion. ABD preload-adjusted maximal power reflected changes in contractile state: increasing with dobutamine infusion from 36+/-14 to 70+/-15 mW/cm4 (p < 0.05 vs. control) and decreasing with propranolol infusion from 35+/-13 to 17+/-7 mW/cm4 (p < 0.05 vs. control). These changes were significantly correlated with calculations of preload-adjusted maximal power using aortic flow (r = 0.90, SEE 10.5 mW/cm4) and load-independent measures of end-systolic elastance from pressure-area loops (r = 0.90, SEE 10.6 mW/cm4). Calculations of normalized preload-adjusted maximal power using arterial pressure were also closely correlated with similar calculations using LV pressure (r = 0.99, SEE 3%). CONCLUSIONS: Preload-adjusted maximal power using echocardiographic ABD can predict LV contractile state relatively independent of loading conditions and has potential for clinical application.

Animals↗

PubMed1998

Heterogeneous immediate effects of partial left ventriculectomy on cardiac performance.

BACKGROUND: Partial left ventriculectomy (PLV) is a novel surgical treatment for severe heart failure consisting of resection of a large wedge of myocardium to reduce wall stress and restore the normal mass-volume ratio. Although ejection fraction (EF) has been shown to improve after PLV, few other physiological data describing its immediate effects on left ventricular (LV) performance are available. METHODS AND RESULTS: Eight patients, 58+/-5 years old, with severe clinical heart failure and EF of 12+/-3% were studied before and immediately after PLV. LV performance was assessed by the predominantly load-insensitive measures of pressure-area relations with high-fidelity pressure catheters and transesophageal automated echocardiographic measures of cross-sectional area as a surrogate for volume. LV end-diastolic volume decreased from 200+/-60 to 89+/-17 mL, EF increased from 12+/-3% to 41+/-8%, and right ventricular (RV) fractional area change increased from 24+/-12% to 37+/-16% (all P<.05 versus before). Changes in pressure-area relations were variable: end-systolic elastance, 6.5+/-3.4 to 4.3+/-2.5 mm Hg/cm2 and preload recruitable stroke work, 33+/-16 to 34+/-19 mm Hg (P=NS versus before). End-diastolic stiffness increased from 0.13+/-0.06 to 0.19+/-0.07 mm Hg/cm2 (P<.05 versus before). Improvement in LV performance was inversely correlated with semiquantitative histological assessment of myocardial fibrosis and positively correlated with nuclear enlargement and hyperchromasia, indicative of myocyte hypertrophy. No long-term follow-up data were available. CONCLUSIONS: PLV resulted in reductions in LV volumes, increases in EF and RV ejection, but increases in LV stiffness. Estimates of LV performance revealed variable results associated with the degree of myocardial fibrosis. Further study of these effects in relation to patient outcome is warranted.

Aged↗

PubMed1998

Quantification of the myocardial response to low-dose dobutamine using tissue Doppler echocardiographic measures of velocity and velocity gradient.

Low-dose dobutamine echocardiography has been clinically useful in myocardial viability studies, although routine visual assessment of wall motion is subjective. The objective was to quantify the incremental myocardial response to low-dose dobutamine infusion using a new semiautomated tissue Doppler (TD) analysis system and to compare these data with routine echocardiographic measures in the same subjects. Twelve subjects had TD and routine echocardiographic studies at baseline and during 10-minute stages of dobutamine infusion at 1, 2, 3, and 5 microg/kg/min. Color TD video data were converted to a digital velocity matrix (4.5 velocity data points/mm at 500 Hz) for analysis of mitral annular velocity, endocardial velocity, and velocity gradient at each stage. Posterior wall percent thickening and ejection fraction were calculated from the routine images. Mitral annular peak systolic velocity significantly increased with only 1 microg/kg/min of dobutamine from 69 +/- 9 to 77 +/- 7 mm/s (p <0.05 vs baseline), and further incremental increases occurred with each subsequent dose. Anteroseptal and posterior wall peak endocardial velocity increased with 2 microg/kg/min of dobutamine from 33 +/- 7 to 46 +/- 15 mm/s and 50 +/- 9 to 61 +/- 10 mm/s, respectively (p <0.01 vs baseline) and further increased with 5 microg/kg/min (p <0.0001 vs 3 microg/kg/min). Posterior wall peak systolic gradient also increased with 2 microg/kg/min of dobutamine from 3.1 +/- 0.6 to 5.4 +/- 1.6 s(-1) (p <0.05 vs baseline). Routine measures of percent wall thickening or ejection fraction did not detect increases until the 3 microg/kg/min dose. TD can detect subtle alterations in contractility induced by low-dose dobutamine and has the potential to quantify regional ventricular function objectively.

Adrenergic beta-Agonists↗

PubMed1997

Quantitative assessment of alterations in regional left ventricular contractility with color-coded tissue Doppler echocardiography. Comparison with sonomicrometry and pressure-volume relations.

BACKGROUND: Tissue Doppler imaging (TDI) is a novel method of color-coding myocardial velocity on-line. The objective of the present study was to evaluate endocardial velocity with TDI as a method of objectively quantifying alterations in regional contractility over a wide range induced by inotropic modulation. METHODS AND RESULTS: Myocardial length crystals were used to simultaneously assess regional left ventricular (LV) function, and high-fidelity pressure and conductance catheters were used to assess global LV contractility by pressure-volume relations in nine open-chest dogs. Mid-LV M-mode and two-dimensional color TDI images were recorded during control and inotropic modulation stages with dobutamine and esmolol. Predicted significant increases in TDI indices occurred with dobutamine: peak systolic velocity of 4.41 +/- 1.07 to 6.67 +/- 1.07 cm/s*, systolic time-velocity integral (TVI) of 0.43 +/- 0.12 to 0.62 +/- 0.10 cm*, and diastolic TVI of 0.49 +/- 0.11 to 0.71 +/- 0.17 cm*. Opposing significant decreases occurred with esmolol: peak systolic velocity of 4.46 +/- 0.94 to 2.31 +/- 0.81 cm/s*, systolic TVI of 0.47 +/- 0.12 to 0.19 +/- 0.11 cm*, and diastolic TVI of 0.55 +/- 0.11 to 0.33 +/- 0.11 cm* (*all P < .001 versus control). Changes in TDI peak systolic velocity were correlated with changes in fractional shortening (r = .88) and shortening velocity (r = .87) by sonomicrometry. Changes in TDI peak velocity from multiple mid-LV sites also correlated significantly with maximal elastance (r = .85 +/- .04) from pressure-volume relations. CONCLUSIONS: TDI measures reflect directional and incremental alterations in regional and global LV contractility and have the potential to quantify regional LV function.

Adrenergic beta-Antagonists↗

PubMed1997

Quantitative evaluation of the segmental left ventricular response to dobutamine stress by tissue Doppler echocardiography.

Tissue Doppler imaging displays color-coded myocardial velocity on-line and has potential to objectively quantify regional left ventricular function. Sixty patients, aged 56 +/- 10 years, were studied to determine the normal and abnormal segmental endocardial velocity response to dobutamine stress, and the sensitivity, specificity, and accuracy of tissue Doppler imaging for detecting abnormal wall motion at peak stress as defined by routine visual interpretation. Separate 2-dimensional routine gray scale and color tissue Doppler image sets were acquired at rest and peak dobutamine stress in a digital cineloop format. Routine wall motion interpretation from gray scale images and color-coded peak systolic endocardial velocity from tissue Doppler images were determined independently. Twenty-two patients who reached their target heart rate and had normal wall motion at peak stress served as a control group. There were 19 patients who had wall motion abnormalities at peak stress. Segmental peak endocardial velocities increased significantly in all segments in the control group. Endocardial velocity was significantly lower at peak stress in the pooled abnormal segments than in the pooled normal segments: 3.1 +/- 1.2 versus 7.2 +/- 1.9 cm/s, respectively (p < 0.05 vs normal control). However, the velocity response of abnormal apical segments could not be distinguished from normal controls by tissue Doppler imaging. Excluding apical segments, a peak velocity of < or = 5.5 cm/s with peak stress had an average sensitivity of 96%, specificity of 81%, and accuracy of 86% for identifying abnormal segments at peak stress as defined by routine 2-dimensional criteria. Tissue Doppler imaging has the potential to quantify regional left ventricular function during dobutamine stress.

Adrenergic beta-Agonists↗

PubMed1997

Right ventricular performance and left ventricular assist device filling.

BACKGROUND: Right ventricular (RV) function is believed to be an important determinant of left ventricular assist device (LVAD) filling. This study was designed to demonstrate this relation in patients. METHODS: To demonstrate the interaction between RV ejection and LVAD filling, 10 patients (mean age, 49 +/- 13 years) supported with an LVAD were studied. Right ventricular pressure-area loops from cross-sectional area using transesophageal echocardiographic automated border detection and high-fidelity RV pressure were recorded simultaneously with LVAD volume during intraoperative inferior vena cava occlusion. Beat-by-beat RV ejection phase indices were calculated: stroke area, peak ejection rate, and stroke work. The LVAD filling rate was calculated as the first derivative of the volume, and the peak filling rate and the mean filling rate during RV systole were determined for each cardiac cycle. RESULTS: Right ventricular stroke area, peak ejection rate, and stroke work were closely correlated with LVAD peak filling rate (r = 0.87 +/- 0.09, r = 0.83 +/- 0.09, and r = 0.85 +/- 0.10, respectively). Also, baseline LVAD mean filling rate correlated with RV stroke work (r = 0.77) and LVAD peak filling rate with RV peak ejection rate for the group (r = 0.75). CONCLUSIONS: These correlations demonstrate predictable associations of RV ejection with LVAD filling.

Heart Failure↗

PubMed1997

Resource utilization for minimally invasive direct and standard coronary artery bypass grafting.

BACKGROUND: Minimally invasive direct coronary artery bypass grafting (MIDCABG) has been recently reintroduced into the cardiac surgical armamentarium for selected patients with suitable coronary anatomy. We hypothesized that MIDCABG had the potential for similar immediate results with decreased perioperative morbidity and decreased resource utilization compared with standard coronary artery bypass grafting (CABG). METHODS: From January 1996 to August 1996, 17 MIDCABG patients were compared with 33 patients with left ventricular ejection fraction greater than 0.50 who underwent CABG with standard technique. No significant differences were observed between the two groups for preoperative variables that are known to affect cost and resource utilization. Length of stay in the hospital was 2.5 +/- 0.8 days for MIDCABG and 5.9 +/- 2 days for CABG (p < 0.0001); length of stay in the intensive care unit was 12.3 +/- 3.3 hours for MIDCABG compared to 32.3 +/- 12.6 hours for the CABG group (p < 0.0001). RESULTS: Forty-one percent of MIDCABG patients were extubated in the operating room and 59% were discharged home on the first or second postoperative day versus none in the CABG group (p < 0.0001). Significantly less morbidity was observed in the MIDCABG group compared with CABG. Total ratio of cost-to-charge was $12,885 +/- $1,511 for MIDCABG and $21,260 +/- $5,497 for CABG (p < 0.0001), with an average savings of $8,375. CONCLUSIONS: Minimally invasive CABG is associated with significant reduction of resource utilization and morbidity related to inital hospitalization compared with CABG.

Aged↗

PubMed1997

Left ventricular performance assessed by echocardiographic automated border detection and arterial pressure.

Automated echocardiographic measures of left ventricular (LV) cavity area are closely correlated with changes in volume and can be coupled with LV pressure (PLV) to construct pressure-area loops in real time. The objective was to rapidly estimate LV contractility from end-systolic relationships of cavity area (as a surrogate for LV volume) and central arterial pressure (Pa) (as a surrogate for PLV) in a canine model using automated algorithms. In eight anesthetized mongrel dogs, we simultaneously measured PLV, LV area, and Pa (fluid-filled catheter). End-systolic pressure-area relationships in terms of pressure-area elastance (E'es)] from pressure-area loops during inferior vena caval occlusions were determined during basal conditions (control), dobutamine infusion (5-10 micrograms.mg-1.min-1), and after bolus propranolol (2 mg/kg) with both PLV and Pa by semiautomated and automated iterative regression methods. E'es increased during dobutamine infusion and decreased after propranolol infusion in all animals and with all iterative methods. Estimates of Ees from Pa were closely correlated with E'es from PLV by both the semiautomated and automated methods (r = 0.93; P < 0.01). The relationship between E'es obtained from Pn for the two methods was also closely correlated. Although the automated methods displayed larger differences from the semiautomated iterative technique by Bland-Altman analysis, the change in E'es with all techniques during dobutamine infusion and after propranolol infusion was of similar magnitude and direction among the three techniques. Greater variability with the dobutamine runs was partially due to abnormally conducted ventricular beats that minimized the number of consecutive beats that could be used for these analyses. We conclude that on-line Pa recordings from fluid-filled catheters can be used with echocardiographic automated border detection to rapidly calculate E'es as a means to estimate LV contractility.

Algorithms↗

PubMed1996

Right ventricular performance and contractile reserve in patients with severe heart failure. Assessment by pressure-area relations and association with outcome.

BACKGROUND: Right ventricular (RV) performance appears to be important in patients with severe heart failure. Although clinical assessments of RV function previously have been limited to load-dependent ejection phase indices, a new method has been developed using the relatively load-insensitive concepts of pressure-volume relations with automated echocardiographic measures of RV cross-sectional area as a surrogate for volume. METHODS AND RESULTS: Sixteen patients with New York Heart Association functional class IV heart failure and group mean left ventricular ejection fraction of 20 +/- 5% were studied. RV pressure-area loops were recorded on-line from echocardiographic measures of RV area and high-fidelity pressure during transient inferior, vena caval balloon occlusions. RV contractile reserve was assessed as its functional response to an increase in dobutamine from 5.7 +/- 4.1 to 13.1 +/- 4.7 micrograms/kg per minute. Complete data sets were available in 13 patients. Group mean RV end-systolic elastance (E'es) and maximal elastance (E'max) increased with augmented dobutamine infusion (2.9 +/- 1.5 to 5.5 +/- 3.3 mm Hg/cm2 and 3.3 +/- 1.6 to 6.4 +/- 3.9 mm Hg/cm2, respectively; P < .01 versus baseline), although individual responses were variable. During a 30-day follow-up, 9 patients remained unstable, requiring continuous intravenous inotropic therapy; 6 of these had profound deterioration requiring mechanical circulatory support. The remaining 4 patients had a comparatively good short-term outcome with clinical stability. A 100% increase in RV E'es or E'max was associated with a good short-term outcome (P < .05). CONCLUSIONS: RV performance can be assessed by pressure-area relations in patients with heart failure. RV contractile reserve in response to increases in dobutamine was associated with a good short-term outcome and may be of prognostic value in patients with severe heart failure.

Adult↗

PubMed1996

Mitral annular descent velocity by tissue Doppler echocardiography as an index of global left ventricular function.

Mitral annular descent has been described as an index of left ventricular (LV) systolic function, which is independent of endocardial definition. Echocardiographic tissue Doppler imaging is a new technique that calculates and displays color-coded cardiac tissue velocities on-line. To evaluate mitral annular descent velocity as a rapid index of global LV function, we performed tissue Doppler imaging studies in 55 patients, aged 56 +/-15 years, within 3 hours of radionuclide ventriculographic ejection fraction. Tissue Doppler M-mode studies were obtained from each of 6 mitral annular sites, as follows: inferoseptal and lateral from apical 4-chamber views, anterior and inferior from apical 2-chamber views, and anteroseptal and posterior from apical long-axis views. Only 1 patient with severe mitral annular calcification was excluded. The group mean 6-site average peak mitral annular descent velocity was 5.5 +/- 1.9 cm/s (range 2.4 to 10.5), and the group mean ejection fraction was 49 +/- 18% (range 17 to 80%). The 6-site average peak annular descent velocity correlated linearly with LV ejection fraction (r = 0.86, SEE = 1.02 cm/s): LV ejection fraction = 8.2 (average peak mitral annular descent velocity) + 3%. The 6-site peak mitral annular descent velocity average >5.4 cm/s was 88% sensitive and 97% specific for ejection fraction >50%. The peak mitral annular descent velocity from the apical 4-chamber view (average from inferoseptal and lateral sites) correlated most closely with the LV ejection fraction (r = 0.85) as an individual view. Peak mitral annular descent velocity by tissue Doppler imaging has the potential to estimate rapidly the global LV function.

Adolescent↗