Estimation of left ventricular volume by one-plane cineangiography

Severe Myocardial Dysfunction after Non-Ischemic Cardiac Arrest: Effectiveness of Percutaneous Assist Devices

Introduction: Despite the improvements in standardized cardiopulmonary resuscitation, survival remains low, mainly due to initial myocardial dysfunction and hemodynamic instability. Our goal was to compare the efficacy of two left ventricular assist devices on resuscitation and hemodynamic supply in a porcine model of ventricular fibrillation (VF) cardiac arrest. Methods: Seventeen anaesthetized pigs had 12 min of untreated VF followed by 6 min of chest compression and boluses of epinephrine. Next, a first defibrillation was attempted and pigs were randomized to any of the three groups: control (n = 5), implantation of an percutaneous left ventricular assist device (Impella, n = 5) or extracorporeal membrane oxygenation (ECMO, n = 7). Hemodynamic and myocardial functions were evaluated invasively at baseline, at return of spontaneous circulation (ROSC), after 10–30–60–120–240 min post-resuscitation. The primary endpoint was the rate of ROSC. Results: Only one of 5 pigs in the control group, 5 of 5 pigs in the Impella group, and 5 of 7 pigs in the ECMO group had ROSC (p < 0.05). Left ventricular ejection fraction at 240 min post-resuscitation was 37.5 ± 6.2% in the ECMO group vs. 23 ± 3% in the Impella group (p = 0.06). No significant difference in hemodynamic parameters was observed between the two ventricular assist devices. Conclusion: Early mechanical circulatory support appeared to improve resuscitation rates in a shockable rhythm model of cardiac arrest. This approach appears promising and should be further evaluated.

“Chess-Board Pattern” Spatial Modulation of Magnetization

Heart motion is a complex combination of translation, rotation, and concentric contraction. Evaluation of these complex motions has been difficult using conventional slice-selective methods. Non-Invasive tagging of the heart has been obtained by the use of slice-selective radiofrequency pulses. Through spatial modulation of the magnetization the entire image can be labeled in different patterns. Two new pulse sequences are presented, giving a chess-board like spatial modulation. These pulse sequences have several advantages compared with the previously published methods, as the modulation time is half that required to obtain a 2-dimensional grid, the area in the image with high signal intensity was significantly larger, and the radiofrequency power deposition was substantially decreased. By labeling the heart at diastole the chess-board pattern tagging of the heart wall could be followed through systole. Using this method the complex motions of the heart can be mapped.

Assessment of Left Ventricular Volume and Function Using Real-Time 3D Echocardiography versus Angiocardiography in Children with Tetralogy of Fallot

BACKGROUND

Evaluation of left ventricular (LV) size and function is one of the important reasons for performing echocardiography. Real time three dimensional echocardiography (RT3DE) is now available for a precise non-invasive ventricular volumetry. Aim of work was to validate RT3DE as a non-invasive cardiac imaging method for measurement of LV volumes using cardiac angiography as the reference technique.

METHODS

Prospective study on 40 consecutive patients with tetralogy of Fallot (TOF) referred for cardiac catheterization for preoperative assessment. Biplane cineangiography, conventional 2 dimensional echocardiography (2DE) and RT3DE were performed for the patients. A control group of 18 age and sex matched children was included and 2DE and RT3DE were performed for them.

RESULTS

The mean LV end diastolic volume (LVEDV) and LVEDV index (LVEDVI) measured by RT3DE of patients were lower than controls (p value = 0.004, 0.01, respectively). There was strong correlation between the mean value of the LVEDV and the LVEDVI measured by RT3DE and angiography (r = 0.97, p < 0.001). The mean value of LV ejection fraction measured by RT3DE was lower than that assessed by 2DE (50 ± 6.2%, 65 ± 4.6%, respectively, p value < 0.001) in the studied TOF cases. There was good intra- and inter-observer reliability for all measurements.

CONCLUSION

RT3DE is a noninvasive and feasible tool for measurement of LV volumes that strongly correlates with LV volumetry done by angiography in very young infants and children, and further studies needed.

Predictive utility of the changes in matrix metalloproteinase-2 in the early phase for left ventricular reverse remodeling after an acute myocardial infarction

BACKGROUND

The relationship between the serum levels of matrix metalloproteinase (MMP) and tissue inhibitors of MMP (TIMP) and left ventricular (LV) reverse remodeling (LV-RR) after an acute myocardial infarction (AMI) has not been sufficiently examined.

METHODS AND RESULTS

In 25 patients with successful reperfusion after an AMI and 15 normal control subjects, the serum MMP-2 and TIMP-2 levels were measured on days 1, 2, 3, and 7 and at 1 and 6 months after the AMI onset. LV-RR was defined as a >15% decrease in the LV end-systolic volume index at 6 months after the AMI. The MMP-2 level on day 1 and TIMP-2 levels throughout the study period were comparable between the patients with and without LV-RR. The MMP-2 on day 7 (P<0.05) and the changes in the MMP-2 from day 1 to day 7 (∆MMP-2; P<0.01) were lower in patients with than in those without LV-RR. The ∆MMP-2 was strongly correlated with the changes in the LV volume and ejection fraction from 1 month to 6 months after the AMI. The ∆MMP-2 value of <-158.5 ng/mL predicted LV-RR with a high accuracy (91.7% sensitivity and 76.9% specificity; area under the curve=0.82).

CONCLUSIONS

Changes in MMP-2 are associated with LV-RR after an AMI. The ΔMMP-2 might be a useful predictor of subsequent LV-RR.

Comparison of LVEF obtained with single-plane RAO ventriculography and echocardiography in patients with and without obstructive coronary artery disease

The left ventricular ejection fraction (LVEF) determined by invasive ventriculography (routine cardiac cath; LV-gram) was compared with that determined by echocardiography in 100 patients scheduled for angiography (86% had LV-gram and 2DE during same hospital admission). Seventy percent of patients had at least single-vessel obstructive coronary artery disease, defined as more than 50% stenosis. By all estimates, the LVEF was higher in patients without coronary artery disease (CAD) compared to patients with CAD. There was an excellent correlation between the LVEF by cath and echo, but this correlation was noticeably less strong in patients with CAD, especially with involvement of the left circumflex artery.

Uterine myometrium as a cell patch as an alternative graft for transplantation to infarcted cardiac myocardium: a preliminary study

PURPOSE

Currently, only a small fraction of patients are able to receive reperfusion therapy for myocardial infarctions. We hypothesize that myometrial cell patch transplantation could be an alternative approach for the treatment of myocardial infarction.

DESIGN

We performed a preliminary study to determine the feasibility of this novel therapeutic approach in a rabbit model.

PROCEDURES

Six adult female New Zealand rabbits were used. Myocardial infarction was induced by left anterior descending artery ligation. A segment of uterus was removed via a laparotomy incision, and this uterine segment was transplanted as an autologous graft over the infarcted myocardium, which was then reinforced by greater omentum. Statistical methods and outcome measures: Hemodynamic measurements and histological studies.

MAIN FINDINGS

All uterine myometrial patches survived in the test animals. Fluoroscopic hemodynamic measurements were made for ejection fractions at 8 weeks after the application of the uterine patch. Histological study demonstrated well-healed myometrial-myocardium junctions with minimum scar tissue. Angiogenesis occurred in the transplanted myometrium. Connexin 43 expression was demonstrated in the transplanted patches.

CONCLUSION

Our noncontrolled preliminary rabbit experiments indicate that patches of uterine myometrium reinforced by greater omentum can be used as autologous transplant therapy for infracted myocardium. This is an innovative technique that could lead to future treatment for individuals who may suffer from an infarcted myocardium and may not be eligible for traditional reperfusion therapy.

Serum interferon-gamma-inducible protein 10 level was increased in myocardial infarction patients, and negatively correlated with infarct size

OBJECTIVES

We examined the serum levels of interferon-gamma-inducible protein 10 (IP-10), an inflammation-induced chemokine, in acute myocardial infarction (AMI).

DESIGN AND METHODS

The subjects were 33 AMI patients, 20 stable angina pectoris patients (AP) and 20 normal subjects. In AMI patients, blood samples were collected before percutaneous coronary intervention (PCI) and on days 3, 7 and 28.

RESULTS

Patients with AMI showed significantly higher serum IP-10 levels (137.5+/-79.8 pg/mL) than control subjects (91.2+/-40.1 pg/mL) and patients with AP (93.3+/-41.1 pg/mL). The serum IP-10 level before PCI was negatively correlated with infarct size, as indicated by cumulative release of creatine kinase (CK) and peak CK and its isoenzyme CK-MB. Stepwise multiple regression analysis revealed that the serum IP-10 level before PCI was an independent predictor of cumulative CK release.

CONCLUSIONS

The serum IP-10 level was increased in AMI, and a higher level of serum IP-10 before PCI may be informative regarding infarct size.

Pravastatin suppresses the increase in matrix metalloproteinase-2 levels after acute myocardial infarction

BACKGROUND

Matrix metalloproteinase (MMP) may contribute to myocardial remodeling after myocardial infarction. The goal of this study was to characterize the effects of pravastatin on circulating levels of MMP and on left ventricular dilatation after acute myocardial infarction (AMI).

METHODS

Thirty-four consecutive patients with successful reperfusion following AMI were assigned to either pravastatin group (group P, n=12) or non-pravastatin group (group NP, n=22). Serum MMP-2 and tissue inhibitor of MMP (TIMP)-2 were measured immediately after reperfusion, on days 2, 3, 7, 30, and at 6 months after MI. Left ventriculography was performed after reperfusion and at 4 weeks and 6 months.

RESULTS

MMP-2 levels were higher in patients with MI than control on days 1, 30, and at 6 months. Left ventricular end-diastolic volume index (LVEDVI) at 6 months correlated with MMP-2 levels on day 30 (r=0.47, p<0.01) and at 6 months (r=0.56, p<0.001). MMP-2 levels at 6 months were significantly lower in group P than group NP. Further, LVEDVI at 6 months tended to be smaller and DeltaLVEDVI was significantly smaller in group P when compared with group NP.

CONCLUSION

Serum MMP-2 varied in a time-dependent manner following AMI and correlated with late changes in LVEDVI. Serum MMP-2 levels were significantly lower in treatment group than in non-treatment group and DeltaLVEDVI was significantly smaller in treatment group after long-term pravastatin administration. Use of statins in AMI patients may provide beneficial effects in terms of preventing heart failure over and above its lipid-lowering effects.

Gene expression profiling of human atrial myocardium with atrial fibrillation by DNA microarray analysis

BACKGROUND

Atrial fibrillation (AF) is the most frequently encountered arrhythmia in the clinical setting. However, a comprehensive investigation of the molecular mechanism of AF has not been performed. The aim of this study was to clarify transcriptional profiling of genes modulated in the atrium of AF patients using DNA microarray technology.

METHODS

We obtained 17 fresh cardiac specimens, right atrial appendages, isolated from 10 patients with normal sinus rhythm and seven chronic AF patients who underwent cardiac surgery. Affymetrix GeneChip (Human Genome U95A) investigating 12,000 human genes was used for each specimen. Quantitative analysis of selected genes was performed by the real-time PCR method.

RESULTS

The left atrial diameter in the AF group was greater than that in the sinus rhythm group. We could identify 33 AF-specific genes that were significantly activated (>1.5-fold), compared with the sinus rhythm group, including an ion channel, an antioxidant, an inflammation, three cell growth/cell cycle, three transcription such as nuclear factor-interleukin 6-beta, several cell signaling and several protein genes, and seven expressed sequence tags (ESTs). In contrast, we found 63 sinus rhythm-specific genes, including several cell signaling/communication such as sarcoplasmic reticulum Ca2+-ATPase 2, several cellular respiration and energy production and two antiproliferative or negative regulator of cell growth genes, and 22 ESTs.

CONCLUSIONS

The present study demonstrated that about one hundred genes were modulated in the atria of AF patients. These findings suggest that these genes may play critical roles in the initiation or perpetuation of AF and the pathophysiology of atrial remodeling.

Assessment of global left ventricular function: comparison of cardiac multidetector-row computed tomography with angiocardiography

OBJECTIVE

Evaluation of left ventricular function using electrocardiogram (ECG)-gated multidetector row CT (MDCT) by using 3 different volumetric assessment methods in comparison to assessment of the left ventricular function by invasive ventriculography.

METHODS

Thirty patients with suspected or known coronary artery disease underwent MDCT coronary angiography with retrospective ECG cardiac gating. Raw data were reconstructed at the end-diastolic and end-systolic periods of the heart cycle. To calculate the volumes of the left ventricle, 3 methods were applied: The 3-dimensional data set (3D), the geometric hemisphere cylinder (HC), and the geometric biplane ellipsoid (BE) methods. End-diastolic volumes (EDV), end-systolic volumes (ESV), the stroke volumes (SV), and ejection fractions (EF) were calculated. The left ventricular volumetric data from the 3 methods were compared with measurements from left ventriculography (LVG).

RESULTS

The best results were obtained using the 3D method; EDV (r = 0.73), ESV (r = 0.88), and EF (r = 0.76) correlated well with the LVG data. The EDV volumes did not differ significantly between LVG and the 3D method (P = 0.24); however, ESV, SV, and EF differed significantly. The ESV were significantly overestimated (P < 0.01), leading to an underestimation of the SV (P < 0.01) and the EF (P < 0.01). The HC method resulted in the greatest overestimation of the volumes. The EDV and the ESV were 31.8 +/- 37.6% and 136.4 +/- 92.9% higher than the EDV and ESV volumes obtained by LVG. Bland-Altman analysis showed systematic overestimation of the ESV using the HC method.

CONCLUSION

MDCT with retrospective cardiac ECG gating allows the calculation of left ventricular volumes to estimate systolic function. The 3D method had the highest correlation with LVG. However, the overestimation of the ESV is significant, which led to an underestimation of the SV and the EF.

Heart failure after myocardial infarction: clinical presentation and survival

OBJECTIVES

To characterize the presentation and outcome of patients with heart failure (HF) after myocardial infarction (MI) according to left ventricular ejection fraction (LVEF) and test the hypothesis that the outcome of HF did not change over time.

BACKGROUND

Little is known about the presentation and outcome of HF post-MI and how these may have changed over time.

METHODS

Using the Rochester Epidemiology Project, all residents of Olmsted County, Minnesota who experienced an incident MI between 1979 and 1998 were identified; MI and HF were validated using standardized criteria. Subjects were followed through their community medical record.

RESULTS

Between 1979 and 1998, 1915 patients with incident MI and no prior history of HF were identified. Of these, 791(41%) experienced new onset HF as defined by Framingham criteria during 6.6+/-5.0 years of follow-up. Forty-seven percent were men, mean age was 73+/-12 years. Forty-four percent had impaired LVEF, 18% preserved LVEF and 38% had no LVEF measurement within 60 days after the HF event. Median survival after HF onset was 4 years and at 5 years after HF onset, only 45% were alive. Older age, male sex, comorbidity, hypertension and no LVEF assessment were associated with increased risk of death, however, patients with impaired LVEF had the worst outcome. Over time, survival did not improve (HR for year: 1.00; 95% CI 0.99, 1.02; P=0.919) even after adjustment for baseline characteristics.

CONCLUSION

In this geographically defined cohort of patients with MI, new onset HF after the MI was frequent. When measured, LVEF was most frequently reduced, consistent with systolic heart failure. Mortality was high and did not decline over time and death was independently associated with male sex, older age, hypertension and comorbidity. It also differed according to LVEF, which was inconsistently ascertained in this setting, potentially representing practice opportunities.

Time-dependent changes in plasma osteopontin levels in patients with anterior-wall acute myocardial infarction after successful reperfusion: Correlation with left-ventricular volume and function

Osteopontin is a secreted extracellular-matrix glycoprotein that plays a role in the healing of remodeling tissue. We examined the relationship of plasma osteopontin levels with left-ventricular (LV) volume and function in 18 consecutive patients who underwent successful reperfusion after anterior-wall acute myocardial infarction (AMI). The plasma osteopontin level was within the control range at admission (mean +/- SD 420 +/- 195 ng/mL), began to increase on day 2 (935 +/- 464 ng/mL), and reached a maximum around day 3 (1139 +/- 482 ng/mL). The level remained high on days 4, 5, and 7 ( approximately 1000 ng/mL) and then decreased on day 14. Maximal plasma osteopontin levels and the difference between maximal and minimal levels were positively correlated with LV end-systolic volume index (r = .58, P < .05; and r = .65, P < .01, respectively) and negatively correlated with LV ejection fraction (r = -.52, P < .05; and r = -.60, P < .01, respectively). The area under the curve of plasma osteopontin levels for 14 days after AMI was significantly correlated with LV end-systolic volume index (r = .66, P < .01), LV end-diastolic volume index (r = .50, P < .05), and LV ejection fraction (r = -.55, P < .05). In subgroup patients with the same area of risk for myocardial infarction (ie, responsible lesions located at the same proximal left anterior descending coronary artery), essentially the same or a closer relationship between plasma osteopontin level and LV volume and function was noted. Plasma osteopontin levels were correlated substantially with plasma levels of high-sensitivity C-reactive protein (hsCRP) and weakly with serum creatine kinase release. In conclusion, the plasma level of osteopontin changes in a time-dependent fashion and is correlated with LV volumes and function and associated substantially with the extent of the inflammatory response indicated by the plasma hsCRP level and weakly with infarct size estimated on the basis of cardiac-enzyme release.

[Improved analysis of left ventricular function using three-dimensional echocardiography]

Left ventricular geometry and function are important pathophysiologic and prognostic parameters. However, especially in patients with cardiac pathologies left ventricular geometry can be complex. Quantification of left ventricular volumes using conventional two-dimensional echocardiography is only possible when simplifying assumptions of left ventricular geometry are made. In contrast three-dimensional echocardiography allows direct quantification of left ventricular volumes even in complex distortions of left ventricular shape. The availability of real-time three-dimensional echocardiography has brought this technique into clinical practice. Three-dimensional echocardiography is a technique that may be used as a routine echocardiographic method in the near future.

Circulating matrix metalloproteinase-2 is elevated in patients with congestive heart failure

BACKGROUND AND AIMS

It has been reported that matrix metalloproteinase (MMP) protein concentration and activity are upregulated in the failing human heart. However, there are few reports describing the role of elevated level of circulating MMPs in congestive heart failure (CHF) patients. This study examined whether circulating matrix metalloproteinases (MMPs) are also related to the pathogenesis of CHF.

METHODS

We measured circulating levels of matrix metalloproteinase-2 (MMP-2) in 52 patients with CHF (left ventricular ejection fraction (LVEF) <50%). The patients were also subdivided into two groups according to NYHA functional class; mild CHF (class II, n=43) and severe CHF (class III, n=9).

RESULTS

The serum level of MMP-2 and MMP-2/TIMP-2 ratio were significantly higher in CHF than in controls (P<0.01). Among patient groups, serum levels of MMP-2 were significantly higher in patients with severe CHF than in patients with mild CHF (P<0.01). Plasma levels of BNP had a significant positive correlation with circulating levels of MMP-2 (r=0.78; P<0.01) and MMP-2/TIMP-2 ratio (r=0.60; P<0.01).

CONCLUSIONS

Our data showed that the circulating MMP-2 concentration was increased in CHF patients and that the levels were related to the plasma levels of BNP in CHF, suggesting that the elevated levels are related to developing heart failure syndrome.

A new radionuclide approach for the quantification of left ventricular volumes: the 'geometric count based' method

A new radionuclide method, called the 'geometric count based' (GCB) method, has been developed for the quantification of absolute left ventricular volume. As the method is based on planar radionuclide ventriculography, it is non-invasive and simple, and avoids the relatively cumbersome and longer lasting, dynamic procedure using single photon computed emission tomography, which can be used for achieving the same goal. The purpose of this study was to describe the exactness of the theoretical approach to the method and validate its accuracy both by physical experiments and the initial clinical trial, as compared to contrast ventriculography. Count based data were combined with the geometric based data assuming an ellipsoid left ventricular shape with identical short axes. The following equation for computing left ventricular end diastolic volume, EDV (in ml) was developed: EDV=2cMCtot/Cmax, where c is the manually drawn short axis (one row pixel ROI) of the prolate ellipsoid in LAO 45 degrees (cm), M is the calibrated pixel size (in cm2), Ctot is the total counts in LV ROI, and Cmax is the maximum pixel counts in the LV ROI. Physical experiments with two different 'heart shaped' phantoms were used to compare the results obtained by the GCB method with the true phantom volumes and with the method assuming LV ball shape (BLV), developed by other authors. The true volumes of cylindrical and ellipsoid phantoms of 112.5 ml and 190.5 ml were computed to be 114 ml and 196 ml by the GCB and 168 ml and 180 ml by the BLV methods, respectively. In a clinical study, GCB volumes were compared to volumes measured by using single plane contrast ventriculography in 38 coronary patients. A good correlation between the GCB method and contrast ventriculography was obtained both for EDV and end systolic ventricular volumes (r=0.94, r=0.90). Both phantom and initial clinical studies indicate that the GCB method is an accurate, non-invasive and simple radionuclide method for measuring left ventricular volumes. Additionally, it could be used even in the smallest nuclear medicine units, for example in intensive care units where there are mobile cameras.

Administration of atrial natriuretic peptide attenuates reperfusion phenomena and preserves left ventricular regional wall motion after direct coronary angioplasty for acute myocardial infarction

To evaluate the effects of synthetic human atrial natriuretic peptide (hANP) on myocardial reperfusion injury and left ventricular remodeling, 19 patients within 12 h of a first attack of anterior myocardial infarction (AMI) underwent intracoronary injection of 25 microg of hANP immediately after coronary angioplasty, combined with intravenous infusion of 0.025 microg x kg(-1) x min(-1) of hANP initiated on admission for 1 week (hANP group); 18 similar patients had saline administered (control group). The incidences of premature ventricular contraction, ventricular tachycardia and/or fibrillation in the hANP group were significantly less than in the control group after coronary angioplasty. Left ventricular ejection fraction was significantly greater and left ventricular end-diastolic volume index was significantly smaller 6 months after coronary angioplasty. Left ventricular regional wall motion of the infarcted segments significantly increased. Thus, hANP remarkably suppressed reperfusion phenomena and preserved left ventricular function through improvement of regional wall motion of the infarcted segments after coronary angioplasty.

In vivo validation of cardiac spiral computed tomography using retrospective gating

BACKGROUND

Cardiac functional assessment represents the basis for diagnostics and cardiac operation planning. Spiral computed tomography (CT) combines the advantages of three-dimensional imaging and high temporal resolution when using gating techniques. However, in vivo validation data of this novel imaging technology are lacking. The purpose of this study was to validate in vivo the new imaging method using retrospective gating and to evaluate the clinical usefulness of the achieved temporal resolution.

METHODS

In domestic pigs (n = 10, weight 35 to 40 kg) a flowmeter was placed surgically on the ascending aorta. Flow velocity integrated over systole served as the gold standard for left ventricular (LV) stroke volume (LVSV-FM). CT signal, projection data, pacemaker signal, and flow velocity were recorded simultaneously at constant heart rate (pacemaker, 90 beats per minute). End-systolic and end-diastolic frames were calculated by retrospective gating. LV volumes were traced, the difference representing CT stroke volume (LVSV-CT). Image data were three-dimensionally reconstructed using ray-tracing.

RESULTS

Temporal resolution was 170 ms. Correlation of stroke volumes was high (r = 0.94, mean difference 1.75 mL). Intraobserver (0.49 mL for LVEDV, 0.31 for LVESV) and interobserver variability (p = 0.21 and p = 0.06, respectively) were low. Postprocessing resulted in four-dimensional beating-heart models useful for operation planning.

CONCLUSIONS

Spiral CT using retrospective gating was validated in vivo. Clinically acceptable temporal resolution and accuracy in determining cardiac stroke volumes were found. As a true volumetric imaging modality the method may now play an important role in computer-assisted diagnostics and surgery.

Treatment of post resuscitation myocardial dysfunction: aortic counterpulsation versus dobutamine

BACKGROUND

Post resuscitation myocardial stunning is well described and recognized as a significant contributor to poor long-term outcome following cardiac arrest. Optimal strategies for treatment have not been determined.

METHODS

Ten domestic swine (49+/-3 kg) underwent 15 min of untreated ventricular fibrillation before being successfully resuscitated. Left ventricular systolic and diastolic function was measured at pre-arrest baseline, at 30 min and at 6 h post resuscitation. Five animals were treated immediately after resuscitation with intra-aortic balloon counterpulsation (IABP) and five were given dobutamine (5 mcg/kg per min).

RESULTS

No baseline differences were found. At 30 min post resuscitation pulmonary capillary wedge pressure and LVEDP were significantly higher (16+/-3 vs. 7+/-1 and 20+/-2 vs. 11+/-1 mmHg) while LV isovolumic relaxation ('Tau') was significantly longer (34+/-2 vs. 20+/-2 ms) in the IABP treated versus the dobutamine treated animals. Likewise, at 6 h post resuscitation LV ejection fraction was significantly less (21+/-6 vs. 39+/-4%), and LVEDP significantly higher (18 vs. 10 mmHg) in the IABP group. Heart rate was not different between the groups at any time post resuscitation.

CONCLUSION

Dobutamine was superior to IABP for treatment of post resuscitation left ventricular systolic and diastolic dysfunction. The hypothesized advantage of IABP for treatment of post resuscitation myocardial stunning without excessively raising the heart rate like dobutamine was not realized.

Time-dependent changes of serum carboxy-terminal peptide of type I procollagen and carboxy-terminal telopeptide of type I collagen concentrations in patients with acute myocardial infarction after successful reperfusion: correlation with left ventricular volume indices

To test the hypothesis that in patients with acute myocardial infarction (AMI), changes in the concentrations of the serum carboxy-terminal peptide of type I procollagen (PICP) and the carboxy-terminal telopeptide of type I collagen (ICTP) reflect extracellular matrix reformation and degradation, respectively, in the infarct healing processes, we measured these serum concentrations by RIA and compared their values with left ventricular (LV) indices obtained by left ventriculography. We studied 13 consecutive patients with their first AMI who underwent successful reperfusion. Blood samples were taken the day of admission and on days 2, 3, 4, 5, 7, and 14. LV volume indices were determined at 1 month after AMI, when LV remodeling was almost completed. The serum concentrations of both PICP and ICTP changed in a time-dependent manner. The average serum PICP concentration was lower than 1 SD below the mean control values on days 2 and 3 and increased thereafter, returning to the lower end of the control range at day 14. The area under the curve (AUC) for PICP was significantly correlated with the LV end systolic (ES) and end diastolic (ED) volume indices and LV ejection fraction for the first 14 days after AMI. The serum PICP on days 5–14 was inversely correlated or tended to be correlated with the LVES and LVED volume indices. The average serum ICTP concentrations on admission were within the control range, began to increase on day 2, and reached maximal concentrations on day 5, remaining at a plateau concentration until day 14. Although the AUC of ICTP for 14 days, the ICTP concentrations on days 1 and 14, and the minimal and maximal concentrations were significantly correlated with creatine kinase (CK) release and the period from AMI onset to the peak CK time, the concentrations were not significantly correlated with any LV indices except for the concentration on day 4, which was weakly correlated with the LVES volume index. The serum concentrations of PICP showed a significant time-dependent change that correlated with LV indices, indicating that PICP may provide additional information for evaluating the healing process because it affects LV remodeling after AMI. Although the serum concentration of ICTP changed in association with CK release, the ICTP concentration was found to be a poor indicator for LV indices.

Left ventricular function and coagulation activity in healed myocardial infarction

We investigated the plasma levels of molecular markers for the thrombotic and fibrinolytic status in patients with healed myocardial infarction to determine the relation between left ventricular (LV) function and coagulation activity. Our findings demonstrated that the coagulation activity was increased in patients with healed myocardial infarction along with LV dysfunction, suggesting that anticoagulant therapy is considered in patients with severe LV dysfunction to prevent systemic thromboembolism.

Morphologic spectrum of primary restrictive cardiomyopathy

A restrictive hemodynamic profile with left ventricular (LV) end-diastolic volume < 100 ml/m2 and LV end-diastolic pressure > 18 mm Hg, in the absence of endomyocardial, pericardial, and specific cardiomyopathy, is a peculiar feature of primary restrictive cardiomyopathy. From 1985 to 1994, 7 hearts of patients who met the above hemodynamic criteria and underwent endomyocardial biopsy because of heart failure, were studied through gross (5 cardiectomies and 2 autopsies), histologic, and electron microscopic investigations. Ages ranged from 9 to 48 years (mean age 29 +/- 13). Four patients (57%) had a positive family history: 2 for hypertrophic and 2 for restrictive cardiomyopathy. Three patterns were identified in the 7 hearts: (1) pure restrictive form in 4 cases with mass/volume ratio 1.2 +/- 0.5 g/ml, ejection fraction 58 +/- 5%, LV end-diastolic volume 67.5 +/- 12.6 ml/m2, LV end-diastolic pressure 26.7 +/- 3.5 mm Hg; (2) hypertrophic-restrictive form in 2 cases with mass/volume ratio 1.5 +/- 0.07 g/ml, ejection fraction 62 +/- 1%, LV end-diastolic volume 69 +/- 10 ml/m2, LV end-diastolic pressure 30 +/- 7 mm Hg; and (3) mildly dilated restrictive form in 1 case with mass/volume ratio 0.9 g/ml, ejection fraction 25%, LV end-diastolic volume 98 ml/m2, LV end-diastolic pressure 40 mm Hg. Histology and electron microscopy disclosed myocardial and myofibrillar disarray and endoperimysial interstitial fibrosis in each pattern. The familial forms suggest the presence of a genetic abnormality. Primary restrictive cardiomyopathy may present with or without hypertrophy and shares similar microscopic pictures with hypertrophic cardiomyopathy. The 2 entities may represent a different phenotypic expression of the same genetic disease.

Time dependent alterations of serum matrix metalloproteinase-1 and metalloproteinase-1 tissue inhibitor after successful reperfusion of acute myocardial infarction

OBJECTIVE

To test the hypothesis that changes in serum matrix metalloproteinase-1 (MMP-1) and tissue inhibitors of metalloproteinase-1 (TIMP-1) after acute myocardial infarction reflect extracellular matrix remodelling and the infarct healing process.

PATIENTS

13 consecutive patients with their first acute myocardial infarction who underwent successful reperfusion.

METHODS

Blood was sampled on the day of admission, and on days 2, 3, 4, 5, 7, 14, and 28. Serum MMP-1 and TIMP-1 were measured by one step sandwich enzyme immunoassay. Left ventricular volume indices were determined by left ventriculography performed four weeks after the infarct.

RESULTS

Serum concentrations of both MMP-1 and TIMP-1 changed over time. The average serum MMP-1 was more than 1 SD below the mean control values during the initial four days, increased thereafter, reaching a peak concentration around day 14, and then returned to the middle control range. Negative correlations with left ventricular end systolic volume index and positive correlations with left ventricular ejection fraction were obtained for serum MMP-1 on day 5, when it began to rise, and for the magnitude of rise in MMP-1 on day 5 compared to admission. Serum TIMP-1 at admission was more than 1 SD below the mean control value, and increased gradually thereafter, reaching a peak on around day 14. Negative correlations with left ventricular end systolic volume index and positive correlations with left ventricular ejection fraction were obtained for serum TIMP-1 on days 5 and 7, and for the magnitude of rise in TIMP-1 on days 5 and 7 compared to admission.

CONCLUSIONS

Both MMP-1 and TIMP-1 showed significant time dependent alteration after acute myocardial infarction. Thus MMP-1 and TIMP-1 may provide useful information in evaluating the healing process as it affects left ventricular remodelling after acute myocardial infarction.

A comparison of hemodynamic parameters derived from transthoracic electrical bioimpedance with those parameters obtained by thermodilution and ventricular angiography

OBJECTIVE

To determine the limits of agreement between the cardiac output and volumetric data estimated by impedance cardiography with the cardiac output determined by thermodilution and the left ventricular ejection fraction and end-diastolic volume estimated from left ventriculography.

DESIGN

A prospective study.

SETTING

The cardiac catheterization laboratory of a university-affiliated teaching hospital.

PATIENTS

Twenty-four patients with coronary artery disease undergoing elective left- and right heart catheterization.

INTERVENTIONS

Cardiac output was measured by the thermodilution method and the ejection fraction and left ventricular volumetric data were determined by ventriculography. These same measurements were obtained by simultaneously performed impedance cardiography using a commercially available bioimpedance device.

MEASUREMENTS AND MAIN RESULTS

The patients' mean cardiac output was 4.6 +/- 1.7 L/min by bioimpedance and 5.0 +/- 1.1 L/min by thermodilution. The limits of agreement between the two methods was -4.1 to 3.5 L/min. The 95% confidence intervals for the lower and upper limits of agreement were -2.7 to -5.5 L/min and 2.1 to 4.9 L/min, respectively. The mean ejection fraction was 63 +/- 8% by bioimpedance and 53 +/- 15% by ventriculography. The limits of agreement between the ejection fraction estimated by bioimpedance and ventriculography was -35% to 37%. The 95% confidence intervals for the lower and upper limits of agreement were -22% to -48% and 24% to 50%, respectively. The mean left ventricular end-diastolic volume was 108 +/- 47 mL, as estimated by bioimpedance, and 121 +/- 35 mL, as estimated by ventriculography. The limits of agreement between the left ventricular end-diastolic volume as estimated by bioimpedance and ventriculography was -139 to 113 mL. The 95% confidence intervals for the lower and upper limits of agreement were -184 to -94 mL and 68 to 158 mL, respectively.

CONCLUSIONS

The 95% confidence range defining the limits of agreement between cardiac output and volumetric data estimated by bioimpedance, with the cardiac output measurement by thermodilution and the volumetric data estimated from left ventriculography, were wide, making the degree of agreement clinically unacceptable. In the opinion of the authors, impedance cardiography should not replace invasive hemodynamic monitoring at this time.

Determination of ventricular ejection fraction: a comparison of available imaging methods. The Cardiovascular Imaging Working Group

Knowledge of left ventricular ejection fraction has been shown to provide diagnostic and prognostic information in patients with known or suspected heart disease. In clinical practice, the ejection fraction can be determined by using one of the five currently available imaging techniques: contrast angiography, echocardiography, radionuclide techniques of blood pool and first pass imaging, electron beam computed tomography, and magnetic resonance imaging. In this review, we discuss the clinical application as well as the advantages and disadvantages of each of these methods as it relates to determination of ventricular ejection fraction.

Evaluation of plasma natriuretic peptides as markers for left ventricular dysfunction

To test the hypothesis that elevated plasma levels of natriuretic peptides may serve to identify patients with left ventricular (LV) dysfunction, we assessed the predictive diagnostic value of natriuretic peptide levels, in addition to clinical and electro-cardiographic risk factors, as noninvasive indicators of cardiac dysfunction. Plasma levels of atrial natriuretic peptide (cANP) (99-126), N-terminal fragment of proANP (nANP) (26-55), nANP(80-96), brain natriuretic peptide (BNP-32), proBNP(22-46), and C-type natriuretic peptide (CNP-22) were measured in 211 subjects before cardiac catheterization. The strongest correlations with parameters of LV function were found for nANP(80-96) (up to r = -0.55, p < 0.0001), whereas there was no significant correlation with proBNP(22-46) or CNP-22. In patients with LV ejection fractions (LVEF) < or = 45% (n = 38) nANP(26-55), nANP(80-96), cANP(99-126), and BNP-32 were significantly increased (p < 0.001). Partition values for elevated versus normal natriuretic peptide levels were obtained from normal controls and used to separate subjects with and without LV dysfunction. Receiver operating characteristic analysis for LVEF < or = 45% indicated a significantly better diagnostic accuracy for high levels of nANP(80-96), nANP(22-56), cANP(99-126), and BNP-32 than for proBNP and CNP-22. Multivariate analysis by logistic regression identified Q waves and bundle branch block in the electrocardiogram as well as elevated plasma levels of cANP, nANP(80-96), and nANP(26-55) as the strongest independent predictors of low ejection fractions. The relative risk of LV dysfunction was raised up to tenfold in subjects with high natriuretic peptide levels (p < 0.001). The addition of nANP(80-96) and nANP(26-55) to the combination of clinical and electrocardiographic risk factors did not further improve the diagnostic sensitivity for the detection of LVEF < or = 45%, but it markedly increased the overall accuracy (59% to 81%, p < 0.001) and specificity (55% to 81%, p < 0.001). Among natriuretic peptides, elevated nANP(80-96) and nANP(26-55) levels have the strongest impact on the detection of LV dysfunction. They add to the diagnostic information contained in clinical and electrocardiographic factors. Plasma levels alone or in combination with clinical factors seem to be of value for a refined identification of abnormal LV function in the individual patient.

Myocardial dysfunction after resuscitation from cardiac arrest: an example of global myocardial stunning

OBJECTIVES

This study investigated the effect of prolonged cardiac arrest and subsequent cardiopulmonary resuscitation on left ventricular systolic and diastolic function.

BACKGROUND

Cardiac arrest from ventricular fibrillation results in cessation of forward blood flow, including myocardial blood flow. During cardiopulmonary resuscitation, myocardial blood flow remains suboptimal. Once the heart is defibrillated and successful resuscitation achieved, reversible myocardial dysfunction, or "stunning," may occur. The magnitude and time course of myocardial stunning from cardiac arrest is unknown.

METHODS

Twenty-eight domestic swine (26 +/- 1 kg) were studied with both invasive and noninvasive measurements of ventricular function before and after 10 or 15 min of untreated cardiac arrest. Contrast left ventriculograms, ventricular pressures, cardiac output, isovolumetric relaxation time (tau) and transthoracic Doppler-echocardiographic studies were obtained.

RESULTS

Twenty-three of 28 animals were successfully resuscitated and postresuscitation data obtained. Left ventricular ejection fraction showed a significant reduction 30 min after resuscitation (p < 0.05). Regional wall motion analysis revealed diffuse, global left ventricular systolic dysfunction. Left ventricular end-diastolic pressure increased significantly in the postresuscitation period (p < 0.05). Isovolumetric relaxation time (tau) was significantly increased over baseline by 2 h after resuscitation (p < 0.05). Similar findings were noted with the Doppler-echocardiographic analysis, including a reduction in fractional shortening (p < 0.05), a reduction in mitral valve deceleration time (p < 0.05) and an increase in left ventricular isovolumetric relaxation time at 5 h after resuscitation (p < 0.05> By 24 h, these invasive and noninvasive variables of systolic and diastolic left ventricular function had begun to improve. At 48 h, all measures of left ventricular function had returned to baseline levels.

CONCLUSIONS

Myocardial systolic and diastolic dysfunction is severe after 10 to 15 min of untreated cardiac arrest and successful resuscitation. Full recovery of this postresuscitation myocardial stunning is seen by 48 h in this experimental model of ventricular fibrillation cardiac arrest.

Tomographic left ventricular volume determination in the presence of aneurysm by three-dimensional echocardiographic imaging. I: Asymmetric model hearts

To improve the accuracy of measurements of left ventricular volume in the presence of an aneurysm, we used three-dimensional echocardiographic imaging to analyze the shape of left ventricles in 23 asymmetric model hearts with eccentric aneurysms of different sizes, shapes, and localizations. A standard 3.75 MHz ultrasound probe with a rotation motor device was used to obtain a three-dimensional data set. By rotating the probe stepwise 1 degree, 180 radial ultrasound pictures were digitized. On the basis of the three-dimensional data set, the following parameters were determined and compared with the dimensions of the model hearts obtained by direct measurement: total left ventricular volume (LVV), aneurysm volume, area of the aneurysm's base, the longest aneurysm long diameter, and the longest aneurysm cross diameter. In addition, quantification of LVV by three-dimensional echocardiography was compared with biplane two-dimensional echocardiographic measurement according to the disk method. Good agreements were found for LVV measured by both techniques, three-dimensional echocardiographic and direct measurement (mean of differences = 0.91 ml; SD of differences = +/- 6.23 ml; line of regression y = 1.07 x - 14.24 ml; r = 0.968; standard error of the estimate [SEE] = +/- 6.17 ml), aneurysm volume (mean of differences = 0.43 ml; SD of differences = +/- 2.14 ml; line of regression y = 1.05 x - 0.81 ml; r = 0.996; SEE = +/- 1.96 ml), area of the aneurysm's base (mean of differences = 0.24 cm2; SD of differences = +/- 1.72 cm2; line of regression y = 1.02 x - 0.02 cm2; r = 0.981; SEE = +/- 1.75 cm2), the longest aneurysm long diameter (mean of differences = -0.26 mm; SD of differences = +/- 1.60 mm; line of regression y = 0.97 x + 1.34 mm; r = 0.996; SEE = +/- 1.54 mm), and the longest aneurysm cross diameter (mean of differences = 1.35 mm; SD of differences = +/- 3.94 mm; line of regression y = 0.95 x + 3.17 mm; r = 0.941; SEE = +/- 3.99 mm). In contrast, in these extremely asymmetric-shaped model hearts, agreement between biplane two-dimensional echocardiographic and both direct LVV measurement (mean of differences = 7.8 ml; SD of differences = +/- 20.8 ml; line of regression y = 1.48 x - 92.45 ml; r = 0.874; SEE = +/- 18.36 ml) and three-dimensional echocardiographic measurements (mean of differences = -7.6 ml; SD of difference = +/- 18.1 ml; line of regression y = 0.59 x + 80.98 ml; r = 0.908; SEE = +/- 10.36 ml) was poor. Thus tomographic three-dimensional echocardiography allowed accurate volume determination of asymmetric model hearts in the shape of left ventricles with eccentric aneurysms.

Echocardiographic assessment of systolic and diastolic left ventricular function using an automatic boundary detection system. Correlation with established invasive and non invasive parameters

Systolic and diastolic left ventricular function was assessed using an echocardiographic automatic boundary detection system (ABD) in 50 unselected patients undergoing left cardiac catheterisation. Automatic boundary detection system derived parameters (fractional area change [FAC], peak positive rate of area change [+dA/dt] and peak negative rate of area change [-dA/dt]) were compared with invasively (left ventricular angiography and pressures) and non invasively (Doppler mitral filling velocities and isovolumic relaxation time) acquired conventional indices of ventricular function. Adequate detection of endocardial boundaries and subsequent measurements using the ABD system were achieved in 40/50 (80%) patients in the short axis parasternal view, in 41/50 (82%) in the apical four chamber view and in 34/50 (68%) in both views. For the whole group of patients the FAC (maximal left ventricular diastolic area--minimal left ventricular systolic area/maximal left ventricular diastolic area) estimated in the short axis view correlated with the angiographic ejection fraction (EF) measured in the right oblique projection (r = 0.51, p < 0.001). There was only a weak correlation of the FAC estimated in the apical four chamber view with the EF (r = 0.36, p < 0.01). The mean FAC (mean value of the FAC in the short axis and apical four chamber views) correlated reasonably with the EF (r = 0.62, p < 0.0001). There was no correlation between ABD derived parameters and left ventricular end diastolic pressure (LVEDP) in these patients. In a subgroup of patients with normal coronary arteries and left ventricular function (n = 17), although there was no correlation between EF and FAC, there was a strong positive correlation between FAC (apical four chamber and mean) and LVEDP (r = 0.77, p < 0.01 and r = 0.87, p < 0.01 respectively). No correlation was found in these patients between EF and LVEDP. In a further subgroup of patients with angiographically abnormal left ventricular function (EF < 45%), there was a positive correlation between FAC (short axis, apical four chamber and mean) and EF (r = 0.52, p < 0.05, r = 0.83, p < 0.0001 and r = 0.80, p < 0.001 respectively) and a negative correlation between FAC (short axis and mean) and LVEDP (r = -0.52, p < 0.05 and r = -0.60, p < 0.01 respectively). There was also a negative correlation between LVEDP and EF in the same subgroup of patients (r = -0.65, p < 0.01).(ABSTRACT TRUNCATED AT 400 WORDS)

Sex differences in the anatomy of coronary artery disease

In a prospective study, the extent and severity of coronary artery disease (CAD) as well as the location of coronary stenoses were studied comparatively, in relation to age and sex, in 192 consecutive women vs 543 selected men, who all underwent coronary angiography during the same time period, and who were found to have significant CAD. Overall, the age of women (59 +/- 8 years) was higher than that of men (55 +/- 8 years), p < 0.001. Also, the prevalence of smoking was higher in men (81% vs 31%, p = 0.0000) and that of diabetes mellitus in women (29% vs 12%, p = 4 x 10(-6)). In addition, women over 50 years old had a higher incidence of hypertension (51% vs 32%, p = 6 x 10(-5)). Although in both sexes the prevalence of multivessel CAD increased with age, the prevalence of one-vessel CAD was significantly more and that of three-vessel CAD significantly less common in women than in men, both overall (35% vs 16%, p = 4 x 10(-8) and 36% vs 54%, p = 2 x 10(-5), respectively) and in all age subgroups. However, the location of coronary stenoses did not show important differences between men and women with the left anterior descending being the most frequently involved artery. Furthermore, the calculated Gensini index, which reflects cumulatively the extent, severity and location of coronary stenoses, was significantly higher in men (59.2 +/- 34.6 vs 52.2 +/- 36.2, p = 0.03), implying more severe and extensive CAD.(ABSTRACT TRUNCATED AT 250 WORDS)

Simulation study on heart failure: effects of contractility on cardiac function

Using the model proposed by Beyar and Sideman, the effect of maximum isometric active stress at optimal sarcomere length (sigma 0) on left ventricular (LV) function was examined. Comparing the results of calculated LV function with those of reported experiments, sigma 0 was shown to be a potential indicator of myocardial contractility, and the model of Beyar and Sideman successfully predicted LV function with various myocardial contractilities. The LVP compensation curve, which describes the relationship between sigma 0 and maximum LV pressure, was then hypothesized. The combination of the Beyar-Sideman model and the LVP compensation curve enabled the prediction and approximation of the actual process of deterioration in heart failure. These models represent a step towards a fundamentally new concept in the current clinical situation of compensated heart failure and also in evaluating the process of heart failure.

Angiotensin converting enzyme inhibition in chronic stable angina: effects on myocardial ischaemia and comparison with nifedipine

OBJECTIVES

To determine the anti-ischaemic effects of a new angiotensin converting enzyme inhibitor, benazepril, compared with nifedipine, alone and in combination, in chronic stable angina caused by coronary artery disease.

DESIGN

Placebo controlled, double blind, latin square design.

SETTING

Regional cardiology service for a mixed urban and rural population.

SUBJECTS

40 patients with stable exertional angina producing at least 1 mm ST segment depression on exercise test with the Bruce protocol. 34 patients completed all four phases of the trial.

INTERVENTIONS

Each patient was treated with placebo, benazepril (10 mg twice daily), nifedipine retard (20 mg twice daily), and a combination of benazepril and nifedipine in the same doses, in random order for periods of two weeks.

MAIN OUTCOME MEASURES AND RESULTS

Total duration of exercise was not increased by any treatment. Exercise time to the development of 1 mm ST segment depression was not significantly changed with benazepril alone or in combination with nifedipine but was increased with nifedipine from 4.18 (1.8) min to 4.99 (1.6) min (95% confidence interval (95% CI) 0.28 to 1.34; p < 0.05). There was a significant relation between increase in duration of exercise and resting renin concentration (r = 0.498; p < 0.01). Myocardial ischaemia during daily activity, as assessed by ambulatory electrocardiographic monitoring, was reduced by benazepril and by the benazepril and nifedipine combination. This was significant for total ischaemic burden (451(628) min v 231(408) min; 95% CI -398 to -41 min; p < 0.05) and maximal depth of ST segment depression (-2.47(1.2) mm v -2.16 mm; 95% CI 0.04 to 0.57; p < 0.05) for the combination and for maximal ST segment depth for benazepril monotherapy (-2.47 (1.2) mm v -1.96(1.2) mm; 95% CI 0.18 to 0.91; p < 0.05). Benazepril significantly altered the circadian rhythm of cardiac ischaemia, abolishing the peak ischaemic periods at 0700 to 1200 and 1700 to 2300 (p < 0.05).

CONCLUSIONS

Benazepril, an angiotensin converting enzyme inhibitor, had a modest anti-ischaemic effect in effort angina, but this effect was not as pronounced as with nifedipine. The anti-ischaemic action was more noticeable in asymptomatic ischaemia during daily activity, whereas nifedipine had little effect on this aspect of myocardial ischaemia. The combination of benazepril and nifedipine reduced ischaemia of daily activity.

Left ventricular volume calculation with integrated backscatter from echocardiography

Integrated backscatter analysis (IB) is a new echocardiographic method for automatically differentiating tissue from blood on the basis of differences in the amplitude of reflected ultrasound. Left ventricular volume was estimated with IB by use of a modification of Pappus' theorem and a summated ellipsoid method. IB measurements correlated well with a standard biplane area-length method derived off-line from endocardial borders drawn by hand from the same echocardiographic data (y = 1.09 x - 35, r = 0.95). Integrated backscatter measurement of ventricular volume derived from six imaging planes with both the Pappus' rule and the summated ellipsoid methods correlated well with magnetic resonance imaging volume estimates (r = 0.91 and r = 0.90, respectively), whereas use of one imaging plane correlated less well (r = 0.75). Automated analysis of integrated backscatter differentiates tissue from blood sufficiently to allow accurate volume calculations compared with magnetic resonance imaging and to standard hand-drawn echo techniques. This method provides accurate measurement of left ventricular volumes that should be useful in clinical hemodynamic assessments.

Color Doppler echocardiographic determination of mitral regurgitant flow from the proximal velocity profile of the flow convergence region

Flow rate across an orifice can be determined from color Doppler echocardiographic maps of the flow convergence region proximal to the orifice. Different methods have been developed in vitro. The proximal velocity profile method was prospectively evaluated in patients with mitral regurgitation. Color Doppler echocardiography was performed in 74 patients before cardiac catheterization. The increasing velocities within the flow convergence region were determined in an apical plane on the straight line from the transducer to the leak; thus the proximal velocity profile was established and plotted on a nomogram. Instantaneous regurgitant flow rate was derived from the position of the resulting curve in relation to the nomogram's reference curves, which were derived from in vitro measurements. Regurgitant stroke volume was calculated as regurgitant flow rate.regurgitant velocity-time integral/regurgitant peak velocity, using additional continuous-wave Doppler. The 55 patients with angiographic regurgitation had a close association between regurgitant flow rate (0 to 600 ml/s) and angiographic grade (Spearman's rank correlation coefficient = 0.91; p < 0.0001). Regurgitant flow rate did not overlap between grades < or = 2+, 3+ and 4+. In 16 patients, regurgitant stroke volume by echocardiography correlated well with that by the angiography/Fick method (r = 0.88; SEE = 17.1 ml), with a regression line close to identity (y = 0.89x + 12.7 ml). The proximal velocity profile method enables determination of mitral regurgitant flow and estimation of regurgitant volume.

Left ventricular volume determined echocardiographically by assuming a constant left ventricular epicardial long-axis/short-axis dimension ratio throughout the cardiac cycle

OBJECTIVES

The purpose of this study was to develop and test a simplified echocardiographic method to calculate left ventricular volume.

BACKGROUND

This method was based on the assumption that the ratio of the left ventricular epicardial long-axis dimension to the epicardial short-axis dimension was constant throughout the cardiac cycle. With use of this constant ratio, the method developed to calculate left ventricular volume at a given point in the cardiac cycle required the left ventricular endocardial long-axis dimension to be measured at only one point in the cardiac cycle.

METHODS

Studies were performed in 13 normal dogs, 8 normal puppies, 9 normal pigs, 12 dogs with aortic stenosis, 13 dogs with acute mitral regurgitation, 12 dogs with chronic mitral regurgitation, 7 dogs that had undergone mitral valve replacement and 6 pigs that had had chronic supraventricular tachycardia. Animals with aortic stenosis developed left ventricular pressure overload hypertrophy with a 60% increase in left ventricular mass; chronic mitral regurgitation caused left ventricular volume overload hypertrophy with a 46% increase in left ventricular volume; supraventricular tachycardia caused a dilated cardiomyopathy with a 55% decrease in left ventricular ejection fraction.

RESULTS

The left ventricular epicardial long-axis/short-axis dimension ratio remained constant throughout the cardiac cycle in each animal group. End-diastolic and end-systolic volumes calculated with the simplified echocardiographic method correlated closely with angiographically measured volumes; for end-diastolic volume, echocardiographic end-diastolic volume = 1.0 (angiographic end-diastolic volume) -1.8 ml, r = 0.96; for end-systolic volume, echocardiographic end-systolic volume = 0.98 (angiographic end-systolic volume) -0.7 ml, r = 0.95.

CONCLUSIONS

Thus the left ventricular epicardial long-axis/short-axis dimension ratio was constant throughout the cardiac cycle in a variety of animal species and age groups and in the presence of cardiac diseases that significantly altered left ventricular geometry and function. The simplified echocardiographic method examined provided an accurate determination of left ventricular volumes.

Effect of an anterior wall motion abnormality on the results of single-plane and biplane left ventriculography

Although the biplane area-length method would be optimal for all left ventriculograms, 2 contrast injections are needed in laboratories with single-plane imaging equipment. The purpose of this study was to develop practical guidelines to identify the need for biplane left ventriculography in laboratories with single-plane equipment. From a retrospective analysis of 91 consecutive biplane ventriculograms (group 1), guidelines were identified that predicted when the ejection fraction calculated by the biplane method would differ significantly from the single-plane value. These guidelines were derived from information immediately available to the operator in the laboratory at the time of the procedure. Patients in group 1 were divided into 3 subgroups: biplane exceeding single-plane ejection fraction by greater than or equal to 0.05 (n = 20); single-plane exceeding biplane ejection fraction by greater than or equal to 0.05 (n = 14); and ejection fractions within +/- 0.04 by the 2 methods (n = 57). By multivariate analysis, the only predictor of a higher ejection fraction calculated by the biplane method was an anterior wall motion abnormality. This finding was tested prospectively in a separate group of 60 patients (group 2). Left ventriculograms in group 2 patients were stratified before analysis by the presence or absence of an anterior wall motion abnormality. In patients with anterior wall motion abnormalities, the biplane ejection fraction was greater than the single-plane value by 0.05 +/- 0.04 (range -0.03 to +0.15). In contrast, this difference in patients without anterior wall motion abnormalities was -0.01 +/- 0.04 (range -0.09 to +0.06; p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Primary restrictive cardiomyopathy: clinical and pathologic characteristics

Twenty-four patients with restrictive cardiomyopathy were identified at St. Thomas' Hospital during a 17-year period. All had endomyocardial biopsy, but in two patients the biopsy specimens were small and nondiagnostic. Seven patients had amyloidosis and five had other specific heart muscle diseases. The remaining 10 patients with primary restrictive cardiomyopathy had myocyte hypertrophy or interstitial fibrosis, or both. Patients with primary restrictive cardiomyopathy presented earlier but survived longer after presentation than did those with amyloidosis. In each group, survival after cardiac catheterization was related to cardiac index but not to filling pressures. Primary restrictive cardiomyopathy was associated with complete heart block in four patients, two of whom had skeletal myopathy. One had a family history of dominantly inherited skeletal myopathy. Primary restrictive cardiomyopathy was present in a mother and daughter. Two other patients had a family history of heart failure, sudden death or complete heart block, alone or in combination, at a young age. Restrictive hemodynamics and complete heart block were present in patients even in the absence of significant fibrosis. The data suggest that primary restrictive cardiomyopathy may be a distinct myopathy with dominant inheritance and incomplete penetrance that is expressed morphologically as myocyte hypertrophy and interstitial fibrosis. Skeletal myopathy may be associated with the cardiomyopathy.

Echocardiographic left ventricular wall thickness: a poor predictor of the severity of aortic valve stenosis

Echocardiographic left ventricular hypertrophy is thought to be helpful in grading the severity of aortic stenosis. This study compared M-mode echocardiographic left ventricular wall dimensions with Gorlin aortic valve area. Good quality echocardiograms were obtained in 294 patients with aortic stenosis who also underwent cardiac catheterization. Patients with grade 3 or 4 aortic regurgitation were excluded. The correlation was calculated between the aortic valve area and the left ventricular wall dimensions. Correlation coefficients were poor; r = 0.13 for the septum, r = 0.15 for the posterior wall, and r = 0.17 for the mean wall dimension. Correlation was not improved significantly if patients with poor left ventricular function or systemic hypertension were excluded. Correlation with other hemodynamic parameters was better, peak left ventricular systolic pressure having r values of 0.36 and 0.30 for posterior wall and septum. Mean and peak aortic valve gradient had r values approaching 0.30 for both dimensions. If the peak gradient was included in multivariate analysis, the wall dimensions then had no predictive power for severity of aortic stenosis. This study demonstrates that the degree of left ventricular wall hypertrophy is not related to the severity of aortic outflow obstruction and therefore cannot be used to grade the severity of aortic stenosis.

Natural history of chronic left ventricular aneurysm; a population based cohort study

In order to evaluate the morbidity and mortality of chronic left ventricular aneurysm a population based cohort study was carried out. All cardiac catheterizations performed in Iceland during the years 1983-1985 were examined (n = 1261). Sixty seven patients with left ventricular aneurysm defined as: (1) normal diastolic contour with segmental dyskinesis (n = 6), (2) abnormal diastolic contour with (a) akinetic (n = 36) or (b) dyskinetic (n = 25) segments in systole, were included. Sixty seven patients with normal diastolic contour and akinetic segments in systole served as controls. The groups had similar mean age, sex ratio, number of diseased vessels and left ventricular end diastolic pressure. Mean ejection fraction was significantly lower in the aneurysm group (46 vs 56%, p = 0.00005). Collaterals were detected significantly more often in controls (88 vs 72%, p = 0.03). At follow up in 1989, 19 in the aneurysm group had died as compared to 12 in the control group. Life table analysis revealed significant differences between survival curves. The relative risk ratio was 2.18 with 95% confidence interval of 1.00-4.74 (p less than 0.05). However, when the amount of myocardial damage was taken into account the differences in survival were no longer statistically significant (relative risk ratio 1.77 with 95% confidence interval of 0.79-3.99). We conclude that the reduced survival probability of patients with chronic left ventricular aneurysm in comparison to controls with akinetic scars is accounted for by the more extensive myocardial damage and not by the presence of aneurysm per se.

An evaluation of central laboratories in three VA cooperative studies

We compared central laboratory with local determinations of key clinical measurements in three VA Cooperative Studies. Electrocardiographic evidence of new myocardial infarction was assessed in the study of Aspirin Therapy and Unstable Angina, ejection fraction measurement in the Coronary Artery Bypass Surgery Trial and lesion size in the Angioplasty Compared with Medicine (ACME) Trial. The findings in the Aspirin Trial indicated that central coding of all serial electrocardiograms in 1266 patients to detect new acute myocardial infarction by computer algorithm was not cost-effective when compared with the local investigator's diagnosis on the basis of a central Electrocardiographic Committee as the reference standard. In the other two trials, the contribution of the central laboratories was important because the assessments of the local investigators generally underestimated the degree of abnormality in the Bypass Trial and overestimated it in the ACME Trial. The VA results have clearly demonstrated two cases in which the decision for central evaluation was prudent, but one case in which it was not cost-effective. These equivocal findings indicate the need to evaluate the contribution of central laboratories when used as an adjunct to local determinations. Such evaluations may provide guidelines for decision-making in the design of future trials.

Four-year follow-up study in patients with angina pectoris and normal coronary arteriograms ("syndrome X")

In patients with typical stress-induced anginal pain, normal coronary arteries, and unimpaired left ventricular performance at rest ("syndrome X"), a reduced coronary dilatory capacity, abnormal lactate metabolism during stress, and reduction of left ventricular functional reserve have been described. A group of 40 patients with syndrome X was followed for several years to determine their long-term prognosis. In 27 patients pulmonary artery pressure and in 19 patients left ventricular ejection fraction were reassessed during rest and exercise approximately 4 years after the initial examination. In patients with stress-induced ST-segment depression, these variables did not change during the observation period. In patients with constant or rate-dependent left bundle branch block, however, there was significant deterioration of left ventricular performance during rest (pulmonary artery mean pressure, 16 +/- 3 vs. 17 +/- 4 mm Hg, p = NS; left ventricular ejection fraction, 62 +/- 5% vs. 55 +/- 5%, p less than 0.05) and exercise (pulmonary artery, 30 +/- 6 vs. 39 +/- 10 mm Hg, p less than 0.005; left ventricular ejection fraction, 59 +/- 6% vs. 49 +/- 5%, p less than 0.01). These findings suggest that in syndrome X two subgroups with distinctly different prognoses may be defined: In patients with stress-induced ST-segment depression during exercise, left ventricular performance remains well preserved; however, in patients with either constant or rate-dependent left bundle branch block, there is significant deterioration of left ventricular function within several years.

Medical compared with surgical management of unstable angina. 5-year mortality and morbidity in the Veterans Administration Study

We evaluated medical in comparison to surgical plus medical (surgical) treatment of unstable angina using a prospective randomized protocol that stratified patients by clinical presentation and by invasive evaluation of left ventricular (LV) function. Clinical presentations were as follows--type 1: progressive or new onset angina relieved by medication; type 2: prolonged bouts of angina poorly or incompletely relieved by medication. Abnormal LV function was arbitrarily defined as ejection fraction less than 0.50 or LV end-diastolic pressure 16 mm Hg or more. Of 468 patients, 237 were assigned to medical and 231 to surgical therapy. There were 374 type 1 and 94 type 2 patients. LV function was normal in 334 and abnormal in 134 patients. Compared with results at 24 months, this 60-month follow-up study showed important differences in survival for patients with three-vessel disease: 75% for medical and 89% for surgical patients (p less than 0.02). The cumulative 5-year rate of repeat hospitalizations for cardiac reasons was less with surgical patients for either clinical presentation. For type 1, medical patients had a 56% rate, and surgical patients had a 42% rate (p = 0.004). For type 2, medical patients had a 62% rate, and surgical patients had a 43% rate (p = 0.05). Overall mortality did not differ between the two treatments, and this remained true in type 1 versus type 2 patients and in those with normal versus abnormal LV function. However, regression analysis of medical and surgical groups with ejection fraction as a continuous variable showed that mortality of medical patients depended on ejection fraction (p = 0.004), whereas the mortality of surgical patients did not (p = 0.76), and survival in the surgical group was higher in the lowest ejection fraction tercile-73% for medical and 86% for surgical patients, p = 0.03. We conclude that surgery improves survival in patients with three-vessel disease and leads to fewer subsequent hospitalizations for cardiac reasons. An impaired ejection fraction had an adverse impact on survival of medical patients but not on surgical patients, and mortality in surgical patients was improved compared with medical patients in the lowest ejection fraction tercile.

Inaccuracies in using aortic valve gradients alone to grade severity of aortic stenosis

The severity of aortic stenosis is an important determinant of prognosis in patients with symptoms who do not undergo valve replacement. To assess the pitfalls of using valve gradients alone 636 patients with aortic stenosis in whom the aortic valve area had been calculated by the Gorlin formula were studied. The correlation between valve area and aortic gradients was poor. No gradient was found that was both sensitive and specific for aortic stenosis. The maximum predictive accuracy was 81% for a mean gradient of 30 mm Hg and 80% for a peak gradient of 30 mm Hg. A mean gradient of 50 mm Hg or a peak gradient of 60 mm Hg were specific with a 90% or more positive predictive value. It proved difficult, however, to find a lower limit with a 90% negative predictive value. Patients with severe aortic stenosis and low gradients (peak or mean gradient of less than 30 mm Hg) had small ventricles (on both angiographic and echocardiographic data) with good ejection fractions and so were unlikely to be detected subjectively. In comparison patients with mild aortic stenosis and low gradients tended to have more aortic regurgitation but have similar degrees of left ventricular hypertrophy on echocardiographic or electrocardiographic criteria. The aortic valve area should be measured in all patients with the suspicion of severe aortic stenosis with a mean gradient of less than 50 mm Hg (50% of patients in this study) or a peak gradient of less than 60 mm Hg (47% of patients in this study).

Factors influencing accuracy in left ventricular volume determination

The accuracy with which left ventricular volume is determined from contrast ventriculograms depends on the care with which the analysis protocol is followed. Therefore, the effect of variations in the method used for calculating the correction factor (CF) that adjusts for magnification and image distortion on volume calculation was measured. The results showed that error in the CF is caused by (in order of decreasing importance): filming the calibration figure at a different magnification mode from that of the ventriculogram, at a different height from the table than the level of the ventricle, or with the image intensifier at a different height than used during ventriculography; use of a calibration figure less than half the size of the ventricle; calculation of the CF from only 1 band pair of a banded catheter; or placement of the calibration figure at the periphery rather than the center of the imaging field. Error in volume determination was proportional to error in the CF. With care, the error in volume can be reduced to that due to interobserver variability in tracing the endocardial contours.

Relation of left ventricular function and Na,K-pump concentration in suspected idiopathic dilated cardiomyopathy

The possible relation between Na-K-pump concentration and left ventricular (LV) function was studied in 24 patients with suspected idiopathic dilated cardiomyopathy. This was done by measurement of 3H-ouabain binding to biopsies obtained during left-sided heart catheterization. In all patients light microscopy of biopsies was compatilel with dilated cardiomyopathy. Nineteen patients had impaired LV function as defined by NYHA/WHO and a Na,K-pump concentration of 331 +/- 19 pmol/g wet weight, whereas 5 patients had normal LV function and a Na,K-pump concentration of 559 +/- 62 pmol/g wet weight (p less than 0.001). The correlation between Na,K-pump concentration and ejection fraction was highly significant n = 24, r = 0.81, p less than 0.001). There was no correlation between volume fraction of collagen tissue and Na,K-pump concentration in the biopsies (n = 24, r = -0.08, p less than 0.80), indicating that the decrease in Na,K-pump concentration with dilated cardiomyopathy is not the simple outcome of increased fibrosis in the myocardium. The results indicate that the decrease in Na,K-pump concentration may be of importance for myocardial dysfunction and suggest a simple biochemical assessment of dilated cardiomyopathy by measurement of 3H-ouabain binding.