Treatment of Acute Myocardial Infarction with Cardiogenic Shock using Left Ventricular Assist Device

We have treated ten cardiogenic shock patients after acute myocardial infarction (AMI) with a left ventricular assist device (LVAD). These patients were later divided into three groups: the first group with ventricular septal perforation, the second with aorto-coronary bypass grafting (ACBG) before LVAD implantation and the third group without ACBG. LVAD maintained the systemic circulation in each group, and cardiac function recovered enough to remove LVAD in 70% of the total patients. Two of three patients in the first group were discharged from hospital. Two weaned cases in the second group died of multiple organ failure and one was discharged, and hemorrhagic necrosis was seen in the bypassed area of the myocardium. One patient of the third group could not be weaned from LVAD because of respiratory failure though his heart function began to recover. Another case in the third group underwent bypass grafting after removal of LVAD. However ACBG surgery should be done very carefully because a patient in shock is occasionally intolerant to major surgery. In all groups, the major cause of death was multiple organ failure which was probably caused by the prolonged low output condition prior to LVAD application. In the light of this experience, it appears that LVAD should be applied before irreversible damage occurs to major organs, including the heart itself. To ensure the timely application of LVAD, some way must be found to introduce systematic application of LVAD into the normal course of AMI treatment.

Lymph node density predicts lung metastases in oral squamous cell carcinoma

The association between lymph node density and survival free of lung metastases in oral squamous cell carcinoma (SCC), has not been investigated so far to our knowledge. Lymph node density ≧ 0.07 has been reported by a multicentre international study to be a significant predictor of shorter survival in patients with oral SCC who have invaded nodes. We investigated whether a lymph node density of ≧ 0.07 correlates with shorter overall survival, survival free of distant metastases, and survival free of lung metastases, in patients with oral SCC and invaded lymph nodes. Thirty-five patients with histologically-confirmed invaded lymph nodes werestudied. Their density was calculated as the ratio of the number of invaded lymph nodes:total number of nodes. A density of ≧ 0.07 correlated significantly with shorter overall survival (p<0.02), survival free of distant metastases (p<0.01), and survival free of lung metastases (p<0.01) on log rank testing. On testing by Cox's proportional hazards model of multivariate survival analysis with adjustment for the pathological stage (pstage IV/pstage III), and invaded surgical margins or extracapsular spread, or both, we found that lymph node density ≧ 0.07 was associated with significantly shorter survival (p<0.02). We conclude that lymph node density predicts lung metastases in patients with oral SCC.

Serial assessment of left and right ventricular filling in patients with congestive heart failure

Serial changes in the diastolic filling of both ventricles were studied using Doppler echocardiography in 19 patients with congestive heart failure from the acute to the convalescent stage. During the acute stage, left ventricular early filling velocity (E) was high (88 +/- 17 cm/s) and atrial filling velocity (A) was low (44 +/- 23 cm/s), whereas the right ventricular E was depressed (17 +/- 8 cm/s) and A was enhanced (40 +/- 9 cm/s). As the condition improved, left ventricular E decreased (43 +/- 11 cm/s, p < 0.01) and A increased (59 +/- 24 cm/s, p < 0.01) along with a decrease in the left ventricular and atrial dimensions. In contrast to the changes in left ventricular filling, right ventricular E increased (31 +/- 10 cm/s, p < 0.01) and A decreased (32 +/- 5 cm/s, p < 0.05). There are opposite directional changes in left and right ventricular filling with clinical improvement from the acute to the convalescent stage of congestive heart failure, which suggest that the changes are related to improvement of the hemodynamic conditions of both ventricles. The changes in the right ventricular filling pattern was likely to be related to changes in right ventricular afterload, ventricular interaction and external constraint rather than a change in right ventricular filling pressure.

[On line display of the reconstructed pressure waves of the radial artery from the monitored output pressure waves at the same site]

The input-output relationship of transducer and catheter system is described by linear, second-order differential equation with three coefficients: inductance (L), resistance (R), and capacitance (C). Once the natural frequency (fo) and the damping ratio (beta) of the monitoring system have been measured, three coefficients of the differential equation are uniquely obtained. We measured the frequency response of the monitoring system, which we usually use in our hospital, to obtain fo and beta, and reconstructed the original input arterial pressure wave from output signal on the display using the simple time-domain approach. The analysis of this linear, second-order differential equation, is applicable in on-line bedside monitoring, because the calculation of this equation is simpler than that using Fourier's translation. The pressure waves of the radial artery both monitored (output) and restored (input) were depicted on the same display at the same time. We can evaluate the changes in systemic circulation from the changes in the wave shapes of arterial blood pressure.

[Effect of oxygen inhalation on myocardial opacification using levovist: an animal experimental study]

OBJECTIVES

Levovist can opacify the myocardium via venous injection, and is widely used in the clinical field. However, left ventricular opacification deteriorates during oxygen inhalation using Albunex, one of the first generation of contrast agents. This study examines the effect of blood oxygen pressure on the myocardial opacification by Levovist.

METHODS

Myocardial contrast echocardiography (Toshiba Power Vision 6000) was performed using second harmonic imaging, intermittent exposure of ultrasound (every 4 cardiac beats) and acoustic power of 1.4 mechanical index. The video intensity of the ventricular septum after venous injection of Levovist (0.5 ml of 300 mg/ml) was measured under various respiratory conditions by manipulating the respirator and oxygen inhalation. Arterial blood gas was measured and correlated with the myocardial video intensity.

RESULTS

The video intensity of myocardial opacification was lower with higher oxygen pressure in the arterial blood. Visual recognition of myocardial opacification was only 14% under high oxygen pressure over 200 mmHg. Microbubbles of Levovist form from normal air, and are easily affected by the gas concentration of the surrounding blood.

CONCLUSIONS

Myocardial opacification using Levovist is deteriorated under high oxygen pressure at examination.

[Optimal setting of focus points for myocardial contrast echocardiography with intravenous Optison (FS-69): an experimental study]

OBJECTIVES

Myocardial contrast echocardiography is useful to assess myocardil perfusion, but myocardial opacification is affected by the setup of the ultrasonic equipment. The optimal setting of focus points for adequate opacification of the myocardium was examined in myocardial contrast echocardiography.

METHODS

Myocardial contrast echocardiography was performed in six dogs using triggered second harmonic technology following intravenous administration of Optison(FS-69). The short-axis view was recorded and baseline subtracted video intensity(peak intensity: PI) was calculated at three regions of the left ventricular wall, the anterior, septum, and posterior walls, to evaluate myocardial opacification. The focus point was set at near(2 cm), middle(4 cm) and far(6 cm)points. The myocardial opacification was evaluated at each focus setting. The effect of the acoustic power was also examined by changing the mechanical index to 1.6, 1.2 or 0.8.

RESULTS

Myocardial opacification was recognized at all focus points, and segments near the focus points had high PI. However, the PI of the posterior wall was lowest at near focus, whereas the PI of the anterior wall was lowest at far focus. The difference of PI between the anterior and posterior walls was significant (p < 0.05, p < 0.01, respectively) at either focus point. Adequate myocardial opacification of all segments was observed when the focus was set at the middle point. The PI of the whole left ventricle increased relative to mechanical index.

CONCLUSIONS

Setting up of focus points at the middle of the left ventricle provides more homogeneous myocardial opacification of the whole left ventricle in myocardial contrast echocardiography, and high acoustic power possibly improves myocardial opacification. Inadequate setting of focus points leads to inadequate estimation of myocardial perfusion by myocardial contrast echocardiography.

[Usefulness of intravenous myocardial contrast echocardiography in rats]

OBJECTIVES

Few intravenous myocardial contrast echocardiography trials have evaluated myocardial perfusion in small animals. The feasibility of using intravenous myocardial contrast echocardiography to assess the ischemic area in rats was investigated.

METHODS

Fourteen open chest Wister male rats were examined. Intravenous myocardial contrast echocardiography was performed by fundamental and intermittent mode using a high frequency (5-12 MHz) transducer (SONOS 5500) with injection of NC100100 (20% dilution) into the femoral vein. The mechanical index was set to 1.6. Baseline-subtracted video intensity (256 level) was measured in the anterior, posterior, septal and lateral walls of the left ventricle. The left anterior descending artery was ligated in 16 rats. The area at risk was evaluated by myocardial contrast echocardiography and compared to the area of defect by Evans Blue staining.

RESULTS

All wall segments were clearly opacified (anterior 63.8 +/- 24.7, posterior 27.0 +/- 11.0, septal 44.5 +/- 11.6, lateral 52.3 +/- 19.1), although the baseline-subtracted video intensity of the posterior wall was low. The area at risk was clearly observed, and there was a good correlation with the nonperfused area by Evans Blue staining (y = 1.13x-3.54, r = 0.98).

CONCLUSIONS

Intravenous myocardial contrast echocardiography can detect the perfusion defect even in rats using a high frequency transducer and suitable setup of equipment.

Myocardial ischemia activates the JAK-STAT pathway through angiotensin II signaling in in vivo myocardium of rats

There have been many studies concerning the hemodynamics and physiological mechanisms in ischemic heart disease, little is known about molecular mechanisms during myocardial ischemia in in vivo study. As the signal transduction pathway responsible for myocardial hypertrophy and apoptosis, janus kinase (JAK) and signal transducers and activators of transcription (STAT) are suggested to play an important role. However, whether in vivo activation of JAK-STAT pathway occurs during myocardial ischemia is still unknown. The purpose of this study was to determine whether myocardial JAK or STAT is activated in ischemic heart, and to evaluate the angiotensin blockade on the pathway. Myocardial infarction was produced by ligation of the coronary artery in Wistar rats. After myocardial ischemia, we analysed both activated levels and total amounts of JAK1, JAK2, STAT1 and STAT3 by Western blot analyses at 0, 5, 15, 30, 60, 120 and 240 min. Compared with JAK activities at 0 min, JAK1 activities were significantly increased at 60 and 120 min (3.0- and 3.7-fold, respectively, P<0.01). JAK2 and STAT1 activities of ischemic myocardium were unchanged through the time course. STAT3 activities were increased at 5 min (3.3-fold, P<0.01) and markedly enhanced at 30, 60 and 120 min (4.6-, 7.7- and 8.7-fold, respectively, P<0.01). Pretreatment with imidapril (ACE inhibitor) and candesartan cilexitil (AT1 receptor antagonist) significantly prevented the increase in the phosphorylation of JAK1 at 120 min and STAT3 at 30 and 120 min. Sis-inducing factor (SIF) DNA complex was supershifted by specific anti-STAT3 antibody, indicating that increased SIF complex at least contained activated STAT3 proteins in ischemic myocardium. Imidapril and candesartan cilexitil inhibited the activation of SIF DNA binding at 1 day after coronary ligation. In conclusion, we showed that JAK1 and STAT3 were activated by ischemia from the basal activities in in vivo rat myocardial ischemia model. Imidapril and candesartan cilexitil prevented the increase in phosphorylated JAK1 and STAT3, thereby suggesting that angiotensin II, especially angiotensin II type I receptor, partially mediates activation of myocardial JAK-STAT pathway in acute myocardial ischemia.

Effects of sildenafil citrate (Viagra) combined with nitrate on the heart

BACKGROUND

Sildenafil citrate (Viagra) is indicated for the treatment of erectile dysfunction. Large and sudden decreases in systemic blood pressure were reported in a substantial number of patients taking sildenafil citrate combined with nitroglycerin. We studied the effect of sildenafil citrate on the relationship between changes in systemic blood pressure and coronary blood flow.

METHODS AND RESULTS

Healthy male beagles were used to assess systemic blood pressure, pulmonary arterial pressure, and flow in the left circumflex artery (in which a critical stenosis was established) and left anterior descending coronary artery. After measurement of the hemodynamic variables, 2 mg/kg sildenafil citrate was administered via a nasogastric tube. Hemodynamic changes were monitored for 1 hour. Subsequently, the acute effect of nitrate combined with sildenafil citrate was studied by the bolus injection of 0.2 mg isosorbide dinitrate before and after sildenafil citrate. Systemic blood and pulmonary arterial pressures and circumflex flow did not change during this study; however, left anterior descending coronary arterial flow increased from 16.0+/-5.8 to 24.6+/-8.7 mL/min 1 hour after administration of sildenafil citrate. The prolongation of systemic blood pressure decrease and the circumflex flow decrement induced by isosorbide dinitrate after sildenafil citrate were significantly larger and longer than those before sildenafil citrate.

CONCLUSIONS

Sildenafil citrate had the effect of vasodilation in a normal coronary artery; however, a combined effect with nitrate resulted in large and protracted decreases in systemic blood pressure and coronary blood flow in vessels with critical stenosis.

Assessment of flow mismatch with pharmacologic stress test on myocardial contrast echocardiography in a model of critical stenosis: adenosine triphosphate and dipyridamole

Although adenosine triphosphate (ATP) is a favorable vasodilator because of its short-acting duration, the agent's effectiveness in facilitating the diagnosis of myocardial ischemia with myocardial contrast echocardiography (MCE) is not fully understood. The goal of this study was to examine the efficacy of intravenous ATP administration (0.15 to 0.30 mg/kg/min for 5 minutes) in diagnosing the flow mismatch with MCE. To achieve this, a critical stenosis was produced in the left circumflex artery in 10 anesthetized dogs. The peak intensity ratio of risk area to control area was reduced by ATP from 0.51 +/- 0.19 to 0.31 +/- 0.12 (P <.05). Systolic wall thickening of the risk area did not change significantly (32.8% +/- 9.8% to 27.5% +/- 12.8%). These changes did not differ from those obtained after dipyridamole. We conclude that MCE with intravenous ATP administration is as useful as the dipyridamole method for diagnosing critical coronary stenosis.

Characteristic cardiovascular manifestation in homozygous and heterozygous familial hypercholesterolemia

BACKGROUND

The aortic valve dysfunction of patients with homozygous familial hypercholesterolemia (FH) suggests that hypercholesterolemia affects not only coronary arteries but also the aortic valve. We studied the aortic root of patients with homozygous FH and those of patients with heterozygous FH to characterize the premature atherosclerotic lesions by using histopathologic specimens.

METHODS AND RESULTS

The aortic roots of 10 patients with homozygous FH, age 9 to 58 years, were studied by cardiac catheterization with several angiographies. The aortic roots of 39 patients with heterozygous FH under age 60 years were also examined for aortic and mitral valvular functions by color Doppler echocardiography, and 30 normocholesterolemic patients with coronary artery disease were examined as control subjects. In addition, in 22 patients with FH and 20 control subjects, the internal diameter of the aortic annulus and the aortic ridge in cardiac cycles were measured. Of the 10 homozygotes with FH, 8 patients had aortic regurgitation demonstrated by aortography; 3 of them showed significant transvalvular pressure gradients. Stenotic changes of coronary ostia were observed in 8 of the 10 homozygotes with moderate coronary atherosclerosis. Of the 39 heterozygotes with FH, 10 patients had aortic regurgitation shown by Doppler echocardiography, as did only 1 of the 30 control subjects (P <.05). The average diameter and distensibility of the ascending aorta were significantly reduced in the heterozygotes compared with the control subjects. The surgically resected cusp specimens of aortic valves obtained from 1 homozygous and 1 heterozygous patient showed significant thickening of the cusp with foam cell infiltration.

CONCLUSIONS

Premature atherosclerosis in FH had a characteristic distribution, affecting the aortic root dominantly. The involvement of the aortic valve indicating "hypercholesterolemic valvulopathy" was a peculiar feature of FH, especially its homozygous form, but was reminiscent of ubiquitous processes caused by hypercholesterolemia.

Preparation and characterization of echogenic liposome as an ultrasound contrast agent: size-dependency and stabilizing effect of cholesterol on the echogenicity of gas-entrapping liposome

The liposome entrapping CO2 gas inside the vesicle, which is called the echogenic liposome, has been made and characterized in vitro as an ultrasound contrast agent. The small unilamellar vesicle (SUV), large unilamellar vesicle (LUV) and multilamellar vesicle (MLV) as echogenic liposomes were compared in their echogenic efficiency and stability, and the effect of size and acoustic property was tested. The acoustic reflectivity increased with the increase in size of the vesicle, largest for the gas filled MLV among the three liposome suspensions. The acoustic reflectivity obtained with the echogenic MLV was larger than that of the gas bubbles enclosed within a surfactant mixture. A half-lifetime of 39 min was observed for the MLV prepared from egg-yolk phosphatidylcholine liposomes. The duration of reflectivity was prolonged drastically to a half-lifetime of 866 min by incorporating cholesterol into the MLV, although the echogenicity was decreased by such incorporation. The stabilizing effect of cholesterol for the ordinary liposomal membrane was thus ascertained in the present case of the gas-entrapping liposome. Our findings encourage the future development of improved gas-entrapping liposomes for the clinical trials of ultrasound contrast agents.

[Levovist]

SH/TA-508 (Levovist) is agglomerates of microparticles consisting of galactose (99.9%) and palmitic acid (0.1%), and the active entity is the microbubbles stabilized by palmitic acid which covers the bubbles. SH/TA-508 micro-bubbles are stable under high-pressure condition and they circulate the whole body for several minutes along with blood flow after the intravenous injection. The left sided cardiac cavities and arteries are clearly opacified by using this contrast agent and the Doppler signals from the mitral, aortic and pulmonic vein are also enhanced significantly. Also microcirculating flow image of the liver, kidney and other organs are well enhanced in the clinical studies. SH/TA-508 improves the capability of ultrasound diagnosis.

Extension of hemorrhage after reperfusion of occluded coronary artery: contrast echocardiographic assessment in dogs

OBJECTIVES

The aim of this study was to elucidate the progression of intramural hemorrhage complicated by reperfusion with the use of myocardial contrast echocardiography.

BACKGROUND

Although hemorrhagic infarction is known to occur in ischemia followed by reperfusion, its onset and sequence have not been well characterized.

METHODS

In 20 anesthetized dogs, 3-h occlusion of the left circumflex-coronary artery was followed by reperfusion. The area at risk during coronary occlusion was approximately 25%. Myocardial contrast echocardiogram was examined, and the time-intensity curves for both ischemic and nonischemic areas were obtained at baseline, at 3 min after reperfusion and then at 15-min intervals until 90 min after reperfusion. The wall thickness of both areas was also measured.

RESULTS

Gross hemorrhage in the reperfused areas was observed in five dogs (Group H) but not in seven dogs (Group NH). All wall segments were opacified at 3 min after reperfusion in both groups. However, the contrast defect spread significantly with time after reperfusion in Group H but not in Group NH (18.7 +/- 3.4% and 3.3 +/- 1.8%, respectively, at 90 min after reperfusion p < 0.005). The wall of the risk area at 90 min after reperfusion had thickened to 1.3 times baseline thickness in Group H but was unchanged in Group NH. The other eight dogs were excluded from study because of fatal arrhythmias or the existence of collateral circulation during coronary occlusion.

CONCLUSIONS

Both progression of the contrast defect area on myocardial contrast echocardiography and a gradual thickening of the wall with reperfusion are characteristic of hemorrhagic infarction.

Relationship between progressive microvascular damage and intramyocardial hemorrhage in patients with reperfused anterior myocardial infarction: myocardial contrast echocardiographic study

BACKGROUND

Recent studies indicated that ischemic microvascular damage may be reversible or progressive after coronary reflow. Intramyocardial hemorrhage is a phenomenon that reflects severe microvascular injury. We examined the relationship between temporal changes in microvascular perfusion patterns detected by myocardial contrast echocardiography (MCE) and intramyocardial hemorrhage detected by magnetic resonance imaging (MRI) in patients with acute myocardial infarction (AMI).

METHODS AND RESULTS

The study population consisted of 24 patients with anterior AMI. All patients underwent MCE shortly after reflow and in the chronic stage (a mean of 31 days after reflow). Wall motion score (WMS) was determined as the sum of 16 segmental scores (dyskinetic/akinetic=3 to normal=0) at days 1 and 31. Gradient-echo acquisition and gadolinium-DTPA-enhanced spin-echo MRI were performed within 10 days after reflow. In MCE shortly after reflow, 16 patients (67%) showed contrast enhancement and the other 8 patients (33%) showed a sizable contrast defect. In the chronic stage, a persistent contrast defect was observed in 7 of 8 patients with a contrast defect shortly after reflow. Consistent contrast enhancement was observed in 12 of 16 patients (75%) with contrast enhancement shortly after reflow, indicating that a contrast defect newly appeared in 4 patients (25%). Intramyocardial hemorrhage was detected in 9 patients (38%): 5 of 7 patients with a persistent contrast defect and in all 4 patients with a new appearance of a contrast defect during the chronic stage. The patients without hemorrhage showed a significant improvement in WMS compared with patients with hemorrhage at day 31 (5+/-5 versus 19+/-6, P<.0005).

CONCLUSIONS

These results suggest that irreversible microvascular damage to the ischemic myocardium may cause intramyocardial hemorrhage after reflow, associated with impaired recovery of left ventricular function. Contrast enhancement within the risk area shortly after reflow does not necessarily indicate long-term microvascular salvage.

Functional myocardial perfusion abnormality induced by left ventricular asynchronous contraction: experimental study using myocardial contrast echocardiography

OBJECTIVES

The aim of this study was to clarify how myocardial perfusion is impaired by asynchronous contraction.

BACKGROUND

False septal hypoperfusion is noted in some patients with left bundle branch block.

METHODS

Eight dogs were examined with epicardial pacing at the left ventricular posterior wall, the right ventricular anterior wall and, as a control, the right atrial appendage. The pacing rate was 80, 110 and 150 beats/min (bpm). Myocardial perfusion was assessed by contrast echocardiography.

RESULTS

Left ventricular pacing at 80 and 110 bpm did not change systolic wall thickening or contrast intensity at the pacing site, although an early excitation notch was noted at the pacing site. However, at 150 bpm, systolic thickening was impaired (23.3 +/- 4.2% vs. 37.0 +/- 2.6% during atrial pacing, p < 0.05), and the peak intensity ratio of the pacing site to the ventricular septum was significantly decreased (24.1 +/- 5.7% vs. 37.0 +/- 2.8% at a pacing rate of 80 bpm, p < 0.01). The peak intensity ratio correlated with systolic wall thickening at the pacing site (y = 0.413 x -0.028, r = 0.81, p < 0.0001). However, right ventricular pacing did not change either systolic thickening or the peak intensity ratio at any pacing rate, although an early excitation notch was noted on the ventricular septum.

CONCLUSIONS

Wall motion abnormalities after early excitation vary depending on the pacing mode. When tachycardia induces regional wall motion abnormalities, the ventricular wall of the pacing site is functionally hypoperfused.

Prolonged myocardial contrast echocardiography via peripheral venous administration of QW3600 injection (EchoGen): its efficacy and side effects

We examined the efficacy and side effects of a newly developed contrast agent for intravenous myocardial contrast echocardiography, QW3600 Injection (EchoGen; Sonus Pharmaceuticals, Bothell, Wash.). Doses of 0.1, 0.2, 0.5, and 0.8 ml/kg of this agent were administered intravenously to 8 open-chested dogs. The left ventricular (LV) myocardium was uniformly well opacified for the 0.5 and 0.8 ml/kg doses, for which the peak intensity was an average of 40 gray levels above the baseline intensity. The myocardial opacification persisted even after the contrast echo intensity in the LV cavity had decreased. After ligation of the coronary artery, the area at risk was clearly delineated by the same doses. The agent emulsion and dissolved bubbles were examined microscopically in vitro and in vivo to elucidate the mechanism of prolonged opacification. A microscopic investigation of the mesenteric vessels of a rat indicated that bubbles had formed, growing as large as 30 to 50 microm [corrected] in diameter. The hemodynamic parameters did not change at low doses (0.1 and 0.2 ml/kg), but the systemic pressure fell and the arterial blood oxygen saturation decreased at high doses (0.5 and 0.8 ml/kg). EchoGen provides prolonged contrast for myocardial contrast echocardiography via peripheral venous administration, although the hemodynamic parameters deteriorate at high doses.

Identification of pseudonormal transmitral flow pattern using color Doppler echocardiography

The jet size of flow in color Doppler is dependent on both jet momentum and the compliance of the receiving chamber. Thus, the jet size of left ventricular (LV) late filling standardized by its jet momentum should reflect LV compliance. We investigated the feasibility of using color Doppler echocardiography to differentiate a pseudonormal from a normal transmitral flow pattern. We divided 37 patients with ischemic heart diseases who demonstrated a "normal" transmitral flow pattern into 2 groups according to their LV end diastolic pressure (LVEDP): a pseudonormalization group (LVEDP > or = 18 mmHg, 16 patients), and a normal group (LVEDP < 18 mmHg, 21 patients). We measured the maximum color Doppler jet length (L) and the peak velocity of transmitral flow during atrial contraction (Av). Filling volume (Q) was measured as the increase in LV volume during atrial contraction. A simplified jet momentum index (M) was obtained from Av x Q, and L/M was considered to reflect LV compliance. L/M was significantly lower in the pseudonormalization group that in the normal group (1.55 +/- 0.46 x 10(-3) vs 2.72 +/- 0.59 x 10(-3) p < 0.01). On the other hand, conventional Doppler variables such as isovolumic relaxation time and the deceleration time of early diastolic filling were not sufficient for discriminating between the 2 groups. In conclusion, color Doppler echocardiogram during atrial contraction was useful for differentiating a pseudonormal from a normal transmitral flow pattern.

[Prediction of ineffective outcome of surgical treatment for constrictive pericarditis]

The preoperative factors predicting the outcome of surgical treatment for constrictive pericarditis were investigated in 22 patients with constrictive pericarditis who underwent pericardiectomy. The NYHA functional class was improved in nine patients after surgery (improved group), but not in the other 13 patients (unimproved group). Preoperative right and left heart catheterization data and echocardiograms were compared between these two groups. Right atrial pressure (RAP) and pulmonary capillary wedge pressure (PCWP) were significantly higher in the unimproved group. The left atrial diameter (LAD) measured by echocardiography was significantly greater in the unimproved group. These results indicate that pericardiectomy will cause a worsened immediate outcome in patients with severe pericardial constriction. LAD was the most useful parameter in predicting the ineffectiveness of the pericardiectomy. If the borderline value of LAD is taken as 40 mm, the sensitivity and specificity predicting ineffective surgery were 92% and 89%, respectively. RAP and PCWP could not separate the two groups satisfactorily. Pericardiectomy should be performed before the pericardial constriction progresses, and before LAD reaches 40 mm.

[Feasibility of the left ventricular volume measurement by acoustic quantification method: comparison with ultrafast computed tomography]

Acoustic quantification (AQ: the real-time automated boundary detection system) allows instantaneous measurement of cardiac chamber volumes. The feasibility of this method was evaluated by comparing the left ventricular (LV) volumes obtained with AQ to those derived from ultrafast computed tomography (UFCT), which enables accurate measurements of LV volumes even in the presence of LV asynergy, in 23 patients (8 with ischemic heart disease, 5 with cardiomyopathy, 3 with valvular heart disease). Both LV end-diastolic and end-systolic volumes obtained with the AQ method were in good agreement with those obtained with UFCT (y = 1.04 x - 16.9, r = 0.95; y = 0.87x + 15.7, r = 0.91; respectively). AQ was reliable even in the presence of LV asynergy. Interobserver variability for the AQ measurement was 10.2%. AQ provides a new, clinically useful method for real-time accurate estimation of the left ventricular volume.

[Diagnosis of coronary artery dehiscence and pseudoaneurysm after modified Bentall operation by Doppler color flow imaging: a case report]

This 48-year-old man presented with anterior chest and back pain in 1981. He was treated with replacement of the ascending aorta and aortic valve under a diagnosis of dissection of the ascending aorta with severe aortic regurgitation. He underwent modified Bentall reoperation for the dilation of the aortic root in 1991. Postoperative two-dimensional echocardiography was performed because of sustained atrial flutter. An echo-free space was detected between the aorta graft and aorta wrapping on the short-axis view. Doppler color flow imaging revealed blood flow from the left coronary artery graft into the echo-free space. This leakage was suspected to be the cause of the echo-free space. Transesophageal echocardiography was performed to conform this hypothesis, which revealed blood flow from the left coronary artery graft into the echo-free space in systole and flow into the left coronary artery graft from the echo-free space in diastole.

Myocardial contrast echocardiography of coronary artery lesions due to Kawasaki disease

In addition to coronary arteriography, myocardial contrast echocardiography (MCE) was performed in 25 patients with coronary artery lesions due to Kawasaki disease, in order to investigate its validity in the evaluation of these lesions and its safety in children. The patients' ages ranged from 1.0 to 15.9 years (mean, 8.6 years). Their coronary artery lesions included occlusion in 9 branches (9 patients), segmental stenosis in 9 (8 patients), localized stenosis in 16 (12 patients), and dilated lesions without coexistent stenotic lesions in 5 patients. Seven patients had coronary artery bypass grafts. Myocardial perfusion patterns of the stenotic lesions and coronary artery bypass grafts could be clearly demonstrated by MCE. For the assessment of safety, electrocardiograms obtained at the time of MCE and coronary arteriography in 14 patients showed no significant difference in the findings between MCE and coronary arteriography. Serum glutamic oxaloacetic transaminase, glutamic pyruvic transaminase, lactic dehydrogenase, and creatine phosphokinase levels were measured before and 1 day after the procedure in 14 patients who underwent MCE and coronary arteriography, and in a group of 14 patients who underwent coronary arteriography alone. No significant difference was noted between the values of the two groups. These results suggested that MCE can be utilized in the assessment of coronary artery lesions due to Kawasaki disease, and confirmed the safety of the procedure even in young children.

Validation of continuous wave Doppler-determined right ventricular peak positive and negative dP/dt: effect of right atrial pressure on measurement

OBJECTIVES

The present study aimed to validate the peak positive and negative values of the first derivative of right ventricular pressure (dP/dt) using Doppler echocardiography and to determine the impact of right atrial pressure on the measurements.

BACKGROUND

A pressure gradient between the right ventricle and the right atrium can be obtained by continuous wave Doppler-derived tricuspid regurgitant velocity using the simplified Bernoulli equation. If right atrial pressure fluctuation during systole and isovolumic diastole were small compared with right ventricular pressure changes, right ventricular pressure could be evaluated, and maximal positive and negative dP/dt could also be determined with Doppler echocardiography.

METHODS

We investigated 11 patients with a wide range of right atrial pressure with tricuspid regurgitation using simultaneous examination by Doppler ultrasound and catheterization. Hemodynamic conditions were altered by the Valsalva maneuver, and a total of 40 beats were analyzed.

RESULTS

There was good correlation between Doppler-derived and catheterization-derived peak positive dP/dt (y = 1.0x - 15.4, r = 0.98, n = 40), irrespective of the level of right atrial pressure. Doppler-derived peak negative dP/dt also showed good correlation with that determined by catheterization (y = 0.9x + 58.2, r = 0.93, n = 40). However, in patients with high right atrial pressure (v wave pressure > or = 10 mm Hg), Doppler-derived peak negative dP/dt tended to show lower values than those from catheterization measurements, except in patients with pulmonary hypertension.

CONCLUSIONS

We conclude that right ventricular dP/dt can be estimated by the Doppler method accurately and noninvasively. However, when right atrial pressure is relatively high compared with corresponding right ventricular pressure changes during isovolumic diastole, Doppler-derived peak negative dP/dt might underestimate catheter-derived measurements.

Early diagnosis of stuck Starr-Edwards disc valve in mitral position: inconstant and interrupted mitral regurgitation

The patient was a 40-year-old man with Starr-Edwards disc valve for 21 years without symptoms. Newly developed systolic murmur at the apex was noticed at the monthly medical examination. Doppler color flow mapping indicated severe mitral regurgitation. However, the appearance of mitral regurgitation was not constant. Continuous wave Doppler recording indicated that some of the mitral regurgitations were abruptly terminated at early or mid systole with the disc closing signal. Mitral regurgitation was observed only at bradycardia and on the left lateral position. Cardiac surgery demonstrated no abnormality on the disc valve except small sulci on the rim of the disc. When the disc was tilted in the cage, it was stuck and did not move. Echocardiography was useful in detecting the early stage of stuck artificial valve that might be fatal in the mitral position.

Efficacy and adverse effects of transpulmonary contrast echocardiography using sonicated albumin

We studied the feasibility and adverse effects of transpulmonary contrast echocardiography using sonicated albumin in 6 dogs. Left heart contrast was observed by two-dimensional echocardiography, monitoring left ventricular pressure, its first derivative (dP/dt) and arterial oxygen saturation. The left heart was adequately opacified in 48 of 55 injections of various intravenous doses of sonicated albumin. Left ventricular myocardial opacification was faintly observed in only 1 injection. After injections of a large dose (0.5 ml/kg), left ventricular systolic pressure decreased, maximal positive dP/dt decreased and negative dP/dt increased, slightly. Hemodynamic parameters showed no significant changes with the other doses. Arterial oxygen saturation tended to decrease after injection, which was most remarkable with a large dose injection. In conclusion, although a large dose of intravenous sonicated albumin may opacify not only the left heart cavity but the ventricular myocardium, it deteriorates hemodynamic parameters and oxygen exchange in the lung.

[Timing of inflow to the atrium after ventricular contraction and relaxation: effect of atrial wall stiffness]

A stiff atrium is sensitive to even a small change in its volume, causing a rapid change in the caval vein flow. We hypothesized that the onset of caval vein flow may follow immediately after the onset of a ventricular event in a patient with a stiff atrium. The timing of inflow into the right ventricle and into the atrium were examined by Doppler echocardiography in 20 healthy subjects, 12 patients with constrictive pericarditis, and 10 patients with cardiac tamponade. The onset of diastolic flow in the superior vena cave followed 17 +/- 14 msec after the onset of early diastolic filling flow into the right ventricle in constrictive pericarditis patients, which was significantly shorter than 107 +/- 45 msec in the healthy subjects. The onset of systolic flow occurred 178 +/- 46 msec after the peak of the R wave of the electrocardiogram in cardiac tamponade patients, which was significantly longer than 129 +/- 17 msec in healthy subjects. This time was slightly shorter in constrictive pericarditis (103 +/- 21 msec). We conclude that a short time lag from the onset of a ventricular event to the onset of caval flow indications that the right atrium is stiff.

Diastolic suction in the human ventricle: observation during balloon mitral valvuloplasty with a single balloon

Diastolic suction has been demonstrated experimentally as a ventricular negative pressure when the ventricle is allowed to relax completely in the absence of filling, but it has not been extensively studied in the in vivo human heart. In balloon mitral valvuloplasty with a single balloon, the mitral orifice is occluded and inflow is considered to be completely obstructed during a balloon inflation. To demonstrate diastolic suction in the human ventricle, we measured left ventricular pressure during valvuloplasty with a high-fidelity catheter tip manometer in 17 patients. Left ventricular pressure fell below zero during a balloon inflation in all patients (-2 to -12 mm Hg). The peak negative diastolic pressure showed significant correlations with end-systolic volume index (r = 0.53, p = 0.03) and with the ejection fraction (r = 0.80, p = 0.0001). Thus diastolic suction was demonstrated in the human beating heart, and the sucking effect was potent in the heart with small end-systolic volume and high-ejection fraction.

Different modes of endothelin-1 action in pressor response in vivo and pulmonary parenchymal contraction in vitro in the guinea pig

Intravenously administered endothelin-1 (ET-1) (2 x 10(-11)-6 x 10(-10) mol/kg) induced dose-dependent pressor responses in anesthetized guinea pigs. Pretreatment with indomethacin (5 mg/kg, i.v.) or with a thromboxane A2/prostaglandin endoperoxide receptor antagonist, ONO-3708 (0.5 and 1.0 mg/kg, i.v.) significantly attenuated the pressor responses. ET-1 (10(-11)-10(-7) M) dose-dependently contracted guinea pig pulmonary parenchymal strips in vitro. However, neither pretreatment with indomethacin (10(-5) M) nor one with ONO-3708 (10(-6) M and 10(-5) M) significantly affected the ET-1-induced guinea pig pulmonary parenchymal contraction in vitro. Moreover, pretreatment with a platelet activating factor receptor antagonist, CV-3988 (2 x 10(-5) M) did not significantly affect the contraction. Thus, in guinea pigs, the mechanism of ET-1-induced pressor response in vivo mediated via cyclooxygenase-generated-eicosanoid(s), possibly, thromboxane A2 is not identical to that of ET-1-induced contraction of pulmonary parenchymal strips in vitro.

Involvement of cyclo-oxygenase-generated vasodilating eicosanoid(s) in addition to nitric oxide in endothelin-1-induced endothelium-dependent vasorelaxation in guinea pig aorta

This study investigates the vasodilatory effects of endothelin-1 (ET-1) in isolated guinea pig aortic rings in vitro. Cumulative dose-response curves to ET-1 were constructed and ET-1 actions on prostaglandin F2 alpha (PGF2 alpha)-precontraction were studied in both endothelium-intact and endothelium-denuded preparations, in the presence or absence of a cyclooxygenase inhibitor (indomethacin) and/or nitric oxide inhibitors (NG-nitro-L-arginine methyl ester and hemoglobin). In endothelium-intact preparations, pretreatment with indomethacin (10(-5) M, 30 min), alone or in combination with NG-nitro-L-arginine methyl ester (L-NAME, 10(-4) M), significantly augmented the constrictive responses to ET-1, whereas indomethacin, L-NAME, and hemoglobin (10(-5) M) had no significant effects in the endothelium-denuded preparations. Furthermore, in PGF2 alpha-precontracted, endothelium-intact preparations, ET-1, at a dose of 10(-9) M, induced initial relaxation followed by subsequent contraction, while it only contracted the endothelium-denuded preparations. The initial relaxation was abolished by indomethacin, but not by L-NAME or hemoglobin. In addition, this relaxation was not inhibited by a specific ETA receptor antagonist, BQ-123 (6 x 10(-6) M). In addition to the involvement of nitric oxide, these results show the involvement of cyclo-oxygenase-generated vasodilating eicosanoid(s) derived from endothelium in ET-1-induced vasorelaxation in guinea pig aorta in vitro. The results also indicate that this vasorelaxation is mediated by ETB receptor activation.

Left main coronary flow velocity associated with stenosis. Evaluation by transesophageal color-guided pulsed Doppler technique

To quantitatively estimate the extent of left main coronary artery (LMCA) stenosis, flow velocity of the LMCA in 33 patients was analyzed by a transesophageal color-guided pulsed Doppler technique. In 11 of 20 patients with LMCA stenosis, coronary flow velocity could be measured. The peak diastolic flow velocity at the stenotic segments was 90 +/- 32 (SD) cm/s which was significantly greater than that at the nonstenotic segments (n = 13; 34 +/- 8 cm/s; p < 0.01), and was correlated with the angiographically determined percentage of diameter stenosis of the vessel which ranged from 52 to 90 percent (r = 0.77; y = 6.34 square root of x + 10.4; p < 0.01). These results suggest that acceleration of flow velocity at the point of stenosis may be correlated with the severity of the stenosis. Measurement of flow at the point of stenosis by transesophageal color-guided pulsed Doppler technique may facilitate the quantitative assessment of LMCA stenosis, although its sensitivity requires improvement.

Plasma atrial natriuretic peptide response to direct current cardioversion of atrial fibrillation in patients with mitral stenosis

OBJECTIVES

The purpose of this study was to evaluate the effect of direct current cardioversion therapy on the plasma concentration of atrial natriuretic peptide and to determine the main factors that influence the change in plasma atrial natriuretic peptide levels in patients with atrial fibrillation.

BACKGROUND

In atrial arrythmias, whether the fast atrial rate itself or the associated elevation of atrial pressure, or both, contributes to the increase in atrial natriuretic peptide is a subject of debate.

METHODS

In 15 patients with mild mitral stenosis, plasma atrial natriuretic peptide levels were measured and transmitral flow pattern was obtained by continuous wave Doppler echocardiography immediately before cardioversion and at 5 min, 4 h, 24 h and 5 days after direct current cardioversion. Mean mitral pressure gradient and atrial filling fraction were calculated on the basis of transmitral flow.

RESULTS

In three patients who did not have a successful return to sinus rhythm, plasma atrial natriuretic peptide levels remained elevated after cardioversion. In 12 patients who maintained sinus rhythm, plasma atrial natriuretic peptide levels were significantly reduced from 79 +/- 29 to 36 +/- 11 pg/ml 4 h after cardioversion to sinus rhythm. However, the mitral pressure gradient did not change significantly during the observation period. There were progressive increases in atrial filling fraction throughout the observation period. From 4 h to 5 days after direct current cardioversion, plasma atrial natriuretic peptide levels gradually increased concomitantly with the recovery of atrial mechanical function.

CONCLUSION

The reduction of plasma atrial natriuretic peptide levels after direct current cardioversion might be due to recovery from the high rate of atrial firing and not to an alteration in the mitral pressure gradient. Direct current cardioversion itself does not seem to influence atrial natriuretic peptide secretion. The increase in atrial natriuretic peptide levels from 4 h to 5 days after cardioversion concomitantly with an increase in atrial filling fraction may be due to recovery of atrial mechanical function.

Enhancement of Doppler flow signals in the left heart chambers by intravenous injection of sonicated albumin

OBJECTIVES

The objective of this study was to evaluate the effect of a transpulmonary contrast agent on Doppler flow signals in the left heart chambers.

BACKGROUND

Echo contrast agents are good ultrasound reflectors and could be used as Doppler signal enhancers. Sonicated albumin microbubbles are transpulmonary echo contrast agents and could enhance left heart Doppler signals after peripheral venous injection.

METHODS

Thirty-one patients with various heart diseases without intracardiac shunts were assessed with Doppler echocardiography before and after injection of sonicated albumin.

RESULTS

After an intravenous injection, pulsed Doppler signals of transmitral flow became more intense in all 16 patients examined, although flow velocity itself was not changed. In Doppler color flow imaging, the maximal mitral regurgitant signal area increased from 312 +/- 405 mm2 to 434 +/- 465 mm2, an average increase of 59 +/- 40% in all 17 patients with mitral regurgitation (p < 0.01). These effects were considered to be due to improvement of signal to noise ratio by the enhancement of Doppler flow signals. The duration of enhancement of pulsed Doppler transmitral flow signals was significantly longer than that of the left ventricular echocardiographic opacification (44 +/- 11 s vs. 17 +/- 7 s, p < 0.01).

CONCLUSIONS

Intravenous injection of sonicated albumin can enhance the Doppler flow signals in the left heart chambers. This effect may be useful to improve the sensitivity of the Doppler system for detecting abnormalities of left heart blood flow such as mitral regurgitation.

Pericardial clot after open heart surgery: its specific localization and haemodynamics

Transoesophageal echocardiography disclosed a localized pericardial blood clot compressing the right atrium (RA) and/or right ventricle (RV) in 15 patients suffering from low cardiac output failure soon after open-heart surgery. The left ventricular end-diastolic diameter was small (38.4 +/- 10.1 mm) and its fractional shortening normal (34.9 +/- 10.2%). These findings suggested cardiac tamponade as a result of pericardial clot. However, the 'y' trough of the RA pressure tracing was prominent, which is not characteristic of typical cardiac tamponade, but rather of constrictive pericarditis. This implies therefore that the pathophysiology of cardiac tamponade by pericardial clot differs from that of tamponade by fluid. Emergency open-chest removal of the pericardial clot was performed in seven patients, with good results. Pericardial clot produces low cardiac output soon after open-heart surgery, but its location is specific and its haemodynamics are not characteristic of cardiac tamponade.

Rapidity of progression of aortic stenosis in patients with congenital bicuspid aortic valves

The rapidity of progression of aortic stenosis in patients with congenital bicuspid aortic valves, and its relation to aging and valve anatomy are not well known. To elucidate these aspects, 75 patients aged 15 to 76 years were examined by echocardiography. Aortic valve sclerosis began from the second decade, the sclerotic index progressing with age (r = 0.72; p < 0.0001). Aortic valve calcium was noted from the fourth decade. Aortic valve pressure gradient increased approximately 18 mm Hg each decade, concomitant with progression of valve sclerosis (r = 0.78; p < 0.0001). Progression of cusp sclerosis was faster in patients with anteroposteriorly located cusps than in those with right-left-located cusps (p < 0.005), and was faster in those with eccentric cusps (width ratio of major and minor cusps > or = 1.2) than in those with symmetric cusps (p < 0.05). In patients with eccentric and anteroposteriorly located cusps, aortic valve pressure gradient increased 27 mm Hg per decade. In patients with congenital bicuspid aortic valves, the progression of aortic stenosis is rapid, and the rapidity depends to some extent on the position and eccentricity of the cusps.

Hypercoagulability in the left atrium: Part II: Coagulation factors

The relationship between a hypercoagulable state and intracardiac thrombus formation is reviewed, with reference to the pathophysiology of intracardiac thrombus in patients with acute cardioembolic stroke, and those with mitral stenosis. When the development or enlargement of intracardiac thrombus is followed serially by echocardiography, the diameter of the inferior vena cava is seen to decrease as the hematocrit increases, particularly in patients with negative water balance taking diuretics. These findings strongly suggest that dehydration could play an important role in the formation of thrombus. A hypercoagulable and secondarily enhanced fibrinolytic state exists in the cardiac chamber of patients with acute cardioembolic stroke or with intracardiac thrombus. This can be evaluated by plasma levels of fibrinopeptide A, fibrinopeptide B beta 15-42, thrombin-antithrombin III complex and D-dimer. Anticoagulant treatment suppresses thrombin activity in the cardiac chamber, allowing plasma fibrinolytic activity to predominate and reduce the size of the intracardiac thrombus.

Hypercoagulability in the left atrium: Part I: Echocardiography

Approximately 15% of patients with mitral valve disease will experience left atrial thrombosis and its consequences. The etiology and diagnosis of left atrial thrombosis are reviewed, stressing the importance of blood stagnation as the most important etiologic factor. Atrial fibrillation, a left atrial diameter greater than 60 mm and absence of significant mitral regurgitation are predictors of left atrial thrombosis in mitral stenosis. Left atrial thrombus can be detected in 50% of patients with all three factors; all influence blood stagnation. Smoke-like echoes in the left atrium, detected by echocardiography, provide a semi-quantitative assessment of left atrial blood stagnation. The incidence of thrombi in patients with well marked smoke-like echoes is 60%, while in those without this echocardiographic finding it is only 9%. Smoke-like echoes provide an early warning system of conditions in the left atrium likely to lead to thrombosis unless the patient is anticoagulated.

Clinical application of transpulmonary contrast-enhanced Doppler technique in the assessment of severity of aortic stenosis

OBJECTIVE

The aim of this study was to demonstrate the clinical usefulness of the transpulmonary contrast-enhanced Doppler technique by using it to assess the severity of aortic stenosis.

BACKGROUND

Sonicated albumin microbubbles can pass through the pulmonary circulation after peripheral venous injection and have been reported to enhance Doppler signals from the left side of the heart. Therefore, their use to determine aortic flow velocity would facilitate the assessment of the severity of aortic stenosis.

METHODS

Twenty-two patients with aortic stenosis and seven normal volunteers were examined. Aortic flow velocity was recorded with continuous wave Doppler technique from an apical window before and after injection of 2 ml of sonicated albumin.

RESULTS

In 10 patients with aortic stenosis, the aortic velocity envelope was too indistinct to determine the peak velocity before sonicated albumin was injected. After injection, the aortic flow Doppler signal was enhanced in 9 of the 10 patients and the velocity envelope became clear enough to measure the peak velocity, enabling calculation of the transaortic pressure gradient. In the remaining 12 patients with aortic stenosis and in all 7 normal volunteers, the velocity envelope was clear before injection and became much clearer after injection. The calculated transaortic pressure gradient showed a good agreement with catheterization measurements (y = 1.1x-6.5, r = 0.88, p less than 0.001, SEE = 16 mm Hg, n = 13). Duration of Doppler signal enhancement was measured as the time during which the envelope was clearer than before injection throughout the ejection period. The duration was significantly shorter in patients with aortic stenosis than in normal volunteers (16 +/- 5 vs. 52 +/- 32 s, p less than 0.01). There was a significant correlation between left ventricular systolic pressure measured by catheterization and the duration of signal enhancement (r = -0.69), suggesting that albumin microbubbles were fragile at high pressure.

CONCLUSIONS

The transpulmonary contrast-enhanced Doppler technique using sonicated albumin is useful for assessing the severity of aortic stenosis even in patients with poor Doppler recordings, although the duration of signal enhancement might be affected by left ventricular systolic pressure.

Serial changes of mitral flow pattern after percutaneous transvenous mitral commissurotomy--assessment of Doppler and two-dimensional echocardiography

To evaluate the acute change in the mitral flow pattern, especially pressure half-time after percutaneous transvenous mitral commissurotomy (PTMC) and to investigate the factors influencing the mitral flow pattern, Doppler and two-dimensional echocardiographic studies were performed in 15 patients before and two, six, 10 and 24 hours and seven days after PTMC. Mitral valve area increased and the mean mitral pressure gradient decreased after PTMC (1.0 +/- 0.4 cm2 to 1.8 +/- 0.4 cm2; 11 +/- 6 mmHg, to 3 +/- 2 mmHg, p < 0.01). Pressure half-time also decreased two hours after surgery, from 292 +/- 70 msec to 176 +/- 48 msec (p < 0.01) and then gradually decreased to 140 +/- 47 msec within seven days of the procedure without remarkable changes in mitral valve area and the mean transmitral pressure gradient. Left atrial dimensions decreased and left ventricular end-diastolic dimensions gradually increased after PTMC (51 +/- 6 mm to 46 +/- 5 mm; 47 +/- 4 mm to 50 +/- 3 mm). The time course of this was similar to that of the pressure half-time. Further study, in which the changes in pressure half-time were evaluated within 30 minutes of PTMC in 17 patients, indicated that pressure half-time significantly decreased from 248 +/- 69 msec to 139 +/- 28 msec five minutes after balloon inflation, slightly increasing again after 30 minutes to 153 +/- 31 msec.(ABSTRACT TRUNCATED AT 250 WORDS)

Left ventricular function and the relationship between left atrial pressure and peak early diastolic filling velocity in dog

OBJECTIVE

The aim was to clarify the roles of left atrial pressure and ventricular function in the determination of early diastolic filling.

METHODS

Various grades of ventricular dysfunction were made in 12 mongrel dogs by coronary microembolization under pentobarbitone anaesthesia. Left atrial pressure was altered by volume loading. Peak early diastolic filling velocity was measured using pulsed Doppler echocardiography. Ventricular fractional shortening was measured using M mode echocardiography.

RESULTS

Peak early filling velocity increased as left atrial pressure increased. There was a direct relationship between mean left atrial pressure and the velocity before and after induction of ventricular dysfunction. The slope of the regression line between mean left atrial pressure and peak early filling velocity decreased as the grade of the dysfunction increased. There was a significant correlation between the slope of the regression line and mean left ventricular fractional shortening (r = 0.65, n = 31, p less than 0.01).

CONCLUSIONS

Early diastolic filling was affected by both left atrial pressure and left ventricular function. These facts are useful in interpreting the various transmitral flow patterns observed clinically.

The gap between mitral leaflets as a cause of mitral regurgitation: relationship to mitral valve prolapse

The gap between the tips of the anterior and posterior mitral leaflets was studied to assess the significance of this gap in the diagnosis of mitral valve prolapse. The subjects were 39 patients in whom the gap was seen and the mitral valve did not exceed the mitral annular line in systole on two-dimensional echocardiography. Forty eight healthy subjects, in whom phonocardiography disclosed no abnormalities, served as controls. The site of the gap as well as the site and severity of mitral regurgitation were assessed with two-dimensional echocardiography and Doppler flow imaging. The incidence of mitral regurgitation was 82%, which was comparable to that in the controls (67%). The site of the gap was consistent with that of regurgitation. The gap was also seen in a low percentage of healthy subjects, but clinically significant mitral regurgitation did not accompany the gap in healthy subjects including the gap-carrying controls. On the other hand, many of the gap-carrying patients showed clinically significant mitral regurgitation. Also the fact that a gap between the tip of the anterior and posterior mitral leaflets was found to be frequently accompanied by phonocardiographical features corresponding to mitral valve prolapse indicates that the presence of a gap is a significant finding.

[High incidence of left ventricular thrombosis and systemic embolism in patients with left ventricular assist system]

The purpose of this study was to determine the incidence of left ventricular (LV) thrombosis and systemic embolism in 14 patients with LV assist systems. Echocardiography was used to detect LV wall motion abnormalities, intracavitary smoke-like echoes and thrombosis, and the effect of anticoagulant therapy was serially examined. During full assist of the circulation, the aortic valve did not open in any patient. Smoke-like echoes were observed in 9 patients (64%) and thrombi in 8 (57%). The thrombus developed within the first 3 assist days. Systemic anticoagulant therapy decreased the thrombus size in only 3 patients, but there was a possibility of intracranial or mediastinal bleeding in other 3 patients. Systemic embolism was noted in 7 of 11 autopsy patients (64%). The characteristic finding was that there were multiple embolized organs, such as the brain, kidneys, spleen and liver, in all patients. Development of a thrombus is a serious complication in all patients with LV assist systems. However, the problem does not lie in the assist system but in the left ventricle of the patient's own heart. It is also noteworthy that systemic anticoagulation is not effective for an LV thrombus. A new method of assisting the failing heart, or a new anticoagulant delivery technique for the LV cavity to prevent LV thrombus development is needed.

Pulmonary venous atrial systolic flow reversal detected by transthoracic Doppler as a sign of congestive heart failure: a case report

Reversal of flow in the pulmonary veins during atrial contraction was detected by transthoracic pulsed Doppler echocardiography in a patient with bicuspid aortic valve and heart failure. The flow reversal disappeared after his recovery from heart failure. Flow reversal during atrial contraction detected by transthoracic Doppler may be a sign of congestive heart failure.

Application of Doppler color flow imaging to determine valve area in mitral stenosis

This study was undertaken to examine whether Doppler color flow imaging could accurately estimate the valve area in mitral stenosis. Doppler color flow assessments were performed in both an in vitro model and in 30 patients with mitral stenosis undergoing cardiac catheterization. In the experimental Doppler study using a circuit model, color jet width correlated well with actual orifice diameter (r = 0.99). In the clinical Doppler study, the mitral valve orifice was assumed to be elliptic and the mitral valve area was calculated from the following equation: (pi/4) (a x b), where a = color jet width at the mitral valve orifice in the apical long-axis view (short diameter) and b = the width in the 90 degrees rotated view (long diameter). Mitral valve area was also determined by two-dimensional echocardiography and the pressure half-time method, and the results for all three noninvasive methods were compared with those obtained at cardiac catheterization. By Doppler color flow imaging, mitral valve area could be determined in all patients and there was a significant correlation between the Doppler jet and catheterization estimates of mitral valve area (r = 0.93). Valve area determined by two-dimensional echocardiography correlated well with catheterization measurements in 26 patients (r = 0.84). However, the area could not be determined in 4 (13%) of the 30 patients because of technical problems. Although there was a fair correlation between the valve area determined by the pressure half-time method and catheterization (r = 0.79), this method tended to overestimate valve area in patients with aortic regurgitation.(ABSTRACT TRUNCATED AT 250 WORDS)