单纯急性下壁心肌梗死及其合并右心室心肌梗死对右心长轴功能的影响

目的应用心肌组织多普勒技术结合M型超声心动图,评价单纯急性下壁心肌梗死及其合并右心室心肌梗死对右心室长轴功能的影响。方法选择首次急性下壁心肌梗死患者28例,分为单纯急性下壁心肌梗死18例(Ⅰ组),急性下壁心肌梗死伴右心室心肌梗死10例(Ⅱ组),另选健康体检者20例(Ⅲ组)。在标准心尖四腔心切面二维图像指引下,应用M型超声记录右心房室环右心室游离壁及中心纤维支架处运动曲线,测量收缩期、舒张早期、舒张晚期最大运动幅度(SD,DED,DAD)及收缩期、舒张早期、舒张晚期平均运动速度(SMV,DEMV,DAMV),计算DED/DAD比值。心肌组织多普勒记录该处运动速度曲线,测量上述各期最大运动速度(Sm、Em、Am)及Em/Am比值。结果与Ⅲ组比较,Ⅰ组和Ⅱ组右心房室环右心室游离壁处SD、DED、DED/DAD、SMV、DEMV、Sm及Em均明显下降。DAD、DAMV、Am虽有下降,但差异无统计学意义。结论急性下壁心肌梗死无论是否合并右心室心肌梗死均可影响右心室长轴功能,导致右心室整体功能降低。     

Influence of respiratory variations on right ventricular function

Respiratory effort during inspiration, expiration, and the Valsalva manoeuvre changes right ventricular preload and afterload. On inspiration these changes should improve systolic emptying of a larger end diastolic volume and so increase the ejection fraction, whereas on expiration the reverse should be true. The resting right ventricular ejection fraction was measured by first pass radionuclide angiography with gold-195m (half life 30.5 s) in 17 individuals at maximal inspiration and expiration and in eight at rest and during the strain phase (phase 2) of the Valsalva manoeuvre. The right ventricular ejection fraction was significantly lower during expiration than during inspiration. There were, however, no significant differences in bolus duration or right ventricular transit time. The Valsalva manoeuvre, in contrast, significantly increased the ejection fraction and also significantly prolonged both the bolus duration and right ventricular transit time. The conformation of the bolus curves during the Valsalva manoeuvre suggested the development of tricuspid regurgitation. These data suggest that relative influences of venous return, pulmonary arterial pressure, pulmonary vascular resistance, and possible functional tricuspid regurgitation vary during inspiration, expiration, and the Valsalva manoeuvre and can affect the right ventricular ejection fraction. Changes in right ventricular function on exercise assessed by first pass radionuclide angiography must be interpreted with caution because maximal respiratory effort may alter the right ventricular ejection fraction independently of ischaemia or other non-ischaemic factors.     

Influence of respiratory variations on right ventricular function.

Respiratory effort during inspiration, expiration, and the Valsalva manoeuvre changes right ventricular preload and afterload. On inspiration these changes should improve systolic emptying of a larger end diastolic volume and so increase the ejection fraction, whereas on expiration the reverse should be true. The resting right ventricular ejection fraction was measured by first pass radionuclide angiography with gold-195m (half life 30.5 s) in 17 individuals at maximal inspiration and expiration and in eight at rest and during the strain phase (phase 2) of the Valsalva manoeuvre. The right ventricular ejection fraction was significantly lower during expiration than during inspiration. There were, however, no significant differences in bolus duration or right ventricular transit time. The Valsalva manoeuvre, in contrast, significantly increased the ejection fraction and also significantly prolonged both the bolus duration and right ventricular transit time. The conformation of the bolus curves during the Valsalva manoeuvre suggested the development of tricuspid regurgitation. These data suggest that relative influences of venous return, pulmonary arterial pressure, pulmonary vascular resistance, and possible functional tricuspid regurgitation vary during inspiration, expiration, and the Valsalva manoeuvre and can affect the right ventricular ejection fraction. Changes in right ventricular function on exercise assessed by first pass radionuclide angiography must be interpreted with caution because maximal respiratory effort may alter the right ventricular ejection fraction independently of ischaemia or other non-ischaemic factors.     

Influence of acute right ventricular dysfunction on cardiac tamponade

Echocardiographic and hemodynamic data were measured in nine closed chest dogs during graded cardiac tamponade (pericardial pressure 5, 10, 15 mm Hg) before and after production of diffuse acute ischemic right ventricular dysfunction. Right ventricular dysfunction was produced by intracoronary injection of nonradioactive microspheres (mean diameter +/- SD 54 +/- 4 microns) and caused a significant increase in right atrial pressure (7.6 +/- 1.4 vs. 1.6 +/- 1 mm Hg, p less than 0.001) and cross-sectional areas of both the right atrium (8.3 +/- 0.3 vs. 5.6 +/- 0.2 cm2, p less than 0.001) and right ventricle (8.8 +/- 0.4 vs. 5.7 +/- 0.4 cm2, p less than 0.001). Right atrial and ventricular collapse required a significantly larger pericardial effusion and pericardial pressure after right ventricular infarction than before. Mean aortic pressure had fallen 1.9 +/- 2% and 6.5 +/- 6.9% at the time of right atrial collapse (p = NS before vs. after right ventricular dysfunction) and 3 +/- 4.1% and 20.1 +/- 20.8% at the time of right ventricular collapse (p less than 0.03) before and after right ventricular dysfunction, respectively. In the presence of ischemic right ventricular dysfunction, echocardiographic signs of cardiac tamponade are less sensitive and occur later in the hemodynamic progression of cardiac tamponade. Pulsus paradoxus with cardiac tamponade was not prevented by coexisting ischemic right ventricular dysfunction.     

右心室流出道间隔部起搏对左心室功能的影响

目的比较右心室流出道间隔部(RVOT)起搏与右心室心尖部(RVA)起搏的血流动力学差异;评估RVOT起搏技术的可行性与安全性。方法选择有永久起搏器置入适应证的患者75例。根据术者建议和患者意愿分为RVOT组(40例)和RVA组(35例)。所有房室传导阻滞及病窦综合征合并一度房室传导阻滞患者采用双腔起搏双腔感知触发抑制型起搏模式,心房颤动伴长间歇患者采用抑制型心室按需起搏模式。比较2组的血流动力学差异。结果 RVOT组的QRS波宽度较RVA组缩窄(23.2±28.7)ms,差异有统计学意义(P<0.01)。与RVA组比较,RVOT组LVEF、左心室短轴缩短率明显升高,左心室舒张末容积明显下降(P<0.05,P<0.01)。与术前比较,RVA组LVEF、左心室短轴缩短率明显下降,左心室舒张末容积明显升高,差异有统计学意义(P<0.01)。结论利用螺旋电极进行RVOT起搏可行且较为安全。RVOT起搏的血流动力学参数优于RVA。     

The influence of hemodilution on left ventricular function

In nine anesthetized mongrel dogs anemia was produced by exchanging blood with plasma substitute thus reducing hemoglobin gradually in three steps. Aortic, atrial and ventricular blood pressures, cardiac output, electrocardiogram, phonocardiogram and the first derivative of the left ventricular pressure were continuously monitored. Blood samples were taken to determine hemoglobin, blood gases and whole blood viscosity. Progressive hemodilution resulted in a significant increase in cardiac output and left ventricular stroke work, while total peripheral resistance, oxygen content and whole blood viscosity decreased significantly. There were no significant changes in cardiac pressures, myocardial contractility, diastolic pressure time index and blood gases. The oxygen supply/demand ratio had gradually declined, while electrocardiogram showed no significant changes. These results suggest that moderate isovolemic hemodilution in animals with normal coronary vessels does not impair left ventricular function as this was manifested by the unchanged hemodynamic and electrocardiographic findings.     

早期康复运动对急性右室梗死病人心功能的影响

目的：观察急性右室梗死病人住期康复运动方案的特点及其疗效。方法：２３例急性右室梗死病人,均合并下壁、后壁或前壁心肌梗死,其中１８例经血管造影发现右冠脉梗死。待病情稳定后均参加３阶段康复运动治疗,根据完成康复运动的天数将病人分为运动１１天（ｎ＝１５）以上和运动１０天（ｎ＝８）以下两组,对比运动后两组心功能容量,冠脉组梗死程度。数量及心功能的差异。结果：运动后心功能容量与康复运动次数呈正相关ｒ＝０．８     

Influence of right ventricular stimulation site on left ventricular function in atrial synchronous ventricular pacing

OBJECTIVESThe study investigates the correlation between left ventricular function and QRS duration obtained by alternate right ventricular pacing sites.BACKGROUND1. Right ventricular apical pacing is associated with alterations of left ventricular contraction sequence. 2. A stimulation producing narrow QRS complexes is supposed to provide for better left ventricular contraction patterns.METHODSFourteen patients with third degree AV block received one ventricular pacing lead in apical position. The alternate lead was attached to that site on the septum that produced the smallest QRS complex as measured from the earliest to the last deflection in any of the orthogonal Frank leads (xyz). During atrial synchronous ventricular pacing, the AV delay was optimized individually and for each stimulation site using mitral valve doppler or impedance cardiography. By radionuclide ventriculography, the phase distribution histogram of left ventricular contraction was evaluated as area under the curve (AuC); systolic function was determined as ejection fraction (EF) and as absolute ejected counts (EC) in random order. The difference (Δ) in QRS duration between apical and septal stimulation (Δxyz) was correlated with the difference in phase distribution (ΔAuC) and ejection parameters (ΔEF, ΔEC).RESULTSQRS duration was shorter with septal than with apical pacing in 9 out of 14 patients (64%); it was longer in 4 (29%), and no difference was seen in 1 patient. There was a significant positive correlation between the change in QRS duration (Δxyz) and phase distribution (ΔAuC: r = 0.66393, p = 0.010) and a significant negative correlation to systolic function (ΔEF: r = 0.70931, p = 0.004; ΔEC: r = 0.74368, p = 0.002).CONCLUSIONSIn atrial synchronous right ventricular pacing, if the AV delay is adapted individually, decreased QRS duration obtained by alternate pacing sites is significantly correlated with homogenization of left ventricular contraction and with increased systolic function in acute tests.     

单纯右冠状动脉狭窄对左心室功能的影响

目的:探讨单纯右冠状动脉（RCA）狭窄不同狭窄程度和狭窄节段对左心室功能的影响。方法:将冠状动脉造影证实为单纯RCA狭窄的患者99例,按不同狭窄程度、不同狭窄节段和不同冠脉优势型进行分组,并与494例无冠状动脉狭窄的对照组比较,经左心室造影测定的左室射血分数（LVEF）和左室舒张末压（LVEDP）。结果:与对照组患者相比,轻度、中度和重度单纯右RCA狭窄患者的LVEF变化不显著,完全闭塞患者的LVEF显著下降（P<0.05）;右冠中段、右冠远段、后降支和侧后支病变患者的LVEF均无有意义变化,右冠近段病变患者LVEF下降有统计学意义（P<0.05）。单纯RCA狭窄患者中,右冠优势组LVEF略低于均衡优势组和左冠优势组,但差异未达显著水平。单纯RCA狭窄对LVEDP的影响并不明显。结论:单纯RCA主干近段狭窄和单纯RCA完全闭塞对左室收缩功能可产生一定程度的损害。     

Importance of left ventricular function and systolic ventricular interaction to right ventricular performance during acute right heart ischemia.

To determine whether modulation of systolic ventricular interaction influences right ventricular performance during right heart ischemia, the effects of septal ischemia and inotropic stimulation were studied in 15 dogs in an open chest preparation. Right coronary branch occlusions led to right ventricular dilation and free wall dyskinesia, reversed septal curvature and reduced left ventricular diastolic volume. In systole, the septum thickened but bulged paradoxically into the right ventricle generating an active but depressed right ventricular systolic pressure (28.9 +/- 5.5 to 22.1 +/- 4.5 mm Hg), with associated decreases in right ventricular stroke work (5.66 +/- 0.94 to 1.92 +/- 0.53 g.m/m2) and left ventricular systolic pressure (123 +/- 11 to 80 +/- 10 mm Hg). Septal ischemia induced systolic septal thinning, left ventricular dilation and decreased left ventricular systolic pressure (80 +/- 10 to 55 +/- 10 mm Hg) and stroke work. Although the extent of paradoxic septal displacement increased, there were further decrements in right ventricular systolic pressure (22.1 +/- 4.5 to 18.7 +/- 4.3 mm Hg) and stroke work (1.92 +/- 0.53 to 0.7 +/- 0.2 g.m/m2). Dopamine infusion augmented left ventricular free wall contraction and increased left ventricular systolic pressure (55 +/- 10 to 172 +/- 17 mm Hg) and stroke work. Although systolic septal thinning persisted, the extent of paradoxic septal displacement increased strikingly and, despite continued right ventricular free wall dyskinesia, right ventricular systolic pressure increased (18.7 +/- 4.3 to 39.6 +/- 6.2 mm Hg) as did right ventricular stroke work (0.7 +/- 0.2 to 7 +/- 1.6 g.m/m2).(ABSTRACT TRUNCATED AT 250 WORDS)     

The effect of acute hypoxia on right ventricular function in healthy adults

Right ventricular ejection fraction and right ventricular volumes were derived in 12 healthy male subjects using krypton-81m equilibrium radionuclide ventriculography whilst subjects breathed 30% (high inspired oxygen) and then 8-12% oxygen in nitrogen mixture (hypoxia). 'Physiological' tricuspid valve regurgitation was identified in 7 of the subjects by Doppler echocardiography, and right ventricular peak systolic pressure was estimated during high inspired oxygen and during hypoxia. Mean right ventricular peak systolic pressure was 24.1 +/- 3.3 mmHg during high inspired oxygen and increased to 41.3 +/- 8.4 mmHg during hypoxia (P less than 0.01). Mean right ventricular ejection fraction was 0.612 +/- 0.075 during high inspired oxygen and was unchanged at 0.590 +/- 0.073 during hypoxia. There was no significant change in right ventricular end-diastolic volume or stroke volume in response to hypoxia. The systolic performance of the normal right ventricle is well-maintained during an acute rise in afterload induced by hypoxia.     

Influence of verapamil and oxygen on pulmonary hypertension and right ventricular function

The study was designed to elucidate verapamil action on the pulmonary vascular bed and right ventricular function and to compare it with the effect of oxygen in view of the fact that calcium antagonists can attenuate hypoxic pulmonary vasoconstriction. 16 patients with secondary, and 4 with primary, pulmonary hypertension and with a mean pulmonary artery systolic pressure of 68.6 +/- 28.7 mmHg were examined. After determination of initial haemodynamic values, the oxygen test (OT) was performed; later on, when the values returned to the initial ones, verapamil was infused into pulmonary artery. Measurements were carried out in the 10th min of OT and until the 30th min after verapamil. While verapamil decreased statistically significantly pulmonary artery pressures and resistances, it did not deteriorate right ventricular systolic function, although it lowered its stiffness significantly. The effect of oxygen was comparable with that of verapamil though the magnitude of changes was smaller.     

Influence of pericardiectomy on cat right ventricular function after pulmonary arterial constriction

Although the results of mitral valve replacement in patients with mitral valve disease and pulmonary arterial hypertension are usually gratifying, persistent right ventricular decompensation occasionally occurs despite successful insertion of a mitral prosthesis. It is possible that when pulmonary hypertension is slow to resolve, the loss of an intact pericardium incurred by the operative intervention allows right ventricular dilatation to occur acutely. In some cases, the latter might lead to chronic irreversible right ventricular failure. To test this hypothesis, right ventricular hypertension and failure were produced in 62 cats by pulmonary arterial banding. Thirty-two of these cats had a total pericardiectomy, and in 30 the pericardium was reconstituted. The mortality rates for each group were similar. Right heart catheterization was performed in the surviving animals 4 to 145 days later. There were no significant differences in the degree of right ventricular failure between cats with and without an intact pericardium. Isometric contractile function of papillary muscles was measured with each muscle at the peak of its length-tension curve (L_max). Active tension, rate of tension development, time to peak tension and the contractile response of the papillary muscles to norepinephrine were similar in each group. Thus, the absence of a pericardium does not seem to affect the degree of experimental right ventricular failure induced by a chronic pressure stress on the right ventricle.     

Influence of PEEP ventilation immediately after cardiopulmonary bypass on right ventricular function

Ventilation with positive end-expiratory pressure (PEEP) is often the appropriate therapy for treating patients with impaired pulmonary function after cardiac surgery procedures. Circulatory depression, however, sometimes limits the level of PEEP. This study was conducted to investigate the effects of PEEP ventilation (+15 cmH2O) immediately after weaning from cardiopulmonary bypass 1) period of PEEP application and 45 min thereafter; 2) period of PEEP application on right ventricular hemodynamics using a new thermodilution technique for measuring right ventricular ejection fraction (RVEF), right ventricular end-diastolic and end-systolic volumes (RVEDV, RVESV). Forty patients undergoing aortocoronary bypass grafting were retrospectively divided into two groups: group 1 (n = 24) in which RVEF was reduced significantly (40----28 percent), and group 2 (n = 16) in which RVEF remained almost unchanged. In patients in group 1, stenosis of the right coronary artery (RCA) was significantly more pronounced in comparison to the others and was detected to be responsible for the different reaction of RVEF (analysis of co-variance). Application of PEEP immediately after weaning from CPB was followed by an increase in RVESV (+4 percent; RVEDV -1 percent) in group 1, whereas patients of group 2 differed significantly (RVESV -14 percent; RVEDV -15 percent). Cardiac index was decreased only in group 1 (-32 percent). During the second period of PEEP application, no further difference could be observed between the groups. We conclude that hemodynamic changes related to PEEP ventilation are minimal in the intact right ventricle. Abnormalities in right ventricular function due to stenosis of the RCA, however, have had marked clinical influence on the circulatory response. Monitoring of right ventricular function seems to be of benefit for cardiac surgery patients in this situation.     

Comparison of left and right ventricular function in acute myocardial infarction

Pulmonary arterial end-diastolic and mean right atrial pressures were compared in 25 patients with acute myocardial infarction and in one patient with unstable angina. No consistent relationship was observed between these pressures. Simultaneous ventricular function curves relating the stroke work of each ventricle to its respective filling pressure were constructed on 34 occasions, dextran infusion or diuresis being used to alter the filling pressure. The curves from each ventricle were described mathematically by a quadratic (parabolic) function as well as by a straight line function and then compared by canonical correlation analysis. Alterations in the left ventricular function curves occurred with and without depression of right ventricular function curves. These hemodynamic measurements demonstrate that acute myocardial infarction can alter the relationship between left and right ventricular function.     

合并肺动脉高压心脏移植患者术后早期血流动力学分析及处理

目的观察和探讨心脏移植患者术前肺动脉压力和肺循环阻力与术后右心功能不全的关系,及降低因术后早期肺动脉高压造成右心功能损害的临床措施。方法54例接受同种原位心脏移植手术的患者,根据术前肺动脉收缩压（sPAP）≥45nmmHg（1mmHg=0．133kPa）或〈45mmHg,分为Ⅰ组34例和Ⅱ组20例。统计术前血流动力学指标心排指数（CI）、肺循环阻力（PVR）、中心静脉压（CVP）。Swan-Ganz导管连续监测术后60h内的平均肺动脉压（mPAP）、PVR、CI等指标的动态变化。床旁超声分别监测和评价术后3、7、14、21天和1个月时的三尖瓣反流程度。术后肺动脉高压及右心功能维护治疗措施包括利尿、NO吸入、静脉注射前列环素（llomedin 20）、血液滤过等。结果本组患者无术后早期死亡（术后30天内）。Ⅰ、Ⅱ组患者术前的sPAP分别为（60±12）mmHg和（25±9）mmHg（P〈0．01）;PVR分别为（358±150）dyn·s^-1·cm^-5和（140±68）dyn·s^-1·cm^-5（P〈0．01）。术后早期出现右心功能不全的患者Ⅰ组24／34（70．6％）例,Ⅱ组7／20（35．0％）例,两组比较,差异有统计学意义（P=0．01）。Ⅰ组患者术后早期肺动脉压力和PVR仍明显高于Ⅱ组患者,并且在较长的时间后才逐渐下降至正常或仍维持偏高水平。Ⅰ组患者术后早期三尖瓣反流的严重程度高于Ⅱ组患者（P〈0．05）,但随着术后时间的延长,两组患者三尖瓣反流程度差异无统计学意义。结论心脏移植患者术前肺动脉高压的严重程度是影响术后早期右心功能的关键因素。通过有效的降低和防治术后早期肺动脉高压,降低右心负荷,可以明确降低和缩短因肺动脉高压造成术后早期右心功能损害的严重程度和持续时间,有利于术后早期心功能的恢复并维持良好的远期心功能状态。     

急性下壁心肌梗死患者右心室功能变化的探讨

目的 应用组织多普勒(TDI)结合M型超声技术评价急性下壁心肌梗死(心梗)患者右心室功能变化. 方法 急性下壁心梗患者50例,男34例、女16例;正常对照组50例,男30例,女20例.急性心梗第4～7天行超声心动图检查,采用M型超声记录三尖瓣环右心室游离壁处运动曲线,测量收缩期、舒张早期和舒张晚期运动幅度(SD、DED和DAD)及DED/DAD比值;并应用TDI技术,记录该处速度曲线,测量右室收缩期、舒张早期和晚期最大运动速度Sm、Em和Am及Em/Am比值. 结果 急性下壁心梗患者三尖瓣环右室游离壁处SD、DED运动幅度、DED/DAD比值均较对照组显著降低[分别为(18.7±5.5)mm和(24.9±2.8)mm、(10.9±3.4)mm和(16.6±3.4)mm、1.5±0.6和2.3±0.9,t值分别为18.711、19.055、6.068,均P＜0.01]Sm、Em和Em/Am明显下降[分别为(12.9±2.8)cm/s和(15.9±2.7)cm/s、(12.3±3.4)cm/s和(16.7±4.7)cm/s、0.9±0.4和1.1±0.3,t值分别为11.851、14.781、2.127,P＜0.01或P＜0.05]. 结论 急性下壁心梗损害右室舒缩功能,表现为既有运动幅度下降又有最大运动速度下降,舒张功能降低以舒张早期性能下降为主.