右美托咪定对心脏手术麻醉诱导期间血流动力学的影响

目的重点研究和探讨右美托咪定对心脏手术的麻醉效果以及麻醉诱导期间血流动力学的影响。方法利用回顾性分析的方法研究和比较对我院于2010年1月1日-2013年11月31日期间收治的114例行心脏手术麻醉患者的临床资料进行回顾性对照分析。将患者随机分为2组,均给予常规静脉麻醉,观察组总计57例在常规静脉麻醉的基础上静脉注射右美托咪定;对照组总计57例在常规静脉麻醉的基础上静脉注射与观察组等量的生理盐水。然后将2组数据结果进行分析,分析探讨两组患者麻醉效果以及麻醉诱导期间血流动力学的影响。结果通过对我院收治的114例行心脏手术麻醉患者的临床资料进行分析,两组患者在注药后5min时MAP值均明显下降,对照组下降幅度更大(P0.05),在注药后10min、15min和30min时MAP值与基础值相比略有下降,但差异无显著性;对照组在注药后5min的HR值比基础值明显增快(P0.05);SPO2两组差异无显著性(P0.05)。观察组患者术后疼痛评分、清醒时间、呼吸恢复时间、阻滞完全时间、定向力恢复时间均好于对照组患者(P0.05)。结论右美托咪定对心脏手术患者具有很好的麻醉效果,并且能够平稳血流动力学相关指标,目前已经成为行心脏手术静脉麻醉患者的主要药物,值得临床借鉴和进一步推广。     

Roles of the right ventricular free wall and ventricular septum in right ventricular performance and influence of the parietal pericardium during right ventricular failure in dogs

The roles of the right ventricular (RV) free wall and ventricular septum in RV performance were studied in the canine heart. The parietal pericardium was kept intact. Acute ischemia of the RV free wall from right coronary ligation decreased the RV stroke work index more than did that of the ventricular septum from the septal branch of the left coronary artery ligation (41 and 23%, respectively, p < 0.01). The response of the RV stroke work index to acute volume loading was also decreased. Left ventricular dysfunction was detected only with ventricular septal ischemia. Combined RV free wall and ventricular septal ischemia produced more severe and predominant RV dysfunction with disproportionate elevation of RV end-diastolic pressure. After combined ischemia, pericardiotomy improved the RV stroke work index as well as the left ventricular stroke work index (40 and 27%, respectively, p < 0.05), although the increase in RV stroke work index was greater than in left ventricular stroke work index (p < 0.05).The results of this study suggest that (1) the RV free wall has a more important role than the ventricular septum in RV performance, (2) predominant RV failure can be induced experimentally after combined RV free wall and ventricular septal ischemia, and (3) the pericardium has a restrictive effect on the damaged and dilated right ventricle.     

Avoidance of right ventricular pacing in cardiac resynchronization therapy improves right ventricular hemodynamics in heart failure patients

Background: Cardiac resynchronization therapy (CRT) applied by pacing the left and right ventricles (BiV) has been shown to provide synchronous left ventricular (LV) contraction in heart failure patients. CRT may also be accomplished through synchronization of a properly timed LV pacing impulse with intrinsically conducted activation wave fronts. Elimination of right ventricular (RV) pacing may provide a more physiological RV contraction pattern and reduce device current drain. We evaluated the effects of LV and BiV pacing over a range of atrioventricular intervals on the performance of both ventricles.
Methods: Acute LV and RV hemodynamic data from 17 patients with heart failure (EF = 30 ± 1%) and a wide QRS (138 ± 25 msec) or mechanical dyssynchrony were acquired during intrinsic rhythm, BiV, and LV pacing.
Results: The highest LV dP/dt_max was achieved during LV pre- (LV paced prior to an RV sense) and BiV pacing, followed by that obtained during LV post-pacing (LV paced after an RV sense) and the lowest LV dP/dt_max was recorded during intrinsic rhythm. Compared with BiV pacing, LV pre-pacing significantly improved RV dP/dt_max (378 ± 136 mmHg/second vs 397 ± 136 mmHg/second, P < 0.05) and preserved RV cycle efficiency (61.6 ± 14.6% vs 68.6 ± 11.4%, P < 0.05) and stroke volume (6.6 ± 4.4 mL vs 9.0 ± 6.3 mL, P < 0.05). Based on LV dP/dt_max, the optimal atrioventricular interval could be estimated by subtracting 30 msec from the intrinsic atrial to sensed RV interval.
Conclusions: Synchronized LV pacing produces acute LV and systemic hemodynamic benefits similar to BiV pacing. LV pacing at an appropriate atrioventricular interval prior to the RV sensed impulse provides superior RV hemodynamics compared with BiV pacing.     

右心室流出道间隔部起搏对心房颤动患者血流动力学和心功能的影响

目的:比较右心室流出道间隔部（RVOTS）起搏和右心室心尖部（RVA）起搏对心房颤动（房颤）患者血流动力学、心功能及主要不良心血管事件的影响,评价RVOTS起搏的中远期疗效。方法: 具备起搏器植入指征的慢性房颤患者68例,随机分配至RVOTS部起搏组(n=34)和RVA部起搏组(n=34),均采用心室抑制型按需起搏模式（VVI）,随访（27±10）个月。观察比较两组患者起搏时心电图QRS时限,血流动力学、心功能及主要不良心血管事件发生情况。结果: RVOTS组起搏心电图的QRS时限较RVA组显著缩短［(146±16) ms vs.(155±13) ms,P<0.05］。随访结束时,RVA组的左室射血分数（LVEF）较术前显著降低（0.58±0.10 vs. 0.64±0.12,P<0.05）,左房内经（LAD）较术前显著扩大［（47±10） mm vs.(44±10) mm,P<0.05）,在RVOTS组虽有类似的变化趋势［LVEF:0.59±0.08 vs. 0.63±0.11;LAD:(47±7) mm vs. (45±7) mm］,但均未达统计学差异,随访结束时两组间比较未达统计学差异;两组患者随访结束时血浆脑钠尿肽（BNP）水平均较术前显著增高［RVA组:（292±168） ng/L vs. (200±70) ng/L,P<0.01;RVOTS组:(225±88) ng/L vs.(192±69) ng/L,P<0.05］,RVA组增高更明显,且较同期RVOT组显著增高（P<0.05）;随访结束时,RVA组的平均NYHA心功能分级较术前显著增高(1.7±0.6 vs. 1.4±0.5,P<0.01) ; RVOTS组有类似的变化趋势（1.5±0.7 vs. 1.3±0.5）,但未达统计学差异,两组间实验后比较差异亦未达统计学意义。两组间因心衰住院率、脑梗死及因心血管死亡均无统计学差异。结论: RVOTS起搏的电和机械同步性比RVA起搏相对较好,其心功能损害及心脏重构也相对较轻,较RVA起搏接近生理。     

The effects of right ventricular hemodynamics on left ventricular configuration

While abnormalities of right ventricular hemodynamics are known to affect interventricular septal position and shape, their effect on left ventricular shape and possibly function have been less well studied. Accordingly, the two-dimensional echocardiographic appearance of the left ventricle was studied in 11 patients with right ventricular volume overload, 16 with right ventricular pressure overload, nine with combined pressure and volume loads of the right heart and 17 normal control subjects. An index of left ventricular shape (SI) was calculated from end diastolic, mid systolic and end systolic left ventricular short axis area (A) and circumference (C) taken at the level of the tips of the mitral leaflets, using the formula SI = 4 pi A/C2. The left ventricles of normal subjects had relatively round configurations throughout the entire cardiac cycle (SI = 0.86 at end diastole, mid and end systole). Pure right ventricular volume overload produced left ventricular deformity at end diastole only (SI at end diastole = 0.78), with a return to normal configuration during systole. Pure right ventricular pressure load resulted in left ventricular deformation throughout the cardiac cycle, with shape indices ranging between 0.77 and 0.80. Combined pressure and volume overload produced left ventricular deformation during the entire cycle which was of an order of magnitude more severe than any other group (SI = 0.69, 0.70 and 0.65, at end diastole, mid and end systole, respectively). The shape index at end systole showed an inverse correlation with the relative right-to-left ventricular systolic pressure ratio (P = 0.001, r = 0.76). It is concluded that left ventricular configuration is affected by right ventricular hemodynamics.(ABSTRACT TRUNCATED AT 250 WORDS)     

Determination of right ventricular volumes during aortic surgery

The aim of the present study was to evaluate right ventricular (RV) preload by measurements of right ventricular volumes during aortic clamping and unclamping. Nine patients (aged 67 ± 9 years) undergoing infrarenal aortic aneurysmectomy were monitored with a pulmonary artery catheter equipped with a fast-response thermistor, allowing determination of RV volumes by the thermodilution technique. Anesthesia consisted of a continuous infusion of alfentanil and 50% N20. Aortic clamping resulted in a significant decrease in cardiac index (CI) and a significant increase in systemic vascular resistance (SVR). There was no significant change in right ventricular ejection fraction (RVEF) (from 35% ± 6% to 33% ± 8%) in the presence of a significant decrease in stroke index (from 37.2 ± 9.8 to 31.1 ± 10.0 mL/beat/m², P < 0.05), indicating a significant decrease in RV end-diastolic volume (from 106 ± 17 to 92 ± 19 mL, P < 0.01). There were no significant changes in cardiac filling pressures. Aortic unclamping was associated with a significant increase in CI and a significant decrease in SVR. There were no significant changes in cardiac filling pressures, RVEF, or RV volumes. Measurements of RV volumes indicated that aortic clamping resulted in a decrease in RV preload, which is usually not demonstrated by measurements of right atrial pressure alone.     

不同部位右室起搏对心功能的影响

目的:比较右室心尖部起搏与右室间隔部起搏对心功能的影响. 方法:将48例高度房室传导阻滞患者随机分为右室心尖部起搏组(25例)或右室间隔部起搏组(23例).随访术后的超声心动图左室舒张末期内径和射血分数变化以及临床的NYHA心功能分级变化. 结果:24个月后,右室间隔部起搏组左室舒张末期内径,射血分数及NYHA分级较术前无明显变化.但右室心尖部起搏组与术前相比,左室舒张末期内径有增大趋势,射血分数显著减低,NYHA心功能分级级别增高.结论:右室间隔部起搏较右室心尖部起搏更有利于双心室电激动的同步性,且不产生对心功能的不良影响.     

不同部位右室起搏对心功能的影响

目的：比较右室心尖部起搏与右室间隔部起搏对心功能的影响。方法：将48例高度房室传导阻滞患者随机分为右室心尖部起搏组（25例）或右室间隔部起搏组（23例）。随访术后的超声心动图左室舒张末期内径和射血分数变化以及临床的NYHA心功能分级变化。结果：24个月后,右室间隔部起搏组左室舒张末期内径,射血分数及NYHA分级较术前无明显变化。但右室心尖部起搏组与术前相比,左室舒张末期内径有增大趋势,射血分数显著减低,NYHA心功能分级级别增高。结论：右室间隔部起搏较右室心尖部起搏更有利于双心室电激动的同步性,且不产生对心功能的不良影响。     

Effect of right ventricular pacing on ventricular rhythm during atrial fibrillation

In 13 patients with atrial fibrillation, the effect of right ventricular pacing at various rates on spontaneous RR intervals was studied. Five hundred consecutive RR intervals were recorded and measured before and during varying right ventricular pacing rates. As anticipated, all RR intervals longer than the right ventricular pacing intervals were abolished. However, RR intervals shorter than the right ventricular pacing intervals were also eliminated. It is difficult to explain the elimination of RR intervals shorter than the pacing intervals with the accepted concepts concerning the mechanisms governing the rate and rhythm of the ventricular response to atrial fibrillation. An alternative explanation may be that during atrial fibrillation the atrioventricular node behaves as a nonprotected pacemaker that is electrotonically modulated by the chaotic atrial electrical activity. The result is a random ventricular rhythm. With right ventricular pacing, the automatic focus is depolarized by the retrogradely concealed conducted ventricular impulses, the short RR intervals are not generated as a consequence and the rhythm becomes pacemaker dependent.     

Decreased right ventricular lateral wall velocities early after cardiac surgery

Background: Right ventricular (RV) function is less often monitored than left ventricular (LV) function and might influence the postoperative period in patients undergoing coronary bypass or heart valve surgery. Our objective was to compare RV lateral wall velocities before and soon after heart surgery. Methods: We examined 87 patients before and at a median time of 5 days after surgery with tissue Doppler echocardiography. On‐pump coronary artery bypass grafting was performed in 40 patients, and valvular surgery in 47 patients. The pulsed Doppler sample was positioned at the midportion of the RV lateral wall, on the septum and on the LV lateral wall to record peak systolic (S), early (E) and late (A) diastolic tissue Doppler velocities. Results: We observed lower values of LV end diastolic volume and left atrial area (P < 0.001) but no differences in RV fractional area change as well as LV ejection fraction between before and after surgery. RV S, E, and A were dramatically lower in the postoperative group (P < 0.001 between before and after surgery), as well as septal S, E, and A (P < 0.005 between before and after). No change occurred on LV lateral S and A, whereas LV lateral wall E velocity was slightly higher in the postoperative group (P < 0.05). Conclusions: Tissue Doppler velocities of the RV free wall are reduced significantly after cardiac surgery despite no reduction in RV fractional area change. (Echocardiography 2011;28:438‐441)     

Enhanced activity of the cardiac endocrine system during right ventricular hypertrophy

In a model of pulmonary hypertension induced by a single injection of monocrotaline (MCT), we observed a time-dependent right ventricular hypertrophy, which became apparent in treated rats 21 days after administration of MCT and progressed through day 45. Associated with this right ventricular hypertrophy were time-dependent increases in ventricular levels of immunoreactive atrial natriuretic peptide (iANP). Forty-five days after MCT treatment, treated rats exhibited a 72-fold increase in right ventricular iANP levels and a 7-fold increase in left ventricular iANP levels. Hybridization analysis of total RNA extracted from cardiac tissue indicated that both atrial and ventricular ANP mRNA levels were elevated in treated rats. These data suggest that during pulmonary hypertension and cardiac hypertrophy the endocrine activity of the heart expands to include ventricular tissue. ANP binding site autoradiography revealed decreased binding site density in the kidney and hearts of treated rats at 49 days, consistent with the occurrence of desensitization/down-regulation. Enhanced ventricular ANP production may serve as a compensatory response to sustained elevation of pulmonary arterial pressure or may function as an autocrine/paracrine system regulating cardiac function. In either case, the effects of augmented ANP production may be subject to modulation by the status of ANP receptors in target organs and cells.     

心脏转位对右心室流出道间隔部起搏的影响

目的评价X线指导起搏器置入电极到位是否准确,观察术前心电图胸前导联移形情况对置入准确性的影响。方法选取2010年1月~2012年10月在解放军总医院第一附属医院行双腔起搏器置入患者102例,术后行超声心动图观察电极头端位置,如电极插入点在二尖瓣水平及乳头肌水平7~11点为间隔起搏组62例,男性41例,女性21例,年龄61~86(77.52±4.83)岁;电极插入点其他部位为游离壁起搏组40例,男性21例,女性19例,年龄64~88(76.90±4.96)岁。比较2组转位情况。结果游离壁起搏组术前心电图心前移形指数明显高于间隔起搏组[(4.10±0.78)vs(2.69±0.84),P=0.000],2组心电图QRS宽度无统计学差异(P0.05)。结论 X线指导右心室流出道间隔部位起搏置入过程准确性有限,需结合超声心动图及心电图等其他手段辅助。     

Diastolic right ventricular hemodynamics in right ventricular overloads assessed by pulsed Doppler echocardiography

To assess right ventricular (RV) filling dynamics, RV inflow velocity patterns of pulsed Doppler echocardiograms and jugular pulse tracings were analyzed in 59 patients with various types of RV overloads and in 20 normal subjects. The patients were classified as (1) RV volume overload group (RVVO) consisting of 25 patients with atrial septal defect (ASD) without pulmonary hypertension (PH), (2) RV pressure overload group consisting of 26 patients including 12 with primary pulmonary hypertension (PPH), eight with mitral stenosis, three with pulmonary stenosis and three with cor pulmonale, and (3) RV volume and pressure overload group consisting of eight patients with ASD and PH. The acceleration time (AT), deceleration time (DT) and the A/D ratio were measured from the RV inflow velocity patterns, and v-y interval and the y/H ratio were measured from jugular pulse tracings. The results were as follows: 1. AT was significantly prolonged in groups with pressure overload as well as pressure and volume overload compared with that of the normal controls. 2. DT was significantly prolonged in all overload groups compared with that of the normal controls except for PPH, and was particularly prolonged in the group with pressure overload. 3. The A/D ratio was significantly increased in all overload groups, particularly in the groups with pressure overload. 4. In patients with volume overloads, the v-y interval was longer and the y/H ratio was higher than in the normal controls. RVVO shifted to the right and superiorly. The reverse was true in the pressure overload group, and the high ratios were observed in the remainder. 5. In 12 patients with ASD evaluated pre- and postoperatively, AT, DT and the A/D ratio were restored to normal after surgery. These findings suggest that RV volume overload was characterized not only by increased inflow velocity during the rapid filling period, but prolongation of this period and compensatory increase of atrial inflow velocity. However, the pressure overload group had disturbed rapid filling and a decrease in end-diastolic RV compliance. The group with both pressure and volume overloads was between the two. In conclusion, the mode of RV filling in patients with RV overload showed various patterns depending on the type of overload. The RV inflow velocity pattern recorded by pulsed Doppler echocardiography is of use in discriminating these varieties.     

Atrialization of right ventricular pressure during acute cardiac allograft rejection

We describe a patient who, during an episode of acute cardiac rejection, developed such severe systolic dysfunction that there was transient near-adynamic function of the right ventricle. This right ventricular dysfunction was reflected hemodynamically by the unusual finding of atrialization of right ventricular pressures. The patient's cardiac function returned to normal after treatment with extensive immunotherapy.     

不同麻醉诱导方法对小儿室间隔缺损修补术中血流动力学影响的对比研究

目的:比较舒芬太尼复合咪达唑仑与七氟烷麻醉诱导,对室间隔缺损修补术患儿血流动力学的影响。方法:择期行室间隔缺损矫治术的1~5岁患儿32例,体质量(12.1±3.1)kg,随机分为静脉组(SM组)和吸入组(S组)。肌注氯胺酮待患儿入睡后,穿刺动脉置管,建立监测。SM组依次给予咪达唑仑-哌库溴铵-舒芬太尼,5分钟肌肉松弛后行气管插管。S组吸入七氟烷,并予哌库溴铵,维持吸入呼末浓度2.0 MAC,5分钟气管插管。使用Mostcare监测仪记录肌注氯胺酮后(T0)、麻醉诱导用药后1分钟(T1)、2分钟(T2)、5分钟(T3)、插管后1分钟(T4)、2分钟(T5)、5分钟(T6)和10分钟(T7)的HR、SBP、DBP、每搏输出量指数(SVI)、心排血量指数(CI)、体循环阻力指数(SVRI)、反映左心室收缩功能的压力升支最大速率(dp/dt)和心动周期效率(CCE)。结果:肌注氯胺酮到诱导后5分钟时间段(T0~T3):静脉组HR明显下降(P<0.01),吸入组HR先下降后上升(P<0.01);两组SBP、DBP、CI、SVI、dp/dt及CCE均明显下降(P<0.01)。CCE组别因素与时间因素存在交互作用(P<0.05)。诱导后5分钟到插管后,10分钟时间段(T3~T7):两组HR、SBP、DBP及dp/dt插管后先上升后下降(P<0.01),CI、SVI上升(P<0.01),SVRI下降(P<0.01)。两组CCE比较,静脉组高于吸入组(P<0.05)。结论:1咪达唑仑复合舒芬太尼静脉麻醉与吸入七氟烷的麻醉诱导方法,均能满足心室间隔缺损修补术患儿的麻醉诱导要求,均可维持dp/dt、CI于正常范围,是安全可靠的诱导用药。2舒芬太尼复合咪达唑仑对循环功能影响更轻,可能更适合循环功能低下的患儿。     

Effect of the undisturbed pericardium on left ventricular size and performance during acute volume loading

Studies in instrumented dogs have suggested that the pericardium alters left ventricular diastolic pressure-volume relations and thus may influence systolic performance. However, the instrumentation used in these studies disrupts the pericardium and may have influenced the results. We therefore studied five conscious dogs by methods not traumatic to the pericardium, before and after pericardiectomy. Although heart rate and left ventricular systolic and end-diastolic pressures were not different before or after pericardiectomy, either at rest or during volume loading, end-diastolic volume measured by biplane two-dimensional echocardiography increased post pericardiectomy at rest from 38 ± 4 (SE) to 61 ± 4 ml (p < 0.05) and during volume loading from 68 ± 5 to 79 ± 5 ml (p < 0.005). After pericardiectomy, ejection fraction was unchanged, but the peak value of the first derivative of left ventricular systolic pressure ($\text{dP}\text{dt}$) increased significantly at rest from 17 ± 2 to 26 ± 4.0 × 10² mm Hg/sec. We conclude that pericardiectomy shifts the left ventricular end-diastolic pressure-volume curve to the right and increases the systolic isovolumic index of $\text{dP}\text{dt}$ in the basal state.     

右室流出道间隔部起搏的血流动力学观测

目的比较右室流出道间隔部（RVS）与右室心尖部（RVA）起搏对血流动力学的影响。方法选择具备起搏器植入指征的患者30例,随机分为RVA组与RVS组,采用超声心动图检测左室射血分数（LVEF）、每搏量（SV）、左室短轴缩短率（FS）、心脏指数（CI）,对比观察术前、术后3,6个月差异。并比较术前与术后心电图QRS波宽度。结果两组患者均顺利完成手术。两组QRS波时限均较自身心律时延长,差异有统计学意义（P<0.01）,RVA组起搏QRS时限显著长于RVS组[（158±15）msvs（132±15）ms,P<0.01];RVA组术后3个月随访LVEF,SV,FS,CI较术前均显著降低,均有统计学意义[（59±3）%vs（51±3）%,（79±15）mlvs（71±16）ml,（0.36±0.11）vs（0.31±0.09）,（2.5±0.4）L/（min·m2）vs（2.1±0.4）L/（min.m2）,均P<0.05];RVS组术后3,6个月随访LVEF,SV,FS,CI与术前无显著性差异,RVS组3,6个月随访LVEF,SV,FS,CI均显著高于同期RVA组,均有统计学意义（均P<0.05）。结论RVS起搏尽可能的保证了心室激动和收缩同步性,实现了比RVA起搏较为良好的血流动力学状态。