The medical disability evaluation of patients with pulmonary hypertension and cor pulmonale]

The purpose of the study was to elaborate criteria for the assessment of the severity of pulmonary hypertension and cor pulmonale in patients with chronic bronchitis and to give rationale for expert medical evaluation of the working capacity of such patients. 94 patients (89 males and 5 females) aged 20 to 60 with chronic bronchitis were examined. Basing on the clinical, x-ray, ECG, VCG and echocardiography data, the gravity of cor pulmonale was assessed by the degree of right ventricular hypertrophy (absent, mild, marked, dramatically marked), changes in the right ventricular echo dimensions and the stage of heart failure, and by the lung vital capacity (in percent of the predicted value). The rationale for expert medical evaluation of patients with associated cor pulmonale and chronic bronchitis is described.     

ECG based diagnosis of right ventricular hypertrophy in patients with chronic obstructive bronchitis

Two mathematical models developed on the basis of a discriminant analysis of the evidence obtained in examination of 84 patients with chronic obstructive bronchitis (COB) are proposed in early diagnosis of right ventricular hypertrophy (RVH) by ECG readings in COB patients. Application of hierarchic classification model is recommended for diagnosis of RVH in screening. The probability model is intended for follow-up of COB patients.     

Use of vectorcardiography in determination of the left ventricular muscle mass

Summary. Many studies have investigated different ECG and vectorcardiographic (VCG): criteria for diagnosis of left ventricular hypertrophy (LVH). In some investigations VCG was more sensitive than ECG in this respect. This study was performed to elucidate whether it is possible also to determine the degree of LVH using VCG. Eighty cardiovascularly healthy subjects aged 15–39 were investigated with ECG, VCG (Frank system) and echocardiography. The echocardiographic left ventricular (LV) mass has been shown by others to correlate closely to the anatomical and the angiographically determined LV mass and was used as reference standard. Thirty-eight of the subjects were endurance sportsmen and had a LV mass above standard reference limits. The measured ECG variables were R-amplitude in aVL, I, V5, V6, S-amplitude in VI and SV1 + RV5/V6 and the VCG variables were QRS spatial area and circumference and left maximal spatial vector. The sensitivity and specificity of single criteria tested were similar for ECG and VCG in the quantitative determination of LVH. The correlations between ECG-amplitudes and the magnitude of the LV mass were weak. The correlations were higher with the VCG-variables, QRS spatial circumference being superior to the others, but not good enough to permit an estimation of the LV mass in individual subjects. In conclusion, normal VCG variables were highly specific for a normal LV mass but in individuals with LVH, VCG was not useful for the estimation of the LV mass.     

Tei指数评价肥厚型心肌病患者的右心室功能

目的探讨Tei指数在评价肥厚型心肌病(HCM)患者右心室功能中的价值及其影响因素。方法测量肥厚型心肌病患者及正常对照组右室Tei指数、心率、右室舒张末期前后径,并进行对比研究及相关分析。结果与对照组相比,HCM患者Tei指数明显增高;HCM患者右室Tei指数与心率、右室舒张末期前后径无相关性。结论Tei指数是评价HCM患者右心室功能的敏感指标,且不受心率、右室几何形态影响。     

Effects on right ventricular function of a change from dopamine to dobutamine in critically ill patients

In 15 critically ill patients requiring adrenergic support, right ventricular ejection fraction (RVEF) and right ventricular (RV) volumes were measured by the thermodilution technique receiving 5 micrograms/kg.min of dopamine and after replacement by the same dose of dobutamine. Shift from dopamine to dobutamine resulted in significant increases in stroke index from 28.1 +/- 3.6 to 31.0 +/- 3.8 ml/m2 (p less than .01) and significant decreases in pulmonary artery balloon-occluded pressure from 15.1 +/- 1.0 to 13.9 +/- 1.2 mm Hg (p less than .05) and right atrial pressure (RAP) from 14.0 +/- 1.3 to 12.2 +/- 1.1 mm Hg (p less than .05). RVEF increased slightly but significantly from 21.5 +/- 2.7% to 23.7 +/- 2.9% (p less than .01) so that RV end-diastolic volume (RVEDVI) was unchanged (140 +/- 12 vs. 141 +/- 12 ml, nonsignificant). RVEDVI/RAP ratio increased from 11.3 +/- 1.0 to 12.9 +/- 1.1 ml/mm Hg (p = .037). These results support the view that dobutamine has more favorable effects on RV function than dopamine in critically ill patients in the absence of profound hypotension and also indicates that higher filling pressures under dopamine administration can be related to changes in ventricular pressure/volume relationship.     

Effect of right ventricular apex pacing on the Tei index and brain natriuretic peptide in patients with a dual-chamber pacemaker

BACKGROUND: Asynchronous electrical activation induced by right ventricular apex (RVA) pacing can cause various abnormalities in left ventricular (LV) function, particularly in the context of severe LV dysfunction or structural heart disease. However, the effect of RVA pacing in patients with normal LV and right ventricular (RV) function has not been fully elucidated. The aim of this study was to characterize the effects of RVA pacing on LV and RV function by assessing isovolumic contraction time and isovolumic relaxation time divided by ejection time (Tei index) and by assessing changes in plasma brain natriuretic peptide (BNP). METHODS: Doppler echocardiographic study and BNP measurements were performed at follow-up (mean intervals from pacemaker implantation, 44+/-75 months) in 76 patients with dual chamber pacemakers (sick sinus syndrome, n=30; atrioventricular block, n=46) without structural heart disease. Patients were classified based on frequency of RVA pacing, as determined by 24-hour ambulatory electrocardiogram (ECG) that was recorded just before echocardiographic study: pacing group, n=46 patients with RVA pacing>or=50% of the time, percentage of ventricular paced 100+/-2%; sensing group, n=30, patients with RVA pacing<50% of the time, percentage of ventricular paced 3+/-6%. RESULTS: There was no significant difference in mean heart rate derived from 24-hour ambulatory ECG recordings when comparing the two groups (66+/-11 bpm vs 69+/-8 bpm). LV Tei index was significantly higher in pacing group than in sensing group (0.67+/-0.17 vs 0.45+/-0.09, P<0.0001), and the RV Tei index was significantly higher in pacing group than in sensing group (0.34+/-0.19 vs 0.25+/-0.09, P=0.011). Furthermore, BNP levels were significantly higher in pacing group than in sensing group (40+/-47 pg/mL vs 18+/-11 pg/mL, P=0.017). With the exception of LV diastolic dimension (49+/-5 mm vs 45+/-5 mm, P=0.012), there were no significant differences in other echocardiographic parameters, including left atrium (LA) diameter (35+/-8 mm vs 34+/-5 mm), LA volume (51+/-27 cm3 vs 40+/-21 cm3), LV systolic dimension (30+/-6 mm vs 29+/-7 mm), or ejection fraction (66+/-9% vs 63+/-11%), when comparing the two groups. CONCLUSIONS: These findings suggest that the increase of LV and RV Tei index, LVDd, and BNP are highly correlated with the frequency of the RVA pacing in patients with dual chamber pacemakers.     

Autoantibody against beta1-adrenergic receptor and left ventricular remodeling changes in response to metoprolol treatment

Autoantibodies specific for the beta(1)-adrenoceptor (beta(1)-AR) have been implicated in the pathology of congestive heart failure (CHF). We hypothesized that the presence of autoantibodies against beta(1)-AR (anti-beta(1)-AR) is associated with left ventricular (LV) remodelling in response to metoprolol. Synthetic beta(1)-AR peptides served as the target antigen in an ELISA (enzyme-linked immunosorbent assay) were used to screen the sera of 106 CHF patients. Patients were separated into positive (+) anti-beta(1)-AR or negative (-) anti-beta(1)-AR groups according to their anti-beta(1)-AR reactivity. Echocardiography (ECG) was performed at baseline and after one year of metoprolol therapy in combination with standard treatment regime for CHF, that is, digoxin, diuretics and an ACEI (angiotensin-converting enzyme inhibitor). The dose of metoprolol was doubled on a biweekly basis up to 50 mg x 2 daily (b.i.d./day) or attainment of maximum tolerated dose. Ninety-six patients completed final data analysis. Fifty-four patients with (+) anti-beta(1)-AR had greater improvements than 42 patients with (-) anti-beta(1)-AR in LVEDD (left ventricular end-diastolic dimension) (P < 0.01, from 69 +/- 0.8 to 58.0 +/- 0.5 mm vs. 69.0 +/- 0.8-63.6 +/- 0.9 mm) and LVESD (left ventricular end-systolic dimension) (P < 0.01, from 57.1 +/- 1.4 to 43.9 +/- 0.8 mm vs. 56.2 +/- 0.9-48.6 +/- 1.0 mm), and LVEF (left ventricular ejection fraction) (P < 0.01, from 35.4 +/- 1.3 to 49.8 +/- 0.6% vs. 34.4 +/- 1.0-44.3 +/- 1.1%) by metoprolol therapy in combination with standard treatment regime for one year. Of the CHF patients with (+) anti-beta(1)-AR, 65.4% responded to target metoprolol dose as compared to 21.4% of CHF patients without anti-beta(1)-AR (P < 0.01). Response to target metoprolol dose occurred more rapidly in (+) anti-beta(1)-AR than (-) anti-beta(1)-AR of CHF patients (67.5 +/- 2.4 vs. 100.8 +/- 3.0 days, P < 0.01). These results demonstrated that CHF patients with (+) anti-beta(1)-AR had greater improvements in LV remodelling and heart function by metoprolol as compared to (-) anti-beta(1)-AR patients. Moreover, patients with (+) anti-beta(1)-AR have better tolerance to metoprolol therapy than patients without anti-beta(1)-AR.     

应变成像技术对肺动脉高压患者右心室非同步运动的研究

目的 探讨应变成像技术评价肺动脉高压患者右室非同步运动的临床意义.方法 60例肺动脉高压患者依据肺动脉收缩压(PASP)分为轻、中、重三组;20例健康志愿者为对照组.测量并计算右心室参数,右心室结构参数包括右室横径/左室横径(RVTD/LVTD)、右室舒张末面积(RVEDA)、右室收缩末面积(RVESA);功能参数包括右室面积变化率(RVFAC)、Tei指数;右心室应变参数包括右室不同室壁节段的收缩期应变峰值(PST)的最大差值(Max-ΔPST)、应变达峰时间(T_(Q-S))的最大差值(Max-ΔT_(Q-S)).结果 与对照组比较,肺动脉高压组Max-ΔT_(Q-S)和Max-ΔPST明显增大(P<0.01).Max-ΔT_(Q-S)与PASP及右心室结构和功能参数均有高度相关性(P<0.01).Max-ΔPST与PASP及Tei指数有一定的相关性(P<0.05,P<0.01).结论 肺动脉高压患者存在右室非同步运动,在轻度肺动脉高压组中即有明显改变,且与右心室结构及功能参数有一定的相关性,提示应变成像技术测量右室非同步参数可用于早期评价肺动脉高压患者的右心室功能.     

Effects of pulmonary thromboendarterectomy on right-sided echocardiographic parameters in patients with chronic thromboembolic pulmonary hypertension

OBJECTIVE: To determine the echocardiographic changes in the heart at 3 months and 1 year after pulmonary thromboendarterectomy (PTE) in patients with chronic thromboembolic pulmonary hypertension (CTEPH). PATIENTS AND METHODS: Thirty-two adult patients who underwent PTE for CTEPH at the Mayo Clinic in Rochester, Minn, from 1997 to 2003 were included in the study. All underwent transthoracic echocardiography before surgery. Follow-up echocardiography was performed within 3 months of surgery in 28 patients and 1 year postoperatively in 17 patients. The results were compared with baseline data. RESULTS: Within 3 months after PTE, the right ventricular end-diastolic area decreased from 38.4 +/- 12.8 cm2 to 32.5 +/- 10.4 cm2 (mean difference, 5.8 +/- 10.4 cm2; P = .02). The right ventricular end-systolic area decreased from 30.4 +/- 12.1 cm2 to 24.1 +/- 8.6 cm2 (mean difference, 6.3 +/- 10.1 cm2; P = .008). The right ventricular systolic pressure decreased significantly from 92.6 +/- 22.0 mm Hg to 55.0 +/- 19.8 mm Hg (mean difference, 40.0 +/- 24.8 mm Hg; P < .001). Tricuspid regurgitation (TR) improved from a mean grade of 2.5 +/- 1.2 to 1.2 +/- 1.1 (mean difference, 1.5 +/- 1.0; P < .001). At 12 months, the right ventricular end-diastolic area, right ventricular end-systolic area, right ventricular systolic pressure, and TR also were significantly lower than baseline values. CONCLUSION: In patients with CTEPH who undergo PTE, echocardiographic measurements of right ventricular size, systolic pressure, and TR show significant improvement immediately after surgery, which is sustained for up to 1 year after surgery.     

二维斑点追踪超声心动图对业余马拉松运动员右心室收缩功能的评估

目的应用二维斑点追踪超声心动图评估业余马拉松运动员右心室收缩功能。 方法2019年1月至2020年12月,在杭州地区招募业余马拉松运动员88例,根据参加马拉松运动时限分为短期组（≤6个月）、中长期组（6个月~3年）和长期组（＞3年）;另选取同一时期在杭州师范大学附属医院体检的健康受试者30例为对照组。应用常规超声心动图测量右心室流出道内径（RVOT）、右心室基底段内径（RVD_basal）及中间段内径（RVD_mid）、右心室剑突下切面室壁厚度（RVWT）、三尖瓣环收缩期位移（TAPSE）、三尖瓣环收缩期速度（S′）、右心室心肌做功指数（RIMP）和肺动脉收缩压（SPAP）,应用二维斑点追踪技术获得右心室整体纵向应变（GLS）和游离壁纵向应变（RVLS）。对业余马拉松运动员在完成全程马拉松运动前、运动后1 h和运动后第4天分别行超声心动图检查。对4组受试者的常规超声心动图参数及右心室应变参数进行比较,并分析马拉松运动员运动前GLS、RVLS与SPAP的相关性。 结果短期组TAPSE高于对照组,差异有统计学意义（P＜0.05）;中长期组RVOT、RVD_basal、RVD_mid、RVWT均高于短期组,差异有统计学意义（P均＜0.05）;长期组RVOT、RVD_basal、RVD_mid均高于中长期组,差异有统计学意义（P均＜0.05）;长期组RVWT、RIMP、SPAP高于对照组,差异有统计学意义（P均＜0.01）。短期组RVLS高于对照组,差异有统计学意义（P＜0.05）;长期组GLS低于短期组及对照组,差异有统计学意义（P均＜0.05）。运动后1 h及第4天中长期组GLS、RVLS低于短期组,差异均有统计学意义（Z=2.416、-2.579,Z=2.254、-3.005,P均＜0.05）,长期组GLS、RVLS亦低于短期组,且差异均有统计学意义（Z=-2.858、-2.825,Z=-3.524、-4.073,P均＜0.05）。组内运动前后比较,中长期组、长期组运动后1 h GLS均低于运动前,差异有统计学意义（Z=-1.968、-1.966,P均＜0.05）;短期组、中长期组和长期组运动后1 h RVLS均低于运动前,差异有统计学意义（Z=2.011、-2.258、-2.026,P均＜0.05）。相关性分析表明,运动员组运动前的GLS、RVLS与SPAP存在相关性（r=0.378、0.325,P均＜0.01）。 结论业余马拉松运动员早期右心室游离壁纵向收缩功能增强,随着运动年限增加右心室整体纵向收缩功能减低;全程马拉松运动后右心室游离壁收缩功能短暂下降。     

A Specific ECG Triad Associated with Congestive Heart Failure

No specific ECG sign of congestive heart failure has been described. This report deiineales a new triad consisting of 1) High precordial QRS voltage (SV1 or SV2 + RV5 or RV6 ≥ 3.5 mV); 2) Relatively low limb lead voltage (total QRS amplitude ≤ 0.8 m V in the limb leads); 3) Poor precordial R wave progression (R/S ratio < 3 in V4). In a retrospective study of 27 patients with idiopathic congestive cardiomyopathy, this triad was noted on at least one occasion in 19 cases (70%). This pattern was not noted at all in a control group of 100 adults without heart disease or in a separate control group of 30 preoperative patients with left venlricular hypertrophy due to aortic valve disease and normal left ventricular function. Three of these patients subsequently developed this pattern as a false positive sign immediately following aortic valve replacement. In a prospective survey of ECGs from 2000 consecutive patients, this triad appeared in 32 cases (1.6% prevalence). Definite evidence of current or previous left ventricular failure, usually severe, was noted in 29 of these cases (91% predictive valuel as evidenced by pulmonary venous hypertension or pulmonary edema on chest x-ray, left ventricular ejection fraction ≤ 40%, or echocardiographic left ventricular end-diastolic dimension ≥ 6.0 cm. The pathophysiology of this highly specific ECG triad probably relates to a number of mechanical and vectorial factors associated with congestive heart failure of a variety of etiologies. Left ventricular enlargement causes increased precordial voltage. In addition, the horizontal plane vector shifts posteriorly, orthogonal to the frontal plane, causing poor R wave progression and low limb lead voltage. Finally, increased extracellular fluid may preferentially attenuate QRS voltage in the more distal (limb) leads. (PAGE, Vol. 5, July-August, 1982)     

Sustained pulmonary hypertension and right ventricular hypertrophy after chronic hypoxia in mice with congenital deficiency of nitric oxide synthase 3.

Chronic hypoxia induces pulmonary hypertension and right ventricular (RV) hypertrophy. Nitric oxide (NO) has been proposed to modulate the pulmonary vascular response to hypoxia. We investigated the effects of congenital deficiency of endothelial NO synthase (NOS3) on the pulmonary vascular responses to breathing 11% oxygen for 3-6 wk. After 3 wk of hypoxia, RV systolic pressure was greater in NOS3-deficient than in wild-type mice (35+/-2 vs 28+/-1 mmHg, x+/-SE, P < 0.001). Pulmonary artery pressure (PPA) and incremental total pulmonary vascular resistance (RPI) were greater in NOS3-deficient than in wild-type mice (PPA 22+/-1 vs 19+/-1 mmHg, P < 0.05 and RPI 92+/-11 vs 55+/-5 mmHg.min.gram.ml-1, P < 0.05). Morphometry revealed that the proportion of muscularized small pulmonary vessels was almost fourfold greater in NOS3-deficient mice than in wild-type mice. After 6 wk of hypoxia, the increase of RV free wall thickness, measured by transesophageal echocardiography, and of RV weight/body weight ratio were more marked in NOS3-deficient mice than in wild-type mice (RV wall thickness 0.67+/-0.05 vs 0.48+/-0.02 mm, P < 0.01 and RV weight/body weight ratio 2.1+/-0.2 vs 1.6+/-0.1 mg. gram-1, P < 0.05). RV hypertrophy produced by chronic hypoxia was prevented by breathing 20 parts per million NO in both genotypes of mice. These results suggest that congenital NOS3 deficiency enhances hypoxic pulmonary vascular remodeling and hypertension, and RV hypertrophy, and that NO production by NOS3 is vital to counterbalance pulmonary vasoconstriction caused by chronic hypoxic stress.     

Biventricular upgrading in patients with conventional pacing system and congestive heart failure: results and response predictors

BACKGROUND: There are few studies on cardiac resynchronization therapy (CRT) in heart failure (HF) patients with preexisting right ventricular (RV) pacing. The purpose of this study was to determine the efficacy of CRT upgrading in RV-paced patients and the predictivity of electromechanical dyssynchrony parameters (EDP) evaluated by standard echocardiography (ECHO) and tissue Doppler imaging (TDI). METHODS: Thirty-eight consecutive patients with HF [New York Heart Association (NYHA) class III or IV, LVEF < 35%], prior continuous RV pacing, and absence of atrial fibrillation were enrolled in the presence of a paced QRS > or = 150 ms and evaluated by ECHO and TDI. A responder was defined as a patient with a favorable change in NYHA class and neither HF hospitalization nor death, plus an absolute increase of LVEF > or = 10 units. RESULTS: At six-months follow-up, the whole study population had significant improvement in symptoms, systolic function, and QRS duration (P < 0.001); 32 (84%) patients had a favorable clinical outcome, 25 (66%) were considered responders according to the previous definition. Postimplant QRS was similarly reduced in both responders and nonresponders, whereas EDP had a significant improvement only in responders (P < 0.05). Using EDP, 23 (79%) patients were responders compared with 2 (22%) patients without mechanical dyssynchrony (P = 0.002). CONCLUSIONS: In HF patients with previous RV pacing, CRT is effective to improve clinical, functional outcome, and LV performance and to reduce electromechanical dyssynchrony in a large proportion of patients. Dyssynchrony evaluated by standard and TDI ECHO can be useful for CRT selection of paced patients.     

Assessment of right atrial (RA) and right ventricular (RV) function by gated blood pool scan with krypton-81m: RA and RV pressure-volume loops with simultaneous pressure data

We developed a new method of analyzing right atrial (RA) and right ventricular (RV) function by Krypton-81m gated blood pool scan (Kr-81m-GBPS). Pressure data were recorded simultaneously with a modified Swan-Ganz catheter. Krypton-81m (Kr-81m) is ideally suited to hemodynamic study of the right heart because of the following characteristics: physical half-life of 13 seconds; high photon yield and gamma ray energy of 190 KeV; low radiation exposure; and deployment during exhalation when the left heart is not active. A computerized method for list mode data acquisition was developed to collect data from the gamma camera, ECG wave, and RA and RV pressure simultaneously. RA and RV volume curves were obtained by calibrating the time-activity curves with end-diastolic volumes and cardiac output. Ejection fraction (EF) was used in the calculation of volume and cardiac output (CO) was measured by the thermodilution method. From RA and RV pressure and volume curves, RA and RV pressure-volume (P-V) loops were created simultaneously and displayed on the same plane. One spanning cardiac cycle of RV beats was separated into four phases: the ventricular emptying phase, the early ventricular filling phase, equilibrium, and the late ventricular filling phase. One spanning cardiac cycle of RA beats also was separated into four phases as follows: the atrial filling phase, the early atrial emptying phase, equilibrium, and the late atrial emptying phase. P-V loops of RA and RV were shifted after sublingual nitroglycerin administration. This new method is potentially useful in the study of right heart hemodynamics.     

超声心动图对左室急性心肌梗塞后右室重构的研究

应用二维超声心动图测量５６例左室急性透壁性心肌梗塞（ＬＶＭＩ）患者的右室舒张末期（ＲＶＤＶ）容积和右室收缩末期容积（ＲＶＳＶ）。左室心梗后，ＲＶＤＶ、ＲＶＳＶ都扩大，但其程度和发生时间有明显不同。无论左室前壁还是下壁梗塞，双室都发生重构，但右室重构的程度较左室轻微，而且其于下壁梗塞时又比前壁梗塞时更轻且仅出现在早期。     

Three-dimensional motion reconstruction and analysis of the right ventricle using tagged MRI

Right ventricular (RV) dysfunction can serve as an indicator of heart and lung disease and can adversely affect the left ventricle. However, normal RV function must be characterized before abnormal states can be detected. We describe a method for reconstructing the 3D motion of the RV by fitting a deformable model to tag and contour data extracted from multiview tagged magnetic resonance images. The deformable model is a biventricular finite element mesh built directly from segmented contours. Our approach accommodates the geometrically complex RV by using the entire lengths of the tags, localized degrees of freedom, and finite elements for geometric modeling. Also, we outline methods for converting the 3D motion reconstruction results into potentially useful motion variables, such as strains and displacements. The technique was applied to synthetic data, two normal hearts, and two hearts with right ventricular hypertrophy (RVH). Noticeable differences were found between the motion variables calculated for normal volunteers and RVH patients.     

Normal human left and right ventricular and left atrial dimensions using steady state free precession magnetic resonance imaging.

PURPOSE: The aim of this project was to establish a database of left and right ventricular and left atrial dimensions in healthy volunteers using steady-state free precession cardiac magnetic resonance imaging, the clinical technique of choice, across a wide age range. METHODS: 108 healthy volunteers (63 male, 45 female) underwent cardiac magnetic resonance imaging using steady-state free precession sequences. Manual analysis was performed by 2 experienced observers. RESULTS: Left and right ventricular volumes and left ventricular mass were larger in males than females: LV end-diastolic volume 160 +/- 29 mL vs. 135 +/- 26 mL, LV end-systolic volume 50 +/- 16 mL vs. 42 +/- 12 mL; RV end-diastolic volume 190 +/- 33 mL vs. 148 +/- 35 mL, RV end-systolic volume 78 +/- 20 mL vs. 56 +/- 18 mL (p < .05 for all). Normalization of values to body surface area removed the statistical differences for LV volumes, but not for LV mass or RV volumes. With increased age, males showed a significant decrease in volume and mass indices for both ventricles, while female values remained unchanged. Compared to females, males had significantly larger maximal left atrial volumes (103 +/- 30 mL vs. 89 +/- 21 mL, p = .01) and left atrial stroke volumes (58 +/- 23 mL vs. 48 +/- 15 mL, p = .01). There was no difference in left atrial ejection fraction between the sexes. CONCLUSION: We have produced a large database of age-related normal ranges for left and right ventricular function and left atrial function in males and females. This will allow accurate interpretation of clinical and research datasets.     

Activation sequence modification during cardiac resynchronization by manipulation of left ventricular epicardial pacing stimulus strength

BACKGROUND: Success of cardiac resynchronization therapy (CRT) depends on altering electrical ventricular activation (VA) to achieve mechanical benefit. That increases in stimulus strength (SS) can affect VA has been demonstrated previously in cardiomyopathy patients undergoing ablation. OBJECTIVE: To determine whether increasing SS can alter VA during CRT. METHODS: In 71 patients with CRT devices, left ventricle (LV) pacing was performed at escalating SS. Timing from pacing stimulus to right ventricular (RV) electrogram, ECG morphology, and maximal QRS duration on 12 lead ECG were recorded. RESULTS: Demographics: Baseline QRS duration 153 +/- 25 ms, ischemic cardiomyopathy 48%, ejection fraction 24%+/- 7%. With increased SS, conduction time from LV to right ventricle (RV) decreased from 125 +/- 56 ms to 111 +/- 59 ms (P = 0.006). QRS duration decreased from 212 +/- 46 ms to 194 +/- 42 ms (P = 0.0002). A marked change in QRS morphology occurred in 11/71 patients (15%). The RV ring was the anode in 6, while the RV coil was the anode in 5. Sites with change in QRS morphology showed decrease in conduction time from LV to RV from 110 +/- 60 ms to 64 +/- 68 ms (P = 0.04). Twelve patients (16%) had diaphragmatic stimulation with increased SS. CONCLUSIONS: Increasing LV SS reduces QRS duration and conduction time from LV to RV. Recognition of significant QRS morphology change is likely clinically important during LV threshold programming to avoid unintended VA change.     

实时三平面超声心动图评价右室容积和功能的临床应用

目的探讨超声实时三平面(tri-plane)法测量右室容积和功能的可行性和准确性.方法应用tri-plane法测量36例健康成人的右室舒张末期容积(RVEDV)、右室收缩末期容积(RVESV)、右室每搏量(RVSV).同时,应用二维超声心动图(2DE)双平面Simpson's法测量左室舒张末期容积(LVEDV)、左室收缩末期容积(LVESV),并计算左室每搏量(LVSV).结果Tri-plane法和2DE双平面法的各项测值之间均具良好的相关性.结论超声实时三平面法能准确测量右室容积与功能,为临床上快速、简便、无创地评价右心功能提供了一种新方法.     

Right ventricular function in acute disease states: pathophysiologic considerations

In critically ill patients, alterations in pulmonary vasomotor tone profoundly influence right ventricular (RV) function. An increase in end-diastolic volume (EDV) follows elevations in the RV afterload, this increase in preload probably subserving the increased RV stroke work (SW) required to ensure unchanged RV pump function. The maintenance of a normal left ventricular (LV) preload is essential in the cardiovascular adaptation to an acute illness. With volume overload of the RV consequent upon pulmonary artery hypertension (PAH), leftward septal shift occurs and reduces LV diastolic compliance. With extremely high levels of RV loading conditions, a depression in RV contractility and reduced RV pump function are eventually seen, both of which then become partially responsible for LV pump failure. Hence, abnormalities in RV function will have a marked clinical influence on the circulatory response seen in critically ill patients. Future investigation should be directed toward the effects of augmenting or improving RV function with pharmacologic agents in this patient population.