实时三维超声定量评价犬急性右室心肌缺血时室间隔功能

目的：探讨实时三维超声（RT-3DE）定量评价犬急性右室心肌缺血时室间隔功能的价值。方法：18只犬，暴露心脏，于右冠状动脉阻断前后分别应用RT-3DE测量右室舒张末容积（RVEDV）、收缩末容积（RVESV）；左室舒张末容积（LVEDV）、收缩末容积（LVESV）；后间隔基底段、中间段的节段射血分数（rEF）。犬右冠状动脉阻断前为正常对照组，阻断后为实验组。结果：阻断右冠状动脉不影响室间隔血供，实验组RVEDV及RVESV均显著增加（P<0.05；P<0.01），LVEDV显著减小（P<0.05）；实验组后间隔的rEF较对照组显著降低（P<0.05）。结论：犬急性右室心肌缺血时室间隔的节段收缩功能减低。RT-3DE能无创定量评价犬急性右室心肌缺血时室间隔的节段收缩功能。     

实时三维超声心动图评价房间隔缺损伴轻、中度肺动脉高压患者右室功能

目的 应用实时三维超声心动图(RT-3DE)技术评价房间隔缺损(ASD)伴轻、中度肺动脉高压(PAH)患者行封堵介入术前后右室收缩功能.方法 63例ASD患者按PAH程度分为轻、中度组,并选取33例健康人作为对照组,运用RT-3DE技术测量ASD患者封堵术前、术后及健康人的右室舒张末期容积(RVEDV)、收缩末期容积(RVESV)、每搏量(RVSV)、射血分数(RVEF).结果 (1)两组ASD患者术前的RVEDV、RVESV、RVSV、RVEF,术后RVEDV、RVESV、RVSV均大于对照组(均P＜0.05). (2)两组ASD患者术后的RVEDV、RVESV、RVEF均小于术前(均P＜0.05).(3) ASD中度PAH组术前、术后的RVEDV、RVESV、RVSV均大于轻度PAH组(均P＜0.05). (4) ASD合并轻度、中度PAH患者封堵术后的RVEF无明显差别.结论 RT-3DE可用于评价ASD患者封堵治疗前后右室功能;轻、中度肺动脉高压的ASD患者行介入封堵术后右室容积及收缩功能可在术后短期内得到改善.     

实时三维超声心动图对法洛四联症手术前后右室收缩功能分析

目的 应用实时三维超声心动图(RT-3DE)检测法洛四联症(TOF)手术前后右室收缩功能.方法 30例TOF患者常规二维超声心动图检查并确诊后,使用RT-3DE采集患者的右室全容积数据库,分析右室舒张末容量(RVEDV)、收缩末容量(RVESV),计算射血分数(EF).比较术前、术后12 d、术后3个月RVEDV、RVESV及EF值的变化.结果 30例患者中20%(6/30)患者术前右室EF低于50%,术后12 d收缩末容量较术前增加(P<0.05),EF值较术前减低(P<0.05),术后3个月RVEDV较术前增大(P<0.05).常规二维超声术后复查,70%患者(21/30)残留肺动脉分支狭窄,所有患者均存在肺动脉瓣反流.结论 RT-3DE能简便、准确地确定右室容积并计算右室收缩功能;TOF患者术后残留肺动脉分支狭窄及肺动脉瓣反流可能导致右室收缩功能下降.     

实时三平面技术与实时全容积技术在评价原发性高血压病右心室收缩功能的研究

目的 采用实时三维超声心动图三平面技术(RT-3PE)及全容积技术(FV-3DE)评价高血压病患者右室收缩功能的变化.方法 按Ganau法将高血压病人分为A、B、C、D4组,共143例,另设对照组35例.用RT-3PE技术及FV-3DE技术分别测定各组的右室舒张末容积(RVEDV)、右室收缩末容积(RVESV)、右室每搏射血量(RVSV)及右室射血分数(RVEF),比较各组间的差异.结果 RT-3PE技术发现高血压病D组RVEF明显低于对照组(P＜0.05),但数值在正常范围内.FV-3DE技术发现高血压D组RVEF明显低于对照组(P＜0.05),且数值低于正常范围下限.结论 RT-3PE技术及FV 3DE技术均能早期发现并检测不同分期的高血压病患者右室收缩功能的损害程度.     

实时三维超声心动图对法洛四联症患儿左、右心室容积及收缩功能的评价

目的：应用实时三维超声心动图(RT-3DE)评价法洛四联症(TOF)患儿左、右心室容积及收缩功能。方法采用 RT-3DE 采集45例 TOF 患儿及46例正常同龄儿左、右室全容积数据,并应用TomTec LV-Analysis及 RV-Function软件分析左室、右室舒张末期容积(LVEDV/RVEDV)、收缩末期容积(LVESV/RVESV)、射血分数(LVEF/RVEF)、容积峰值收缩速率(LVPSVR/RVPSVR)、每搏量(LVSV/RVSV)、心输出量(LVCO/RVCO),计算 EDV、SV、CO 经体表面积(BSA)标化测值(indexed EDV,indexed SV,indexed CO),比较两组心室容积及收缩功能,并分析两组左、右室容积和收缩功能是否存在平衡。结果①TOF 组标化容积指标：indexed LVEDV 小于正常对照组(P =0.000),而 indexed RVEDV大于正常对照组(P =0.002);TOF 组收缩功能指标 LVEF、RVEF、LVPSVR、RVPSVR 均小于正常对照组(P <0.05),indexed LVSV、indexed LVCO 均减低(P <0.05),indexed RVSV与正常对照组差异无统计学意义(P >0.05),而indexed RVCO 增高(P =0.016);②正常对照组除LVEF稍大于RVEF (P =0.000)外,余两侧心室容积及收缩功能指标差异均无统计学意义(P >0.05);TOF 组 RVEDV、RVSV、RVCO 均大于左室(P <0.05),但 RVEF小于 LVEF(P =0.039)。结论 TOF患儿两侧心室容积、收缩功能均减低且泵血功能失平衡,右室在容量及压力负荷过重情况下通过代偿性心率增高完成泵血功能。     

超声心动图评价肺栓塞患者右心室功能

目的 运用二维超声心动图(2DE)、组织多普勒成像(TDI)、实时三维超声心动图(RT-3DE),评估肺栓塞(PE)患者右心室形态及功能改变,并探讨其准确性、敏感性及优越性.方法 正常对照组30例,肺栓塞组28例,依据预期的PE相关早期病死率进行危险分层为:高危、中危、低危亚组.所有研究对象行2DE测量右心室常规超声指标,TDI测算右心室Tei指数,RT-3DE测量右心室舒张期末及收缩期末容积、每搏输出量和射血分数(RVEDV、RVESV、RVSV、RVEF).结果 与对照组相比,PE高危组右房室增大及肺动脉压显著升高,右室Tei指数、RVEDV、RVESV明显增大(P＜0.05),RVEF明显减小(P＜0.05);中危组虽无明显右房室增大,但右室Tei指数、RVEDV、RVESV、RVEF均出现异常(P＜0.05);低危组上述指标与对照组比较无统计学差异(P＞0.05).中危组右室Tei指数、RVEDV、RVESV大于低危组而小于高危组,RVEF小于低危组而大于高危组.结论 肺栓塞患者右心室功能可出现不同程度受损;TDI测算右室Tei指数和RT 3DE测量RVEF可客观、准确、较敏感地反映右室功能的变化,是评价肺栓塞患者右室功能的较好指标.     

实时三维超声心动图定量评价犬右室心肌梗死后右室容积及心内异物的实验研究

目的探讨实时三维超声（RT-3DE）定量评价犬右室心梗后右室容积（RVV）及心内异物大小的价值。方法阻断11只犬部分左、右冠状动脉造成犬右室心肌梗死模型;按离体前右室舒张末压（RVDEP）充盈右室并放入异物;应用二维超声（2DE）、RT-3DE测量RVV及异物最大直径和面积并与实际值比较。结果RT-3DE成像所测RVV与实际容积相比较无统计学差异（P〉0.05）且相关性良好;二维Simpson法所测RVV与实际容积有相关性,但有统计学差异（P〈0.01）且低估22.9%;RT-3DE、2DE测量的异物直径和面积与实测值相关性良好,但二维直径和面积测值与实测值比较有统计学意义（P〈0.01）且分别低估22.3%、21.9%。结论RT-3DE较2DE能准确测定犬右室心肌梗死后RVV及心内异物最大直径和面积。     

实时三维超声心动图评价右室收缩功能的初步临床研究

目的 应用实时三维超声心动图(RT-3DE)检测右室收缩功能,并与传统二维超声心动图对照,探讨该技术的可行性与准确性。方法 使用RT-3DE系统采集32例健康志愿者的右室“金字塔”型数据库,结合容积分析软件,采用心尖八平面法勾勒右室舒张末期容积(RVEDV)和收缩末期容积(RVESV),并计算右室每搏量(RVsV)和射血分数(RVEF);同时在M型超声心动图上测量右室游离壁三尖瓣环处的收缩期位移(TASE)、二维超声心动图上勾画右室面积变化分数(FAC),比较三维容积法测定的收缩指数与TASE、FAC间的相关性。结果 RT-3DE测量的RVSV、RVEF均与TASE呈显著正相关(r=0．90;r=0．83);RVEF与FAC之问呈正相关(r=0．63)。结论 实时三维超声容积成像能快速简便、准确无创地确定右室容积,为临床早期评估右心收缩功能提供了有力手段,具有极其广阔的发展前景。     

实时三维超声心动图评价法洛四联症患者右心室收缩功能的研究

目的：应用实时三维超声心动图（RT-3DE）研究法洛四联症（TOF）患者右心室收缩功能的改变。方法：应用RT-3DE及二维方法测量29例TOF患者及10例正常儿童的右心室舒张末期容积（RVEDV）、收缩末期容积（RVESV）、每搏量（RVSV）及射血分数（RVEF）。结果：二维及RT-3DE均测得29例患者中41%术前RVEF低于50%,两种方法测得的TOF患者术前RVEDV及RVESV比较有统计学差异,RVSV及RVEF无统计学差异。TOF患者三维右心室容积曲线（RVVC）幅度较正常人减小,收缩峰值后移。结论：RT-3DE能通过测量右室容积及射血分数来评价TOF患者右室功能的变化。     

常规与对比增强实时三维超声心动图评价右心室容积-功能的准确性和可重复性研究

目的 评价对比-增强(cRT3DE)和常规(rRT3DE)实时三维超声心动图在评估右室舒张末(RVEDV)及收缩末容积(RVESV)和射血分数(RVEF)的准确性和可重复性.方法 35例健康志愿者中符合入选要求者30例,在24 h内进行rRT3DE、声诺维cRT3DE和心脏电影磁共振成像(cMRI).分别采用Tom-Tec 4D RV-Function CAP软件对RT3DE及Argus软件对cMRI图像进行脱机分析,获得右室容积及功能测值.结果 与rRT3DE比较,cRT3DE右室图像质量指数显著增加(3.2±0.7对2.5±0.8,P＜0.001).与cMRI比较,rRT3DE高估RVESV、低估RVEDV及RVEF(P均＜0.05);而cRT3DE仅有高估RVESV、低估RVEDV及RVEF的趋势,但差异无统计学意义.较之rRT3DE,cRT3DE右室容积及功能测值与cMRI的相关性更强(RVEDV,r=0.95对0.85;RVESV,r=0.95对0.81;RVEF,r=0.91对0.81).Bland-Altman分析显示,较之rRT3DE,cRT3DE和cMRI右室容积及功能测值一致性界限更窄,cRT3DE测值在观察者间及观察者内的变异更小.结论 声诺维对比增强造影显著改善实时三维超声心动图评价右心室容积和射血分数的准确性及可重复性.     

Aberrant Ventricular Conduction Resembling Ventricular Premature Beats

Patients who complain of gaseous indigestion may be more sensitive to an underlying intestinal motor abnormality than are others with similar dysfunctbn. Modifications in living and eating habits are basic steps that can be taken to relieve the problem; drugs that alter intestinal activity or responses may be effective.     

Two Cases of Ventricular Parasystole Associated with Ventricular Tachycardia

In two patients, ventricular pamsystole (VP) was associated with ventricular tachycardia (VT), and in one patient, catheter ablation was successful. In patient 1, with dilated cardiomyopathy, VP led to VT, which converted to ventricular fibrillation. In patient 2, VP led to symptomatic nonsustained polymorphic VT. The origin of parasystolic focus was determined byendocardial mapping, and a radiofrequency current was delivered to patient 2. Both VP and VT disappeared immediately, and no recurrence has been observed during a follow-up of 8 months. Catheter ablation to the parasystolic focus was effective and a relationship between VP and VT was strongly suggested.     

Entrainment of Ventricular Tachycardia in Arrhythmogenic Right Ventricular Tachycardia

In two patients with arrhythrnogenic right ventricular dysplasia (ARVDJ, sustained ventricular tachycardia (VT) was induced by programmed stimulations during serial drug testings. One patient had five and the other had two VT morphologies, and the sites of origin were determined by endocardial catheter mappings. When overdrive pacing was performed, constant fusion in the QflS complex was observed in the two patients. Constant fusion of a different degree was also observed at different paced cycle lengths. Both patients had dilated right ventricles and wall-motion abnormality, and the diagnosis of ARVD was further confirmed by the specimen resected at the site of origin of VT. Therefore, VT in ARVD can be entrained and reentry is the most likely mechanism of such VT.     

Ventricular Activation Onset-Triggered Left Ventricular Pacing:

Ventricular activation onset-triggered (VAOT) left ventricular pacing modalities synchronize left ventricular paced activation with existing intrinsic ventricular activation, in patients with complete LBBB and adequate rate. The purpose of this study was to evaluate the safety and feasibility of VAOT pacing with one left ventricular pacing lead, during temporary pacing in the postoperative period following open heart surgery. VAOT pacing was studied in five patients with LBBB and two patients with previously implanted right ventricular pacemakers. The VAOT pacing system used was assembled by modifying the function of existing equipment and its programming is described in detail. Comparative ECGs are reported, documenting the changes in ventricular activation produced by VAOT pacing. Stability of surface ECG acquisition was found to be essential to the success of temporary VAOT pacing and inappropriate pacing due to ECG instability is described. Patients were studied at rest and none experienced congestive heart failure. In the comparison of cardiac output, with and without VAOT pacing, no significant differences were found in LBBB patients or those with right ventricular pacemakers. In the comparison of arterial pressure, with and without VAOT pacing, no significant differences were found in six patients, however, in one LBBB patient with intrinsic predominant ventricular trigeminy, VAOT pacing was observed to have an antiarrhythmic effect resulting in suppression of ventricular ectopy and stabilization of arterial pressure. All patients survived VAOT pacing and the postoperative period without complications requiring additional intervention or treatment. (PACE 2004; 27[Pt. I]:730–739)     

Ventricular arrhythmias

Sudden cardiac death remains a leading cause of death in the United States. It is usually due to ventricular arrhythmia, either ventricular tachycardia or ventricular fibrillation. The probability of life threatening ventricular arrhythmia correlates closely with underlying structural heart disease. In any patient presenting with a ventricular arrhythmia, a careful search for underlying causes is required, and treatment should be considered primarily if it will prolong survival. Treatment of patients without underlying heart disease who are experiencing ventricular ectopy, and/or nonsustained ventricular tachycardia, consists of reassurance and education. If symptoms are severe, a beta-blocker is an appropriate choice for drug treatment. Patients with ventricular arrhythmia and structural heart disease are generally best managed in conjunction with a cardiologist.     

Ventricular remodeling

Ventricular remodeling is an extremely complicated process that is not well understood. There seem to be multiple feedback loops that respond to mechanical events as well as to neurohormonal stimulation, cytokine release, and other, yet unidentified, agents. The progression of ventricular remodeling after the index event includes: Myocyte slippage and thinning of infarct area, chamber dilatation. Fibrosis and scar formation. Collagen strut dissolution and excessive accumulation of interstitial matrix. Increased wall stress. Myocyte hypertrophy. Neurohormonal activation. Cytokine release. Ongoing myocyte hypertrophy. Cell apoptosis and necrosis. Continued deterioration of cardiac function. It is impossible to place the sequence of events in order, because the multiple feedback systems create a complex interactive process. A basic awareness of the pathophysiology of ventricular remodeling can aid in understanding current and future treatments for heart failure. It is clear that therapeutic interventions solely aimed at improving cardiac pump function do not slow the progression of heart failure or reduce mortality. Drugs that block the neuroendocrine contribution to the remodeling process have been shown to have a greater impact. Current therapies with angiotensin-converting enzyme inhibition, beta blockade, and aldosterone antagonism are associated with significant reductions in morbidity and mortality in heart failure. Other therapeutic strategies suggested by knowledge of remodeling mechanisms, such as drugs to block cytokines, endothelins, and MMPs, may offer further benefit to patients with heart failure in the future.     

Right Ventricular Radiofrequency Ablation of Ventricular Tachycardia After Myocardial Infarction

Radiofrequency transcatheter ablation of ventricular tachycardia in the setting of a prior myocardial infarction is typically performed with application of energy to the left ventricular endocardium. In this article, two cases are described in which successful radiofrequency transcatheter ablation of ventricular tachycardia occurred with energy delivery to the right ventricular septum after failed ablation attempts from the left ventricle. Both patients had tachycardias with a left bundle branch block morphology and markedly presystolic activity recorded from the right ventricular septum. Right ventricular septal activation mapping during ventricular tachycardia should be performed in patients with left bundle branch block tachycardia morphology and coronary artery disease to maximize efficacy of the catheter ablation procedure.