Prediction of functional recovery of viable myocardium after delayed revascularization in postinfarction patients: accuracy of dobutamine stress echocardiography and influence of long-term vessel patency.

OBJECTIVES: We sought to evaluate dobutamine stress echocardiography (DSE) for predicting recovery of viable myocardium after revascularization with cineangiography as a gold standard for left ventricular (LV) function. We studied the influence of late vessel reocclusion on regional LV function. BACKGROUND: Dobutamine stress echocardiography is a well established evaluation method for myocardial viability assessment. In previous studies the reference method for assessing LV recovery was echocardiography, long-term vessel patency has not been systematically addressed. METHODS: Sixty-eight patients with a first acute myocardial infarction (AMI) and residual stenosis of the infarct related artery (IRA) underwent DSE (mean +/- standard deviation) 21 +/- 12 days after AMI to evaluate myocardial viability. Revascularization of the IRA was performed in 54 patients by angioplasty (n = 43) or bypass grafting (n = 11). Coronary angiography and LV cineangiography were repeated at four months to assess LV function and IRA patency. RESULTS: Sensitivity and specificity of DSE for predicting myocardial recovery after revascularization were 83% and 82%. In the case of late IRA patency, specificity increased to 95%, whereas sensitivity remained unchanged. In the 16 patients with myocardial viability and late IRA patency, echocardiographic wall motion score index decreased after revascularization from 1.83 +/- 0.15 to 1.36 +/- 0.17 (p = 0.0001), and left ventricular ejection fraction (LVEF) increased from 0.52 +/- 0.06 to 0.57 +/- 0.06 (p = 0.0004), whereas in five patients, reocclusion of the IRA prevented improvement of segmental or global LV function despite initially viable myocardium. CONCLUSIONS: Dobutamine stress echocardiography is reliable to predict recovery of viable myocardium after revascularization in postinfarction patients. Late reocclusion of the IRA may prevent LV recovery and influence the accuracy of DSE.     

Prediction of cardiac sympathetic nerve activity and cardiac functional outcome after treatment in patients with dilated cardiomyopathy: examination using dobutamine gated blood pool scintigraphy

OBJECTIVES: This study evaluated whether dobutamine gated blood pool scintigraphy can predict improvement of cardiac sympathetic nerve activity and cardiac function. METHODS: Sixteen patients(10 men and 6 women, mean age 59 +/- 13 years) with dilated cardiomyopathy underwent dobutamine gated blood pool scintigraphy to measure left ventricular ejection fraction (LVEF) using tracer at 0, 5, 10 and 15 micrograms/kg/min before treatment. Patients were divided into good responders (LVEF increase > or = 15%) 8 patients(GR Group) and poor responders(LVEF increase < 15%) 8 patients (PR Group) after treatment with beta-blocker or amiodarone with a background treatment of digitalis, diuretics and angiotensin converting enzyme inhibitor. I-123 metaiodobenzylguanidine(MIBG) imaging to evaluate cardiac sympathetic nerve activity and echocardiography were performed before and at one year after treatment. MIBG imaging was obtained 4 hours after tracer injection, and the heart/mediastinum count ratio(H/M ratio) calculated from the anterior planar image and the total defect score(TDS) from the single photon emission computed tomography image. LVEF and left ventricular endo-diastolic dimension (LVDd) were measured by echocardiography and New York Heart Association(NYHA) functional class was evaluated. RESULTS: The GR Group showed TDS decreased from 28 +/- 6 to 17 +/- 12(p < 0.05), H/M ratio increased from 1.79 +/- 0.26 to 2.07 +/- 0.32(p < 0.05), LVEF increased from 29 +/- 8% to 48 +/- 10%(p < 0.01), and LVDd decreased from 65 +/- 4 mm to 58 +/- 5 mm(p < 0.05). In contrast, the PR Group showed no significant changes in TDS, H/M ratio, LVEF and LVDd. NYHA functional class improved in both groups. The improvement was better in the GR Group than in the PR Group. CONCLUSIONS: Dobutamine gated blood pool scintigraphy is useful to predict the improvement of the cardiac sympathetic nerve activity and cardiac function, and symptoms after treatment in patients with dilated cardiomyopathy.     

Myocardial viability estimation during the recovery phase of stress echocardiography after acute beta-blocker administration

BACKGROUND: Myocardial viability assessment in severely dysfunctional segments by dobutamine stress echocardiography (DSE) is less sensitive than nuclear scanning. AIM: To assess the additional value of using the recovery phase of DSE after acute beta-blocker administration for identifying viable myocardium. METHODS: The study included 49 consecutive patients with ejection fraction (LVEF)or=4 viable segments were considered viable. Coronary revascularization followed within 3 months in all patients. Radionuclide evaluation of LVEF was performed before and 12 months after revascularization. RESULTS: Viability with DISA-SPECT was detected in 463 (59%) segments, while 154 (19.7%) segments presented as scar. The number of viable segments increased from 415 (53%) at DSE to 463 (59%) at DSE and recovery, and the number of viable patients increased from 43 to 49 respectively. LVEF improved by >or=5% in 27 patients. Multivariate regression analysis showed that, DSE with recovery phase was the only independent predictor of >or=5% LVEF improvement after revascularization (OR 14.6, CI 1.4-133.7). CONCLUSION: In this study, we demonstrate that the recovery phase of DSE has an increased sensitivity for viability estimation compared to low-high dose DSE.     

Detection of Viability of Dysfunctional Myocardium in Coronary Heart Disease. II. Echocardiography

The detection of viable myocardium in patients with severe left ventricular (LV) dysfunction is important because these patients benefit most from revascularization. Three echocardiographic techniques can be used for the noninvasive assessment of functional correlates of viable myocardium. Two-dimensional echocardiography (2DE) is well suited for quantifying resting LV regional and global systolic function and dysfunction before and after revascularization, in addition to providing data on chamber size, shape, and wall thicknesses. The presence of hypokinesis on a resting 2DE indicates that viable myocardium is definitely present, but presence of dykinesis does not exclude viability. Dobutamine stress echocardiography (DSE) before revascularization unmasks viability by demonstrating augmentation of systolic function. Several clinical studies have shown that improvement of regional function during DSE indicates contractile reserve and predicts improvement of function after revascularization. A biphasic response on DSE appears to predict residual coronary artery stenosis and is a reliable marker of viability. DSE also appears to be useful after revascularization for unmasking contractile reserve. Myocardial contrast echocardiography (MCE) detects viability by defining microvascular perfusion, the extent of myocardium at risk, and coronary flow reserve. The clinical utility of MCE is undergoing evaluation. The combination of DSE and MCE might provide an improved estimate of the extent of viable myocardium based on assessment of function and perfusion. Meanwhile, echocardiographic and nuclear techniques can be used to complement each other in the assessment of myocardial viability.     

Individual prediction of functional recovery after coronary revascularization in patients with ischemic cardiomyopathy: the scar-to-biphasic model

Currently, the prediction of improvement of left ventricular (LV) ejection fraction (EF) after revascularization in patients with ischemic cardiomyopathy relies only on viable myocardium extent, whereas both the amount of viable and scar tissue may be important. A model was developed, based on the amount of viable and nonviable myocardium, to predict functional recovery. Viable and scarred myocardium was defined by dobutamine stress echocardiography (DSE) in 108 consecutive patients. LVEF before and 9 to 12 months after revascularization was assessed by radionuclide ventriculography; an improvement of ≥5% was considered significant. In the 1,089 dysfunctional segments (63%), DSE elicited biphasic response in 216 segments (20%), sustained improvement in 205 (19%), worsening in 43 (4%), and no change in 625 (57%). LVEF improved in 39 patients (36%). Only the numbers of biphasic and scar segments were predictors of improvement or no improvement of LVEF (odds ratio 1.5, 95% confidence interval 1.2 to 1.7, p <0.0001 for biphasic segments; odds ratio 0.8, 95% confidence interval 0.7 to 0.9, p <0.0005 for scarred segments). The sustained improvement and worsening pattern were not predictive of improvement or no improvement. A regression function, based on the number of scar and biphasic segments, showed that the likelihood of recovery was 85% in patients with extensive biphasic tissue and no scars and 11% in patients with extensive scars and no biphasic myocardium. Patients with a mixture of scar and biphasic tissue had an intermediate likelihood of improvement (50%). In patients with ischemic cardiomyopathy and a mixture of viable and nonviable tissue, both numbers of viable and nonviable segments should be considered to accurately predict functional recovery after revascularization.     

Functional recovery after coronary artery bypass grafting in patients with severe left ventricular dysfunction and preserved myocardial viability in the left anterior descending arterial territory as assessed by thallium-201 myocardial perfusion imaging.

To evaluate the functional recovery after coronary bypass surgery in patients with severe left ventricular (LV) dysfunction (ejection fraction (EF) < or = 35%), 100 consecutive patients with viable myocardium in the territory supplied by the left anterior descending artery (LAD) underwent coronary bypass grafting. In addition, cardiac catheterization and single-photon emission computed tomography (SPECT) perfusion imaging with thallium-201 were repeated 1-year postoperatively. Although 12 patients with severe LV dysfunction were preoperatively in a worse New York Heart Association functional class (3.1+/-0.7 vs 2.4+/-0.8; p<0.01), had a higher incidence of heart failure (10/12 vs 14/88; p<0.001) and had a worse LVEF (29+/-5 vs 61+/-14%; p<0.001) compared with 88 patients without severe LV dysfunction, the operative mortality was similar in the 2 groups (1/12 vs 2/88; p=NS). The postoperative NYHA functional class in the patients with severe LV dysfunction was similar to that in the patients without such dysfunction (1.6+/-0.7 vs 1.3+/-0.6; p=NS). In addition, the 1-year postoperative study revealed a significant improvement in the thallium defect score in both the LAD territory (1.7+/-1.2 to 0.7+/-1.0, p=0.01) and all the territories (5.2+/-2.2 to 3.2+/-1.9, p=0.002) in patients with severe LV dysfunction, whereas no improvement in defect score was found in either of these territories in those without severe LV dysfunction (LAD: 0.6+/-1.4 to 0.4+/-1.2, p=NS; All: 1.9+/-2.2 to 1.8+/-2.0, p=NS). Furthermore, a marked 1-year postoperative improvement (15-24%; 95% confidence interval) in LVEF (29+/-5 to 48+/-10%, p<0.001) was demonstrated in patients with severe LV dysfunction, but not in those without such dysfunction (60+/-13 to 61+/-11%, p=NS). These results indicate that myocardial viability in the LAD territory, as demonstrated by thallium-201 SPECT perfusion imaging, predicts a significant improvement in functional class and LVEF of at least 10% or more after coronary artery bypass grafting in patients with severe LV dysfunction.     

Coronary artery bypass grafting in patients with poor left ventricular function

Coronary artery bypass grafting (CABG) in patients with poor left ventricular function remains a surgical challenge and is still controversial. The purposes of this study were to evaluate the effectiveness of CABG in such patients when performed without case selection on the basis of preoperative viability tests and to determine the predictors of postperative outcome. The preoperative, perioperative, and postoperative early and mid-term follow-up data of 273 patients with < or = 30% left ventricular ejection fraction (LVEF) who underwent isolated CABG between January 1995 and November 2000 were evaluated. Preoperative echocardiography and cardiac catheterization, and postoperative control echocardiography were performed in all patients. Follow-up was achieved via monthly periodical examinations in the first 6 months, and thereafter by either regular visits or phone contact. Preoperatively, 242 (88.65%) patients were in NYHA class III or IV, and the mean LVEF was 26.51 +/- 3.64%. The overall hospital mortality total was 14 (5.13%) patients. There were 44 (16.12%) late mortalities. Postoperative morbidities were observed in 74 (27.1%) patients. Two-hundred and two (93.95%) of the surviving 215 (78.75%) patients were in NYHA class I or II at 49.55 +/- 14.84 months of follow-up. Postoperative follow-up echocardiographic examinations revealed a mean LVEF of 39.66% +/- 5.43%. The improvements in functional capacity and LVEF were significant. Advanced age, diabetes, hypertension, cross-clamp time >60 min, bypass time>120 min, and severity of functional class (class III-IV of NYHA) were found to be the determinants of mortality. However, multivariate analyses revealed only older age and class III-IV of NYHA and CCS were predictors of mortality. The low mortality and morbidity rates as well as satisfactory postoperative improvements in functional capacity and LVEF measurements support the use of CABG without the need for any viability assessment in patients with left ventricular dysfunction.     

Original Article--Value of Pathological Q Waves and Angiographic Collateral Grade in Patients Undergoing Coronary Chronic Total Occlusion Recanalization: Cardiac Magnetic Resonance Study

Background/aimSuccessful coronary chronic total occlusion (CTO) revascularization was found by many studies to be associated with improved left ventricular (LV) systolic function and survival if evidence of viability is present. Little is known about the association of CTO revascularization in patients with electrocardiographic Q waves and improvement in angina burden as a measurement of health-related quality of life (HRQOL) afterwards.MethodsIn this study, 100 patients with single vessel CTO were included. Myocardial viability was tested by late gadolinium enhancement (LGE) on cardiac magnetic resonance (CMR) and 50 patients showed evidence of viability. Seattle Angina Questionnaire (SAQ) scores were used as a measure of HRQOL.ResultsPathological Q waves were present in 48 patients (including 19 patients with viable CTO territory) out of 100 patients. Patients with Q waves tended to have worse Seattle Angina Questionnaire (SAQ) scores compared to those with no Q waves (31.2 ± 11.7 vs 45.3 ± 13.9 respectively, p = 0.002), worse LV systolic function and wall motion score index (WMSI) on CMR. They also had significantly less prevalence of viability (p < 0.001). Patients with Q waves and positive viability had lower SAQ scores (37.2 ± 10.1 vs 52.7 ± 13.2 respectively, p = 0.02), higher LVEF and lower WMSI. They also had well developed collateral grade (2.1 ± 1.03 vs 0.7 ± 0.82 respectively, p < 0.001). After successful percutaneous coronary intervention (PCI), in the viable LV group, presence of Q waves was not associated with better LV functional recovery, while those with higher collateral grades were more likely to have better LV functional recovery post CTO-PCI. Patients with Q waves and viable CTO territory showed significantly better SAQ scores compared to pre-PCI (87.3 ± 12.2 vs 37.2 ± 10.1 respectively, p < 0.001). For angina frequency, post–PCI score was 80.2 ± 7.9 compared to 39.2 ± 7.1 before PCI, p < 0.001). Multivariate regression analysis showed that pathological Q waves, Rentrop''s collateral grade and the Canadian Cardiovascular Society (CCS) angina class before PCI were the most significant independent predictors of improved HRQOL as reflected by SAQ (OR for Q waves 7.83, 95% CI 1.62–18.91,p 0.003), (OR for Rentrop''s collateral grade 8.31,95% CI 2.21–26.33, p < 0.001), (OR for CCS class 8.39, 95% CI 1.21–20.8, p 0.01).ConclusionWell-developed collateral circulation could independently predict LV functional recovery after CTO-PCI. Patients with Q waves and viable CTO territory tend to have higher CCS class before revascularization and get significant improvement of HRQOL after PCI. Other predictors of improved HRQOL are Rentrop''s collateral grade and worse CCS class before PCI.     

激光心肌血管重建联合非体外循环冠状动脉旁路移植术的随访研究

目的探讨激光心肌血管重建联合非体外循环冠状动脉旁路移植手术(TMLR + OPCAB)的安全性及中远期临床疗效。方法1999年10月至2005年2月,在北京大学人民医院及第三医院启动了针对TMLR+OPCAB的前瞻性、多中心临床试验。遴选罹患冠状动脉粥样硬化性心脏病,经冠状动脉造影证实存在弥漫性冠状动脉病变的患者共80例,分为联合手术组(n=40)及单纯非体外循环旁路移植手术(OPCAB)组(对照组,n=40)。比较两组手术及围术期相关指标,术后连续观察患者心绞痛分级[参考加拿大心脏病学会的劳力型心绞痛分级标准(CCSC)]、心功能分级[参考纽约心脏学会心功能分级(NYHA)]、6分钟步行试验(6MWT)的结果,并经超声心动检查检测左室射血分数(LVEF)等的变化。结果两组之间手术及围术期指标差异无统计学意义;TMLR+OPCAB不会增加围术期病死率及严重并发症的发生率。经过平均(3.4±1.7)年的随访,试验组患者的心绞痛分级明显低于对照组(P=0.030),复发严重心绞痛或再次接受再血管化治疗的患者数相对较少(尸=0.113);6MWT距离亦优于对照组(P=0.006);两组间在LVEF等心功能指标上差异无统计学意义(P=0.164)。结论与单纯冠状动脉旁路移植术相比,TMLR+OPCAB更有利于缓解患者的心绞痛症状,改善生活质量,但对心功能无明显提高。     

Effect of spironolactone on cardiac sympathetic nerve activity and left ventricular remodeling in patients with dilated cardiomyopathy

OBJECTIVES: We sought to evaluate the effects of spironolactone on cardiac sympathetic nerve activity and left ventricular (LV) remodeling in patients with dilated cardiomyopathy (DCM). BACKGROUND: Aldosterone prevents the uptake of norepinephrine and promotes structural remodeling of the heart. Spironolactone, an aldosterone receptor blocker, improves LV remodeling in patients with DCM, but its influence on cardiac sympathetic nerve activity has not been determined. METHODS: We selected 30 patients with DCM who were treated with an angiotensin-converting enzyme inhibitor and a loop diuretic. Fifteen patients were assigned to receive spironolactone additionally, whereas the remaining 15 patients continued their current regimen. The delayed heart/mediastinum (H/M) count ratio, delayed total defect score (TDS), and washout rate (WR) were determined from iodine-123 ((123)I)-meta-iodobenzylguanidine (MIBG) images before and six months after treatment. The left ventricular end-diastolic volume (LVEDV) and left ventricular ejection fraction (LVEF) were determined by echocardiography, and New York Heart Association (NYHA) functional class was estimated.RESULTS: In the spironolactone group, the TDS decreased from 36 +/- 9 to 24 +/- 13 (p < 0.0001), the H/M ratio increased from 1.64 +/- 0.20 to 1.86 +/- 0.27 (p < 0.0001), and WR decreased from 55 +/- 12% to 41 +/- 15% (p < 0.0005). In addition, the LVEDV decreased from 187 +/- 26 to 154 +/- 41 ml (p < 0.005), and LVEF increased from 33 +/- 6% to 39 +/- 6% (p < 0.005). However, there were no significant changes in these parameters in the control group. There was a significant correlation between changes in the (123)I-MIBG findings and changes in LVEDV with spironolactone treatment (TDS: r = 0.684, p = 0.0038; H/M ratio: r = -0.878, p < 0.0001; and WR: r = 0.737, p = 0.0011). The NYHA functional class improved in both groups but showed a greater improvement in the spironolactone group than in the control group (p < 0.01). CONCLUSIONS: Spironolactone improves cardiac sympathetic nerve activity and LV remodeling in patients with DCM.     

Prognostic importance of the quantification of myocardial viability in revascularized patients with coronary artery disease and moderate-to-severe left ventricular dysfunction

The aim of this study was to assess the prognostic value of the amount of dysfunctional but viable myocardium in revascularized patients with coronary artery disease and left ventricular dysfunction. To quantify the amount of dysfunctional but viable myocardium, low-dose dobutamine echocardiography was performed. The wall motion was scored using a 16-segment model. The dysfunctional segments were defined as viable if they exhibited functional improvement of at least 1 grade with any dose of dobutamine, or only worsening with dobutamine infusion. Two hundred and twenty patients were revascularized and followed-up for a mean period of 33+/-23 months (range, 0-86) for cardiac-related death and hospitalization for heart failure. Standard follow-up echocardiography was performed 3-6 months after revascularization. Receiver operating characteristic curve analysis identified six dysfunctional but viable segments as the optimal cutoff value for discriminating patients with and without risk of cardiac events. Thirty-eight patients exhibited a large amount of dysfunctional but viable myocardium (>or=6 segments, group A), 103 patients had a small amount of dysfunctional but viable myocardium (2-5 segments, group B), and 79 patients were found to have dysfunctional myocardium irreversibly damaged (group C). Similar baseline left ventricular ejection fractions of 36+/-4, 34+/-5, 35+/-5% in groups A, B, and C increased to 46+/-6% (P<0.01 versus baseline and versus groups B and C), to 39+/-5% (P<0.01 versus baseline and group C), and to 36+/-7% (P<0.01 versus baseline), respectively, after revascularization. The greatest functional improvement after revascularization in group A patients was accompanied by a lower frequency of cardiac events during follow-up (1 vs. 27 in group B, P<0.01, and versus 18 in group C, P<0.01) and by a better cardiac event-free survival according to Kaplan-Meier survival analysis (P<0.01 versus groups B and C, respectively). In conclusion, in revascularized patients with coronary artery disease and moderate-to-severe left ventricular dysfunction, the presence of >or=6 dysfunctional but viable segments identifies patients with the best prognosis.     

Prognostic power of dobutamine echocardiography after uncomplicated acute myocardial infarction in the elderly

STUDY OBJECTIVES: To assess the prognostic value of dobutamine-atropine stress echocardiography (DSE) after uncomplicated acute myocardial infarction (AMI) in elderly patients. DESIGN: We analyzed 59 consecutive patients (42 men) aged > or = 70 years (mean +/- SD age, 75 +/- 4 years) who underwent DSE within 10 days after uncomplicated AMI. DSE was carried out following the standard protocol. Five myocardial responses were considered: (1) negative, (2) sustained improvement of contractility, (3) biphasic response (initial improvement followed by worsening), (4) worsening of contractility in the infarcted area, and (5) worsening at a distance. RESULTS: Mean follow-up duration was 13 +/- 8 months. Twenty-one patients had an event: cardiac death (n = 5), myocardial infarction (n = 1), heart failure (n = 1), unstable angina (n = 10), and revascularization (n = 4). Clinical and stress echocardiographic variables previously related to adverse prognosis were entered in Cox regression analysis, and the predictors of impaired outcome were inducible ischemia during DSE (hazard ratio [HR], 2.97; 95% confidence interval [CI], 1.77 to 4.99; p < 0.001) and resting wall motion score index (WMSI) > 1.6 (HR, 1.68; 95% CI, 1.02 to 2.77; p = 0.04). After excluding revascularization procedures and considering only spontaneous events, the following predictors were found: ischemia during DSE (HR, 2.95; 95% CI, 2.78 to 3.12; p < 0.001) and resting WMSI > 1.6 (HR, 2.53; 95% CI, 1.30 to 4.93; p = 0.006). CONCLUSIONS: Inducible ischemia during DSE within 10 days after uncomplicated AMI predicts an impaired outcome in the elderly.     

Prospective validation of stress echocardiography as an identifier of cardiac resynchronization therapy responders.

BACKGROUND: Cardiac resynchronization therapy (CRT) provides benefit for congestive heart failure (CHF), but predictors of the clinical response are debated. OBJECTIVE: The aim of this prospective study was to assess the predictive role of dobutamine stress echocardiography (DSE) in identifying a suitable candidate for CRT. METHODS: From March 2001 to December 2003, 71 CHF patients were prospectively enrolled on the basis of four criteria: New York Heart Association (NYHA) class III and IV; QRS > or =150 ms with a left bundle branch block pattern, and left ventricular ejection fraction (LVEF) < or =35% under optimal medical treatment. The combined endpoints were hospital readmission for class IV CHF, heart transplant (HT), and CHF-related death. RESULTS: The 67 patients completing the study presented with the following characteristics: age (70 +/- 10 years; 11 women); etiology (idiopathic in 44, ischemic in 23); NYHA class (40 in class III and 27 in class IV); LVEF 26% (+/-5%); QRS duration (190 +/- 28 ms); 6-minute walk test 330 m (+/-108); peak oxygen uptake 10.7 (+/-3.3 mL/kg/min); mitral insufficiency in 42 (> or =III grade); interventricular (IV) delay (62 +/- 21 ms); and intraventricular dyssynchrony in 30 patients. Over the follow-up period of 12.1 +/- 8.7 months, 20 (29.9%) of 67 patients presented with at least one hemodynamic event: hospitalization for CHF in 19 (28%) of 67, HT in 2 (3%) of 67, and CHF death in 7 (10%) 67. Univariate analysis identified NYHA class (P = .03), LVEF (P = .015), IV dyssynchrony before (P = .038) and after CRT (P = .0035), IV delay after CRT (P = .002), 6-minute walk distance (P = .01), and DSE Res+ (P = .008) as significant predictors of clinical events. A receiver operating curve established a cut-off value of 1.25 for the DSE responders (Res+: 34 patients at 10 microg/kg/min infusion rates), and the improvement at the 10 microg/kg/min level was 41% +/- 7% in Res+ and 29% +/- 8% in nonresponders (P<.0001). With a cut-off value of 1.25-fold the LVEF increase, the DSE test exhibits 70% sensitivity, 61.7% specificity, 43.8% positive predictive value, and 82.9% negative predictive value. Cox analysis identified IV dyssynchrony before CRT (P = .01) and DSE Res+ (P = .003) as independent predictive factors. CONCLUSIONS: Independent predictive factors of severe hemodynamic clinical outcome in patients with CRT are IV dyssynchrony and DSE.     

Tissue velocity imaging during dobutamine stimulation for assessment of myocardial viability: segmental analysis in patients after myocardial infarction

BACKGROUND: Dobutamine stress echocardiography (DSE) is an established method for the detection of viable myocardium, but evaluation of this method is subjective. Tissue velocity Imaging (TVI) allows quantitative analysis of regional myocardial wall motion by assessment of systolic myocardial velocities. The aim of this study was to evaluate the diagnostic value of DSE and TVI for detection of viable myocardium. METHODS: In 56 patients (58+/-12 years) with previous myocardial infarction (130+/-42 days, mean ejection fraction 42+/-15%) low-dose DSE was combined with analysis of peak systolic myocardial velocities (Vpeak) by TVI for assessment of myocardial viability. As reference served a follow-up echocardiography after successful revascularization (mean 91+/-3 days). RESULTS: Of a total of 896 segments 200 showed abnormal wall motion (31 mildly hypokinetic, 50 severely hypokinetic, 115 akinetic, 4 dyskinetic). In 125 of these 200 segments regional improvement of regional wall motion was observed (62.5% viable). An increase of Vpeak>1 cm/s during dobutamine stimulation allowed the identification of viable myocardium with a sensitivity of 82% and a specificity 82% (DSE: 77% and 80%). By receiver operating characteristic (ROC) curve analysis, a cut-off value of 1.0 cm/s was the best parameter to differ viable from nonviable myocardium (area under the curve 0.85; p<0.01; 95% CI 0.79 to 0.90). Improvement of global ejection fraction after revascularization (47+/-13%, p=0.11) corresponded with three TVI viable segments with a sensitivity of 92% and a specificity of 89% (p=0.012). CONCLUSIONS: TVI allows the identification of viable myocardium during dobutamine stimulation and enables a quantitative interpretation of DSE.     

药物负荷三维超声心动图检测存活心肌的价值

目的：利用药物负荷三维超声心动图试验,检测心肌梗死患者的存活心肌。方法：50例心肌梗死患者行冠脉血液灌注重建术（PCI,CABG）,在术前行三维超声心动图检查和多巴酚丁胺负荷超声试验,根据术后一个月复查心脏超声结果左室整体EF较术前改善〉5％与否分为存活心肌组（41例）和无存活心肌组（9例）,三维超声检查时进行左室三维重建,将左心室分为17个节段,比较负荷试验前后左室整体射血分数（EF）及左室壁各节段的射血分数EF值。结果：术后1月多巴酚丁胺负荷三维超声试验：与负荷试验前比较,存活心肌组于负荷试验时左室整体EF值[（40±13）％比（53±15）％,P〈0．05],梗死区相关节段EF值[（33±12）％比（50±18）％,P〈0．01]均明显改善;无存活心肌组负荷试验前后左室整体EF值,梗死区相关节段EF值无明显改善（P均〉0．05）。心梗患者于冠脉术后1月复查三维超声心动图,存活心肌组左室整体EF值术前、术后为（40±13）％,（49±15）％,改善20％,无存活心肌组EF值术前、术后为（36±8）％,（38±10）％,改善≤5％。结论：多巴酚丁胺负荷三维超声心动图检查对心肌梗死患者存活心肌的检测客观、可定量,有一定的临床应用价值。     

QT dispersion correlates to myocardial viability assessed by dobutamine stress echocardiography in patients with severely depressed left ventricular function due to coronary artery disease

BACKGROUND: QT dispersion is prolonged in numerous cardiac diseases, representing a general repolarization abnormality. AIM: To evaluate the influence of viable myocardium on QT dispersion in patients with severely depressed left ventricular (LV) function due to coronary artery disease. METHODS AND RESULTS: 103 patients with ischemic cardiomyopathy (LV ejection fraction [EF]: 25+/-6%) were studied. Patients underwent 12-lead electrocardiography to assess QT dispersion, and two-dimensional echocardiography to identify segmental dysfunction. Dobutamine stress echocardiography (DSE) was then performed to detect residual viability. Resting echo demonstrated 1260 dysfunctional segments; of these, 476 (38%) were viable. Substantial viability (> or =4 viable segments on DSE) was found in 62 (60%) patients. QT dispersion was lower in these patients, than in patients without viability (55+/-17 ms vs. 65+/-22 ms, P=0.012). Viable segments negatively correlated to QT dispersion (r=-0.333, P=0.001). In contrast, there was no correlation between LVEF and QT dispersion (r=-0.001, P=NS). CONCLUSIONS: There is a negative correlation between QT dispersion and the number of viable segments assessed by DSE. Patients with severely depressed LV function and a low QT dispersion probably have a substantial amount of viable tissue. Conversely, when QT dispersion is high, the likelihood of substantial viability is reduced.     

Functional status and quality of life in patients with heart failure undergoing coronary bypass surgery after assessment of myocardial viability

OBJECTIVES: The aim of this study was to evaluate whether preoperative clinical and test data could be used to predict the effects of myocardial revascularization on functional status and quality of life in patients with heart failure and ischemic LV dysfunction. BACKGROUND: Revascularization of viable myocardial segments has been shown to improve regional and global LV function. The effects of revascularization on exercise capacity and quality of life (QOL) are not well defined. METHODS: Sixty three patients (51 men, age 66+/-9 years) with moderate or worse LV dysfunction (LVEF 0.28+/-0.07) and symptomatic heart failure were studied before and after coronary artery bypass surgery. All patients underwent preoperative positron emission tomography (PET) using FDG and Rb-82 before and after dipyridamole stress; the extent of viable myocardium by PET was defined by the number of segments with metabolism-perfusion mismatch or ischemia. Dobutamine echocardiography (DbE) was performed in 47 patients; viability was defined by augmentation at low dose or the development of new or worsening wall motion abnormalities. Functional class, exercise testing and a QOL score (Nottingham Health Profile) were obtained at baseline and follow-up. RESULTS: Patients had wall motion abnormalities in 83+/-18% of LV segments. A mismatch pattern was identified in 12+/-15% of LV segments, and PET evidence of viability was detected in 30+/-21% of the LV. Viability was reported in 43+/-18% of the LV by DbE. The difference between pre- and postoperative exercise capacity ranged from a reduction of 2.8 to an augmentation of 5.2 METS. The degree of improvement of exercise capacity correlated with the extent of viability by PET (r = 0.54, p = 0.0001) but not the extent of viable myocardium by DbE (r = 0.02, p = 0.92). The area under the ROC curve for PET (0.76) exceeded that for DbE (0.66). In a multiple linear regression, the extent of viability by PET and nitrate use were the only independent predictors of improvement of exercise capacity (model r = 0.63, p = 0.0001). Change in Functional Class correlated weakly with the change in exercise capacity (r = 0.25), extent of viable myocardium by PET (r = 0.23) and extent of viability by DbE (r = 0.31). Four components of the quality of life score (energy, pain, emotion and mobility status) significantly improved over follow-up, but no correlations could be identified between quality of life scores and the results of preoperative testing or changes in exercise capacity. CONCLUSIONS: In patients with LV dysfunction, improvement of exercise capacity correlates with the extent of viable myocardium. Quality of life improves in most patients undergoing revascularization. However, its measurement by this index does not correlate with changes in other parameters nor is it readily predictable.     

Nonselective beta-adrenergic blocking agent, carvedilol, improves arterial baroflex gain and heart rate variability in patients with stable chronic heart failure

OBJECTIVES: The purpose of this study was to investigate in a case-controlled study whether carvedilol increased baroreflex sensitivity and heart rate variability (HRV). BACKGROUND: In chronic heart failure (CHF), beta-adrenergic blockade improves symptoms and ventricular function and may favorably affect prognosis. Although beta-blockade therapy is supposed to decrease myocardial adrenergic activity, data on restoration of autonomic balance to the heart and, particularly, on vagal reflexes are limited. METHODS: Nineteen consecutive patients with moderate, stable CHF (age 54 +/- 7 years, New York Heart Association [NYHA] class II to III, left ventricular ejection fraction [LVEF] 24 +/- 6%), treated with optimized conventional medical therapy, received carvedilol treatment. Controls with CHF were selected from our database on the basis of the following matching criteria: age +/- 3 years, same NYHA class, LVEF +/- 3%, pulmonary wedge pressure +/- 3 mm Hg, peak volume of oxygen +/- 3 ml/kg/min, same therapy. All patients underwent analysis of baroreflex sensitivity (phenylephrine method) and of HRV (24-h Holter recording) at baseline and after six months. RESULTS: Beta-blockade therapy was associated with a significant improvement in symptoms (NYHA class 2.1 +/- 0.4 vs. 1.8 +/- 0.5, p < 0.01), systolic and diastolic function (LVEF 23 +/- 7 vs. 28 +/- 9%, p < 0.01; pulmonary wedge pressure 17 +/- 8 vs. 14 +/- 7 mm Hg, p < 0.05) and mitral regurgitation area (7.0 +/- 5.1 vs. 3.6 +/- 3.0 cm2, p < 0.01). No significant differences were observed in either clinical or hemodynamic indexes in control patients. Phenylephrine method increased significantly after carvedilol (from 3.7 +/- 3.4 to 7.1 +/- 4.9 ms/mm Hg, p < 0.01) as well as RR interval (from 791 +/- 113 to 894 +/- 110 ms, p < 0.001), 24-h standard deviation of normal RR interval and root mean square of successive differences (from 56 +/- 17 to 80 +/- 28 ms and from 12 +/- 7 to 18 +/- 9 ms, all p < 0.05), while all parameters remained unmodified in controls. During a mean follow-up of 19 +/- 8 months a reduced number of cardiac events (death plus heart transplantation, 58% vs. 31%) occurred in those patients receiving beta-blockade. CONCLUSIONS: Besides the well-known effects on ventricular function, treatment with carvedilol in CHF restores both autonomic balance and the ability to increase reflex vagal activity. This protective mechanism may contribute to the beneficial effect of beta-blockade treatment on prognosis in CHF.     

Post-systolic shortening during dobutamine stress echocardiography predicts cardiac survival in patients with severe left ventricular dysfunction

BACKGROUND: Patients with severe left ventricular dysfunction and myocardial viability by dobutamine stress echocardiography (DSE) or F18-fluorodeoxyglucose-single-photon emission computed tomography (FDG-SPECT), experience improved survival after coronary revascularization. Pulsed wave-tissue Doppler imaging (PW-TDI)-derived ejection phase shortening (EPS) and post-systolic shortening (PSS) velocities may help to quantify DSE. We assessed these variables in a prospective long-term follow-up. METHODS: Eighty patients (58 men, mean age 63+/-9 years) with left ventricular dysfunction (radionuclide ventriculography mean ejection fraction, 34+/-11%) underwent both DSE and FDG-SPECT for myocardial viability. Viable myocardium was improvement from rest to low dose or worsening of wall motion at peak DSE and normal perfusion, mildly reduced perfusion with FDG uptake or severely reduced or absent perfusion with increased FDG uptake (mismatch) at FDG-SPECT. EPS, PSS velocities and EPS/PSS ratio during DSE were analysed using a six-segment model. Coronary revascularization bypass grafting was performed in 62 patients. All patients completed a long-term (9-year) follow-up for cardiac death. RESULTS: The segmental prevalence of severe dyssynergy was 77%. On a patient basis myocardial viability was detected by EPS/PSS ratio (31%), FDG-SPECT (34%) and DSE (26%). A significant improvement of Kaplan-Meier survival was predicted in viable compared with nonviable revascularized patients (P < 0.01). Both EPS/PSS ratio and FDG-SPECT, compared to DSE alone, tended to allocate more accurately univariate prediction of death-free outcome (odds ratio, 2.5 and 2.7 compared with 2.1). CONCLUSIONS: TDI adds objective variables to DSE, helping to recognize viable myocardium and optimize prediction of death-free outcome in long-term follow-up, with favorable comparison with nuclear techniques.     

Extent of myocardial viability predicts response to biventricular pacing in ischemic cardiomyopathy

BACKGROUND: The clinical response to biventricular pacing is unpredictable, especially in patients with ischemic cardiomyopathy. OBJECTIVES: The purpose of this study was to prospectively examine the relationship between the extent of myocardial viability and the response to cardiac resynchronization therapy. METHODS: Twenty-one patients with ischemic left ventricular (LV) dysfunction (left ventricular ejection fraction [LVEF] 21 +/- 5%), New York Heart Association (NYHA) functional class III-IV, and QRS >120 ms received biventricular devices. Myocardial viability was assessed by myocardial contrast echocardiography, and a perfusion score index (PSI) was calculated from summed segmental perfusion scores. LV performance was assessed by echocardiography on the day after implantation and at 6 months. RESULTS: PSI was closely correlated with acute improvement in LVEF (P = .003, r = 0.65), stroke volume (P = .02, r = 0.54), and end-systolic volume (P = .05, r = -0.49). PSI also correlated with early diastolic LV relaxation (E', P < .05, r = 0.50) and global myocardial performance or Tei index (P = .003, r = 0.63). By multiple linear regression analysis, PSI provided incremental predictive value to the degree of dyssynchrony, measured by tissue Doppler imaging, for predicting improvement in LVEF. At 6 months, PSI remained positively correlated with improvement in ventricular performance and with reduction in LV end-diastolic dimension (P = .003, r = -0.68). PSI also influenced the clinical variables of NYHA class, 6-minute walk distance, quality-of-life score, and number of hospitalizations for heart failure. CONCLUSION: In patients with ischemic cardiomyopathy, the extent of myocardial viability predicts acute and long-term improvement in LV performance, exercise tolerance, and reduction in LV end-diastolic dimension with biventricular pacing.