Intrathoracic impedance monitoring to detect chronic heart failure deterioration: relationship to changes in NT-proBNP

BACKGROUND: An alert algorithm, based on intrathoracic impedance monitoring, has been incorporated into a cardiac resynchronisation device (CRT) to detect pulmonary fluid accumulation, and to audibly alert patients to decompensating chronic heart failure (CHF). AIMS: To evaluate this algorithm, alert events were correlated with changes in NT-proBNP concentration and CHF status. METHODS AND RESULTS: In a prospective observational study of 62 patients (89% male, aged 67+/-1 year), NT-proBNP plasma concentrations, clinical CHF status, and device data were collected at enrolment, during regular follow-up and at device alerts. Over a mean follow-up of 27+/-2 weeks, pooled data indicated a weak, but significant inverse relationship between relative changes in intrathoracic impedance and NT-proBNP (r=-0.3; p<0.001). In 52 device alerts from 35 patients, NT-proBNP increased by 66+/-19% from 2039+/-331 pg/ml (p<0.001). The increase in NT-proBNP was higher in alerts with clinical signs of CHF deterioration (n=30, 89+/-25%; p<0.001) than in alert events without clinical signs (n=22, 25+/-15%; p=n.s.). CONCLUSION: Intrathoracic impedance based alert events are associated with a significant increase in NT-proBNP concentration. These data indicate that intrathoracic impedance monitoring might facilitate the outpatient management of CHF patients with implanted CRT devices.     

The effect of endurance training on exercise capacity following cardiac resynchronization therapy in chronic heart failure patients: a pilot trial.

BACKGROUND: Both endurance training (ET) and cardiac resynchronization therapy (CRT) improve quality of life (QOL) and exercise tolerance in patients with advanced chronic heart failure (CHF). DESIGN: A randomized intervention trial to study the effect on exercise capacity of ET in addition to CRT in patients with CHF and dyssynchrony. METHODS: Seventeen patients (eight men, aged 59+/-9 years) with CHF and dyssynchrony were randomized to CRT with (n=8) or without (n=9) ET and compared with two matched control CHF groups (standard care with ET: n=9, standard care only: n=10). At baseline and after 5 months, exercise tolerance, left ventricular (LV) remodelling, QOL and NT-pro brain natriuretic peptide (NT-proBNP) levels were assessed. RESULTS: Peak oxygen consumption (VO2peak), maximal workload (Wattmax), circulatory power, LV ejection fraction, dyssynchrony and QOL improved in both CRT groups. However, the increase in VO2peak (+40% versus +16%, P=0.005), Wattmax (+43% versus +13%, P=0.0005), and circulatory power (+74% versus +32%, P=0.01), was significantly greater in the trained versus the untrained CRT patients. Comparison of the four patient groups confirmed the cumulative effects of CRT plus ET. CONCLUSIONS: ET in resynchronized CHF patients is feasible and further enhances exercise tolerance. Patients with severe CHF should be prescribed an exercise training programme after implantation in order to maximize the expected benefit.     

The role of exercise ventilation in clinical evaluation and risk stratification in patients with chronic heart failure

BACKGROUND: Patients with chronic heart failure (CHF) are characterised by an increased ventilatory response to exercise. The role of exercise ventilation in the risk stratification and evaluation of patients with CHF has not yet been established. AIM: To examine the relationship between exercise ventilation indices and clinical parameters of CHF and to assess the prognostic value of the ventilatory response to exercise. METHODS: The study group consisted of 87 patients with CHF (72 males, mean age 58 years) with a mean left ventricular ejection fraction of 32%. Ten patients were in NYHA class I, 38 - in NYHA class II, 34 - in NYHA class III, and 5 - in NYHA class IV. The control group consisted of 20 patients without CHF (13 males, mean age 58 years, mean LVEF - 61%). All studied subjects underwent maximal exercise test with gas-exchange measurement. The following parameters were analysed: peak exercise oxygen consumption [peak VO(2) (ml/kg/min)], VE-VCO(2) index [a coefficient of linear regression analysis depicting an association between ventilation (VE) and carbon dioxide production (VCO(2)) during exercise] and VE/VCO(2) ratio at peak exercise to VE/VCO(2) ratio while at rest (VE/VCO(2 peak/rest)). RESULTS: Ventilatory response indices were significantly higher in patients with CHF compared with controls: VE-VCO(2) - 37.9+/-11.1 vs 27.1+/-4.1; VE-VCO(2 peak/rest) - 0.89+/-0.14 vs 0.75+/-0.10 (p<0.001). In CHF patients a significant positive correlation between ventilatory response parameters and NYHA class (VE-VCO(2) - r=0.52; VE/VCO(2 peak/rest) - r=0.47) and a negative correlation with peak VO(2) (VE-VCO(2) - r=-0.52; VE/VCO(2 peak/rest) - r=-0.49) were noted (p<0.0001 for all correlations). No correlation was found between ventilatory parameters and echocardiographic variables or CHF aetiology. During the follow-up period lasting at least 12 months, 17 (22%) patients died. In the univariate Cox model, NYHA class III-IV, decreased peak VO(2) and increased VE-VCO(2) and VE/VCO(2 peak/rest) values were significantly associated with the risk of death. The multivariate analysis revealed that VE/VCO(2 peak/rest) > or =1.0 was the adverse prognostic factor, independent of peak VO(2) (p=0.02) and NYHA class (p=0.01). The Kaplan-Meier analysis showed that prognosis during the 18-month follow-up period in patients with enhanced exercise ventilation was worse than in the remaining patients (59% survival in patients with VE/VCO(2 peak/rest) > or =1.0 59% vs 91% survival in patients with VE/VCO(2 peak/rest) <1.0, p=0.001). CONCLUSIONS: In patients with stable CHF simple exercise ventilation parameters may provide important clinical and prognostic information.     

CRT improves the exercise capacity and functional reserve of the failing heart through enhancing the cardiac flow- and pressure-generating capacity

BACKGROUND: While information on how cardiac resynchronisation therapy (CRT) affects cardiac performance at rest is readily available, the mechanisms whereby CRT alters cardiac function during maximal exercise are unclear. AIMS: We examined the medium-term effects of CRT on cardiac and physical functional reserve of patients with severe heart failure (CHF) and prolonged QRS duration. METHODS: Seventeen consecutive patients with severe CHF (NYHA III-IV) and widened QRS underwent maximal cardiopulmonary exercise testing with non-invasive central haemodynamic measurements before and 6-8 weeks after CRT pacemaker implantation. RESULTS: After CRT there were significant increases in exercise cardiac output by 19.3% (P=0.0048) from 9.5+/-3.4 l min(-1), peak mean arterial blood pressure by 14.1% (P=0.0001) from 91.3+/-13.6 mm Hg, and peak cardiac power output by 37.2% (P=0.0008) from 1.92+/-0.74 W. There were no significant changes in these variables at rest. Exercise duration (+42.3%, P=0.0002), NYHA functional class (P=0.0001) and SF-36 symptom score (P=0.0006) were also significantly improved. Powerful surrogate indicators of prognosis were also significantly improved with CRT: peak O(2) consumption (+20.9%, P=0.0007), VE/VCO(2) slope (-20.0%, P=0.005) and circulatory power (+42.0%, P=0.0012). CONCLUSION: In this cohort of patients, post-implant CRT significantly improved the flow-, pressure- and power-generating capacity of the failing hearts. This may be causally related to the improvements observed in exercise capacity, functional class and symptom scores.     

心脏再同步化治疗对充血性心力衰竭患者内皮功能的影响

目的:探讨心脏再同步化治疗(CRT)对充血性心力衰竭(心衰)患者内皮功能的影响。方法:扩张型心肌病并发心衰患者分为药物治疗组(10例)和CRT+药物治疗组(12例),分别在治疗前、治疗12周末,检测心脏超声、血管内皮功能、脑钠肽(BNP)。结果:与药物治疗组比较,CRT+药物治疗组明显增加患者的心脏输出量[(4.32±1.50)L/min∶(3.41±1.00)L/min,P<0.05]及肱动脉内径的变化率(FMD)[(1 718±123)%∶(976±118)%,P<0.05],FMD和心输出量呈正相关(r=0.6,P=0.003)。结论:CRT可以提高内皮细胞的功能,其机制可能是通过增加心输出量来实现的。     

Oxidative capacity of skeletal muscle in heart failure patients versus sedentary or active control subjects

OBJECTIVES: We investigated the in situ properties of muscle mitochondria using the skinned fiber technique in patients with chronic heart failure (CHF) and sedentary (SED) and more active (ACT) controls to determine: 1) whether respiration of muscle tissue in the SED and ACT groups correlates with peak oxygen consumption (pVO(2)), 2) whether it is altered in CHF, and 3) whether this results from deconditioning or CHF-specific myopathy.BACKGROUND: Skeletal muscle oxidative capacity is thought to partly determine the exercise capacity in humans and its decrease to participate in exercise limitation in CHF.METHODS: M. Vastus lateralis biopsies were obtained from 11 SED group members, 10 ACT group members and 15 patients with CHF at the time of transplantation, saponine-skinned and placed in an oxygraphic chamber to measure basal and maximal adenosine diphosphate (ADP)-stimulated (V(max)) respiration rates and to assess mitochondrial regulation by ADP. All patients received angiotensin-converting enzyme (ACE) inhibitors.RESULTS: The pVO(2) differed in the order CHF < SED < ACT. Compared with SED, muscle alterations in CHF appeared as decreased citrate synthase, creatine kinase and lactate dehydrogenase, whereas the myosin heavy chain profile remained unchanged. However, muscle oxidative capacity (V(max), CHF: 3.53 +/- 0.38; SED: 3.17 +/- 0.48; ACT: 7.47 +/- 0.73, micromol O(2).min(-1).g(-1)dw, p < 0.001 vs. CHF and SED) and regulation were identical in patients in the CHF and SED groups, differing in the ACT group only. In patients with CHF, the correlation between pVO(2) and muscle oxidative capacity observed in controls was displaced toward lower pVO(2) values.CONCLUSIONS: In these patients, the disease-specific muscle metabolic impairments derive mostly from extramitochondrial mechanisms that disrupt the normal symmorphosis relations. The possible roles of ACE inhibitors and level of activity are discussed.     

Biventricular pacing: impact on exercise-induced increases in mitral insufficiency in patients with chronic heart failure

INTRODUCTION:

Mitral regurgitation (MR) in chronic heart failure (CHF) patients frequently worsens with exercise. Cardiac resynchronization therapy (CRT) reduces MR at rest, but its effects on exercise-induced worsening of MR are incompletely explored. The present study examined the influence of CRT on MR during submaximal exercise in CHF patients.

METHODS:

Eleven patients with CHF who were treated with CRT underwent echocardiography while performing steady-state exercise during four conduction modes (intrinsic rhythm, right ventricular [RV], biventricular [BiV] and left ventricular [LV] pacing). Measurements of MR were jet area planimetry, effective regurgitant orifice area, peak MR flow rate and regurgitant volume.

RESULTS:

At rest and during exercise, there were no differences in dyssynchrony between intrinsic rhythm and RV pacing. BiV and LV pacing reduced dyssynchrony at rest and during exercise compared with intrinsic conduction and RV pacing, and there were no differences in the magnitude of these effects between these two pacing modes. At rest, RV pacing increased MR compared with intrinsic conduction (MR regurgitant volume; P<0.05), whereas BiV and LV pacing reduced MR (reductions in effective regurgitant orifice area and jet area; P<0.02, and MR flow rate; P<0.05 with BiV pacing from intrinsic conduction). MR significantly increased on exercise with intrinsic rhythm and RV pacing, whereas with LV and BiV pacing, there were no significant exercise-induced increases in any MR variable. There were relationships between changes in measures of dyssynchrony and reductions in MR at rest and during exercise.

CONCLUSIONS:

CRT reduces MR at rest and during exercise, and prevents exercise-induced MR. Reductions in MR during exercise correlate with improvements in dyssynchrony.     

Transpulmonary passage of Albunex as a marker of intracardiac hemodynamics and outcome in chronic congestive heart failure

BACKGROUND: Aggressive management to reduce pulmonary artery systolic pressure (PASP) and pulmonary capillary wedge pressure (PCWP) reduces hospitalization rates and is crucial for patients awaiting transplantation but may require periodic invasive monitoring with right heart catheterization. METHODS: The purpose of this study was to define the relation of transpulmonary passage of Albunex (Mallinckrodt Medical, St Louis, Mo) to intracardiac hemodynamics and clinical outcome in patients with chronic congestive heart failure (CHF). Patients (n = 38) with chronic CHF underwent graded dobutamine infusion (baseline, 5, 10, 20 microg/kg per minute; 5-minute stages) with 5.0 mL Albunex injected intravenously at each stage. The dobutamine dose at which Albunex appeared in the left ventricle was determined. All patients had right heart catheterization to determine PASP and PCWP. RESULTS: Transpulmonary passage of Albunex at baseline or at 5 microg/kg per minute dobutamine infusion predicted PCWP <20 mm Hg with a positive predictive value of 100% and a negative predictive value of 79%. Initial appearance of Albunex in the left ventricle at a dobutamine dose of 20 microg/kg per minute or failure to appear at any dose predicted a PCWP >20 mm Hg with a positive predictive value of 100% and a negative predictive value of 94%. No patient with Albunex passage at baseline sustained a major adverse event. Major adverse events occurred in 11 of 21 patients in whom Albunex either failed to cross or crossed the pulmonary bed at a dose of 20 microg/kg per minute of dobutamine. CONCLUSION: In patients with chronic CHF, transpulmonary passage of Albunex during dobutamine infusion can be used to predict both elevated and normal intracardiac pressures and to identify a subset of patients at high risk for an adverse outcome.     

脑利钠肽对心力衰竭远期心脏事件的预测价值

目的:研究血浆脑利钠肽(BNP)对慢性心力衰竭(心衰)患者远期心脏事件的预测价值.方法:入选134例心衰患者,双抗体夹心免疫荧光法测定血浆BNP浓度,记录发生的心脏事件.结果:134例中随访资料完整130例,随访时间平均(708±220)d.130例中发生心脏事件者44例(心脏事件组),未发生心脏事件者86例(非心脏事件组),心脏事件组左室舒张末期内径、心胸比率、BNP均较非心脏事件组显著升高(均P<0.01).多元logistic回归分析显示,BNP为心衰患者远期心脏事件独立的预测因子.BNP预测心源性死亡ROC曲线下面积为0.846.BNP取值702.5 ng/L预测心源性死亡的敏感度和特异度达最高.血浆BNP≤702.5 ng/L患者生存率高于BNP>702.5 ng/L者(P<0.05). 结论:BNP是影响慢性心衰患者远期心脏事件的独立预测因素.     

Implantation of cardiac resynchronization therapy systems in the CARE-HF trial: procedural success rate and safety.

AIMS: To assess procedural characteristics and adjudicated procedure-related (300 cm(3); and, influence of the participating study-centres. Implantation was attempted in 404/409 patients assigned to CRT, and in 65/404 patients assigned to medical therapy. Among these 469 patients, 450 (95.9%) received a successfully implanted and activated device. Complications occurred within 24 h in 47 patients (10.0%), mainly lead dislodgments (n = 10, 2.1%) and coronary sinus dissection/perforation (n = 10, 2.1%), and between 24 h and 30 days in 26 patients (5.5%), mainly lead dislodgment (n = 13, 2.8%). Mean LV lead stimulation threshold was significantly higher than at the right atrium or right ventricle, though remained stable, delivering effective, and reliable CRT. Implanting experience was the only predictor of procedural outcome. CONCLUSION: Transvenous CRT system implantation, using a CS lead designed for long-term LV pacing, was safe and reliable. As implanting centres become more experienced, this success rate is expected to increase further.     

Hydrotherapy--a new approach to improve function in the older patient with chronic heart failure

AIMS: Hydrotherapy, i.e. exercise in warm water, as a rehabilitation program has been considered potentially dangerous in patients with chronic heart failure (CHF) due to the increased venous return caused by the hydrostatic pressure. However, hydrotherapy has advantages compared to conventional training. We studied the applicability of an exercise programme in a temperature-controlled swimming pool, with specific reference to exercise capacity, muscle function, quality of life and safety. METHODS AND RESULTS: Twenty-five patients with CHF (NYHA II-III, age 72.1+/-6.1) were randomised into either 8 weeks of hydrotherapy (n=15), or into a control group (n=10). The training program was well tolerated with no adverse events. Patients in the hydrotherapy group improved their maximal exercise capacity (+6.5 vs.-5.9 W, P=0.001), isometric endurance in knee extension (+4 vs.-9 s, P=0.01) together with an improvement in the performance of heel-lift (+4 vs. -3 n.o., P=<0.01), shoulder abduction (+12 vs. -8 s, P=0.01) and shoulder flexion (+6 vs. +4, P=0.01) in comparison to patients in the control group. CONCLUSION: Physical training in warm water was well tolerated and seems to improve exercise capacity as well as muscle function in small muscle groups in patients with CHF. This new approach broadens the variety of training regimes for older patients with CHF.     

Amrinone therapy for congestive heart failure in outpatients with idiopathic dilated cardiomyopathy

Amrinone, 100 mg orally every 8 hours, was administered to 13 patients with moderate-to-severe congestive heart failure (CHF) for 1 month on an outpatient basis to determine the beneficial and undesirable effects of this new cardioactive agent in this clinical setting. These subjects received conventional CHF medications during the course of study. Ten patients who received conventional CHF medications alone served as a control group. Changes in functional classification were not significantly different between the 2 treatment groups. Amrinone augmented exercise capacity 37% above baseline compared with a 12% improvement for the control group. Noninvasive indexes of resting left ventricular function (echocardiography and systolic time intervals) did not change significantly for either group, nor was there a significant change in the exercise ejection fraction. All patients treated with amrinone had ≥ 1 symptom-related or laboratory-detected adverse effect. An increase in the frequency of ventricular ectopic beats was noted at rest in 4 and with exercise in 6 patients (salvos of nonsustained ventricular tachycardia in 2). Six subjects treated with amrinone had gastrointestinal symptoms and 8 developed a viral-like illness. Other adverse effects noted in the amrinone-treated group included near-syncope, headaches, marked anxiety, chest pain, palpitations, maculopapular rash, hypokalemia, and elevation of serum transaminase levels. The control patients had significantly fewer adverse effects.Although individual patients with CHF may benefit from long-term amrinone therapy, the low benefitto-risk-adverse effect ratio does not warrant widespread application of this drug in the outpatient management of CHF and requires caution when prescribing.     

Intrathoracic impedance changes reflect reverse left ventricular remodeling in response to cardiac resynchronization therapy in chronic heart failure patients

Intrathoracic impedance monitoring has been reported to be useful for prediction of worsening chronic heart failure (CHF). However, it has not revealed the relation between changes in intrathoracic impedance and improvement of cardiac function in CHF patients with cardiac resynchronization therapy (CRT) implantation. Therefore, we investigated whether intrathoracic impedance change reflects reverse left ventricular (LV) remodeling in response to CRT in patients with CHF. The study subjects consisted of 29 CHF patients (23 males, mean age 64 ± 12 years) with CRT-defibrillator (CRT-D) implantation. The patients were divided into two groups based on whether the Opti-vol Fluid Index^? reached over 60 ohms (group A, n = 7) or not (group B, n = 22) within 6 months of observation after CRT-D implantation. Levels of plasma B-type natriuretic peptide (BNP) were measured, and LV end-diastolic volume (LVEDV), LV end-systolic volume (LVESV), and LV ejection fraction (LVEF) were evaluated before and 6 months after CRT-D implantation. In group B, BNP (556 ± 88 pg/mL versus 330 ± 70 pg/mL, P < 0.05), LVEDV (177 ± 18 mL versus 149 ± 14 mL, P < 0.01), and LVESV (128 ± 14 mL versus 100 ± 12 mL, P < 0.01) were significantly decreased 6 months after CRT-D implantation. LVEF (28 ± 2% versus 35 ± 2%, P < 0.01) was significantly increased after CRT-D implantation. On the other hand, no significant changes were detected in any parameters in group A. These data showed intrathoracic impedance changes reflected reverse LV remodeling in response to CRT in patients with CHF. Therefore, the monitoring of changes in intrathoracic impedance is useful for predicting CRT responders in patients with CHF.     

Left ventricular volume and ejection fraction response to exercise in chronic congestive heart failure: difference between dilated cardiomyopathy and previous myocardial infarction

To determine if cause influences the left ventricular (LV) volume and ejection fraction (EF) response to exercise, 24 patients with chronic congestive heart failure (CHF) (13 dilated cardiomyopathy [DC], CHF-DC group; 11 previous myocardial infarction [MI], CHF-MI group) and 6 age-matched control subjects underwent simultaneous hemodynamic monitoring and radionuclide ventriculography during semiupright bicycle exercise. Both CHF groups had similar hemodynamic values, LV volumes and EF at rest. Exercise hemodynamics were also similar, but LV volume and EF responses to exercise were different. In the CHF-DC group LV end-diastolic volume increased by 15% during exercise, significantly less (p less than 0.01) than the 44% increase in CHF-MI group. During exercise, EF increased in CHF-DC group, but did not change in CHF-MI group because of a larger increase in end-systolic volume. The slope of mean pulmonary wedge pressure-LV end-diastolic volume relation was steeper in CHF-DC group than in CHF-MI group (p less than 0.01). The study suggests that LV volume and EF response to exercise in patients with CHF depends on the origin of the CHF.     

Clinical and electrocardiographic predictors of a positive response to cardiac resynchronization therapy in advanced heart failure.

AIMS: Cardiac resynchronization therapy (CRT) is an effective treatment for refractory congestive heart failure (CHF). However, up to 30% of patients do not respond to CRT. The aim of this study was to identify clinical and electrocardiographic (ECG) predictors of a positive response to CRT. METHODS AND RESULTS: This retrospective study included 139 consecutive patients successfully implanted with a CRT device (mean age, 68+/-9 years, 113 men). At baseline, 69% of patients were in New York Heart Association (NYHA) functional class III, and 31% in class IV, mean left ventricular ejection fraction was 21+/-6%, and mean QRS duration was 188+/-28 ms. In each patient, left and right ventricular leads were placed to attain the shortest QRS duration during biventricular stimulation. Patients were classified at 6 months as responders to CRT (n=100) if they were alive, they had not been re-hospitalized for management of CHF, and the NYHA class had decreased by 1 point, and/or peak VO(2) or 6 min hall-walk increased by >10%. All others were classified as non-responders (n=38; one patient was lost to follow-up). Uni- and multivariate logistic regression analyses were performed to detect a pre- or intra-operative predictor of a positive response to CRT. Among multiple demographic, clinical, and ECG variables, the amount of QRS shortening (DeltaQRS) associated with biventricular stimulation was the only independent predictor of a positive (37+/-23 ms) vs. negative (11+/-23 ms) response to CRT (P<0.001). CONCLUSION: A positive response to CRT was observed in 73% of patients at 6 months and predicted only by DeltaQRS.     

Cardiac resynchronization therapy in patients with heart failure and conduction abnormalities other than left bundle-branch block: analysis of the Multicenter InSync Randomized Clinical Evaluation (MIRACLE)

BACKGROUND: Cardiac resynchronization therapy (CRT) has been proposed as a treatment for patients with congestive heart failure (CHF) and prolonged QRS durations. Previous studies have predominantly included patients with left bundle-branch block (LBBB). The Multicenter InSync Randomized Clinical Evaluation (MIRACLE) investigators assessed the efficacy of CRT in patients with CHF with QRS durations > or = 130 ms and found that CRT lead to improvement in several measures of functional capacity and exercise tolerance. HYPOTHESIS: We designed this retrospective study to determine whether patients with CHF who have conduction abnormalities other than LBBB also respond favorably to CRT. METHODS: We divided patients enrolled in the MIRACLE trial into three subgroups according to conduction abnormality--LBBB, right bundle-branch block (RBBB), and nonspecific interventricular conduction delay (IVCD)--and compared the response among and within these groups to CRT or no CRT at baseline and 6-months' follow-up. RESULTS: We found 313 patients with LBBB, 43 with RBBB, and 35 with IVCD. When they received CRT, significant improvement was achieved in functional class (p = 0.001) by patients with RBBB, and in quality of life (p = 0.038) by patients with IVCD. Patients in the RBBB and IVCD groups showed improvement in exercise time and peak oxygen consumption after CRT. Most patients with RBBB (82%) also had either left anterior fascicular block or left posterior fascicular block. CONCLUSIONS: Patients with CHF with RBBB and IVCD do benefit from CRT. Improvement with CRT in patients with RBBB may be due to concomitant left-sided conduction abnormalities. Further subgroup analyses of other CRT trials are necessary to validate these results.     

心电图ST段压低、QTc、QTd及投影间夹角有助于判断慢性心力衰竭患者心脏同步化治疗的预后

目的:探讨心肌复极异常心电图对慢性心力衰竭（CHF）患者心脏再同步化治疗（CRT）预后的预测价值。方法：收集102例CHF且行CRT治疗患者的临床病历资料，术后随访3年，依据随访终点情况分为死亡组25例和存活组77例。CRT术前完善所有患者心电图及心脏彩超，比较2组患者ST段压低、QTc、QTd、投影间夹角（TMD）及QRS波时限情况；采用多因素Logistic回归分析影响CHF患者CRT治疗预后的因素；绘制心电图指标对CHF患者预后的受试者工作特征（ROC）曲线，判断心电图ST段压低、QTc、QTd及TMD对CHF患者CRT治疗预后的预测价值。结果：2组的病程、纽约心脏协会（NYHA）分级、并发心房颤动、左室射血分数(LVEF)、左心室内径（LVD）及左心房内径（LAD）比较，差异有统计学意义（P均＜0.05）；死亡组病例心电图具有明显更高的ST段压低、QTc、QTd及TMD（P均<0.05）。多因素Logistic回归分析可知，NYHA分级、心房颤动、ST段压低、QTc、QTd、TMD、LVEF、LVD及LAD均是CHF患者CRT治疗预后的独立危险因素。ROC曲线显示，TMD具有最大的预测效能，其曲线下面积（AUC）为0.839，约登指数为0.61；其次为QTd，AUC为0.817，约登指数为0.44；ST段压低的AUC为0.748，约登指数为0.41；最低为QTc，AUC为0.724，约登指数为0.36。结论：心电复极参数ST段压低、QTc、QTd及TMD异常增加均提示CHF患者CRT治疗预后效果较差。     

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.     

冠心病慢性心力衰竭患者室性心律失常的临床治疗分析

目的：研究冠心病慢性心力衰竭患者室性心律失常患者的临床治疗资料,为后期治疗提供可靠的参考数据。方法选取我院2012年3月-2013年2月收治的180例冠心病慢性心力衰竭患者,随机把患者分为对照组及观察组各90例,对照组采用西药,观察组在对照组基础上加以中药联合治疗,分析对比两组患者用药后的临床疗效及不良反应。结果观察组疗效及不良反应均优于对照组,观察组总有效率为90%,而对照组总仅仅达到72.2%,组间总有效率比较,具有显著差异性。结论应用中西医结合治疗冠心病慢性心力衰竭并发室性心律失常,其临床疗效显著,可有效地控制心律失常,减少不良反应,是临床用药的好方法,值得临床上大力推广。     

Predictive significance for sudden death of microvolt-level T wave alternans in New York Heart Association class II congestive heart failure patients: a prospective study

BACKGROUND: Sudden cardiac death (SDC) is responsible for approximately 60-70% of deaths in New York Heart Association (NYHA) class II congestive heart failure (CHF) patients. Recently, microvolt-level T wave alternans has been proposed as a new noninvasive tool to identify CHF patients at risk for SCD and ventricular tachycardia/fibrillation (VT/VF). OBJECTIVES: To determine the prognostic value of MTWA in NYHA class II patients. METHODS: Among 181 consecutive CHF patients with ischemic and nonischemic cardiomyopathy, 73 patients in NYHA class II with left ventricular ejection fraction <45% were selected and prospectively investigated. MTWA was determined during bicycle exercise testing. The study end point was defined as SCD, documented sustained VT/VF and appropriate implantable cardioverter defibrillator (ICD) shock. RESULTS: MTWA was positive in 30 (41%) patients, negative in 26(36%) patients and indeterminate in 17 (23%) patients. During an average follow-up of 17.1+/-7.4 months, seven patients had an arrhythmic event in the MTWA positive group, whereas one and no events occurred in the indeterminate and negative group, respectively. From Kaplan-Meier univariate analysis and multivariate Cox analysis, MTWA was a significant arrhythmic risk stratifier (p=0.01 and p=0.03, respectively). Sensitivity, specificity, negative and positive predictive values of MTWA were 100%, 53%, 100% and 24%, respectively. CONCLUSION: Our data suggest that MTWA is a promising predictor of arrhythmic events in NYHA class II CHF patients.