Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0018801 (heart failure)
 72,216 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A 70-year-old woman with dilated cardiomyopathy and recurrent severe heart failure was admitted for biventricular pacing (BVP), which was recently reported to have clinical efficacy for severe heart failure with intraventricular conduction delay. An electrocardiogram showed complete left bundle branch block, and the QRS interval was markedly prolonged at 195 msec. Echocardiogram showed marked dilatation, diffuse hypokinesis and dyssynchrony of the left ventricle, and grade III mitral valve regurgitation. The patient underwent implantation of an atriobiventricular pacemaker and three pacing leads transvenously. The QRS interval shortened to 165 msec immediately after the BVP therapy, and improvements in echocardiographic parameters were seen at 5 months after BVP therapy. Myocardial oxidative metabolism was assessed by the monoexponential clearance rate of [11C]acetate (Kmono) as measured by positron emission tomography (PET), and myocardial efficiency was assessed by the work metabolic index (WMI) at 1 and 5 months after the BVP therapy. The PET images obtained 5 months after BVP therapy showed a decrease in the clearance of [11C]acetate compared with that obtained 1 month after BVP therapy. The Kmono of the whole left ventricle decreased from 0.051 at 1 month to 0.038 min-1 at 5 months after BVP therapy, and that of the septum, anterior wall, lateral wall and posterior wall also decreased. The WMI increased from 4.2 x 10(6) to 6.8 x 10(6) mmHg. ml/m2. These results suggest that BVP improved left ventricular function without increasing myocardial oxidative metabolism, resulting in improved myocardial efficiency, and that BVP may improve the long-term prognosis of heart failure patients with ventricular dyssynchrony. [11C]acetate PET is a useful method of evaluating global and regional myocardial oxidative metabolism in patients who have undergone BVP therapy.
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PMID:Changes in myocardial oxidative metabolism after biventricular pacing as evaluated by [11C]acetate positron emission tomography. 1465 62

Congestive heart failure afflicts 2 to 4 million people in the US and nearly 15 million people worldwide. Accepted goals of heart failure treatment include: improvement of symptoms;prevention of disease progression; and reduction in morbidity and mortality. Complex pharmacological therapies achieve these goals, but not in all patients with heart failure. Cardiac resynchronization therapy (CRT) represents a new therapeutic approach in patients with chronic heart failure. CRT is only applicable to a subgroup of patients with ventricular conduction system delay, characterized by prolonged QRS duration. Bundle branch block impacts 20 to 30% of patients with New York Heart Association (NYHA) functional class III-IV heart failure and consists predominantly of left bundle branch block. When left ventricular (LV) conduction delay is superimposed upon ventricular dysfunction, it appears to be a marker of disease severity. These conduction abnormalities have deleterious effects both on systolic function and LV filling, and they can induce or enhance mitral functional regurgitation. CRT attempts to correct the deleterious effect of dysynchrony by increasing LV filling time, decreasing septal dyskinesis and reducing mitral regurgitation. Several observational studies and randomized, controlled trials have shown the benefit of CRT in a subgroup of patients with heart failure, with conduction delays. Improvements were found in the mean distance walked in 6 minutes, quality of life (QOL), NYHA functional class, in peak oxygen uptake (V-dot(2)), total exercise time, reduction of hospitalization, LV function and reduction of the LV end-diastolic diameter. These studies support the therapeutic value of ventricular resynchronization in patients with severe heart failure, who have intraventricular conduction delay but who do not have a standard indication for the implantation of a pacemaker. In respect to these study results, possible indications for a biventricular pacing device at this time are as follows: NYHA functional class III, LV ejection fraction <35%, sinus rhythm, QRS duration >150 msec and drug refractory despite individual optimal heart failure therapy. CRT significantly improved symptoms, exercise tolerance and QOL in most patients. However, further studies are needed to assess long-term clinical effects and prognosis, as well as economic benefit of this therapeutic approach.
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PMID:Cardiac resynchronization therapy in patients with chronic heart failure: pathophysiology and current experience. 1472 67

Heart failure is associated with poor long term survival due to progressive refractory heart dysfunction and sudden cardiac death. Cardiac resynchronization through atrio-biventricular pacing has been introduced to treat patients affected by drug-refractory heart failure with desynchronized ventricular activation, as for complete left bundle branch block. The technique is aimed to overcome interventricular and intraventricular conduction delays leading to ventricular dysynchrony, paradoxical septal wall motion, presystolic mitral regurgitation and reduced diastolic filling times. Short term studies demonstrated that biventricular pacing (and perhaps left ventricular pacing alone) may improve both systolic and diastolic function. Initial studies in patients receiving long term pacing consistently showed significant QRS shortening associated with improvement in symptoms, left ventricular ejection fraction, exercise tolerance, quality of life and New York Heart Association functional class. As far as sudden cardiac death prevention in heart failure is concerned, implantable cardioverter defibrillator (ICD) implantation has been demonstrated to be the most effective therapy in patients with prior cardiac arrest due to ventricular fibrillation or poorly tolerated ventricular tachycardia. Low left ventricular ejection fraction, unsustained ventricular tachycardia and inducibility at electrophysiological study also may identify high risk patients requiring ICD implantation. Further studies are needed to evaluate the effect of cardiac resynchronization on hard end-points, such as survival and long term clinical outcome, and to upgrade risk stratification criteria to be used in selection of candidates for ICD implantation.
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PMID:Electrotherapeutic management of patients with heart failure. 1472 22

Cardiac resynchronization therapy has been proven to improve symptoms and indices of left ventricular function in patients with heart failure and intraventricular conduction delays. We present a case of a patient with New York Association Class III heart failure and left bundle branch block, who received a biventricular pacemaker in order to achieve cardiac resynchronization. Her symptoms improved markedly, as did left ventricular ejection fraction and dimensions. In addition, her intrinsic QRS duration normalized. This may represent a salutory effect of biventricular pacing on electrical remodeling.
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PMID:Loss of left bundle branch block following biventricular pacing therapy for heart failure: evidence for electrical remodeling? 1527 49

This study was designed to examine the effect of left bundle branch block (LBBB) on systolic and diastolic function of the left ventricle (LV) in patients with heart failure and in normal subjects. Thirty-six patients with heart failure and LBBB (group I), 36 patients with heart failure with normal conduction (group II), and 41 subjects with isolated LBBB (group III) were compared. Coronary angiography was performed and LV end diastolic pressure was calculated. Echocardiography was performed on all patients. LV ejection fraction and mean rate of circumferential shortening were calculated. The following Doppler parameters were evaluated: peak rapid filling velocity (E wave), peak atrial filling velocity (A wave), E- and A-wave integrals, E-wave acceleration time and deceleration time (EDT) and rates (EAR and EDR), the E/A ratio and its integral, and diastolic flow time (DT). The ejection time, isovolumetric relaxation time (IRT), and preejection period were measured using the aortic and mitral flow. LV end diastolic pressure was calculated as 28 +/- 4 mm Hg, 22 +/- 5 mm Hg, and 15 +/- 3 mm Hg in groups I, II, and III, respectively. Although the systolic function parameters in group III patients were different, the diastolic function parameters of group II were found to be quite similar to those of group III patients. Comparison of group I patients with group II patients showed that there was a similarity between LV systolic function parameters while the diastolic function parameters were different (E/A, p = 0.004; EAR, p < 0.001; EDR, p < 0.001; EDT, p < 0.001; IRT, p = 0.024; DT, p = 0.03). In conclusion, this study evaluating the effects of LBBB in normal subjects (isolated LBBB) and patients with heart failure showed that LBBB causes diastolic function impairment in normal subjects similar to those of patients with heart failure, and also increases impairment of diastolic function in patients with heart failure.
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PMID:Effect of left bundle branch block on systolic and diastolic function of left ventricle in heart failure. 1475 91

Landmark trials have demonstrated that biventricular pacing (also called cardiac resynchronisation therapy or CRT) in chronic heart failure due to left ventricular dysfunction improves symptomatic status, exercise capacity and quality of life. Yet critically, all-cause mortality has not been demonstrated to be reduced in any of the four randomised controlled trials with mortality data (CONTAK-CD, InSync implantable-cardioverter defibrillator (ICD), MIRACLE and MUSTIC). With the much larger COMPANION study now terminated, however, the currently available pooled data from all five trials shows a significant reduction in all-cause mortality, odds ratio (OR), 0.74: 95% confidence interval (CI) 0.56-0.97. This may now establish biventricular pacing as a standard therapy for a specific subset of patients with chronic heart failure and LBBB.
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PMID:Cardiac resynchronisation may reduce all-cause mortality: meta-analysis of preliminary COMPANION data with CONTAK-CD, InSync ICD, MIRACLE and MUSTIC. 1608 Sep 92

Cardiac resynchronization therapy (CRT) is a recently introduced therapeutic option for patients with severe heart failure and intraventricular conduction disturbances. However, it is estimated that 20% to 30% of patients may not respond to CRT. Patients with ischemic cardiomyopathy (IC) may respond less favorably to CRT compared with patients with idiopathic dilated cardiomyopathy (IDC). Accordingly, the beneficial effects of CRT were evaluated in 2 subsets of patients (IC and IDC). Seventy-four patients with end-stage heart failure, New York Heart Association (NYHA) class III or IV, left ventricular (LV) ejection fraction <35%, QRS >120ms, and left bundle branch block received a biventricular pacemaker. At baseline and 6 months after implantation these parameters were evaluated: NYHA class, Minnesota quality-of-life score, QRS duration, and 6-minute walking distance. LV ejection fraction and severity of mitral regurgitation were assessed before and 6 months after CRT using 2-dimensional echocardiography. Long-term follow-up and hospitalization rates were obtained up to 2 years. Of the 74 patients, 46% (n = 34) had IC and 54% (n = 40) IDC. At 6 months follow-up all clinical parameters, QRS duration, LV ejection fraction, and mitral regurgitation improved significantly in both groups. Long-term (2-year) follow-up showed a survival rate of 87.5% for patients with IDC and 88.3% for patients with IC. The percentages of responders to CRT (defined as an improvement in NYHA class >or=1 grade) were comparable in both groups (65% vs 71%). Therefore, the underlying etiology of heart failure (IC vs IDC) was not related to the response to CRT.
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PMID:Comparison of benefits from cardiac resynchronization therapy in patients with ischemic cardiomyopathy versus idiopathic dilated cardiomyopathy. 1505 Apr 89

Dyssynchronous ventricular contraction, often associated with delayed electrical activation, contributes to worsened clinical status in patients with chronic dilated heart failure. There are three levels of impaired electromechanical synchrony that can be recognized and potentially improved with pacing methods. Prolonged atrioventricular (AV) delay can promote presystolic mitral regurgitation and impaired left ventricular (LV) filling. Interventricular conduction delay with right ventricular (RV) activation preceding LV activation often occurs in the setting of left bundle branch block or RV apical pacing, and can result in impeded LV filling and ejection. Activation delays within the LV itself (intraventricular dyssynchrony) can cause decreased efficiency of contraction, increased mitral regurgitation, and abnormal ventricular remodeling. Cardiac resynchronization therapy (CRT) can improve ventricular performance in two thirds of patients selected based on QRS duration alone. Improved understanding of the pathophysiology of cardiac dyssynchrony will aid in patient selection and in assessment and optimization of response to CRT.
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PMID:Physiology of cardiac resynchronization. 1507 53

A 73-year-old woman with dilated cardiomyopathy presented with heart failure. The ECG showed sinus rhythm with left bundle branch block, left-axis deviation and prolonged QRS duration and frequent ventricular premature complexes from the left ventricular septal wall were present. Ventricular premature beats had narrower QRS duration than sinus node beats conducted through the His-purkinje fibers consistent with resynchronizing beats. The mechanisms of narrowing of the QRS complex produced by premature beats in cases of impaired intra and interventricular conduction are discussed.
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PMID:Spontaneous cardiac resynchronization. 1512 81

Cardiac resynchronization therapy (CRT) or biventricular pacing is a novel adjunctive therapy for patients with advanced heart failure (HF). Many patients with severe HF have a left bundle branch block or an intraventricular conduction delay, with up to 25% of patients with a QRS > 120 ms, resulting in significant left ventricular (LV) dyssynchrony and a high mortality rate. The efficacy of CRT is based on the reduction in the conduction delay between the two ventricles and optimization of the ejection fraction, decrement in mitral regurgitation, LV remodeling, thus resulting in symptom improvement. Cardiac resynchronization therapy can be achieved both transvenously using a coronary sinus branch, or epicardially. Clinical trials have demonstrated a significant improvement in the NYHA class and the exercise capacity as well as a marked reduction in the hospitalization rate. More recently, the COMPANION trial showed a 43% reduction in a composite endpoint of all-cause mortality and hospitalization in the group receiving a CRT device in combination with an implantable cardiac defibrillator (ICD). Thus, management of patients with reduced LV function, wide QRS, and symptomatic refractory HF, despite optimal drug therapy, should include CRT as an option. The adjunct of an ICD combined with CRT should be considered if the LV ejection fraction (ischemic cardiomyopathy) is <30%. There are still significant unanswered questions regarding the nonresponder population and the role of tissue Doppler imaging techniques, the impact of CRT on total mortality and CRT in dilated cardiomyopathy or chronic atrial fibrillation. The use CRT postoperatively or at time of cardiac surgery, as well as new epicardial approaches using a thoracoscopic approach or robotically assisted surgery in patients not suitable for coronary vein leads are challenging topics to address in the years to come.
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PMID:Cardiac resynchronization therapy: device-based medicine for heart failure. 1515 61


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