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Query: UMLS:C0018801 (heart failure)
 72,216 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Resynchronization with biventricular pacing is a relatively new and important nonpharmacological therapy for patients with heart failure. A prolonged PR interval, a wide QRS, and left bundle branch block are typical conduction disturbances associated with left ventricular dysfunction. The intraventricular conduction delays often lead to loss of synchronization of ventricular contraction, thus contributing to additional problems for the heart failure patient. Biventricular pacing offers (surgically implanted leads implies a thoracotomy or mini-thoracotomy for an epicardial lead and not the preferred transvenous approach) for an endocardial lead, considerable promise for improving the quality of life, exercise tolerance, as well as for decreasing hospitalization for patients with Class III or Class IV heart failure.
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PMID:Biventricular pacing for congestive heart failure. 1266 48

Biventricular pacing has been used as an adjunct to standard heart failure therapy in symptomatic patients with left bundle branch block (LBBB). Estimates of the number of patients for whom this treatment is appropriate are unavailable, but are of clinical and socioeconomic importance. LBBB combined with a low (< 0.35) ejection fraction was found in 7,121 consecutive patients referred for elective diagnostic angiography in 1996 through 2000 from a total population of about 125,000 residents. Patients with LBBB (n = 289, 4%) had lower ejection fractions (0.53 +/- 0.23) in comparison with patients without LBBB (P < 0.0001). The ejection fraction was < 0.35 in 558 (8%) patients. LBBB was combined with a low ejection fraction in 96 (1.4%) patients (i.e., 19 patients per year and about 15 patients per year per 100,000 residents). Of these 96 patients, 80 had normal sinus rhythm, 82 had mitral regurgitation (grade > II), 86 were < 75 years of age, and 68 had coronary artery disease. Holter recordings performed in 47 of 96 patients showed nonsustained VT in 28 (60%). LBBB, low ejection fraction, sinus rhythm, and age < 75 years were found in 71 (1%) patients (i.e., 11 patients per year per 100,000 residents). The prevalence of LBBB combined with severely impaired left ventricular ejection function is about 1-2% in patients who undergo cardiac catheterization. The authors estimate that biventricular pacing might be considered as an adjunct to standard heart failure therapy in five to ten patients per year per 100,000 residents in industrial countries. About half of these patients are potential candidates for implantation of cardioverter defibrillators combined with permanent pacing.
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PMID:Proportion of candidates for cardiac resynchronization therapy. 1268 2

Biventricular pacing has been suggested as offering greater hemodynamic benefit than single site pacing in patients with advanced heart failure and left bundle branch block. This was tested using acute multisite pacing. Eighteen such patients were atrialsensed, ventricular multisite paced in random order for 5 minutes. The best achieved measure of cardiac output (CO), pulmonary capillary wedge pressure (PCWP) and left ventricular (LV) + dP/dtmax at RV, LV, and biventricular pacing sites compared. Baseline PCWP, CO, and LV + dP/dtmax were 20 +/- 10 mmHg 4.8 +/- 1.3 L/min and 680 +/- 173 mmHg/s respectively. In all 18 patients CO and in 17 of 18 patients LV + dP/dtmax and PCWP improved with pacing. In the group as a whole, no significant hemodynamic difference between pacing sites was observed in PCWP (pacing site RV 19 +/- 10 mmHg, LV 17 +/- 10, biventricular 18 +/- 11) or CO (RV 5.2 +/- 1.5 L/min, LV 5.1 +/- 1.5, biventricular 5.3 +/- 1.7). Increased stroke volume/PCWP with LV (5.6 +/- 3.7 mLs/mmHg) and biventricular pacing (5.4 +/- 4.0) were not significantly greater compared to RV pacing (4.7 +/- 3.0, ANOVA P = 0.20). Increase in LV + dP/dtmax with pacing at LV (814 +/- 190 mmHg/s) and biventricular (839 +/- 290) sites was not significantly greater than the increase with RV pacing (769 +/- 203 mmHg/s, ANOVA P = 0.30). Pacing in patients with heart failure and conduction delay can produce a hemodynamic benefit. There is individual variation in the pacing site that leads to the greatest improvement. In the group as a whole, biventricular and LV pacing produced only modest improvements compared to RV pacing.
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PMID:Comparison between biventricular pacing and single site pacing in patients with poor ventricular function: a hemodynamic study. 1271 Mar 13

Cardiac resynchronization therapy is a novel nonpharmacologic approach to treating patients who have advanced heart failure with left bundle branch block (LBBB). Such a therapy is based on the original theory that synchronous biventricular pacing is able to reduce the interventricular delay caused by LBBB in patients with heart failure. Although there is convincing evidence that biventricular pacing increases the left ventricular ejection fraction, decreases mitral regurgitation, and improves symptoms caused by heart failure, the percentage of nonresponders to such therapy has been described as high as about one third of patients with heart failure having LBBB. Factors responsible for this relatively high prevalence are reviewed, the most important of them probably being left intraventricular dyssynchrony, which can persist after biventricular pacing, notwithstanding right and left interventricular resynchronization. Such a dyssynchrony, as evaluated by tissue Doppler imaging, may be because of the discordance between the site of the left ventricular pacing and the site of the left ventricular delay. Therefore, to characterize the pathophysiologic pattern of LBBB, the investigators suggest an assessment of the electromechanical dysfunction with a noninvasive reliable technique, such as tissue Doppler imaging, which can be repeated after biventricular pacing.
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PMID:Biventricular pacing in heart failure: back to basics in the pathophysiology of left bundle branch block to reduce the number of nonresponders. 1272 51

Two fatal cases of human chronic chagasic cardiomyopathy are reported, for the first time, in autochthonous patients from Rio Negro, Amazonas state. Both cases, (45 year old man and 44 year old woman) who were born and lived their whole lives in the Rio Negro region, in the northern part of the state of Amazonas, reported having been bitten several times by triatomine bugs in their camping huts while gathering pia ava fibers. The patients, who had confirmed positive serology for Trypanosoma cruzi antibodies (indirect immunofluorescence, ELISA and Western blot), developed in the last 5-7 years a progressive cardiac failure, with global enlargement of the heart, atrioventricular and left bundle branch block, ventricular extrasystoles, both dying from irreversible cardiac insufficiency. The histopathology of a post-mortem surgical cardiac biopsy performed in one of the cases showed chronic myocarditis with diffuse mononuclear cell infiltrates, with areas of focal cell accumulation, fibrosis, lytic necrosis of myocardial fibers, suggestive of chronic chagasic myocarditis. An in situ PCR was positive for Trypanosoma cruzi.
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PMID:[Dilated cardiomyopathy in patients with chronic chagasic infection: report of two fatal autochthonous cases from Rio Negro, State of Amazonas, Brazil]. 1290 42

Despite the major advances in medical drug therapy, heart failure remains a syndrome with high mortality and morbidity. Biventricular pacing is being tested in congestive heart failure patients with left bundle branch block of an advanced degree. The aim is to resynchronize the dyscoordinate left ventricle contraction. A number of studies are underway, but it is clear that while some patients respond remarkably, this method in highly variable. Accurate identification of patients likely to benefit will be crucial.
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PMID:[Ventricular resynchronization in the treatment of heart failure]. 1296 47

Cardiac resynchronization therapy (CRT) can improve cardiac function in patients with heart failure and left bundle branch block. To test a new synchrony index derived from mitral annular velocity by color tissue Doppler, 19 subjects were studied: 9 patients with heart failure and left bundle branch block at baseline and at 1, 3 and 6 months after CRT and 10 normal controls. The synchrony index in patients with heart failure was less than that in controls at baseline (r = 0.60 +/- 0.13 vs 0.94 +/- 0.02; p <0.01), but improved at 6 months after CRT (r = 0.77 +/- 0.09; p <0.05 vs baseline).
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PMID:Regional correlation by color-coded tissue Doppler to quantify improvements in mechanical left ventricular synchrony after biventricular pacing therapy. 1297 28

Transvenous Biventricular Pacing in Children. Cardiac resynchronization therapy improves short-term and long-term hemodynamics in adult patients with congestive heart failure and left bundle branch block. We describe the feasibility of transvenous biventricular pacemaker implantation in a 6-year-old child with heart failure and wide QRS complex after congenital heart surgery. Myocardial tissue Doppler imaging was used to demonstrate intraventricular dyssynchrony and resynchronization after cardiac resynchronization therapy. During 1-year follow-up, symptomatology and hemodynamic parameters improved.
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PMID:Transvenous biventricular pacing in a child after congenital heart surgery as an alternative therapy for congestive heart failure. 1452 66

We evaluated patients with end-stage heart failure who have a high likelihood of response to cardiac resynchronization therapy (biventricular pacing). It appears that 20% of patients do not respond to this expensive therapy despite the use of selection criteria (dilated cardiomyopathy, heart failure, New York Heart Association class II or IV, left ventricular ejection fraction <35%, left bundle branch block, and QRS >120 ms). The presence of left ventricular dyssynchrony is needed to result in improvement after cardiac resynchronization therapy.
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PMID:Left ventricular dyssynchrony predicts benefit of cardiac resynchronization therapy in patients with end-stage heart failure before pacemaker implantation. 1460 10

Ventricular pacing and left bundle branch block (LBBB) are two of the most common causes of asynchronous electrical activation of the ventricles. The sequence of activation is an important determinant of cardiac pump function. The sequence of activation during LBBB and during pacing at the conventional pacing site, the RV apex, is similar. In this article the literature on the effect of RV pacing and LBBB on regional and global LV pump function, on long-term adaptations (remodeling) and on their possible contribution to the development of heart failure is discussed. Evidence is increasing that asynchronous electrical activation contributes significantly to the development of heart failure.
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PMID:Relation between abnormal ventricular impulse conduction and heart failure. 1463 54


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