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

The challenge of preventing arrhythmic sudden death is one of the major issues of today's treatment of heart failure. To pursue this aim, an accurate selection of candidates for sudden death has to be routinely carried out, while a maximized and individualized drug treatment has to be extensively administered in all high-risk selected patients. However, in clinical practice there is no agreement on the selection criteria of sudden death risk, particularly in patients with advanced heart failure. Furthermore, the real impact of each category of drugs in reducing the risk of sudden death in heart failure patients is still under debate. As far as non-pharmacological options are concerned, implantable cardioverter-defibrillators (ICD) have 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. However, such a stratification seems to be effective in ischemic more than in non-ischemic patients, while generally the primary prevention of sudden death is still restricted to a minority of patients. Biventricular pacing has been proven to be effective in optimizing left ventricular function in more than 50% of left bundle branch block and advanced heart failure patients, while further studies are needed to evaluate the real impact of cardiac resynchronization therapy on hard endpoints, such as survival and long-term clinical outcome. Therefore, the selection criteria of "responders" to this novel non-pharmacological therapy still have to be defined. There is convincing evidence in the literature that tailored drug therapy can be highly effective in preventing heart failure progression as well as in reducing total and sudden mortality. Nevertheless, prevention of sudden death is still a debated point in heart failure treatment. For this reason, we aimed to provide heart failure specialists with updated reviews on this topic, such as those published in this issue of the Italian Heart Journal Supplement. Therefore, we are proud to present all the authors who contributed with the high quality of their articles to this editorial effort. Obviously, we have to thank the authors, but we also have to address the readers, thanking them in advance for their interest in such an initiative.
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PMID:[Arrhythmia risk stratification in patients with heart failure. Foreword]. 1183 45

Heart failure (HF) is associated with a poor long-term survival due to progressive refractory heart dysfunction and sudden cardiac death. Cardiac resynchronization through three-chambered atriobiventricular pacing has been introduced to treat patients with drug-refractory HF and unsynchronized ventricular activation due to left bundle branch block (LBBB). The technique is aimed to overcome inter- and intraventricular conduction delays leading to a ventricular dyssynchrony, characterized by paradoxical septal wall motion, presystolic mitral regurgitation, and reduction in diastolic filling times. Acute studies demonstrated that biventricular pacing (and maybe left ventricular pacing alone) may improve both systolic and diastolic function. First studies on chronically paced patients consistently showed that the QRS shortening was associated with a significant improvement in symptoms, NYHA functional class, left ventricular ejection fraction (LVEF), exercise tolerance, and quality of life. As far as sudden cardiac death prevention in HF is concerned, the implantable cardioverter-defibrillator (ICD) 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 LVEF, unsustained ventricular tachycardia and inducibility at electrophysiological study also may identify high risk patients requiring ICD implantation. Further studies are needed in evaluating the impact of cardiac resynchronization on hard endpoints, such as survival and long-term clinical outcome, as well as in upgrading risk stratification criteria to be used in candidate selection to ICD implantation. However, HF patients with prior cardiac arrest and LBBB should be considered as the optimal candidates to the "ICD implantation combined with biventricular pacing". Conversely, HF patients with LBBB, but without cardiac arrest, could be considered for "biventricular pacing combined with an ICD". The selection criteria for this novel non-pharmacological therapy still have to be defined. The authors emphasize the main indication to ICD implantation combined with biventricular pacing, i.e. HF patients with prior cardiac arrest and LBBB; controversially, while they discuss the other indications to biventricular pacing combined with an ICD.
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PMID:[Indications and potential benefits of implantable automatic defibrillator endowed with biventricular pacing]. 1183 53

Positive responses to left (LV) and biventricular (BV) stimulation observed in heart failure patients with left bundle branch block (LBBB) suggest a possible mechanism of LV resynchronization. An anesthetized canine LBBB model was developed using radio frequency ablation. Before and after ablation, LV pressure derivative over time (dP/dt) and aortic pulse pressure (PP) were assessed during normal sinus rhythm with right ventricle (RV), LV, or BV stimulation combined with four atrioventricular delays in six dogs. In three more dogs, M-mode echocardiograms of septal and LV posterior wall motion were obtained before and after LBBB and during LV stimulation. LBBB caused QRS widening and hemodynamics deterioration. Before ablation, stimulation alone worsened LV dP/dt and PP. After ablation, LV and BV stimulation maximally increased LV dP/dt by 16% and PP by 7% (P < 0.001), whereas little improvement was observed during RV stimulation. M-mode echocardiogram showed that LBBB resulted in a paradoxical septal wall motion that was corrected by LV stimulation. In conclusion, LV and BV stimulation improved cardiac function in a canine LBBB model via resynchronization of LV excitation and contraction.
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PMID:Left ventricular resynchronization therapy in a canine model of left bundle branch block. 1200 33

Ventricular contraction is achieved by the coordinated electrical activation of the ventricles through the action of the cardiac conduction system. In the presence of left bundle branch block (LBBB) or interventricular conduction delay (IVCD), the ventricular contraction pattern is desynchronized and the stroke volume is reduced as a consequence. In patients with congestive heart failure (CHF) due to systolic dysfunction, the presence of LBBB or IVCD further degrades ventricular function, contributing directly to the severity of their CHF symptoms. Cardiac resynchronization therapy (CRT) through biventricular pacing relieves CHF symptoms and improves functional status in patients with medically refractory heart failure due to left ventricular systolic dysfunction and LBBB or IVCD. The benefits of CRT are due to improvement in the ventricular activation sequence, resulting in a more coordinated and efficient ventricular contraction. In addition to symptomatic benefits, available data support the hypothesis that CRT alters the natural history of CHF in patients with intraventricular conduction delay.
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PMID:Resynchronization Therapy for Congestive Heart Failure. 1209 85

Biventricular pacing has been introduced to treat patients with end-stage heart failure, and short-term results of this technique are promising. Because data on longer follow-up are limited to 3-month follow-up, the sustained effect of biventricular pacing is unclear and long-term survival is unknown. Forty patients with end-stage heart failure in New York Heart Association (NYHA) functional class III or IV with left ventricular (LV) ejection fraction (EF) <35%, QRS duration >120 ms, and left bundle branch block morphology received a biventricular pacemaker. At baseline, and at 3 and 6 months after implantation, the following parameters were evaluated: NYHA class, Minnesota quality-of-life score, QRS duration on surface electrocardiogram, 6-minute walking distance, and LVEF. Long-term follow-up was obtained for up to 2 years. All clinical parameters improved significantly at 3 months and remained unchanged at 6-month follow-up. LVEF increased from 24 +/- 9% to 34 +/- 11%. Before implantation, patients were hospitalized (for congestive heart failure) an average of 3.9 +/- 5.3 days/year compared with 0.5 +/- 1.5 days/year after implantation. Long-term follow-up showed a survival of 87.5% at 2 years. Thus, biventricular pacing resulted in improvement of symptoms and quality of life, accompanied by improvement in 6-minute walking distance and LVEF. These effects were observed at 3 months after implantation and were maintained at 6-month follow-up. Moreover, 2-year survival was excellent.
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PMID:Effectiveness of resynchronization therapy in patients with end-stage heart failure. 1216 Dec 26

Ventricular dysfunction is a hallmark of heart failure, and is often linked to ventricular dilatation and ventricular conduction delays. Recent studies have demonstrated that systolic function can be improved in patients with left bundle branch block by pre-exciting the site of late activation, usually the left ventricular free wall. Furthermore, it has been recently reported that this improvement is associated with a decrease in myocardial oxygen consumption. We hypothesize that the pre-excitation of the region covered by the blocked bundle acts as an "electrical bypass," resynchronizing the contraction of the septum and the left ventricular free wall. In addition, optimization of the electronic atrioventricular delay allows the simultaneous resynchronization of the atrioventricular contractions, and minimization of diastolic mitral regurgitation. Systolic mitral regurgitation may also be reduced by removing the geometric distortion introduced by the left bundle branch block. The recently reported positive outcome of the PATH-CHF I controlled trial reinforces that the positive acute and chronic results that have been reported up to now may translate into long-term clinical benefit for patients with heart failure and conduction defects. Larger studies are needed to confirm these initial results and to establish the impact of this new therapeutic modality on morbidity and mortality. (c)2000 by CHF, Inc.
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PMID:Cardiac resynchronization for heart failure: present status. 1218 38

QRS widening has important clinical and prognostic implications in patients with chronic heart failure. Ventricular conduction abnormalities such as a left bundle branch block, cause ventricular dysynchrony and several hemodynamic disadvantages. The presence of ventricular dysynchrony results in abnormal wall motion, impaired ventricular contractility, decreased ventricular filling, and increased mitral regurgitation. Biventricular pacing has been recently proposed as an adjunct therapy for advanced heart failure in patients with ventricular conduction abnormalities. Biventricular pacing acutely increases the + dP/dt of left ventricle, the systolic blood pressure and the pulse pressure, prolongs the diastolic left ventricular filling time, shortens the mitral regurgitation duration, and reduces the pulmonary wedge pressure. The implantation of biventricular pacemaker results in improvements of the functional class, exercise capacity, quality of life, echocardiographic findings, and neurohormonal data. Although the indication for biventricular pacing has not yet established, patients with functional class III or IV and left bundle branch block or left ventricular conduction delay showing QRS duration > or = 150 ms are good candidates.
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PMID:[Biventricular pacing]. 1238 49

The pathophysiological background of cardiac resynchronization therapy is represented by the intraventricular conduction delay such as left bundle branch block, present in about one third of patients with dilated cardiomyopathy. Intraventricular conduction block, with or without atrioventricular delay, adversely influences ventricular function due to unsynchronized contraction and is associated with a poor prognosis. Contractile dyssynchrony and abnormal atrioventricular delay can be corrected by non-conventional stimulation modalities such as left ventricular pacing or biventricular pacing associated with preexcitation to restore the physiological atrioventricular timing. Over the last decade several studies have reported the short- or long-term favorable effects of resynchronization therapy on the left ventricular function and remodeling, the quality of life, the functional capacity, the adrenergic activity, and the reduced rehospitalization rate. The most significant results have been reported in patients with a QRS duration > or = 150 ms, while the InSync Italian Registry has shown improvement even in patients with a QRS duration < 150 ms as well as in patients with atrial fibrillation. On the basis of such data it may be argued that the activation sequence of the different walls of the left ventricle is likely more important than the QRS duration. Inclusion criteria commonly used in the published or ongoing trials are: moderate to severe congestive heart failure (NYHA functional class III-IV) on optimized pharmacological treatment; left ventricular ejection fraction < or = 35%; left ventricular diastolic diameter > 60 mm; end-diastolic mitral regurgitation; no need of conventional pacing. While with regard to the surrogate endpoints the results of published trials are very encouraging, we do not yet know whether resynchronization therapy prolongs the life expectancy of patients with heart failure. Studies able to provide important answers to these problems are near completion. In the meanwhile, in agreement with the guidelines of the European Society of Cardiology, it seems prudent to employ such a therapy only in case of patients satisfying the above-mentioned criteria.
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PMID:[Refractory heart failure. Multisite stimulation]. 1240 38

Most of patients with heart failure present a left ventricular systolic dysfunction usually, if not always, associated with a diastolic dysfunction. Clinical manifestations and physical examination allows a presumed diagnosis. Some signs guide toward a systolic heart failure: deviation of cardiac impulse, protodiastolic gallop, functional mitral insufficiency, radiological cardiomegaly associated with signs of postcapillary hypertension, anterior Q wave or complete left bundle branch block. Bed-side dosage of B-type natriuretic peptide is useful to make or exclude the diagnosis of heart failure in patients with acute dyspnea from various causes. Doppler echocardiography is essential to confirm the left ventricular systolic dysfunction and its mechanism: ischemic, valvular or myocardial. The value of shortening fraction is better than eye evaluation. Coronary angiography is indicated when the mechanism of heart failure is unclear and if the patient is relevant to revascularization.
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PMID:[Diagnosis of systolic heart failure]. 1243 92

We assessed the feasibility of cardiac contractility modulation (CCM) by electric currents applied during the refractory period in patients with heart failure (HF). Extracellular electric currents modulating action potential and calcium transients have been shown to potentiate myocardial contractility in vitro and in animal models of chronic HF. CCM signals were biphasic square-wave pulses with adjustable amplitude, duration, and time delay from sensing of local electric activity. Signals were applied to the left ventricle through an epicardial vein (in 12 patients) or to the right ventricular (RV) aspect of the septum endocardially (in 6 patients). Simultaneous left ventricular (LV) and aortic pressure measurements were performed using a Millar catheter (Millar Instruments, Houston, Texas). Hemodynamics during RV temporary dual-chamber pacing was regarded as the control condition. Both LV and RV CCM stimulation increased dP/dt(max) to a similar degree (9.1 +/- 4.5% and 7.1 +/- 0.8%, respectively; p <0.01 vs controls), with associated aortic pulse pressure changes of 10.3 +/- 7.2% and 10.8 +/- 1.1% (p <0.01 vs controls). Regional systolic wall motion assessed quantitatively by color kinesis echocardiography was markedly enhanced near the CCM electrode, and the area of increased contractility involved 4.6 +/- 1.2 segments per patient. In 6 patients with HF with left bundle branch block, CCM signals delivered during biventricular pacing (BVP) produced an additional 16.1 +/- 3.7% increase in dP/dt(max) and a 17.0 +/- 7.5% increase in pulse pressure compared with BVP alone (p <0.01). CCM stimulation in patients with HF enhanced regional and global measures of LV systolic function, regardless of the varied delivery chamber or whether modulation was performed during RV pacing or BVP.
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PMID:Cardiac contractility modulation by electric currents applied during the refractory period in patients with heart failure secondary to ischemic or idiopathic dilated cardiomyopathy. 1248 39


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