Device Therapy for Heart Failure

Division of Cardiology, Department of Medicine, Penn State University College of Medicine, Hershey Medical Center, Hershey, Pennsylvania 17033, USA.
The American Journal of Cardiology (Impact Factor: 3.28). 04/2003; 91(6A):53D-59D. DOI: 10.1016/S0002-9149(02)03380-5
Source: PubMed


Although pharmacologic therapy has made impressive advances in the past decade and is the mainstay of therapy for heart failure (HF), there is still a large unmet need, because morbidity and mortality remain unacceptably high. Implanted medical devices are gaining increasing utility in this group of patients and have the potential to revolutionize the treatment of HF. The majority of devices in clinical use or under active investigation in HF can be grouped into 1 of 4 categories: devices to monitor the HF condition, devices to treat rhythm disturbances, devices to improve the mechanical efficiency of the heart, and devices to replace part or all of the heart's function. There are several devices either approved or under development to monitor the HF condition, ranging from interactive weight scales to implantable continuous pressure monitors. The challenge is to demonstrate that this technology can improve patient outcomes. Pacemakers and implantable cardioverter defibrillators (ICDs) are used to treat heart rhythms in a broad range of patients with heart disease, but they now have a special place in HF management with the prophylactic use of ICDs in patients who have advanced systolic dysfunction. The Multicenter Automatic Defibrillator Implantation Trial (MADIT) II study demonstrated a 29% reduction in all-cause mortality with ICDs in patients with a history of a myocardial infarction and a left ventricular (LV) ejection fraction <0.30. LV and multisite pacing are means of improving the mechanical efficiency of the heart. The concept is to create a more coordinated contraction of the ventricles to overcome the inefficiency associated with conduction system delays, which are common in HF. The acute hemodynamic effect can be impressive and is immediate. Several studies of intermediate duration (3 to 6 months) have consistently demonstrated that biventricular pacing improves symptoms and exercise capacity. Mechanical methods of remodeling the heart into a more efficient shape have been under scrutiny for several years. New methods of restraining the heart with prosthetic material are under investigation in humans, with encouraging pilot results. Heart replacement has been evaluated clinically with LV assist devices for several decades. The Randomized Evaluation of Mechanical Assistance Therapy as an Alternative in Congestive Heart Failure (REMATCH) study has demonstrated a proof of concept for the use of mechanical blood pumps to improve survival, functional capacity, and symptoms. Several assist devices with such features as total implantability, improved durability, and smaller size are now under study; these may further improve the outcomes of patients. One year ago, the world witnessed the first clinical use of a totally implantable total artificial heart. Although the long-term outcomes were limited, the device demonstrated an impressive ability to improve organ function and extend survival in the population facing imminent death. Further development in this field is expected. The use of devices in HF now has a strong foothold, and the potential exists for substantially greater use of a broad range of devices in the near future.

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    • ". The prevalence of this disease has been increasing substantially over the past two decades [3] [4] and is likely to increase further in the future due to ageing of the population, improved survival from heart attack and heart failure, patients receiving revascularisation and surgical correction of valvular abnormalities who would otherwise not have survived, the increased use of implantable defibrillators and cardiac resynchronisation, the increased prevalence of diabetes and obesity in the population and the wider use of sensitive diagnostic technology [5]. A diagnosis of heart failure is associated with poor prognosis, high mortality and substantial economic burden [6] as highlighted by the estimated 50% five year mortality rate [7] [8]. Much of the morbidity associated with heart failure is related to hospitalisation for worsening disease. "
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    ABSTRACT: Heart failure is a condition which has an increasing incidence as the population ages, leading to increasing prevalence globally and in Australia. This condition also carries very high morbidity and mortality rates, attributed in part to electrical conduction disturbances which lead to sudden cardiac death or pathophysiological cardiac changes due to delayed activation of the left free wall and mechanical dyssynchrony. Current pharmacologic therapy has made impressive advances in improving survival rates in this population, but morbidity and mortality rates still remain high. Additionally, there is also a population of heart failure patients on optimal medical therapy who still suffer from functionally debilitating symptoms of heart failure. Device therapy comprising of implantable cardioverter-defibrillator (ICD) and cardiac resynchronisation therapy (CRT) are used to treat heart rhythm disturbances in a broad range of patients with heart disease and have now become established therapies in patients with heart failure receiving standard medical therapy. This review examines current evidence for the use of implantable cardioverter-defibrillators in the reduction of sudden cardiac death in patients with advanced systolic dysfunction and the use of cardiac resynchronisation therapy in improving ventricular performance as well as mortality and morbidity rates.
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    ABSTRACT: 73, presents with a three-year, progressive shortness of breath (New York Health Association [NYHA ] Class III), chest discomfort upon walking short distances and fatigue. Faye has a history of dyslipidemia, but no history of diabetes mellitus or hypertension. She is an ex-smoker and has no history of alcohol intake. Three years earlier, myocardial perfusion scans showed mild anterior and sepal ischemia. Subsequent cardiac catheterization showed diffuse but non-critical coronary artery disease. She was not a revascularization candidate. Faye's echocardiogram at that time showed a severely reduced left ventricular (LV) ejection fraction of 15% and regional LV wall abnormalities. The LV was dilated with an end-diastolic diameter of 63 mm (normal < 50 mm) and an end-systolic diameter of 57 mm (normal < 33 mm). A moderate mitral regurgitation (MR) was noted. The right ventricle (RV) was normal in diameter and function. Faye was treated with aggressive medical therapy. Her medications at presentation included: • Metoprolol SR, 100 mg, every day (qd) • Candesartan 4 mg, qd (she could not tolerate an angiotensin-converting enzyme inhibitor because of cough) • Spironolactone, 25 mg, qd • Atorvastatin, 10 mg, qd • Acetylsalicylic acid, 325 mg, qd • Nitroglycerine patch, 0.4 mg/hour, qd • Furosemide, 60 mg, qd Continued on page 26.
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    ABSTRACT: Aims Cardiac resynchronization therapy (CRT) has been shown in several clinical trials to improve symptoms and exercise capacity in patients with advanced heart failure. The first clinical trials of CRT-D devices were based on populations who already met a standard indication for implantable cardioverter defibrillator (ICD) therapy. In these patients, when CRT is contemplated, a CRT-D device is used. In a broad population of patients with advanced heart failure, the choice of adding ICD therapy is less clear. Methods and results Results of several clinical trials of CRT and ICD use in heart failure are reviewed. An analysis of data suggests that CRT may reduce death due to progressive heart failure. Recently, the COMPANION trial has reported that CRT can reduce long-term morbidity and mortality. CRT can be delivered as a pacemaker only, or in combination with an ICD. Taken alone, an ICD can improve survival in select groups of patients with left ventricular dysfunction; however, adverse effects have been seen, such as worsening heart failure. Conclusion There are no clinical trials designed specifically to address the relative merits of CRT delivered by pacemaker versus ICD. Based on our knowledge of the effects of both, along with data from recent clinical trials, it appears as though the preponderance of evidence is in favor of CRT-D. More will be learned from clinical trials currently underway. (C) 2004 Published by Elsevier Ltd on behalf of The European Society of Cardiology.
    Preview · Article · Aug 2004 · European Heart Journal Supplements
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