Arrhythmias in heart failure - therapeutic challenges
Article Abstract:
Heart failure is a condition in which the heart can no longer keep up with the needs of the body; the condition is progressive and involves many physiological changes. Among the physiological changes that occur are changes in the rhythm of the heartbeat itself. While different studies have indicated slightly different rates of arrhythmias, or abnormalities of the heartbeat, all have found that arrhythmias are common among patients with heart failure. Normally, the heartbeat begins at a specialized point in the heart called the sinoatrial node, sometimes referred to as the 'pacemaker'. A heartbeat that does not begin at this node is called ectopic. Ectopic beats will be off in their timing; occasional single ectopic beats are found in 83 percent of all patients with heart failure. Atrial fibrillation, in which the atria of the heart flutter rather than beat in a coordinated fashion, occurs chronically in about a third of patients with heart failure. Supraventricular tachycardia, in which the heart beats too fast as a result of abnormal timing control, is characterized by sudden periodic attacks and occurs in 57 percent of heart failure patients. The powerful ventricles of the heart, which should be doing the majority of the work of pumping blood, occasionally contract prematurely in 87 percent of heart failure patients. Nonsustained ventricular tachycardias, quick contractions in rapid bursts, occur in 54 percent of heart failure patients. Heart failure itself has a particularly poor prognosis, but little is known about the degree to which these abnormalities of heart beat contribute to the deterioration and possible death of the patient. In addition, little is known about whether the treatment of these conditions contributes to improved survival in these patients. Some preliminary studies have suggested that the drug amiodarone may improve the survival of patients with heart failure, but these studies have not been randomized in prospective controlled studies. Therefore, while arrhythmias are common among patients with heart failure, determining the role of these abnormalities in the survival of the patient, and determining the best treatment, still awaits the results of further study. (Consumer Summary produced by Reliance Medical Information, Inc.)
Publication Name: American Journal of Medicine
Subject: Health care industry
ISSN: 0002-9343
Year: 1991
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Reversal of cardiac dysfunction secondary to type I primary hyperoxaluria after combined liver-kidney transplantation
Article Abstract:
Primary hyperoxaluria is an inherited disease that causes overproduction of oxalic acids. The excess produced is excreted by the kidneys, but it eventually begins to damage them and they often completely fail. Once this happens, the oxalic acids, in the form of calcium oxalate, deposit in various parts of the body and cause damage. The heart is often involved. Dialysis can remove oxalate, but not at the rate it is produced. Kidney transplants are usually the only way to increase survival time, by returning normal excretion, although the underlying defect is not treated by such transplants and the transplants eventually fail. Combined liver-kidney transplants can possibly also fix the defect as well as return normal kidney function so that the oxalate can be excreted. The case is reported of a 23-year-old man initially diagnosed when a visit to the emergency room led to abnormal urine tests. He began dialysis, but over time a number of side effects caused by the disease began to occur. His heart was affected by uptake of calcium oxalate, over time increasing in size and decreasing in function. The patient eventually underwent a liver-kidney transplant. Liver function returned almost immediately after the transplant, but the kidneys did not start functioning for many weeks. Intensive dialysis after the operation helped remove excess oxalate, with the new liver helping to decrease its production. The patient's heart began to decrease in size, and left ventricular ejection fraction (the portion of blood pumped into the body by the ventricle - an index of heart function) increased. Tests a few months after the transplantation showed cardiac tissue was clear of calcium oxalate. Other clinical problems caused by the disease also improved. These results show that cardiac disease resulting from primary hyperoxaluria can be improved or reversed when a liver-kidney transplant is performed and normal oxalate production and removal is obtained. (Consumer Summary produced by Reliance Medical Information, Inc.)
Publication Name: American Journal of Medicine
Subject: Health care industry
ISSN: 0002-9343
Year: 1991
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Abnormal pulmonary function specifically related to congestive heart failure: comparison of patients before and after cardiac transplantation
Article Abstract:
Congestive heart failure is the inability of the heart to pump blood, resulting in congestion or accumulation of fluid within the lungs. The effect of heart disease on lung function was assessed by spirometry, the measurement of air capacity within the lungs, before and 15 months after heart transplantation. The study included 17 patients of average age 44 years, including 11 patients with a history of smoking. The forced vital capacity (FVC), or amount of air forcefully inhaled and expired, and the forced expiratory volume (FEV1) at one second were increased after heart transplantation. The ratio of FEV1 to FVC did not differ among patients within the entire group or between patients with and without a history of smoking. However, patients without a smoking history developed normal lung volumes after transplant, compared with patients with a history of smoking. The increase in FVC after heart transplantation correlated with a reduction in the capacity of the heart associated with heart transplantation. The results show that enlargement of the heart associated with congestive heart failure contributes to a decrease in lung volumes. Other features of congestive heart failure such as accumulation of fluids within the cells and in the lung cavity may also contribute to reduced lung volumes. Abnormalities of the lung can be reversed by treating abnormalities in heart structure and function, as is accomplished by heart transplantation. (Consumer Summary produced by Reliance Medical Information, Inc.)
Publication Name: American Journal of Medicine
Subject: Health care industry
ISSN: 0002-9343
Year: 1990
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