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

To analyze the prognosis of the sick sinus syndrome (SSS), we compared the clinical aspects among unpaced, ventricular paced, and physiologically paced patients who were followed over a long period. Unpaced intrinsic SSS was not always progressive and patients did not necessarily require permanent pacing. The incidence of concomitant AV conduction disturbance was 65.6% before pharmacologic autonomic block, (PAB), but this was significantly reduced to 31.7% after PAB. Follow-up study of the physiologically paced groups revealed no development of either new or more than second degree AVB. The VVI group had significantly more complications (68%) than the physiologically paced groups, mainly chronic atrial fibrillation (36%) and thromboembolism (20%). In addition, cardiothoracic ratio (CTR) in the VVI group was significantly greater compared with that in the physiologic groups. Nine deaths occurred during the follow-up period in the pacing groups, including six with VVI and three with physiologic pacing. In the VVI pacing group, heart failure and thromboembolism were most commonly the causes of death, while in the physiologic pacing groups, the causes of death were noncardiac. Although the survival rate in the ventricular paced group was not significantly different from that in the physiologic pacing groups, cardiac deaths were fewer in the latter group. Considering our clinical data, the decision to use ventricular pacing needs to be carefully weighed in patients with sick sinus syndrome, and physiologic pacing is more highly recommended.
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PMID:Long-term follow-up of patients with sick sinus syndrome: a comparison of clinical aspects among unpaced, ventricular inhibited paced, and physiologically paced groups. 246 43

The place of digoxin in the pediatric cardiologist's armamentarium remains uncertain. As an antiarrhythmic, its use in the Wolff-Parkinson-White syndrome is obsolete, but it remains useful in the treatment of the chronic atrial fibrillation seen in some patients postoperatively and in children with dilated cardiomyopathy. The efficacy of digoxin in heart failure is unproven. There is some evidence of improvement in non invasive left ventricular contractile indices in neonates and infants, but it is unclear whether this is associated with sustained clinical improvement. There is even less evidence of its effectiveness in the older child. Whilst the measurement of any effect will undoubtedly be difficult, the time has come for double-blind, placebo-controlled trials in selected groups of patients. These should be designed not only to test the notion that digoxin does not improve ventricular function, but also to embrace the possibility that its administration may result in clinical improvement over and above that following diuretics alone. An absence of proof of efficacy must be distinguished from no efficacy--more data are needed.
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PMID:Does digoxin have a place in the treatment of the child with congenital heart disease? 248 20

Significant variations in the ECG have been observed in a female aged 77 with heart failure and chronic atrial fibrillation during an occasional increase in blood potassium followed by normalization. The major phenomena observed during hyperkalemia, due to a severe dehydration, were a transient sinus rhythm with atrio-ventricular block followed by atrial activity disappearance and advent of interventricular and fascicular block. Therapeutic normalization of blood potassium leads to a progressive disappearance of intraventricular and fascicular block, a temporary sinus rhythm and finally the return to atrial fibrillation which was the steady state of the patient before the blood potassium imbalance.
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PMID:[Increase in blood potassium and subsequent normalization: effects on the electrocardiogram. Case report]. 260 90

Heart failure is almost without exception associated with arrhythmias, which may be either supraventricular or ventricular. Supraventricular arrhythmias include frequent supraventricular extrasystoles, and episodic or chronic atrial fibrillation. The absence of atrial contraction may further reduce cardiac output, as may impaired control of QRS frequency. Therefore, supraventricular arrhythmias may be markers of the degree of heart failure and these arrhythmias will respond to heart failure therapy including diuretics, nitrates and, possibly, angiotensin-converting enzyme (ACE) inhibitors. Ventricular rate will be controlled by cardiac glycosides and further rate reduction obtained by verapamil or diltiazem. The rationale for this therapy is to optimize heart rate without compromising contractility. Severe heart failure is generally accompanied by severe ventricular arrhythmias including repetitive forms. Improving left ventricular function by ACE inhibition is accompanied by a reduction in the number of ventricular premature complexes and also a reduction in the rate of ventricular tachycardia. ACE inhibition reduces mortality but does not seem to influence sudden death rate, and sudden death patients may have different neurohormonal responses compared with patients destined to die of progressive heart failure. Uncontrolled trials with class IA or class III antiarrhythmic drugs have suggested that prognosis may be improved, but other studies have pointed out the increased risk of proarrhythmic responses in patients with low ejection fraction.
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PMID:Arrhythmias and their treatment in patients with heart failure. 268 90

Electrophysiological defects are common and diverse features of heart failure. Cardiac arrhythmias may be precipitated by mechanical factors, catecholamine release, ischaemia drug therapy or drug-induced hypokalaemia. There is a high prevalence of ventricular and supraventricular arrhythmias, and chronic atrial fibrillation is also common. Ventricular arrhythmias are characterized by multiform, bigeminal and paired beats. There is also a high incidence of non-sustained ventricular tachycardia. These abnormalities are particularly prevalent amongst patients in New York Heart Association (NYHA) functional class IV. Although the presence of complex ventricular arrhythmias and non-sustained ventricular tachycardia are regarded as prognostic markers, their role in the initiation of sudden death has yet to be proven. The results of a recent placebo-controlled clinical trial have indicated that combined therapy with isosorbide dinitrate and hydralazine can reduce mortality due to sudden death or pump failure, and is superior in this respect to prazosin. In another key study, enalapril was superior to placebo at lowering mortality caused by pump failure, but did not reduce the incidence of sudden death. These findings point to new directions of investigation which might clarify the importance of arrhythmias in heart failure, and reveal improved ways of controlling cardiac rhythm and improving prognosis.
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PMID:Electrophysiological alterations in heart failure. 280 89

Atrial fibrillation is associated with an increased risk of stroke. Different risk factors may be of importance regarding stroke incidence and mortality in atrial fibrillation. Retrospectively, we studied 786 patients with chronic atrial fibrillation, 229 with rheumatic heart disease and 557 without. In all, 127 patients had stroke (16%). Using Cox's proportional hazard model for failure-time data with age, gender, etiology, degree of heart failure and cardiac enlargement as explanatory (independent) variables, only etiology (rheumatic heart disease) was a significant risk factor for stroke (P less than 0.006). Significant risk factors for death in 653 patients without stroke were age (P = 0.000) and congestive heart failure at the onset of atrial fibrillation (P = 0.000). The need to identify other risk factors for stroke in patients with atrial fibrillation is emphasized, for selecting patients at high risk for prophylactic treatment with anticoagulants or aspirin.
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PMID:Risk factors for stroke in chronic atrial fibrillation. 296 47

The major antihypertensive mechanism of calcium antagonists is by decreasing the systemic vascular resistance, modified by the counter-regulatory responses of the baroreflexes and the renin-angiotensin-aldosterone system. In severe hypertension, the concept that calcium overload of the vascular myocyte could precipitate or aggravate peripheral vasoconstriction provides a logical basis for the use of these agents as first choice therapy; nifedipine, especially, has been well tested. As monotherapy for mild to moderate hypertension each of the three first-generation agents compares well with beta-blockers. Calcium antagonists may have a special role in the therapy of certain patient groups (elderly, black) or in those subjects whose life style involves intense physical or mental exertion (hemodynamics better maintained than with beta-blockade) or in patients with early end-organ damage such as left ventricular hypertrophy or renal insufficiency. However, the goal blood pressure may not be reached during monotherapy so that drug combinations may be required. Further indications for these compounds are as follows. Verapamil and diltiazem are frequently used in supraventricular tachycardias including acute and chronic atrial fibrillation. In the arrhythmias of the Wolff-Parkinson-White syndrome, there is the potential danger of provocation of anterograde conduction. Further indications for calcium antagonists, still under evaluation, include congestive heart failure (controversial), hypertrophic cardiomyopathy (verapamil), primary pulmonary hypertension (high doses required), Raynaud's phenomenon (nifedipine and diltiazem effective), peripheral vascular disease (proof not yet documented), cerebral insufficiency and subarachnoid hemorrhage (nimodipine promising), migraine, exertional bronchospasm, renal disease, atherosclerosis (experimental), and primary aldosteronism (nifedipine inhibits aldosterone release). Second-generation agents include dihydropyridines, such as nitrendipine, nicardipine, felodipine, amlodipine, nisoldipine, nimodipine, and isradipine. From these will be selected agents that are longer acting and provide higher vascular selectivity. New preparations of existing agents include slow-release formulations of nifedipine, verapamil, and diltiazem. Minor side effects include those caused by vasodilation (flushing and headaches), constipation (verapamil), and ankle edema. Serious side effects are rare and result from improper use of these agents, as when intravenous verapamil is given to patients with sinus or atrioventricular nodal depression from drugs or disease, or nifedipine to patients with aortic stenosis. The potential of a marked negative inotropic effect is usually offset by afterload reduction, especially in the case of nifedipine. Yet caution is required when calcium antagonists, especially verapamil, are given to patients with myocardial failure unless caused by hypertensive heart disease. Drug interactions of calcium antagonists occur with other cardiovascular agents such as alpha-adrenergic blockers, beta-adrenergic blockers, digoxin, quinidine, and disopyramide.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Calcium channel antagonists. Part III: Use and comparative efficacy in hypertension and supraventricular arrhythmias. Minor indications. 315 29

Chronic atrial fibrillation without valvular disease has been associated with increased stroke incidence. The impact of atrial fibrillation on the risk of stroke with increasing age was examined in 5184 men and women in the Framingham Heart Study. After 30 years of follow-up, chronic atrial fibrillation appeared in 303 persons. Age-specific incidence rates steadily increased from 0.2 per 1000 for ages 30 to 39 years to 39.0 per 1000 for ages 80 to 89 years. The proportion of strokes associated with this arrhythmia was 14.7%, 68 of the total 462 initial strokes, increasing steadily with age from 6.7% for ages 50 to 59 years to 36.2% for ages 80 to 89 years. In contrast to the impact of cardiac failure, coronary heart disease, and hypertension, which declined with age, atrial fibrillation was a significant contributor to stroke at all ages.
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PMID:Atrial fibrillation: a major contributor to stroke in the elderly. The Framingham Study. 363 64

In nine patients with chronically implanted ventricular pacemaker (VVI), diurnal variation of the QT interval was studied. The mean age of the patients was 74.2 years and underlying diseases were atrioventricular block (three patients), sick sinus syndrome (four patients) and chronic atrial fibrillation with bradycardia and heart failure (two patients). Eight of the nine patients showed longer QT intervals during sleep than during waking. Only one patient showed no change in QT interval during sleep and during wake time. The mean QT interval of the nine patients at each hour was slightly longer (9 msec) during sleep than that during each awake hour (p less than 0.001). The prolongation of QT interval during sleep may offer a possible mechanism of some nocturnal arrhythmias.
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PMID:Diurnal variation of QT interval in patients with VVI pacemaker. 404 Jun 62

In the Framingham Study 2325 men and 2866 women 30 to 62 years old at entry were followed biennially over 22 years for the development of chronic atrial fibrillation in relation to antecedent cardiovascular disease and risk factors. During surveillance, atrial fibrillation developed in 49 men and 49 women. The incidence rose sharply with age but did not differ significantly between the sexes. Overall, there was a 2.0 per cent chance that the disorder would develop in two decades. Atrial fibrillation usually followed the development of overt cardiovascular disease. Only 18 men and 12 women (31 per cent) had chronic atrial fibrillation in the absence of cardiovascular disease. Cardiac failure and rheumatic heart disease were the most powerful predictive precursors, with relative risks in excess of sixfold. Hypertensive cardiovascular disease was the most common antecedent disease, largely because of its frequency in the general population. Among the risk factors for cardiovascular disease, diabetes and electrocardiographic evidence of left ventricular hypertrophy were related to the occurrence of atrial fibrillation. The development of chronic atrial fibrillation was associated with a doubling of overall mortality and of mortality from cardiovascular disease.
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PMID:Epidemiologic features of chronic atrial fibrillation: the Framingham study. 706 92


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