Advances in the evaluation and management of chronic cardiac failure

To what extent do congestive heart failure patients in sinus rhythm benefit from digoxin therapy? A systematic overview and meta-analysis

PURPOSE

To reappraise the effectiveness of digoxin for the treatment of congestive heart failure (CHF) in patients with sinus rhythm in light of data from recently published randomized controlled trials and to quantitatively assess its usefulness.

STUDY IDENTIFICATION

Computerized searches of the MEDLINE database were performed, and the reference list of each retrieved article was reviewed.

STUDY SELECTION

Review of more than 360 citations and the reference lists of 19 review articles and 61 potentially relevant articles revealed seven double-blind randomized controlled trials that were included in this overview.

DATA EXTRACTION

Study quality was assessed and descriptive information concerning the study populations, the specific interventions, and clinically relevant outcome measurements was extracted.

RESULTS OF DATA SYNTHESIS

The common odds ratio for CHF deterioration while receiving digoxin versus placebo was 0.28, with a 95% confidence interval of 0.16 to 0.49. Predictors of digoxin benefit included presence of a third heart sound and the severity and duration of CHF.

CONCLUSION

Data from seven trials of high methodologic quality suggest that, on average, one out of nine patients with CHF and sinus rhythm derive a clinically important benefit from digoxin (with a 95% confidence interval of 1/33 to 1/5).

[Peritoneal dialysis in the treatment of the low cardiac output after extracorporeal circulation]

Low cardiac output after cardiopulmonary bypass is not uncommon. This per- and postoperative cardiac depression is accompanied by an impairment of renal function, which recovers with the improvement of the low cardiac output. These two correlated failures may become resistant to cardiotonic and diuretic drugs. Indeed the fluid balance is strongly disturbed, although venous pressure is only moderately increased. The only possible treatment could be water withdrawal. Nine patients are reported, all suffering from cardiac and renal failure after cardiopulmonary bypass. They were successfully treated with the method of continuous ambulatory peritoneal dialysis. This method allowed us to stop all intravenous cardiac drugs within 36 h, whilst diuresis reappeared together with a better efficacy of diuretic drugs. This beneficial haemodynamic effect of water withdrawal is discussed. This phenomenon may be related to an influence of right ventricular filling on the left ventricle. Low cardiac output may occur as a result of septal displacement, especially if there is concomitant myocardial suffering. Withdrawing a small volume of water may have modified the septal displacement, and improved cardiac output. Continuous ambulatory peritoneal dialysis was simple and well tolerated; it seemed to have contributed to the haemodynamic recovery of all the nine patients.

Acute hemodynamic and metabolic effects of ICI 118,587 (Corwin), a selective partial beta 1 agonist, in patients with dilated cardiomyopathy

The effects of acute intravenous administration of ICI 118,587 (Corwin), a partial beta 1 agonist, were studied in nine patients with dilated cardiomyopathy and symptomatic congestive heart failure. Hemodynamic and metabolic parameters were measured using Swan-Ganz, arterial, and coronary sinus catheters. Repeated doses of Corwin produced no significant change in left ventricular performance, while a trend towards decreased blood pressure and stroke work was seen. No change occurred in coronary sinus blood flow, transmyocardial lactate extraction, or catecholamine release. One patient had significant depression of left ventricular function with hypotension. Thus, acute infusion of Corwin produced no beneficial inotropic responses, but rather produced features suggestive of further myocardial depression.

Cardiopulmonary exercise testing for evaluation of chronic cardiac failure

The heart, lungs and hemoglobin form the body's gas transport system, which links the atmosphere and its supply of O2 with tissue, while simultaneously providing for the elimination of the metabolic end-product, CO2, into the atmosphere. The transport of these respiratory gases must be in accordance with metabolic need. This is particularly evident during the physiologic stress of isotonic exercise, when the O2 requirements and CO2 production of skeletal muscle are increased. The monitoring of these respiratory gases during exercise, referred to as cardiopulmonary exercise testing (CAR-PET), can be used to assess heart and lung function in patients with cardiovascular or lung disease or both. Chronic cardiac failure (CCF) may be defined in physiologic terms as that circumstance in which the heart fails to provide tissue with O2 at a rate commensurate with aerobic requirements. In patients with CCF, CAR-PET represents a noninvasive means to determine aerobic capacity (that is, maximal O2 uptake) and anaerobic threshold during incremental treadmill exercise. It can also provide an objective measure of the severity of failure, the functional status of the patient and the heart's pump reserve. By using additional measurements of ventilation, arterial O2 saturation and, in selected cases, hemodynamic monitoring, the nature and severity of cardiovascular and pulmonary disease may be evaluated.