European Heart Journal (1992) 13, 243-250
Muscle water and electrolytes in severe chronic congestive heart failure before and after treatment with enalapril M. BROQVIST*, U. DAHLSTROM*, E. KARLSSON* AND J. LARSSONt
From *the Division of Cardiology, Department of Medicine and t the Department of Surgery, University Hospital, Linkoping, Sweden KEY WORDS: Chronic heart failure, electrolytes, enalapril, healthy individuals, muscle, water. To investigate the electrolyte and water content in peripheral skeletal muscle in patients suffering from severe chronic congestive heart failure, New York Heart Association functional class IV, and to study the influence of the angiotensinconverting enzyme inhibitor, enalapril, 22 patients were randomized in a double-blind study to receive either placebo (n=ll) or enalapril (n = ll) in addition to their conventional treatment. The patients included a subgroup in the previously published CONSENSUS study. At the beginning of the study, the content of potassium and magnesium was significantly reduced in muscle as compared with healthy subjects while sodium and water were increased. The muscle content was not predictable from the serum concentrations of the electrolytes. Following study treatment no significant changes occurred, neither within nor between the two subgroups. Thus, patients with severe chronic congestive heart failure, New York Heart Association functional class IV, displayed disturbed electrolyte and water content in muscle, which, in this study, was not corrected by treatment with enalapril. Introduction
Congestive heart failure (CHF) is a common syndrome with a poor prognosis. Less than 50% of the patients survive 5 years after diagnosis1'1. About 40% of all deaths are sudden and probably due to ventricular arrhythmias, which are extremely common in patients with CHF*2'. Electrolyte depletion may be one of the predisposing factors to these arrhythmias, especially depletion of potassium and magnesium121. Since these electrolytes are major intracellular cations with less than 2% of the total body content in the extracellular fluid compartment, deficiencies may exist although the serum concentrations are normal'2'3'. Patients with CHF often have deficits of total body and intracellular potassium and magnesium, and studies have shown that electrolyte repletion may abolish malignant ventricular ectopic rhythms'2-3'. The neurohumoral mechanisms, including the renin-angiotensin-aldosterone system, activated in congestive heart failure, and conventional treatment with digitalis and diuretic drugs contribute to electrolyte depletion'2"51. On the other hand, when spironolactone, a competetive antagonist of aldosterone, is added to diuretics, the intra- and extracellular levels of potassium and magnesium mostly are maintained'61. Furthermore, the angiotensin-converting enzyme (ACE) inhibitor captopril has been shown to correct hypokalaemia and total body potassium depletion in severe CHF171. The present investigation was performed in a subgroup of those patients participating in the previously published CONSENSUS study18'. The aim of this study was to Submitted for publication on II April 1990, and infinalrevised form 20 March 1991. Correspondence: Mats Broqvist, MD. Division of Cardiology, Department of Medicine, University Hospital, S-581 85 Linkdping, Sweden. 0I95-668X 92 020243 + 08 J03.00/0
examine the electrolyte situation in peripheral skeletal muscle in patients with severe chronic CHF, New York Heart Association (NYHA) functional class IV, administered conventional treatment with digitalis and diuretics and compare it with healthy individuals. Furthermore, our aim was also to study the influence of the longeracting ACE inhibitor, enalapril, on electrolyte balance. Materials and methods PATIENTS
This study was performed on 22 patients participating in the CONSENSUS trial, which was a randomized, double-blind, placebo-controlled, parallel-group trial studying the effect of enalapril on mortality in patients with severe CHF, i.e. NYHA functional class IV"". The diagnosis of CHF was based on clinical criteria: a history of heart disease with symptoms of dyspnoea or fatigue or both, together with signs of fluid retention and no evidence of primary pulmonary disease. The patients were all in hospital because of severe CHF and all were complaining of dyspnoea at rest (NYHA functional class IV) and had signs of fluid retention (pulmonary congestion, distended neck veins, hepatomegaly or peripheral oedema). The radiographic heart size had to be more than 600ml.m~2 of body surface area in men (normal,
Muscle water and electrolytes in severe chronic congestive heart failure before and after treatment with enalapril M. BROQVIST*, U. DAHLSTROM*, E. KARLSSON* AND J. LARSSONt
From *the Division of Cardiology, Department of Medicine and t the Department of Surgery, University Hospital, Linkoping, Sweden KEY WORDS: Chronic heart failure, electrolytes, enalapril, healthy individuals, muscle, water. To investigate the electrolyte and water content in peripheral skeletal muscle in patients suffering from severe chronic congestive heart failure, New York Heart Association functional class IV, and to study the influence of the angiotensinconverting enzyme inhibitor, enalapril, 22 patients were randomized in a double-blind study to receive either placebo (n=ll) or enalapril (n = ll) in addition to their conventional treatment. The patients included a subgroup in the previously published CONSENSUS study. At the beginning of the study, the content of potassium and magnesium was significantly reduced in muscle as compared with healthy subjects while sodium and water were increased. The muscle content was not predictable from the serum concentrations of the electrolytes. Following study treatment no significant changes occurred, neither within nor between the two subgroups. Thus, patients with severe chronic congestive heart failure, New York Heart Association functional class IV, displayed disturbed electrolyte and water content in muscle, which, in this study, was not corrected by treatment with enalapril. Introduction
Congestive heart failure (CHF) is a common syndrome with a poor prognosis. Less than 50% of the patients survive 5 years after diagnosis1'1. About 40% of all deaths are sudden and probably due to ventricular arrhythmias, which are extremely common in patients with CHF*2'. Electrolyte depletion may be one of the predisposing factors to these arrhythmias, especially depletion of potassium and magnesium121. Since these electrolytes are major intracellular cations with less than 2% of the total body content in the extracellular fluid compartment, deficiencies may exist although the serum concentrations are normal'2'3'. Patients with CHF often have deficits of total body and intracellular potassium and magnesium, and studies have shown that electrolyte repletion may abolish malignant ventricular ectopic rhythms'2-3'. The neurohumoral mechanisms, including the renin-angiotensin-aldosterone system, activated in congestive heart failure, and conventional treatment with digitalis and diuretic drugs contribute to electrolyte depletion'2"51. On the other hand, when spironolactone, a competetive antagonist of aldosterone, is added to diuretics, the intra- and extracellular levels of potassium and magnesium mostly are maintained'61. Furthermore, the angiotensin-converting enzyme (ACE) inhibitor captopril has been shown to correct hypokalaemia and total body potassium depletion in severe CHF171. The present investigation was performed in a subgroup of those patients participating in the previously published CONSENSUS study18'. The aim of this study was to Submitted for publication on II April 1990, and infinalrevised form 20 March 1991. Correspondence: Mats Broqvist, MD. Division of Cardiology, Department of Medicine, University Hospital, S-581 85 Linkdping, Sweden. 0I95-668X 92 020243 + 08 J03.00/0
examine the electrolyte situation in peripheral skeletal muscle in patients with severe chronic CHF, New York Heart Association (NYHA) functional class IV, administered conventional treatment with digitalis and diuretics and compare it with healthy individuals. Furthermore, our aim was also to study the influence of the longeracting ACE inhibitor, enalapril, on electrolyte balance. Materials and methods PATIENTS
This study was performed on 22 patients participating in the CONSENSUS trial, which was a randomized, double-blind, placebo-controlled, parallel-group trial studying the effect of enalapril on mortality in patients with severe CHF, i.e. NYHA functional class IV"". The diagnosis of CHF was based on clinical criteria: a history of heart disease with symptoms of dyspnoea or fatigue or both, together with signs of fluid retention and no evidence of primary pulmonary disease. The patients were all in hospital because of severe CHF and all were complaining of dyspnoea at rest (NYHA functional class IV) and had signs of fluid retention (pulmonary congestion, distended neck veins, hepatomegaly or peripheral oedema). The radiographic heart size had to be more than 600ml.m~2 of body surface area in men (normal,
