Hypomagnesemia in heart failure with ventricular arrhythmias. Beneficial effects of magnesium supplementation.
OBJECTIVE
To assess the role of electrolyte imbalance in cardiac arrhythmias associated with congestive heart failure.


METHODS
Serum magnesium and potassium levels, urine magnesium excretion and the incidence of ventricular arrhythmias were assessed throughout the study. The patients who displayed complex arrhythmias after the first week of hospital medication were randomized 2:1 to double-blind magnesium supplementation or placebo.


METHODS
The study was carried out in one municipal hospital, providing primary care.


METHODS
A total of 588 consecutive patients were screened for eligibility (clinical heart failure >/=6 months; NYHA class II-IV; left ventricular ejection fraction </=40%; sinus rhythm; serum creatinine </=2 mg dL-1). A total of 78 patients entered and 68 patients completed the study.


METHODS
Intravenous administration of magnesium (magnesium sulphate 8 g in 250 mL of 5% glucose) or placebo (250 mL of 5% glucose) over 12 h.


METHODS
(i) Incidence of ventricular arrhythmias in patients with hypomagnesemia; (ii) effects of magnesium supplementation on ventricular arrhythmias.


RESULTS
On admission, hypomagnesemia was found in 38% and excessive magnesium loss in 72% of patients. Serum magnesium levels were lower and urine magnesium excretion was greater in patients with complex ventricular arrhythmias, both on admission and after treatment for heart failure. Intravenous administration of magnesium caused a significant decrease in the number of ventricular ectopic beats (P < 0.0001), couplets (P < 0.003) and episodes of nonsustained ventricular tachycardia (P < 0.01).


CONCLUSIONS
Hypomagnesemia, probably related to increased urine magnesium excretion, is an essential feature of heart failure associated with complex ventricular arrhythmias. These arrhythmias can be alleviated/abolished by magnesium supplementation.
Ceremuzyński
L
L
Klinika Kardiologii CMKP, Szpital Grochowski, Warszawa, Poland.
Gebalska
J
J
Wolk
R
R
Makowska
E
E
D000368:Aged; D001145:Arrhythmias, Cardiac / Q000097:blood* / Q000150:complications* / Q000503:physiopathology; D015986:Confounding Factors, Epidemiologic; D004311:Double-Blind Method; D005260:Female; D006333:Heart Failure / Q000097:blood* / Q000150:complications* / Q000503:physiopathology; D006339:Heart Rate; D006801:Humans; D008274:Magnesium / Q000097:blood* / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D013318:Stroke Volume; D013997:Time Factors; D016896:Treatment Outcome
D008274:Magnesium