Abstract. Ceremuz Çyn  ski L, Ge Îbalska J, Woøk R, Makowska E (Klinika Kardiologii CMKP, Szpital Grochowski, Warszawa, Poland). Hypomagnesemia in heart failure with ventricular arrhythmias. Beneficial effects of magnesium supplementation. J Intern Med 2000; 247: 78±86.Objective. To assess the role of electrolyte imbalance in cardiac arrhythmias associated with congestive heart failure. Design. 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. Setting. The study was carried out in one municipal hospital, providing primary care. Subjects. 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 21 ). A total of 78 patients entered and 68 patients completed the study. Interventions. Intravenous administration of magnesium (magnesium sulphate 8 g in 250 mL of 5% glucose) or placebo (250 mL of 5% glucose) over 12 h. Main outcome measures. (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.

Di †usion of hydrogen in the a-phase PdÈ and systems was investigated at 298 K by Pd 81Pt 19 ÈH electrochemical methods in an aqueous solution of Smooth or Pd-black covered specimens were used. H 2 SO 4 . The concentration of hydrogen in the metal matrix was gradually increased by control of the electrode potential ; equilibrium concentrations were attained. The di †usion coefficient of hydrogen was evaluated by impedance spectroscopy close to equilibrium inside the specimen, at various hydrogen concentrations. The hydrogen evolution parallel to its absorption and di †usion was taken into account in the analysis of the experimental data. At the largest concentrations, the larger the concentration the smaller is the di †usion coefficient in both systems. This is especially evident for the matrix. The di †usion coefficient Pd 81 Pt 19 evaluated from the rate of hydrogen stripping from specimens saturated to various concentrations of hydrogen was of lower reliability. The Pd-black coverage of the specimens decreased the reliability of estimates of the hydrogen di †usion coefficient and of its concentration. The temporary formation of directly under the b-PdH n specimen surface during Pd-black deposition, resulting in the creation of hydrogen traps, is postulated.

Background: Paroxysmal atrial fibrillation (PAF) and paroxysmal supraventricular tachycardia (PSVT) leading to hemodynamic compromise are among the most common reasons for admission to the coronary care unit (CCU) and need prompt and efficient therapy. Direct current cardioversion is the therapy of choice, but if found contraindicated or unavailable some antiarrhythmie agents are usually given to restore sinus rhythm. Many of these drugs have obvious limitations, especially in patients with acute myocardial infarction and/or heart failure. Hypothesis: The aim of the present study was to assess the safety and efficacy of intravenous amiodarone in the acute termination of PAF or PSVT refractory to other antiarrhythmie agents in a large group of patients consecutively admitted to our CCU. Methods: In the present study, we evaluated the safety and efficacy of amiodarone given intravenously in 142 consecutive patients with PAF or PSVT lasting < 24 h. In 37% of patients no evidence of underlying heart disease which may have caused arrhythmias were defined. A median of two other antiarrhythmic agents given prior to the first amiodarone injection had been ineffective. Results: Sinus rhythm was restored in 91 patients (64%) (65% in the PAF group and 61% in the PSVT group). The mean time to rhythm conversion was 5.5 ± 6.1 h for patients with PAF and 1.2 ± 1.2 h for patients with PSVT. The mean dose of amiodarone administered up to conversion was 340 ± 220 mg for PAF and 220 ± 105 mg for PSVT. Except for transient first‐degree atrioventricular block in two patients, no adverse effects possibly related to amiodarone were observed (including proarrhythmia and incidence or aggravation of heart failure symptoms). Conclusion: Amiodarone given intravenously for acute termination of supraventricular tachyarrhythmias is completely safe and seems effective. The results of this study, which is the largest ever made, indicate a need of randomized, controlled trials for the ultimate assessment of the efficacy of amiodarone in this clinical setting.

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