The Clinical Studies on Congestive Heart Failure

OBJECTIVE: To survey the causes of clinical hypomagnesemia and Mg deficiency. The relationship of hypomagnesemia to digitalis toxicity, congestive heart failure, arrhythmias, and acute myocardial infarction is discussed, as is the clinical interrelationship of Mg and K concentrations, the principal intracellular cations. DATA SOURCES: A MEDLINE search and retrieval was used to identify relevant references. STUDY SELECTION: Clinical reports, as well as studies, were selected for this review. DATA EXTRACTION: There were very few placebo-controlled clinical studies. Clinical observations were related primarily to compilation of series in which Mg was administered and clinical results reported. In addition, conclusions derived from review articles on the subject of clinical Mg depletion were used. DATA SYNTHESIS: Clinical diagnosis of Mg deficiency is ascertained most expeditiously by estimating serum Mg concentrations. Although available on order by physicians, the lack of routine serum Mg analysis as part of the “electrolyte panel” impedes the diagnosis of clinical Mg deficiency. Renal loss of Mg resulting from the widespread use of loop diuretics is responsible for significant numbers of patients with Mg deficiency and hypomagnesemia. Life threatening cardiac arrhythmias and seizures represent the most serious manifestations of clinical hypomagnesemia and Mg depletion. In the most critically ill patients, treatment with intravenous Mg is recommended. Oral repletion of Mg is reserved for the less critically ill hospitalized patients and ambulatory patients. Close attention must be paid to optimizing K replenishment in hypokalemic patients by concurrent treatment of any accompanying hypomagnesemia to avoid the problem of refractory K repletion. CONCLUSIONS: Hypomagnesemia is one of the most frequent serum electrolyte abnormalities in current clinical practice. Routine inclusion of serum Mg analysis in the electrolyte panel will enhance the clinical recognition and treatment of hypomagnesemic Mg-depleted patients. Failure to respond to treatment of recurrent ventricular tachycardia/fibrillation to usual antiarrhythmic therapy in patients with acute myocardial infarction, idiopathic dilated cardiomyopathy, and congestive heart failure should alert the clinician to consider administering intravenous Mg. Repair of coexisting hypomagnesemia in hypokalemic patients is essentialto avoid the problem of refractory K repletion caused by coexisting Mg depletion. More controlled clinical studies of Mg deficiency are necessary to ascertain the cost-effectiveness of Mg replacement therapy.

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Clinical studies of the blood volume. III. Changes in blood volume, venous pressure, and blood velocity rate in chronic congestive heart failure

American Heart Journal ◽

10.1016/s0002-8703(38)90945-7 ◽

1938 ◽

Vol 16 (1) ◽

pp. 131

Keyword(s):

Heart Failure ◽

Congestive Heart Failure ◽

Blood Volume ◽

Clinical Studies ◽

Venous Pressure ◽

Blood Velocity ◽

Chronic Congestive Heart Failure

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Mibefradil: A New Class of Calcium-Channel Antagonists

Annals of Pharmacotherapy ◽

10.1345/aph.17323 ◽

1998 ◽

Vol 32 (6) ◽

pp. 659-671 ◽

Cited By ~ 15

Author(s):

Sarah J Billups ◽

Barry L Carter

Keyword(s):

Heart Failure ◽

Congestive Heart Failure ◽

Calcium Channel ◽

Clinical Studies ◽

Chronic Stable Angina ◽

Slight Reduction ◽

Calcium Channel Antagonists ◽

Once Daily ◽

New Class ◽

Reflex Tachycardia

OBJECTIVE: To describe the pharmacology, pharmacokinetics, and clinical efficacy of mibefradil compared with other agents used for hypertension and angina. DATA SOURCES: A MEDLINE search was performed for the period of January 1980 through September 1997 using the key terms mibefradil or Ro 40–5967. All articles written in English were considered for review. STUDY SELECTION AND DATA EXTRACTION: All clinical studies involving mibefradil were evaluated. Preclinical data were included if these data were not adequately represented in clinical (human) studies. DATA SYNTHESIS: Mibefradil is the first member of a new class of calcium-channel antagonists (CCAs) that block the T-type calcium channels. A long elimination half-life makes once-daily dosing feasible, and the drug's lack of negative inotropy and reflex tachycardia distinguishes it from other available CCAs. When administered at recommended dosages (50 or 100 mg once daily), mibefradil reduces blood pressure over 24 hours in patients with hypertension, improves exercise capacity, and relieves anginal symptoms in patients with chronic stable angina pectoris. CONCLUSIONS: Clinical studies have found that the antihypertensive effects of mibefradil are comparable with those of nifedipine, verapamil, and amlodipine, and more effective than those of diltiazem. These effects result from peripheral vasodilation and a slight reduction in heart rate. Selective vasodilation of the coronary vasculature makes it an effective antianginal agent when used alone or added to β-blocker therapy. Mibefradil demonstrates no significant effects on cardiac contractility, and no adrenergic stimulation resulting in reflex tachycardia. Therefore, it may have some advantages over currently available CCAs, especially in patients with congestive heart failure, although such advantages are unproven in published clinical trials. Ongoing clinical studies, including the Mortality Assessment in Congestive Heart Failure Trial (MACH-1) currently in progress, are needed to clarify mibefradil's place in cardiovascular therapy.

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