PubMed Health⌕ Search

Biomedical subjects

J Christiana

Publications and source records attributed to J Christiana.

4 recordsLinked to original sources

Testosterone and other anabolic steroids as cardiovascular drugs.

There has been much interest in the effect of sex hormones on cardiovascular risk factors and as a therapeutic modality in both men and women. In this article, testosterone is considered as a possible therapy for cardiovascular disease. It has been shown that the level of serum testosterone decreases in men as they age. Healthy men with low testosterone levels have increased cardiovascular risk factors, including high fasting and 2-hour plasma glucose, serum triglycerides, total cholesterol and low-density lipoprotein (LDL) cholesterol, and apo A-I lipoprotein. Injections of testosterone to raise the levels to midnormal range have been shown to decrease total cholesterol and LDL cholesterol, while increasing high-density lipoprotein (HDL) cholesterol. Testosterone affects the clotting system by increasing thromboxane A (2) receptor activity and platelet aggregability. Testosterone has also been shown to augment the fibrinolytic system and antithrombin III activity. In men, testosterone has been shown to have antianginal effects, and endogenous levels have an inverse relationship to systolic blood pressure. Testosterone can be given in oral, injectable, pellet, and transdermal patch forms. There may be a role in administering testosterone to return men to normal physiologic range who have low serum levels. This treatment increases the risk of prostatic cancer, benign prostatism, erythrocytosis, and edema. No long-term studies of the effects of long-term testosterone replacement have been undertaken, so it is difficult to recommend this treatment as yet, but it is being considered as a therapy for augmenting skeletal muscle strength in patients with congestive heart failure.

Anabolic Agents↗

How to use calcium antagonists in hypertension: putting the JNC-VI guidelines into practice. Joint National Committee for the Prevention, Detection, Evaluation and Treatment of High Blood Pressure.

The prevention and treatment of hypertension remain as major challenges for clinicians all over the world. The recently published Sixth Report of the Joint National Committee for the Prevention, Detection, Evaluation and Treatment of High Blood Pressure (JNC-VI) uses evidence-based medicine in providing guidelines to aid clinicians in the prevention, detection and treatment of high blood pressure, including pharmacological approaches. Calcium antagonists are used widely for the treatment of hypertension, and JNC-VI focuses on specific situations where calcium antagonists could be considered as preferred treatments. There are a large number of calcium antagonists available, with a variety of pharmacodynamic and pharmacokinetic actions. Several sustained-release formulations of these drugs are also available. In terms of blood pressure control, calcium antagonists are more effective as antihypertensive treatments than beta-blockers, ACE inhibitors and angiotensin II receptor blockers in Black patients. The dihydropyridine calcium antagonists have been shown to reduce morbidity and mortality in elderly patients with isolated systolic hypertension. The rate-lowering calcium antagonists can be used as alternatives to beta-blockers in patients with coronary artery disease and hypertension. Calcium antagonists can be used as alternatives to ACE inhibitors in patients with hypertension and concomitant diabetes mellitus and/or renal disease. Some dihydropyridine calcium antagonists may be useful as alternatives to ACE inhibitors in patients with hypertension and systolic heart failure. Calcium antagonists appear to be extremely useful in patients with cyclosporin-induced hypertension, and in patients with hypertension and concomitant Raynaud's phenomenon and/or migraine. The rate-lowering agents can be used in patients with atrial tachyarrhythmias and hypertension. Clinicians should be aware of drug-drug interactions involving calcium antagonists, especially after the recent problems with mibefradil. Although retrospective studies have caused controversy regarding the safety of calcium antagonists in patients with hypertension, recent prospective studies have revealed no major safety concerns with these drugs.

Age Factors↗

Experience with the Mitroflow aortic bioprosthesis.

From October 1985 to May 1990, the Mitroflow bovine pericardial valve was placed in the aortic position in 168 patients (97 men, 71 women) with a mean age of 69.7 years. Eighty-nine patients had isolated aortic valve replacement, and 79 had aortic valve replacement and additional procedures. Follow-up over 7 1/2 years includes 781 patient years (426 for isolated aortic valve replacement). Mean follow-up time is 56 months. Peak-to-peak gradients (in millimeters of mercury) measured in the intraoperative period averaged 11.0 +/- 8.7, 11.8 +/- 10.8, and 8.6 +/- 8.2 for 19 mm, 21 mm, and 23 mm valves, respectively. Hospital mortality was 7.3% (14 patients); all deaths were non-valve related. Late mortality of 20.1% in 31 patients resulted from cardiac failure (n = 8), sepsis (n = 4), valve reoperation (n = 1), non-cardiac causes (n = 15) and sudden, unknown causes (n = 3). Fifteen thromboembolic episodes occurred, but only three late thromboembolic episodes occurred in isolated aortic valve replacement without other risk factors. Four early and four late episodes of endocarditis occurred. Seven patients had clinical valve dysfunction, and five others required reoperation for structural deterioration, with one death. At 94 months, overall survival was 64% +/- 5%. Freedom from thromboembolic episode was 87% +/- 3% and 90% +/- 4% for isolated aortic valve replacement. Freedom from combined reoperation or clinical dysfunction was 75% +/- 8%: 64% +/- 15% for those under 70 years of age, and 87% +/- 7% for those 70 years of age and older. The valve has favorable hemodynamics. Durability begins to decline during the sixth year after implantation, possibly at a slower rate in patients older than 70 years of age.

Adolescent↗

Radiofrequency catheter ablation: the first decade.

Radiofrequency catheter ablation (RFCA) has become a safe and effective procedure for treatment of supraventricular and ventricular arrhythmia in children and adults. Anatomic data and mapping experience obtained from surgical and direct current ablation procedures paved the way for radiofrequency ablation. Radiofrequency energy is a power source well suited to place focal catheterization lesions. A large variety of supraventricular tachycardias can be successfully cured with a high success rate with minimal complications. Also, a growing number of ventricular tachycardias can be cured or palliated with this procedure. Ongoing research may increase the scope of this procedure to provide primary cures for atrial fibrillation and ventricular tachycardia associated with coronary artery disease. These procedures are highly complex and should be performed in a high-volume center.

Arrhythmias, Cardiac↗