Evidence of a selective increase in cardiac sympathetic activity in patients with sustained ventricular arrhythmias

Article Abstract:

Ventricular tachyarrhythmia (erratic beating of the left ventricle, the heart chamber that pumps blood to the body) is a common cause of sudden cardiac death. Although the cause of sudden cardiac death is not clear, most affected patients also have coronary artery disease and poor left ventricular function. Patients with impaired left ventricles and ischemic heart disease (reduced heart circulation) often show abnormal ventricular rhythms on ambulatory electrocardiograms, and they are more likely to die of sudden cardiac death. One of the functions of the sympathetic nervous system is to regulate the heart, and it is suggested that there is a relationship between cardiac sympathetic activity and ventricular arrhythmia. To quantify sympathetic nervous activity in the hearts of high-risk patients, 10 men and 2 women who had an episode of life-threatening heart rhythm disturbance during the previous seven weeks were studied. Radiotracer kinetic techniques (methods of measuring a substance in the blood using radioactive isotopes) were used to trace norepinephrine, an adrenal hormone that regulates the sympathetic nervous system. An almost five-fold increase in cardiac norepinephrine spillover into the bloodstream was found, providing evidence of long-lasting activation of the sympathetic nervous system in these patients. Whether such a measurement will be useful in predicting which patients are at greatest risk has not been determined. (Consumer Summary produced by Reliance Medical Information, Inc.)

Risk factors, Cardiac arrest, Ventricular tachycardia

---

Exercise training in patients with heart failure: a randomized, controlled trial

Article Abstract:

Exercise training in patients with heart failure may improve functioning without increasing risk. Researchers randomly assigned 40 men with stable heart failure due to heart disease or of unknown cause to three, 43-minute, aerobic exercise sessions per week or to no exercise. Heart rate and rhythm were continuously monitored. Fifteen in the exercise group and 14 in control group completed the study. Older, sicker patients with heart disease were more likely to drop out due to choice or illness. Exercisers gained improved exercise capacity on measures of oxygenation, heart rate, exercise duration, and power output compared with non-exercisers. Since patients with heart failure often tolerate exercise poorly, modest gains could make an important difference in the patient's ability to carry out routine daily activities.

Health aspects, Care and treatment, Exercise, Heart failure

---

Effects of cardiac sympathetic innervation on coronary blood flow

Article Abstract:

Blood flow in the coronary arteries appears to be directly influenced by sympathetic nerves. Researchers studied 14 patients who had received a heart transplant to determine whether increased blood flow following a stimulus depended on intact nerves. This was possible because many of the nerves supplying the heart are severed when a heart is removed for transplant. However, the nerves can grow back, particularly in the area of the left anterior descending artery. Upon stimulation, blood flow increased 46% in this area of the heart, but only by 16% on the right side of the heart.

Blood flow, Measurement, Blood flow measurement, Heart, Cardiac nerves

Similar abstracts:

• Abstracts: Elevated serum levels of endometrial secretory protein PP14 in patients with advanced endometriosis. Uterine innervation after hysterectomy for chronic pelvic pain with, and without, endometriosis
• Abstracts: Prehospital thrombolytic therapy in patients with suspected acute myocardial infarction. Aspirin, heparin, and fibrinolytic therapy in suspected acute myocardial infarction
• Abstracts: Septic shock in pregnancy associated with legionella pneumonia: case report. Ultrasonographic detection of ureteral jets in normal pregnancy
• Abstracts: Warfarin Use among Ambulatory Patients with Nonvalvular Atrial Fibrillation: The AnTicoagulation and Risk Factors in Atrial Fibrillation (ATRIA) Study
• Abstracts: Muscle manager. Basic training. Spin cycle

This website is not affiliated with document authors or copyright owners. This page is provided for informational purposes only. Unintentional errors are possible.