Bradyarrhythmias There are two broad categories of abnormally slow heart rhythms—the failure of pacemaker cells to generate appropriate electrical impulses (disorders of automaticity) and the failure to propagate electrical impulses…
The Anatomy of the Heart’s Electrical System The heart’s electrical impulse originates in the sinoatrial (SA) node, located high in the right atrium near the superior vena cava. The impulse…
Cardiac Resynchronization Therapy (CRT) How it Works Cardiac resynchronization therapy (CRT), also referred to as biventricular pacing, is aimed at improving the disordered patterns of ventricular contraction—referred to as ventricular…
Pharmacologic Therapy Antiarrhythmic drugs are not arrhythmia suppressants in the same way that menthol is a cough suppressant. They do not work by soothing irritable areas. In fact, most antiarrhythmic…
The Three Steps in Evaluating and Treating Cardiac Arrhythmias The appropriate management of cardiac arrhythmias involves following a predetermined plan of therapy aimed at achieving specific goals. Those goals, in…
The Dysautonomias Patients who in 1900 would have been called neurasthenics are today saddled with one or more of a host of diagnoses. These include chronic fatigue syndrome (CFS), fibromyalgia,…
Causes of Syncope Table 10.1 lists the major causes of syncope, divided into five major categories. Diagnosing syncope associated with the first four categories depends on taking a careful history…
Chapter 2 Routine Clinical Electromyography NERVE CONDUCTION STUDIES There are three types of NCS that are used in clinical practice: motor, sensory, and mixed NCS. The motor fibers are assessed…
