Thoracic Key

Arrhythmias Cardiac arrhythmias were first noted in antiquity, when physicians began to palpate the arterial pulse. Hippocrates noted that a slow pulse in elderly men heralded sudden death, and Galen…

Heart Failure Heart failure is a common, progressive, and usually lethal syndrome that represents a final common pathway by which a variety of disease processes impair cardiac function. In the…

The Electrocardiogram The electrocardiogram (abbreviated ECG from the English spelling, or EKG from the Dutch) uses electrodes placed on the body surface to record the electrical activity of the heart….

The Cardiac Action Potential The cardiac action potential, which is generated by the orchestrated opening and closing of the ion channels described in Chapter 13, is much more complex than…

The Ischemic Heart The heart requires an uninterrupted supply of oxygen to meet its high energy needs, which can be satisfied only by oxidative metabolism (Chapter 2). Coronary artery occlusion…

The Working Heart More than a century ago, Woods (1892) related the different shapes of the right and left ventricles (see Chapter 1) to the law of Laplace. Using measurements…

Cardiac Ion Channels Cardiac myocytes are activated by an electrical signal, the action potential, in which changes in electrical potential across the plasma membrane (Em) result from an elaborate sequence…

The Heart as a Muscular Pump Unlike the contraction of a skeletal muscle, which is characterized by changes in tension and length, the beating heart generates pressure and ejects a…

Regulation of Cardiac Muscle Performance Regulatory Mechanisms in Cardiac and Skeletal Muscle Muscle performance can be regulated by the four mechanisms listed in Table 10-1. To meet different physiological and…

Signal Transduction: Proliferative Signaling The signaling systems that regulate cell size, shape, and composition play an important role in the pathophysiology of cardiac disease. These systems, along with those that…