Aneurysm
An aneurysm (AN-yŭ-rizm) is a dilation or bulging of a blood vessel caused by weakened vessel walls. Aneurysms can occur in vessels throughout the body but are more commonly found in arteries due to their increased pressure. Aneurysms can be caused by a variety of factors, including smoking, atherosclerosis (fatty plaque buildup in a vessel), and hypertension.[1] See Figure 9.9[2] for an illustration of thoracic and abdominal aneurysms.
Aneurysms are often asymptomatic and detected incidentally during diagnostic tests that are being done for other reasons. The force of blood pumping through the vessel with an aneurysm can split the layers of the artery wall, allowing blood to leak in between them, called a dissection. An aneurysm can burst completely, called a rupture, and cause severe, life-threatening bleeding. Aneurysms are managed with antihypertensive medications or may require surgical repair.[3]
Arrhythmia
A heart rhythm that follows the regular conduction system of the heart is called normal sinus rhythm (SĪ-nŭs RITH-ŭm). For example, bradycardia and tachycardia that occurs during normal sinus rhythm have abnormally slow or fast rates but have a regular rhythm.
- Bradycardia (brad-ē-KAR-dē-ă) refers to a slow resting heart rate of less than 60 beats per minute. A normal resting heart rate for an adult is 60 to 100 beats per minute (bpm). However, heart rates can vary widely among individuals based on several factors like age, fitness level, overall health, and medication side effects. Physically fit athletes may have a heart rate of 50 to 60 bpm at rest with no symptoms. However, individuals with bradycardia whose heart is not pumping enough blood to sufficiently supply the brain and body tissues with oxygen may have symptoms, such as feeling tired, dizzy, short of breath, or confused. Individuals with symptomatic bradycardia may experience syncope (SING-kŏ-pē), a medical term for a brief lapse in consciousness, commonly referred to as fainting. Bradycardia is a common side effect of many cardiac medications and can also be caused by several cardiac diseases and disorders. Treatment of symptomatic bradycardia includes medications to increase heart rate or surgical implantation of a pacemaker in the heart to maintain a normal heart rate.
- Tachycardia (tak-ē-KAR-dē-ă) is a rapid heart rate greater than 100 bpm. Tachycardia can be caused by stress, side effects of medications, and several medical conditions. When the heart beats too rapidly, its chambers do not have time to sufficiently fill with blood, resulting in a decreased amount of oxygenated blood being pumped to body tissues and organs. For this reason, symptoms of tachycardia are similar to symptoms of bradycardia. The individual may also have palpitations (pal-pĭ-TĀ-shŏnz), a sensation that the heart is racing, pounding, fluttering, or skipping a beat. Treatment is based on the underlying cause and may include medications or surgery.
Arrhythmia (ā-RITH-mē-ă) does not mean