Heart & Cardiovascular  Disorders

Symptoms or the physical examination may suggest a cardiovascular disorder. For confirmation, selected noninvasive and invasive tests are usually done :

History

A thorough history is fundamental; it cannot be replaced by testing. A family history is taken because many cardiac disorders (eg, coronary artery disease, systemic hypertension, bicuspid aortic valve, hypertrophic cardiomyopathy, mitral valve prolapse) have a heritable basis.

Major cardiac symptoms include chest pain or discomfort, dyspnea (see Approach to the Patient With Pulmonary Symptoms: Dyspnea), weakness, fatigue, palpitations, light-headedness, sense of an impending faint, and syncope. These symptoms commonly occur in more than one cardiac disorder and in noncardiac disorders.

Physical Examination

Complete examination of all systems is essential to detect peripheral and systemic effects of cardiac disorders and evidence of noncardiac disorders that might affect the heart.

Vital signs: Blood Pressure is measured in both arms and, for suspected congenital cardiac disorders or peripheral vascular disorders, in both legs. The bladder of an appropriately sized cuff encircles 80% of the limb's circumference, and the bladder's width is 40% of the circumference. The 1st sound heard as the Hg column falls is systolic pressure; disappearance of the sound is diastolic pressure (5th-phase Korotkoff sound). Up to a 15 mm Hg pressure differential between the right and left arms is normal; a greater differential suggests a vascular abnormality (eg, dissecting thoracic aorta) or a peripheral vascular disorder. Leg pressure is usually 20 mm Hg higher than arm pressure. Ankle-brachial index (ratio of ankle to arm systolic BP) is normally > 1.

Heart rate and rhythm are assessed by palpating the carotid or radial pulse.

BP and heart rate are measured with the patient supine, seated, and standing, with 1 min between each change in position. A difference of ≤ 10 mm Hg is normal; the difference tends to be a little greater in the elderly.

Respiratory rate, if abnormal, may indicate cardiac decompensation or a primary lung disorder. The rate increases in patients with heart failure or anxiety and decreases in the moribund. Shallow, rapid respirations may indicate pleuritic pain.

Temperature may be elevated by acute rheumatic fever or cardiac infection (eg, endocarditis). After MI, fever is very common, and other causes are sought only if fever persists > 72 h.

Pulsus paradoxus: Normally during inspiration, systolic arterial BP can decrease up to 10 mm Hg, and pulse rate increases to compensate. A greater decrease in systolic BP or weakening of the pulse during inspiration is considered pulsus paradoxus. It occurs commonly in cardiac tamponade; occasionally in constrictive pericarditis, severe asthma, or COPD; and rarely in restrictive cardiomyopathy, severe pulmonary embolism, or hypovolemic shock.BP decreases during inspiration because negative intrathoracic pressure increases venous return and hence right ventricular (RV) filling; as a result, the interventricular septum bulges slightly into the left ventricular (LV) outflow tract, decreasing cardiac output and thus BP. This mechanism (and the drop in systolic BP) is exaggerated in disorders that cause high negative intrathoracic pressure (eg, asthma) or that restrict RV filling (eg, cardiac tamponade, cardiomyopathy) or outflow (eg, pulmonary embolism).

Pulsus paradoxus is quantified by inflating a BP cuff to just above systolic BP and deflating it very slowly (eg, ≤ 2 mm Hg/heartbeat). The pressure is noted when Korotkoff sounds are first heard (at first, only during expiration) and when Korotkoff sounds are heard continuously. The difference between the pressures is the “amount” of pulsus paradoxus.

Pulses: Major peripheral pulses in the arms and legs are palpated for symmetry and volume (intensity); elasticity of the arterial wall is noted. Absence of pulses may suggest an arterial disorder (eg, atherosclerosis) or systemic embolism. However, peripheral pulses may be difficult to feel in obese or muscular people. The pulse has a rapid upstroke, then collapses in disorders with a rapid runoff of arterial blood (eg, arteriovenous communication, aortic regurgitation). The pulse is rapid and bounding in thyrotoxicosis and hypermetabolic states; it is slow and sluggish in myxedema. If pulses are asymmetric, auscultation over peripheral vessels may detect a bruit due to stenosis.

Observation, palpation, and auscultation of both carotid pulses may suggest a specific disorder (see Table 1: Approach to the Cardiac Patient: Carotid Pulse Amplitude and Associated Disorders). Aging and arteriosclerosis lead to vessel rigidity, which tends to eliminate the characteristic findings. In very young children, the carotid pulse may be normal, even when severe aortic stenosis is present.  Continue to read more about cardiovascular disorders . Check out cardiovascular and heart disorders related resources below as well.

source: merck online library