Page 379 - Robbins Basic Pathology by Vinay Kumar, Abul K. Abbas, Jon C. Aster

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CHAPTER CONTENTS

Overview of Heart Disease 365 Arrhythmias 385 Prosthetic Cardiac Valves 395
Heart Failure 365 Sudden Cardiac Death 386 Cardiomyopathies 396
Left-Sided Heart Failure 367 Hypertensive Heart Disease 386 Dilated Cardiomyopathy 397
Systemic (Left-Sided) Hypertensive Heart
Right-Sided Heart Failure 368 Disease 387 Hypertrophic Cardiomyopathy 400
Congenital Heart Disease 368
Left-to-Right Shunts 370 Pulmonary Hypertensive Heart Disease— Restrictive Cardiomyopathy 401
Cor Pulmonale 388
Right-to-Left Shunts 372 Valvular Heart Disease 388 Myocarditis 401
Degenerative Valve Disease 389 Pericardial Disease 403
Obstructive Lesions 373 Pericarditis 403
Ischemic Heart Disease 374 Rheumatic Valvular Disease 391
Angina Pectoris 376 Pericardial Effusions 404
Infective Endocarditis 392 Cardiac Tumors 404
Myocardial Infarction 377 Metastatic Neoplasms 404
Noninfected Vegetations 394 Cardiac Transplantation 405
Chronic Ischemic Heart Disease 384
Carcinoid Heart Disease 395
Cardiac Stem Cells 385

The heart is a truly remarkable organ, beating more than some cases, the muscle cannot relax sufficiently to permit
40 million times a year and pumping over 7500 liters of ventricular filling, resulting in diastolic dysfunction.
blood a day; in a typical lifespan, the cumulative volume • Obstruction to flow. Lesions that prevent valve opening
would fill three “supertanker” ships. The cardiovascular (e.g., calcific aortic valve stenosis) or cause increased
system is the first organ system to become fully functional ventricular chamber pressures (e.g., systemic hyperten-
in utero (at approximately 8 weeks of gestation); without a sion or aortic coarctation) can overwork the myocar-
beating heart and vascular supply, further development dium, which has to pump against the obstruction.
cannot occur, and fetal demise is inevitable. When the • Regurgitant flow. Valve lesions that allow backward
heart fails postnatally, the results are equally catastrophic. flow of blood create conditions that add increased
Indeed, cardiovascular disease remains the leading con- volume workload to the affected chambers with each
tributor to mortality worldwide and accounts for nearly contraction.
40% of all U.S. deaths—approximately 1 death every 30 • Shunted flow. Defects (congenital or acquired) that divert
seconds, or 750,000 deaths each year (accounting for 50% blood inappropriately from one chamber to another, or
greater mortality than for all forms of cancer combined). from one vessel to another, lead to pressure and volume
The annual economic impact of ischemic heart disease, the overloads.
most prevalent form of heart disease, is in excess of $100 • Disorders of cardiac conduction. Uncoordinated cardiac
billion. Moreover, almost a third of these deaths are “pre- impulses or blocked conduction pathways can cause
mature,” occurring in persons younger than 75 years of arrhythmias that reduce contraction frequency or dimin-
age; thus, an additional economic burden is imposed ish effective cardiac output.
through lost years of productivity. • Rupture of the heart or major vessel. Loss of circulatory
continuity (e.g., gunshot wound through the thoracic
OVERVIEW OF HEART DISEASE aorta) leads to exsanguination, hypotensive shock, and
death.
Although a host of diseases can affect the cardiovascular
system, the pathophysiologic pathways that result in a HEART FAILURE
“broken” heart distill down to six principal mechanisms:
• Failure of the pump. In the most common situation, the Heart failure generally is referred to as congestive heart
failure (CHF). CHF is the common end point for many
cardiac muscle contracts weakly and the chambers forms of cardiac disease and typically is a progressive
cannot empty properly—so-called systolic dysfunction. In