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1

Cardiac System

Sean M. Collins

Introduction

Physical therapists in acute care faci lities commonly encounter patients

with cardiac system dysfunction as either a primary morbidity or

comorbidity. Based on current estimates, 59,700,000 Americans have

one or more types of cardiovascular disease (CVD), making the prevalence rate for men and women 20% ' In 1 997, CVD ranked first among all disease categories and accounted for 6, 1 45,000 inpatient

admissions.' In the acute care setting, the role of the physical therapist

with this diverse group of patients remains founded in examination,

evaluation, intervention, and discharge planning, for the purpose of

improving functional capacity and minimizing disabiliry. The physical

therapist must be prepared to safely accommodate for the effects of

dynamic (pathologic, physiologic, medical, and surgical intervention)

changes into his or her evaluation and intervention.

The normal cardiovascular system provides the necessary pumping

force to circulare blood through the coronary, pulmonary, cerebral,

and systemic circulation. To perform work, such as during functional

rasks, energy demands of the body increase, therefore increasing the

oxygen demands of the heart. A variery of pathologic states can create

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Acme CARE HANDBOOK FOR PHYSICAL THERAPISTS

impairments in the cardiac system's ability to successfully meet these

demands, ultimately leading to functional limitations. To fully

address these functional limitations, the physical therapist must

understand normal and abnormal cardiac function, clinical tests, and

medical and surgical management of the cardiovascular system.

The objectives of this chapter are to provide the following:

1 . A brief overview of the Structure and function of the cardio-

vascular system

2.

An overview of cardiac evaluation, including physical exami-

nation and diagnostic testing

3.

A description of cardiac diseases and disorders, including

clinical findings and medical and surgical management

4.

A framework on which to base physical therapy evaluation

and intervention in patienrs with CVD

Structure

The heart and the roots of the great vessels ( Figme 1 - 1 ) occupy the pericardium, which is located in the mediastinum. The sternum, the costal cartilages, and the medial ends of the third to fifth ribs on the left side of

the thorax create the anterior border of the mediastinum. It is bordered

inferiorly by the diaphragm, posteriorly by the vertebral column and ribs,

and laterally by the pleural cavity (which contains the lungs).' Specific

cardiac structures and vessels and their respective functions are outlined

in Tables 1 - 1 and 1-2.

Note: The mediastinum and the heart can be displaced from their

normal positions with changes in the lungs secondary to various disorders. For example, a tension pneumothorax will shift the mediastinum away from the side of dysfunction (see Chapter 2 for further description of pneumothorax).

Function

The cardiovascular system must adjust the amount of nutrient and oxygen rich blood pumped out of the heart (cardiac output [CO]) to meet the wide spectrum of daily energy (metabolic) demands of the body.

CARDIAC SYSTEM

3

Superior Vena ClIVI

Pulm��", Art,,,,

Branch

Sinus Node Branch

rush'

Branches

"n'''''

Branch

Right Coronary

Art,,>,

Inferior Vena CO'"

PostcnOf Dcscmdlng

Art,,,,

Pulmonary Artery

Left Atrium

Ldt Main Coronary

Artery

lsI Diagonal Branch

Left Venuicle

2nd Diagonal Branch

Left Anterior

Descending Artery

Apical Branches

Figure 1-1. Anatomy of the right coronary artery and Jeft coro,wry artery,

including left maiu, left auterior descending, and left circumflex coronary

arteries. (Reprinted with permissioll (rom R C Becker. Chest Pain: The Most

Common Complaints Series. Boston: Butterworth-Heinemann, 2000;26-28.)

The heart's ability to pump blood depends on the following

characteristics3:

• Automaticity-the ability to initiate its own electrical

impulse

•

Excitability-the ability to respond to electrical stimulus

4 AClJTE CARE HANDBOOK FOR PHYSICAL THERAPISTS

Table 1-1. Primary Structures of the Hearr

Structure

Description

Function

Pericardium

Double-walled sac of elas

Prorects against infection

tic connective tissue, a

and trauma

fibrous outer layer and

serous inner layer

Epicardium

Outermost layer of car

Protects against infection and