Adult Health 1 - Exam 2 Flashcards - AI generated from class materials (book,notes,lecture)

Cardiac output (CO)

The amount of blood pumped from the left ventricle per minute; CO = HR × SV.

Stroke volume (SV)

The amount of blood ejected from the ventricle with each cardiac cycle.

Preload

The stretch of the myocardium or end-diastolic volume of the ventricles; volume in a ventricle just before systole.

Afterload

The amount of pressure the heart needs to exert to eject blood during ventricular contraction; recorded as systolic pressure.

Diastole

The relaxation and filling phase of the atria and ventricles; about two-thirds of the cardiac cycle.

Systole

The contraction and emptying phase of the atria and ventricles.

Systolic blood pressure

The pressure generated by the left ventricle to distribute blood into the aorta with each contraction.

Diastolic blood pressure

The pressure or force against arterial walls during the relaxation phase of the cardiac cycle.

Coronary artery blood flow

Occurs primarily during diastole when coronary vascular resistance is minimized.

Minimum MAP needed for coronary blood flow

At least 60 mm Hg.

MAP needed for major organ perfusion

Between 60 and 70 mm Hg to maintain perfusion of organs such as the kidneys and brain.

MAP formula

MAP = DP + 1/3(SP − DP).

Effect of increased heart rate

Increases myocardial oxygen demand.

Vascular system

Provides a route for blood to travel, nourishes tissues, carries cellular wastes to excretory organs, allows lymphatic flow, and returns blood to the heart.

Arterial system

Delivers oxygen and nutrients to body tissues.

Venous system

Returns blood from capillaries to the right side of the heart.

Baroreceptors

Sensory receptors in the aortic arch and origin of the internal carotid arteries that are stimulated when arterial walls are stretched by increased BP.

Modifiable cardiovascular risk factors

Cigarette smoking, physical inactivity, obesity, and psychological variables.

Nonmodifiable cardiovascular risk factors

Age, sex assigned at birth, ethnic origin, and family history of CVD.

Major CVD risk factor specifically noted

Cigarette smoking is a major risk factor for CAD and peripheral vascular disease.

General cardiovascular assessment

Assess general build, skin color, distress level, level of consciousness, shortness of breath, position, and verbal responses.

Poor cardiac output and cerebral perfusion may cause

Confusion, memory loss, and slowed verbal responses, especially in older adults.

Late severe right-sided HF signs

Ascites, jaundice, and anasarca.

Best areas to assess circulation

Nail beds, mucous membranes, and conjunctival mucosa.

Vascular changes from reduced blood supply

Paresthesia, muscle fatigue/discomfort, numbness, pain, coolness, and loss of hair distribution.

Lateral or displaced PMI may indicate

Left ventricular hypertrophy.

Normal aging cardiac changes

Hardening, stiffening and calcification; fewer pacemaker cells; increased SA node induction time; increased ventricle size; decreased speed; thicker/stiffer large arteries; increased BP; LV hypertrophy; less-sensitive baroreceptors.

Aging and orthostatic hypotension

Risk increases because baroreceptors become less sensitive.

Conductivity

The ability of a cell to send an electrical stimulus from cell membrane to cell membrane.

Automaticity

The ability of cardiac cells to generate an electrical impulse spontaneously and repetitively.

Excitability

The ability of nonpacemaker heart cells to respond to an electrical impulse.

Contractility

The ability of atrial and ventricular muscle cells to shorten in response to electrical stimulation, causing pressure to push blood forward.

Normal primary pacemaker

The sinoatrial (SA) node.

SA node rate

60-100 beats/min.

P wave

Represents atrial depolarization.

AV junction

Includes the AV node and Bundle of His; represented by the PR segment.

Bundle of His

Divides into the right and left bundle branch systems.

Purkinje fibers

Responsible for rapid conduction within the ventricles.

Conditions that can cause abnormal automaticity

Myocardial ischemia, electrolyte imbalance, hypoxia, drug toxicity, and infarction.

ECG

The graphic representation of cardiac electrical activity.

Isoelectric line

The ECG baseline; occurs when there is no current flow after complete depolarization or repolarization.

Telemetry system

A battery-operated transmitter used for ambulatory patients.

ECG paper speed

Usually 25 mm/sec.

Five large ECG blocks

Equal 1 second.

Thirty large ECG blocks

Equal 6 seconds.

300 large ECG blocks

Equal 1 minute.

6-second method

Count QRS complexes in 6 seconds and multiply by 10.

Rule of 300

Count large blocks between consecutive R waves and divide 300 by that number.

PR interval

Measured from the beginning of the P wave to the end of the PR segment; represents atrial depolarization plus impulse travel through the AV node, Bundle of His, bundle branches, and Purkinje fibers.

QRS complex

Represents ventricular depolarization.

ST segment

Represents early ventricular repolarization.

T wave

Represents ventricular repolarization.

QT interval

Represents total ventricular depolarization and repolarization time.

QT interval and heart rate

QT lengthens with slower heart rates and shortens with faster heart rates.

Normal heart rate

60-100 beats/min.

Bradycardia

Heart rate less than 60 beats/min.

Tachycardia

Heart rate greater than 100 beats/min.

Normal sinus rhythm rate

60-100 beats/min.

Normal sinus rhythm PR interval

0.12-0.20 seconds and constant.

Normal sinus rhythm QRS

0.06-0.11 seconds and constant.

Sinus tachycardia

Heart rate greater than 100 beats/min caused by increased sinus node discharge.

Causes of sinus tachycardia

Physical activity, anxiety, pain, stress, fever, anemia, hypoxemia, hyperthyroidism, drugs, dehydration, hypovolemic shock, MI, infection, and HF.

Drugs listed as causes of sinus tachycardia

Epinephrine, atropine, caffeine, alcohol, nicotine, cocaine, aminophylline, and thyroid medications.

Sinus tachycardia assessment

Assess for hypovolemia and dehydration, including increased pulse, decreased urine output, decreased BP, and dry skin/mucous membranes.

Symptoms of sinus tachycardia

Dizziness, SOB, lightheadedness, palpitations, chest pain, and syncope.

Management of sinus tachycardia

Treat the underlying cause.

Sinus bradycardia

Heart rate less than 60 beats/min caused by decreased sinus node discharge.

Causes of sinus bradycardia

Normal in athletes; beta-adrenergic blockers, calcium channel blockers, digoxin, vomiting, and suctioning.

Symptoms of sinus bradycardia

Syncope, dizziness, chest pain, SOB, and diaphoresis; may also be asymptomatic.

Management of sinus bradycardia

IV atropine, IV fluids, oxygen if saturation is below 94% or patient is short of air, discontinue suspected drugs, and prepare for pacing if needed.

Supraventricular tachycardia (SVT)

Rapid stimulation of atrial tissue at 100-280 beats/min in adults.

SVT ECG characteristics

Rate 100-280 beats/min, narrow QRS, and P waves may be absent/not visible.

Cause of SVT

Usually a reentry mechanism in which one impulse repeatedly circulates through the atrial pathway.

SVT symptoms

Palpitations, chest pain, anxiety, low BP, and SOB.

SVT management

Treat the cause, vagal maneuver, carotid sinus massage, or synchronized cardioversion.

SVT medications

Adenosine, calcium channel blockers, and beta blockers.

Adenosine patient teaching

Warn the patient about the impending-doom feeling before administration.

Atrial fibrillation

Multiple rapid impulses from many atrial foci depolarize the atria in a totally disorganized manner.

Atrial fibrillation ECG characteristics

Chaotic rhythm, no clear P waves, no atrial contractions, loss of atrial kick, and irregular ventricular response.

AF symptoms

Irregular apical pulse, SOB, palpitations, fatigue, dizziness, lightheadedness, chest discomfort, and anxiety.

AF management

Correct rhythm and control rate to restore blood flow, help prevent embolus formation, and increase cardiac output.

AF anticoagulation

Anticoagulation is used for permanent AF.

Other AF management

Echocardiogram to rule out clots, cardioversion, biventricular pacing, and radiofrequency catheter ablation.

Cardioversion

Low-energy synchronized countershock for a patient with a pulse.

PVC

Premature ventricular complex; an early ventricular complex followed by a pause.

May be asymptomatic, or may cause palpitations and chest discomfort.

Frequent PVCs can lead to ventricular tachycardia or ventricular fibrillation.

Ventricular tachycardia (VT)

Repetitive firing of an irritable ventricular ectopic focus.

Sustained VT

Lasts longer than 15-30 seconds.

VT assessment

Assess airway, breathing, level of consciousness, oxygen level, and pulse.

VT with a pulse

Cardioversion, amiodarone, or lidocaine.

VT without a pulse

CPR, defibrillation, and ACLS protocol.

Ventricular fibrillation (VF)

Rapid, ineffective quivering of the ventricles leading to no cardiac output or pulse.

VF assessment

Absent pulse, no BP, absent heart sounds, LOC changes, and respiratory/metabolic acidosis.

VF treatment

CPR with immediate defibrillation and ACLS. "If it is VFIB, you DFIB."

Asystole

Absence of ventricular electrical activity. No pulse, no respirations, no BP, full cardiac arrest, and absence of QRS complexes.

Causes of asystole

Myocardial hypoxia, severe hyperkalemia, acidosis, and severe ventricular conduction blocks.

Asystole ECG

Possibly P waves only if the SA node is still firing; most commonly a flat line.

Asystole treatment

CPR, ACLS, and epinephrine. Do NOT defibrillate asystole.

Synchronized cardioversion purpose

Terminates certain dysrhythmias by delivering an electrical shock synchronized to the QRS complex.