7. Obstructive Heart Defects

what is an obstructive heart defect?

a narrowing of a major vessel that makes it harder for blood to leave the heart

• the heart must generate more pressure to push blood through the narrowed area

which heart defects are classified as obstructive?

• coarctation of the aorta

• pulmonary stenosis

• aortic stenosis

what is coarctation of the aorta?

narrowing of the aorta

• pressure is higher before the narrowing and lower beyond it

how does coarctation of the aorta affect pressure around the narrowing?

pressure is higher before the narrowing (supplying the head and neck) and lower beyond it (supplying the lower body)

what upper-extremity findings are expected with coarctation of the aorta?

too much blood is sent to the head and neck

• increased BP

• strong, bounding pulses in the arms

• nosebleeds

what lower-extremity findings are expected with coarctation of the aorta?

not enough blood is sent to the lower body

• decreased BP and weak

• absent pulses in the legs

why does coarctation of the aorta cause different findings in the arms and legs?

blood reaches the arms before the usual narrowing, while blood traveling to the legs must pass through it

what symptoms can occur with coarctation of the aorta?

• irritability

• frequent nosebleeds

• leg pain with activity

• dizziness or fainting

• headaches

• systolic murmur

what serious complications can occur with coarctation of the aorta?

• aortic rupture (tearing open of the aorta)

• aortic aneurysm (abnormal bulging of the aortic wall)

• stroke

what heart sound may be heard with coarctation of the aorta?

a systolic murmur

what is pulmonary stenosis?

narrowing of pulmonic valves that obstructs blood flow from the right ventricle toward the pulmonary arteries and lungs

what does the extra pressure from pulmonary stenosis cause?

right ventricular hypertrophy

how does the severity of pulmonary stenosis affect symptoms?

mild narrowing may cause no symptoms, while severe narrowing greatly limits blood flow to the lungs

what assessment findings can occur with pulmonary stenosis?

• dyspnea fatigue with activity

• signs of heart failure

• cyanosis if severe

• high pitched click after 2nd heart sound

• murmur

• may be asymptomatic

what is aortic stenosis?

narrowing of aortic valves that obstructs blood flow from the left ventricle into the aorta

aortic stenosis _____ cardiac output

decreases

how does aortic stenosis affect left ventricular pressure?

pressure rises because the left ventricle must push harder to move blood through the narrowed outlet

increased left ventricular pressure in aortic stenosis causes _____

ventricular hypertrophy

how can aortic stenosis eventually cause fluid buildup in the lungs?

the overworked left ventricle can fail, causing pressure to back up through the left atrium into the lung vessels

what assessment findings can occur with aortic stenosis?

• easily fatigue

• chest pain, dizziness with prolonged standing

• a thrill (vibration)at the base of the heart

• systolic murmur

• faint pulses if severe