Lecture 12- Cardiac Phys IIII Flashcards
How deadly is coronary heart disease in the UK and how is it caused?
- In the UK, 1/7 men and 1/11 women die from coronary heart disease.
- CHD is responsible for nearly 70,000 deaths in the UK each year
- An average of 190 people each day, or one death around every eight
minutes.
How can CHD be diagnosed?
Diagnosis of CHD
Electrocardiogram (ECG)
Stress test
Nuclear scanning
Coronary angiography
What happens to the ECG when someone has CHD?
they have an abnormal heartbeat
-ST elvatation
-flattened and longer T wave
-possibly an inverted T wave
What is an angiography and what does it do?
it is type of angiography used to visualize the coronary arteries, which supply oxygen-rich blood to the heart muscle (myocardium).
- catheter is inserted in the leg and guided up aorta
- catheter tip stops at left coronary artery
- contrast agent injected into arteries. X-ray imaging shows stenosis in left coronary artery
What are the uncontrollable factors of CHD?
Gender
Heredity
Age
Ethnicity
What are the controllable risk factors of CHD?
Smoking
Obesity
Physical inactivity
Diabetes
High blood pressure (hypertension)
High blood cholesterol
Stress
What does the distress and eustress curve tell us?
stress is multifactoral and can result from too much or too little stimulation
-Eustress is good
-distress is bad
What is the sympathetic adrenomedullary axis and the 4 steps involved?
- Adrenaline released from the
adrenal medulla. - Adrenaline acts as a potent
vasoconstrictor and increases
heart rate, blood pressure, and
breathing rate. - This prepares the body to
respond to the perceived threat
by either “fighting” or “fleeing”. - SAM stress response is a rapid
and short-lived response
(seconds to minutes after the
onset of stress). Primarily
designed to provide a quick burst
of energy for survival in an
emergency situation.
What is the hypothalamic-pituitary adreno-corto axis?
- Hypothalamus releases
corticotropin-releasing
hormone (CRH), which
signals the pituitary gland to
secrete adrenocorticotropin
hormone (ACTH). - ACTH then stimulates the
adrenal glands to produce
and release cortisol. - Cortisol increases glucose
release, suppresses immune
system, and regulates the
stress response itself by
inhibiting the release of CRH
and ACTH (negative
feedback loop).
What are the 3 phases of stress?
Alarm –> Resistance –> Exhaustion
During alarm phase, there is physiological arousal and sympathetic
nervous system activation.
* The resistance phase recruits the hypothalamic–pituitary–adrenal
(HPA) axis.
* Exhaustion phase is associated with reduced metabolic and immune
functioning
What happens during the resistance phase?
During the resistance phase of the GAS (i.e. it is chronic rather than acute
stress), animals will often adopt strategies of counteraction (‘coping’)
These vary between species and between individuals
What are maladaptive coping mechanisms and what are their problems?
Maladaptive coping may be combined with
lifestyle factors that can exacerbate CV
problems
-problematic adaptations to deal with stress such as drinking or doing drugs
How is a fight or flight response stimulated?
- Acute stress – sympathetic
adrenomedullary system
(SAM) - Fight or flight
What are the effects of stressors on the heart?
- Increased HR
- Increased BP
- Release of catecholamines (adrenaline, cortisol) from the adrenal
glands - Increased O2
demand on the body (temporarily higher metabolic
rate) - Lower threshold for abnormal heart rhythms including ventricular
tachycardia, ventricular fibrillation, and atrial fibrillation. Electrical
instability in the heart makes it easier for these abnormal heart
rhythms to occur. - Spasm of coronary (heart) blood vessels, leading
to ischemia (inadequate blood flow to the heart)
What is the difference between myocardial infarction and cardiac arrest?
MI
* Complete obstruction of blood flow to
coronary artery
* Death of an area of tissue because of
lack of blood supply
Cardiac arrest
* Cessation of effective heartbeat
* Could stop completely or
ventricular fibrillation
