1) What are some non-pathological reasons for bradycardia? Pathological?
Athlete, Beta-blockers, Sleeping, Vagal response (bearing down)
Fluid overload, late hypoxia, Vagal stimulation
2) What are some non-pathological reasons for tachycardia? Pathological?
Exercise, Nicotine, Caffeine, Anxiety
Hypoxia, Respiratory distress, Fever
3) Cardiac Output = Heart Rate x Stroke Volume
a) ↓HR x ↑SV = _↑_ CO
b) ↑HR x ↑SV = _↑_ CO
c) ↑HR x ↓SV = _↓_ CO
NOTE: Think about when the heart is beating WAAAY too fast. Does the heart have time to refill between each beat?
d)Normal CO is = 5 Liters/minute
4) You already know many factors that affect Heart Rate. What are the 3 factors that affect SV?
1. Preload: Amount of blood returning to heart and filling the atria
2. Afterload: Systemic vascular resistance
3. Contractility: How hard the heart can squeeze. (Ventricular compliance & filling pressures influence this)
5) Think about and describe some examples of how the 3 factors that determine SV would affect CO.
– Increased Preload, increased CO
– Increased Afterload, decreased CO
– Decreased Contractility, decreased CO (Contractility decreases with age)
– Increased Contractility, increased CO (more stretch in heart chambers, more contractility)
CARDIAC CONDUCTION SYSTEM (helps you understand some dysrhythmias)
How many bpm is the base rate for each node?
Sinoatrial (SA) node → Atrioventricular (AV) node → Bundle of His → Purkinje fibers
ADULT CARDIAC ISSUES (PRIMARILY ACQUIRED)
6) What’s the difference between Atherosclerosis and Arteriosclerosis? What can be a resulting symptom or problem of each?
Atherosclerosis: fatty build up of blockages within arteries
Arteriosclerosis: Hardening or thickening of arterial walls.
7) Cardiac Ischemia
Partial/temporary loss of blood flow
If it is severe enough to cause PAIN, it is Angina
If it is severe enough to cause CELL DEATH, it is Myocardial Infarction (Heart Attack)
NOTE: Chest pains are caused by build-up of lactic acid, just like when you are doing strenuous exercise and your skeletal muscles are working so hard they’re using up the oxygen.
8) Heart Failure
Left Failure: Where is the blood backing up? So what are the symptoms? What is causing the blood to back up? So what are some causes?
– Respiratory symptoms (Pink-tinged sputum, Difficulty breathing, Pulmonary hypertension, pulmonary edema, crackles, orthopnea, nocturia)
– Hypertension , MI
Right Failure: Where is the blood backing up? So what are the symptoms? What is causing the blood to back up? So what are some causes?
– Systemic symptoms (Ascites, Hepatomegaly, Edema, Increased Venous Pressure (jugular venous distention))
– Pulmonary diseases (Pulmonary hypertension, Emphysema); LEFT SIDED FAILURE
NOTE: Notice that some of the causes of one are possible symptoms of the other. Often, Left-sided failure can lead to Right-sided failure.
9) What are some treatments for Angina? MI? Heart Failure?
Angina: aspirin therapy, Nitroglycerin, rest, oxygen, cholesterol-lowering drugs. Basically, anything that will increase oxygen supply, decrease oxygen demand, and/or improve the underlying cause (arterial blockages usually!).
MI: Similar as for Angina, but also insert IV line and medicate for pain.
Heart Failure: Diuretics, vasodilators, ACE inhibitors, b-adrenergic blockers, Angiotensin II Receptor Blockers, Oxygen, rest, pacemaker, heart transplant
EXTRA CREDIT: Which chamber of the heart is the largest? Why do you think that is?