Stressors to Coronary Circulation Part 1/Test 2 Flashcards
What is the order of the circulation of the heart?
Venous capillaries Veins Heart Arteries Arterioles Arterial capillaries Venules
Purpose of the heart
- returning oxygen poor blood from body to right heart
- Pumped into lungs
- Exchanged for oxygen rich blood returning to Left heart
- Pumped into systemic circulation
Heart structures
-2 pumps
–R-pulmonic circulation
–L- systemic circulation
4 valves
–AV- Mitral & Tricuspid
–SL- Pulmonic & Aortic
3 Layers
–Epicardium
–Myocardium
–Endocardium
Electrical system
Conduction system
- An electrical impulse is initiated by the SA node, which is the hearts pacemaker (intrinsic rate of 60-100 bpm); this causes depolarization of the cells & contraction of the atria
- It then travels to the AV node (intrinsic rate 40-60 bpm) and moves through the bundle of His & the left right bundle branches
- The action potential diffuses widely through the walls of both ventricle by means of the Purkinje fibers (intrinsic rate of 20-40 bpm), triggering ventricular contraction
Right and left branch off the aorta
Grip the heart and feed from the surface inward. They dilate with exercise
Functioning of circulation depends on
- Pump
- Electricity
- Volume
Oxygenation: Decreased cardiac output=
Ineffective tissue perfusion which leads to Impaired gas exchange which leads to Activity intolerance= Hypoxia
Cardiac output=
Heart rate x Stroke volume
Ejection Fraction
Percentage of blood ejected from the heart during systole- 60-80% normal
Preload
The degree of fiber stretch at the end of diastole- determined by volume returning to the heart.
Afterload
The pressure or resistance the ventricles must overcome to eject blood through the SL valves
PVR or SVR
Resistance of the arterial walls. If B/P is increased-PVR is decreased
Neuro Regulation: Sympathetics
Stimulate Alpha 1-peripheral
Beta 1- Cardiac
Neuro Regulation: Parasympathetic
Inhibits valves
Neuro Regulation: Receptors in aortic and carotid
Stretch sensitive, acid and oxygen sensitive. When stretched by volume, B/P is high
Cardiac Regulation
The autonomic nervous system consists of the sympathetic nervous system and the parasympathetic nervous system.
Parasympathetics
Receptor are muscarinic and are located in smooth muscle; activation (as in vagal stimulation) causes decreased HR ans slower conduction
Sympathetics
Increase HR , speed of impulse conduction and the force of contractions a (in heart)- increased contractility a (in smooth muscle)- vasoconstriction. B (in heart)- increased HR, increased conduction, increased contractility. Dopaminergic (located in coronary, renal, mesenteric, and visceral vessels)- increased dilation.
Cardiac regulation/Hormonal response- Angiotensin
as CO decreases, kidneys release renin= angiotensinogen which causes vasoconstriction (increased BP) and release of aldosterone
Cardiac regulation/Hormonal response- Aldosterone
Causes Na+ retention, which makes body retain water to increase blood volume to increase CO
Cardiac regulation/Hormonal response- Antidiuretic Hormone
hold unto urine, so volume increases
Circulation assessment basics:
BP ---normal 120-80 ---HTN- >139/89 ---Hypotension- <90/60 HR ---normal rate & regularity ---tachycardia ---bradycardia
Sound heard when valves close:
S1/S2
S1 lub closure of
Mitral and Tricuspid
S2 dub closure of
Aortic and Pulmonic
Extra Sounds:
Gallops S3 S4
S3
Early filling phase
S4
Late filling phase
Pericardial rub
Inflammation of visceral and pericardial sack
Murmurs
Incompetent valves- swoosh
Murmur: Systolic
Closure of aortic and pulmonary
Murmur: Dyastolic
Closure of mitral and tricuspid
Assessment of peripheral arteries
Pulses: Location Head/toe Quality of grading +1 +2 +3 color movement sensation claudication presenceof edema document
Assessment and aging
HR BP Heart size Conduction Vessels Decreased reserve
Assessment/aging
Fatigue Fluid retention Irregular heartbeat Dyspnea Pain Calf tenderness Syncope Neuro changes Leg pain
Risk factors: Modifiable
Habits- smoking, diet, weight, exercise, coping w/stress
Increased cholesterol
HTN
Increased BG
Risk factors: Nonmodifiable
Age
Gender
Presence of DM/Disease
Family
Diagnostics for coronary circulation
Cholesterol
Lipids, LDL, HDL, Triglycerides, CK-MB, Troponin, Echocardiagram, TEE, Stress test, Angiography, Coag panel, INR, EKG 12 lead, BNP, Potassium, Chest xray, ABG’s, CBC
Diagnostics: Serum studies-lipid studies
LDL’s-bad ones-CAD s- good ones- great if elevated
Total cholesterol- keep 140-200
Triglycerides- keep 40-190
Diagnostics: Isoenzyme
CKMB >5-6% positive for MI
Diagnostics: Troponin
2.3 positive for MI
Brain Natriuretic Peptide
Used with symptoms of CHF
Differentiates cardiac from pulmonary causes of dyspnea
0-100 pg/ml normal
100-400 patient should respond well to treatment
>400 will be more difficult and take longer for positive response
Coagulation
Normal values Pt- 11-13 seconds PTT- 25-32 seconds INR usually <1 Platelets 150-400 thousand
PT control
1 1/2-2 times Coumadin
PTT control
1 1/2- 2 1/2 times- Heparin
INR
2.-3.0 Coumadin If mechanical valve patient then 2.5-3.5
Diagnostics Echocardiogram
US checks fluid movement through the heart, valve function, ejection fraction
TEE
Invasive-see posterior wall of heart, can identify and clots that develop with Afib
Reversal of coumadin
Vit K and aquamafitin
With a TEE you can see
the posterior wall of the heart and identify any clot formation as well
It’s important to check for clots before cardioversion because
You don’t want to break the clot loose
For cardioversion, pt needs to be
NPO for 4-6 hrs before and will remain NPO until gag reflux returns
MUGA Scan
Stands for multi-unit gated analysis
A gated pool scan that uses radioisotope dye to show how blood pools in your heart during rest, exercise, or both
Also good for EF
Stress test
Exercise- Thallium
Chemical- Adenosine
Vessels should _____to give extra cardiac output needed during exercise
Dilate
For stress test patient needs to
be NPO or clear fluids Wear good walking shoes Baseline VS attached to telemetry should report pain, SOB, dizzyness staff monitor for changes in heart rhythm, ie PVCs, and other symptoms of decreased CO
Cardiac cath post procedure
Assess VS, distal pulse, site q15m x 4 then q30 min x2, then qh x 4, or protocol given by MD, keep flat for several hours as ordered , minimum 15-30 degree elevation while eating.
Let finish at least 1 liter of IV fluids to help rid body of dye and its hyperosmotic effect
Report any changes
keep on telemetry
if no problems discharge teaching
Complications of Cardiac cath
dysrhythmias
hemmorrhage
thrombus formation
infection
Angioplasty
Cath with inflatable balloon on tip to flatten the plaque
Stent insertion
do angioplasty
after angioplasty insert the stent to keep the vessel open
post procedure- follow the basic cardio cath protocol
Venography
Evaluates for DVT’s. Dye injected into the venous side and traced with flouroscopy
D= Dimer blood test
Assess for increased fragmin = DVT
Doppler US
detects reflection of increased RBC’s in arteries and veins, produces a wave form or audible sound =DVT
CVP
(5-11 mm Hg) done with central line in place. Tells you volume without being super invasive
