Cardiac physiology
Terms used for ventricular pumping and ventricular refilling
WHAT IS: Systole and diastole
NOTE: failure of the ventricles to refill is called diastolic failure. Failure of the ventricles to pump is systolic failure. In left sided diastolic dysfunction there may be a normal ejection fraction.
Significance of the p wave and QRS complex - depolarization or repolarization and contraction or refilling?
P WAVE DEpolarization of the atrium and contracting
QRS DEpolarization of the ventricles and contracting
1st line of defense for treatment of heart failure
Angiotension converting enzyme inhibitors (ACE) to increase flow to the heart, decrease the work of the heart, increase kidneys excretion of sodium
Betablockers have side effect of bradycardia. Betablockers are often prescribed with ACE and ARB (angiotensin II receptor blocker) to treat heart failure.
What is a MI, what is major cause, what type of MI is most damaging
Blockage in blood supply to the myocardium resulting in tissue necrosis. Major cause is coronary artery disease. Others - drugs (cocaine), uncontrolled hypertension, coronary artery dissection. Left coronary artery is the most damaging affecting anterior and left ventricle Left ventricle pumps oxygenated blood to body parts)
Describe cause of mitral valve stenosis, treatment, nursing implications
rheumatic fever effects mitral valve (bi cuspid) on left side, results in shortness of breath, congestion and pulmonary edema. Treatment balloon valvoplasty
Function of the left side of the heart and signs and symptoms of left sided heart failure
Pumps oxygenated blood to all parts of the body and the blood returns to the left side for re oxygenation. Left sided failure results in backing up in lungs - cough, crackles, orthopnea. NOTE: Patients with difficulty breathing due to heart failure - assist to high fowlers position. Severe heart failure - patient may have bloody, frothy sputum
Significance of T wave and factors that effect it
Ventricles REpolarizing, refilling Hyperkalemia can elevate T wave Losartan (angiotension receptor blocker- ARB) and spironolactone (a K+ sparing diuretic) may elevate K.
ARB and ACE inhibitors (lisinopril) may elevate K+ ARB side effect - cough Normal values for K+ 3.5 - 5.1 mEq/L
Abnormality in the T - increased risk for stroke
Digoxin, describe action including in relation to chronotropic and inotropic effect, therapeutic range, side effects of excess, nursing implications.
Digoxin a cardiac glycoside has a negative chronotropic effect slowing heart to improve filling. Also positive inotropic effect improving the force of contractions and improving output. Therapeutic range 0.6 to 1.2ng/ml. Levels above 4.0 can be life threatening. Digibind is antidote. Side effects - visual (halos) and bradycardia. Nurse should check apical pulse one full min before admin. Hypokalemia - more dig toxicity
Describe MI including compensatory phase of cardiogenic shock, management, nursing implications
Initially possibly minimal signs 6 - 8 hr, as myocytes die myoglobulin is released 1 hr post injury, myocytes die and TROPONIN levels rise 2 - 4 hr after injury (measure q 6 x 3), CK is used but not specific for MI so CK-MB 4- 6 hr required. 24 - 26 hr neutrophils arrive increasing the risk for cardiogenic shock. 10 days granulation occurs at infarct site. 2 months scarring.
Describe signs and symptoms of cardiac tamponade
JVD, muffled heart sounds, tachycardia, decreased chest tube drainage
What is BNP (b type natriuretic peptide) what does an elevation indicate?
BNP <100 pg/ml = No heart failure
100- 300 present
>300 mild
> 600 moderate >900 severe
Describe atrial fibrillation and flutter appearance of EKG
fibrillation waves, difficult to count, no p waves, rate of R irregular
flutter saw tooth fluttering appearance, no p waves,r waves usually regular
Describe how nitroglycerine works, side effects, implications for nursing
Nitro dilates blood vessels resulting in flushing, possible hypotension
Describe the symptoms of MI using CRUSHING and treatment
Chest pain - Radiation to left arm, jaw, back- Unrelieved by nitro or rest- Sweating- Hard to breathe- Increased heart rate- Nausea and vomiting-Going to be anxious TREATMENT: ONMA Oxygen, Nitro (vasodilators) , Morphine (analgesic), Aspirin (Anticoagulant) (Also other anticoagulants Heparin, enoxaparin a low molecular weight heparin)
Describe hypertrophic cardiomyopathy causes, treatment
Genetics. At risk for sudden heart failure, cardiac arrest and death. Need a heart transplant.
Define the electrical conduction system in the heart
Describe emergency cardiac meds
Lidocaine for PVC's
Sodium bicarbonate to reverse acidosis due to rising Co2 levels
Epinephrine for asystole - dont give if on MAOI
Amiodarone for V tach of fib
Causes and signs and symptoms of cardiogenic shock
>40% of heart damage to left ventricle
CAUSES: end stage CHF, cardiac tamponade, pulmonary embolism, cardiomyopathy, arrythmias
S/S tachycardia, hypotension, decreased urine output, change in LOC, respiratory distress, cool clammy, decreased peripheral pulses, chest pain
Describe risk factors for heart failure using FAILURE
Faulty valves - Arrythmia - Infarction - Lineage (family history) - Uncontrolled hypertension - Recreational drug use -Evades (didnt get flu vacine)
What is heparin induced thrombocytopenia. Normal values for platelets? What is heparin antidote
Normal platelet count is above 150,000. Heparin can induce a drop in the platelet count. <150,000 is thrombocytopenia. Normal PTT for heparin is 1.5 to 2.5 times normal control value, approx. 60-100
Antidote is protamine sulfate
Emergency management of cardiac arrest
Airway - Breathing - Circulation - Defib for VT or VF
Describe cardiac valvular disease
CONGENITAL - stenosis or insufficient ACQUIRED 1. degenerative 2. rheumatic 3. Infective endocarditis from strep - SPECIFIC: Mitral valve prolapse, regurgitation (systolic murmur, crackles), stenosis (diastolic murmur, cyanosis, cough, anticoag for a fib) Aortic regurgitation (left ventricle volume increases and dilates decreased COP, diastolic murmur), stenosis systolic murmur, S4 sounds, pulmonary edema)