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41 Cards in this Set
- Front
- Back
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Define Cardia Arrhythmias |
loss of normal heart rate and rhythm; dysrhythmias |
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What may result from damage to the hearts conduction system? |
-Deviations from normal rate or rhythm may result from damage to the hearts conduction system or systemic causes such as electrolyte abnormalities, fever, hypoxia, stress, infection or drug toxicity - Interference with the conduction system may result from inflammation or scare its associated with rheumatic fever to MI |
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What do Dysrhythmias reduce? |
They reduce the efficiency of the hearts pumping cycle; irregular contraction are inefficient because they interfere with the normal filling and emptying cycle |
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Sinus Node abnormalities, What is the Sinus Node ? |
The sinus node is the pacemaker for the heart and its rate can be altered, thus; sins node abnormalities |
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What are some sinus node abnormalities? |
(1) Bradycardia
(2) Tachycardia (3) Sick Sinus Sindrome |
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Sinus Node Abnormalities: What is bradycardia? |
Refers to a regular BUT slow heart rate, less than 60BPM; it often results from vagal nerve or parasympathetic nervous system stimualtion |
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Sinus Node Abnormalities: What is Tachycardia? |
Refers to a regular rapid heart rate, 100-160 BPM. This may be a normal response to sympathetic stimulation, exercise, fever or stress or it may be compensation for decrease blood volume |
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Sinus Node Abnormalities: What is Sick Sinus syndrome? |
It is a heart condition marked by alternating bradycardia and tachycardia and often requires mechanical pacemaker |
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Dysrhythmias originating in the ventricles are the most serious, why ? |
A slight increase in heart rate increases cardiac output, but a very rapid heart rate prevents adequate filling during diastole (filling period), reducing cardiac output, and a very slow rate also reduces output to the tissues, including the brain and the heart itself. - irregular contractions are inefficient because they interfere with the normal filling and emptying cycle. |
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What causes damage to the conduction systems of the heart? |
Electrolyte imbalances, stress, fever, hypoxia, infection, or drug toxicity |
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What are the effects of arrhythmias |
- Reduce the efficiency of the hearts pumping cycle - A slight increase in heart rate can be compensatory and increase cardiac output |
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What is the effect of a very rapid heart rate on the cardiac output and explain why this occurs ? |
A very rapid heart rate prevents adequate filling during diastole, reducing cardiac output |
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What is the effect of a very slow heart rate on cardiac output and oxygen perfusion to the tissues? |
A very slow rate also reduces output to the tissues, including the brain and heart itself |
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What is the effect of irregular contractions on the normal functioning of the heart? |
Irregular contractions are inefficient because they interfere with the normal filling and emptying cycle. |
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What are the most common dysrhythmias ? |
Atrial conduction abnormalities are the most common (i.e. clinical abnormalities of the heart conduction) --> most common is AFIB (Atrial fibrillation) |
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What is the normal conduction system ? |
SA NODE- AV NODE- BUNDLE OF HIS- PURKENJIE FIBRE- HEART CONTRACT- PUSH BLOOD OUT- RELAX |
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What is depolarization ? |
Heart contractions ( when sodium goes in and calcium move out) |
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What is depolarization? |
Heart relax |
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If there is any problem in conduction pathway, what will happen ? |
Then the heart will beat irregularly; it will lead to cardiac disturbances |
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What happen if the electrical activity happens other than SA node ? |
- You will not get a normal conduction system - Heart will not beat normal - This will cause cardiac disturbances |
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What is ectopic foci? |
Any cells that conduct electrical activity outside SA NODE is called atopic foci |
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What factors causing abnormal firing of the heart or conduction outside the SA NODE? |
- Fever - Electrolyte imbalance -Hypoxia -Hyperkalemia -Hypokalemia |
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What is the normal heart beat? What is fast heart rate? What is slow Heart rate? |
- 60-100 BPM - Tachycardia - Bradycardia |
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What are the two types of dysrhythmias? |
1. Afib 2. Ventricular fibrilation |
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IF there is cardia disturbances, what will happen if the atrium is beating too fast, what will happen to cardiac output? |
Decrease cardiac output because its not contracting well enough, not pushing the blood from atrium to ventricle - Atrium is responsible for 30 percent of blood supply |
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Why are ventricular arrhythmias are more dangerous? |
Because L ventricular oxygenated blood to the rest of the body |
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Explain why there are more chances of clot formation in R atrium |
Because if the atrium is not pumping well enough, the blood will just stay in the atrium it will lead to clot formation and might travel to the brain, lung = stroke and pneumonia
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What happens when the heart is beating too fast? |
Heart needs O2 to the coronary artery supply the heart during diastole the heart is beating too fast- no relaxation , not enough time to rest = decreased O2 supply to the heart because coronary arteries not able to supply blood to the heart, Leads to less cardiac output- heart itself not getting enough O2 to function well |
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What happens when the heart is pumping too slow ? |
Means the heart is not pumping enough blood to the chambers = decreased output |
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What are the 3 degrees in Atrioventricular Node Abnormalities- Heart Blocks |
1st Degree: conduction delay prolongs the PR interval, the time between the atrial ad ventricular contractions 2nd Degree: in which longer delay leads periodically to a missed ventricular contraction 3rd /total: occur when there is no transmission of impulses from the atria to the ventricles. The ventricles contract spontaneously at a slow rate 30-45 BPM, totally independent of the atrial contraction, which continues normally; in this case CO is reduced, sometimes to the point of syncope (fainting) causing a stokes-Adams attack or cardiac arrest
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Define what heart block is ? |
occurs when conduction is excessively delayed or stopped at the AV node or bundle of his |
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What are some ventricular conduction abnormalities? |
1. bundle- branch block 2. Ventricular tachycardia 3. ventricle fibrillation 4. Premature ventricular contractions (PVC) |
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What is bundle-branch block ? ventricular conduction abnormalities |
Refers to the interference with conduction in one of the bundle branches; this does not usually alter cardiac output but does appear on the ECG as a wide QRS wave |
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What is Ventricular tachycardia ? ventricular conduction abnormalities
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Is likely to reduce cardiac output because the filling time is reduced and the force of contraction is reduced |
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What is ventricular filtration? ventricular conduction abnormalities |
the muscle fibres contract independently and rapidly (uncoordinated quivering) and therefore are ineffective in ejecting blood. the lack of cardiac output causes severe hypoxia in the myocardium, and contraction ceases |
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What is premature ventricular contractions (PVC)? ventricular conduction abnormalities |
Are additional beats arising from a ventricular muscle cell or ectopic pacemaker. occasional PVC do no interfere with heart function, but increasing frequency, multiple equities sites, or paired beats are of concern because ventricular fibrillation can develop from these, leading to cardiac arrest |
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Treatment: What do atrial dysrhythmias often respond to? |
digoxin: which slows AV node conduction and strengthens the contraction, thus increasing efficiency |
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Treatment: How do you treat SA nodal problems or heart block |
The only way to do so is to implant a pacemaker, either a temporary attachment or a device that is permanently implanted in the chest |
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What are the categories of antidysrhythmics? |
1.Sodium Channel blockers ( Class I) 2.Beta- adrenergic blockers (class II) 3.Potassium channel blockers (class III) 4.Calcium Channel Blockers (Class IV) 5.Miscellaneous antidysrhythmic drugs |
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What do beta-adrenergic blockers do in dysrhythmias? |
They slow down the heart rate and decrease conduction velocity through the AV node. Myocardial automaticity is reduced, and many types of dysrhythmias are stabilized. |
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What is the main purpose of beta-adrenergic blockers for treatment of dysrhythmias? |
It is to treat atrial dysrhythmias associated with heart failure |
