Cardiovascular Flashcards
List the path a cardiac electrical impulse travels through the heart.
Sinoatrial node (SA) in upper right atrium over the atrial myocardium via Bachmann’s bundle and internodal pathways, causing atrial contraction.
Then to atrioventricular (AV) node through the bundle of His and down the left and right bundle branches, ending in the Purkinje fibers, which transmit the impulse to the ventricles resulting in ventricular contraction.
SA—>AV—>bundle of His—> Purkinje fibers
(S..A..B..P)
Which components of the autonomic nervous system affect the heart?
Right and left vagus nerve fibers of the parasympathetic nervous system and fibers of the sympathetic nervous system.
Plays a role in the rate of impulse formation, speed of conduction and strength of cardiac contraction
Sinus bradycardia has normal sinus rhythm but SA fires slower than 60bpm.
What are causes?
Athlete Valsalva maneuver Hypothermia Parasympathomimetic drugs Hypothyroidism Increased intracranial pressure Obstructive jaundice Inferior wall myocardial infarction
Treatment for bradycardia
Atropine (anticholinergic)
Pacemaker
Sinus tachycardia- normal sinus rhythm but at a rate greater than 100 bpm.
What are causes?
Vagal inhibition or sympathetic stimulation Exercise, Fever, Pain, anxiety, Hypotension, Hypovolemia Anemia, Hypoglycemia Myocardial ischemia, Heart failure Hyperthyroidism Side effect of drugs
What is PAC?
Premature Atrial Contraction
Contraction in atria with ectopic focus (other than SA node). Similar to PVC but in atrium. Usually not significant.
Usually caused by caffeine tobacco alcohol, hypoxia or electrolyte imbalance,
or hyperthyroidism, COPD, CAD
What is paroxysmal supra ventricular tachycardia (PSVT)?
What are causes and treatments?
Dysrhythmia that is usually triggered by a PAC.
associated with over exertion, emotional stress, caffeine and tobacco.
Can also be associated with rheumatic heart disease, digitalis toxicity, CAD and cor pulmonale.
Treatment includes vagal stimulation and drug therapy possibly IV adenosine.
What is atrial flutter?
What are some causes?
Atrial tachidysrhythmia identified by recurring regular sawtooth shaped flutter waves.
Associated with CAD, hypertension,
mitral valve disorders, pulmonary embolus, chronic lung disease, cardiomyopathy, hyperthyroidism,
use of drugs such as digoxin, quinidine, and epinephrine.
What are some consequences of atrial flutter?
And what would be treatment?
Heart rate over 100 bpm and the loss of the atrial “kick” can cause decreased Cardiac output and cause serious consequences such as chest pain and heart failure.
Increase risk of stroke because of the risk of thrombus formation in atria from stasis of blood.
Goal of treatment of atrial flutter is to slow ventricular response by increasing AV block.
What is atrial fibrillation?
Who is at risk for a fib?
Total disorganization of atrial electrical activity due to multiple ectopic foci resulting in loss of effective atrial contraction.
A fib is associated with CAD, rheumatic heart disease, cardio myopathy, heart failure, pericarditis.
Can be caused by thyrotoxicosis, alcohol intoxication, caffeine, electrolyte disturbances, stress and cardiac surgery.
What are some complications from Atrial fibrillation and
what is the goal of treatment?
Complications: can result in decreased cardiac output.
thrombi may form and the atria as a result of blood stasis consequently causing a stroke or pulmonary embolism.
Goals of treatment include a decrease in ventricular response and prevention of cerebral embolic events.
What is heart block?
Heart block is an abnormal heart rhythm where the heart beats too slowly (bradycardia). In this condition, the electrical signals that tell the heart to contract are partially or totally blocked between the upper chambers (atria) and the lower chambers (ventricles). For this reason, it is also called atrioventricular block (AV block).
What is first degree heart block?
AV block
First-degree heart block - The electrical impulses are slowed as they pass through the conduction system, but they all successfully reach the ventricles. First-degree heart block rarely causes symptoms or problems. Well-trained athletes may have first-degree heart block. Some medications can also cause this condition. No treatment is generally needed for first-degree heart block.
What is Second degree AV block type 1
Also called Mobitz 1 or Wenckebach heart block
Second-degree heart block (Type I) - The electrical impulses are delayed further and further with each subsequent heartbeat until a beat fails to reach to the ventricles entirely. This type of block most often is physiologic and is seen in a highly relaxed state and during sleep. It rarely causes symptoms. It sometimes causes dizziness and/or other symptoms.
What is second Degree AV block type 2?
Mobitz 2 heart block
Second-degree heart block (Type II) - With this condition, some of the electrical impulses are unable to reach the ventricles. This condition is less common than Type I, and is more serious.
Usually, pacemaker treats type II second degree heart block, as it frequently progresses to third degree heart block.
What is third degree AV block or complete heart block?
none of the electrical impulses from the atria reach the ventricles. When the ventricles do not receive electrical impulses from the atria, they may generate some impulses on their own, called junctional or ventricular escape beats. Ventricular escape beats, the heart naturally occurring backups, are usually very slow. Patients frequently feel fatigue, lightheadedness, and decreased stamina in complete heart block. Patients are usually treated by implanting a permanent pacemaker.
Premature ventricular contraction PVC?
And treatment?
Contraction originating in an ectopic focus in ventricle.
Usually benign. Associated with stimulants, caffeine, alcohol, and nicotine, epinephrine, digoxin.
Treatment if needed: Beta blockers, procainamide, amiodarone, lidocaine
What is Ventricular tachycardia (VT)?
VT is a run of three or more PVCs. It occurs when an ectopic focus or foci fire repetitively in the ventricle takes control as the pacemaker.
This is a life-threatening dysrhythmia because of decreased cardiac output and the possibility of deterioration to Ventricle fibrillation.
What can cause ventricle tachycardia VT?
VT is associated with MI, CAD,
significant electrolyte imbalances, cardiomyopathy,
mitral valve prolapse, digitalis toxicity and
central nervous system disorders.
VT Can be:
stable: patient has a pulse
OR
unstable: patient is pulseless.
Ventricular fibrillation VF
What is it and what can cause it?
Severe derangement of heart rhythm. Mechanically the ventricle is simply quivering and no effective contraction consequently no cardiac output occurs.
Occurs in acute MI, myocardial ischemia, chronic diseases such as CAD and cardiomyopathy.
What is the treatment for V fib?
V fib results in unresponsive, pulseless, apneic state. If not rapidly treated the patient will die.
Treatment consists of immediate CPR and ACLS measures with the use of defibrillation and definitive drug therapy
Asystole
Total absence of ventricular electric goal activity. No ventricular contraction occurs.
Asystole is a lethal dysrhythmia that requires immediate treatment consisting of CPR, ACLS such as intubation, IV therapy with epinephrine and atropine.
Pulseless electrical activity (PEA)
Electrical activity can be observed on ECG, but there is no mechanical activity of the ventricles and the patient has no pulse.
Prognosis is poor unless underlying cause can be identified and quickly corrected. Treatment begins with CPR followed by intubation and IV therapy with epinephrine.
