EKG strips

Atrial Fluitter

HR: greater than 250 bpm (faster than SVT); R-R interval: regular; P wave: not distinguishable; PR interval: cannot calculate; QRS: 0.06; QT interval: cannot be determined; appears as saw tooth or flutter waves; Treatment: cardioverson is preferred. Ca2+ channel blockers, beta blockers, and digitalis may be used.

Class 4 Agents

Ca2+ Channel blockers, blocking the Ca2+ through the cell membranes, thereby decreasing depolarization. It works by reducing automaticity in the SA node and slows conduction in the AV node; SE: hypotension, AV block; Nurse: correct K+ and Mg+ prior to administration, monitor drug levels (digoxin), use in caution with elderly (kidney function);

Supraventricular Tachycardia (SVT)

a type of atrial dysrhythmia; HR: 150-250 bpm; Rhythm: regular; P waves not distinguishable and are buried in the T waves; QRS complex: normal; P-R Interval: cannot calculate; Treatment: Valsava's manuever or Adenosine

Third Degree AV block

atria and ventricles contract independently and this requires emergency treatment; impulses are not conducted through the AV node; this is usually associated with MI. Usually the patient will experience an alternation in mental status and syncope. Complete block can progree to ventricular fibrillation; Treatment: same for 2nd degree heart block. Patient may have a permanent pacemaker inserted; If symptomatic, the patient will be administered atropine, dopamine, or epinephrine. P-P and R-R intervals are regular but have no relationship to each other.

Class 2 Agents

block the effects of catecholamines (eg: epinephrine); the are the beta blockers; the work by decreasing the SA node autonomaticity and slow AV conduction, decreasing cardiac stimulation and may produce vasodilation and bronchoconstriction; Major SE: anaphylactic reactions, Steven-Johnson Syndrome, bronchoconstriction, bradycardia; Nurse: monitor for hypotension during titration phase and when increasing dosage. They are used in patients with severe CHF, significant bradycardia, and 2nd degree or higher heart blocks. They are contradicted in asthma b/c of bronchoconstriction.

Class 3 Agents

blocks K+ channels thereby delaying repolarization and prolonged refractory period. A prolonged QT may develop. They treat atrial and ventricular dysrhythmias (life threathening); SE: dizziness, hypotension, sinus arrest; Nurse: correct K+/Mg+ levels prior to initiation of drug, monitor for hypotension and sustained monitoring is essential due to long half-life.

Ventricular Dysrhythmias

can be life-threatening due to inadequate ventricular ejection which produces inadequate stroke volume. If prolonged, O2 to the body's tissues is compromised, producing ischemia, then organ failure, and cell death. 2 common types are: ventricular tachycardia and ventricular fibrillation

Ventricular Tachycardia (VT)

classified as 3 or more consecutive PVCs occurring at a rapid rate, usually > 100 bpm; SA node fires spontaneously; P waves: not identifiable and buried in the QRS complex; R-R interval: regular; PR interval: none; the danger with this is that it may go into ventricular fibrillation; Treatment: cardioversion may be used to convert the rhythm and when pulseless, defibrillation is used. Drugs include: amiodarone, lidocaine, Mg+

Premature Atrial Contractions (PACs)

common phenomenon; originate from an excitable focus outside the normal SA node; they are usually caused by enhanced automaticity of cardiac cells resulting from a stimulus such as caffeine, nicotine, alcohol, stress. In pts with cardiovascular disease, the most dangerous cause is cardiac ischemia; they originate from unifocal (one) or multifocal (more) ectopic pacemakers located in the atria; PR interval: may be normal or prolonged; QRS complex: normal; There is a characteristic short pause called NONCOMPENSATORY PAUSE; these are generally benign but may serve as an early warning sign for afib or aflutter or SVT so they warrant close observation

Ventricular Fibrillation

most common cause of sudden death; pattern is chaotic; rhythm: irregular; patient will be unresponsive without a pulse and will require emergency treatment and resusication; Treatment: defibrillation, drugs: epinephrine or vasopressin. If patient is pulseless, CPR and attempts at defibrillation continues. For persistent pulseless ventricular fibrillation, amiodarone, lidocaine and Mg+ is used; Causes: MI and Premature ventricular beats, hypovolemia, electrolyte imbalances, hypothermia, cardiac tamponade, pneumothorax, pulmonary thrombosis, trauma. P wave and QRS: absent; no pulse present

Asystole

represents complete cessation of electrical impulses; Treatment: Cardiopulmonary resuscitation immediately. It is imperative to check the rhythm on 2 separate leads. Other treatments: Atropine, epinephrine, or vasopressin. Possible causes: hypovolemia, hypoxia, electrolyte imbalances (acidosis, K+), hypoglycemia, hypothermia, pulmonary or coronary thrombosis, and trauma. Often, despite rigorous efforts, asystole is a terminal rhythm.

Adenosine / Digoxin

do not fit into a major class; they both reduce AV node automaticity and slow AV conduction; Digoxin is used to treat supraventricular tachycardia / ventricular fibrillation / Atrial Flutter. Adenosine is only used for Supraventricular Tachycardia

Class 1 Agents (Antiarrythmic agents)

fast Na+ channel blockers; they work by slowing conduction through the atria, ventricle and bundle of his; SE: may widen QRS complex, prolong QT intervals, induce heart block; Nurse: monitor cardiac rhythm and immediately report the following: widening of the QRS, changes in QT interval, disappearance in P waves, sudden onset or increase in ectopic ventricular beats

Atrial Fibrillation

most common sustained arrhythmia; atria is contracting so fast and the ventricles are inadequately filled and stroke volume is decreased by 25%; blood in the atria is prone to forming clots (so many people require anticoagulant therapy such as Warfarin), which increases the risk of thrombotic stroke. RR Interval: irregular (meaning that the R's are not spaced out in a systematic fashion and are irregular); Rate: unable to calculate but can be as high as 400 bpm; P wave: cannot see; PR interval: cannot see; QRS complex: 0.06; QT interval: cannot be determined; Treatment: Amiodarone, digoxin, beta blockers and Ca2+ channel blockers. Note: Afib is not treated if its of long standing duration and does not produce symptoms;

Sinus Bradycardia

originates from the SA node; HR: under 60 bpm; Rhythm: regular; P waves: upright, consistent, normal in duration; P-R Interval: between 0.12-0.20 sec in duration; QRS Complex: less than 0.12 sec.; athletes may be sinus bradycardia due to optimal cardiac stroke volume that requires less HR to yield acceptable cardiac output; may also be produced by Vagal Stimulation or due to Sick Sinus Syndrome; expect a narrow QRS with upright P waves; R-R interval: regular; PR interval: 0.20; P wave precedes QRS; The only abnormality here is the rate; Treatment: not treated unless the person experiences of decreased cardiac output, such as synocope, hypotension and angina; Symptomatic sinus bradycardia is treated with Atropine b/c it blocks the parasympathetic innervation of the SA node allowing normal sympathetic innervation to gain control and increase SA node firing

Sinus Tachycardia

originates from the SA node; there are no abnormalities except the rapid rate; HR: greater than 100 bpm but no more than 150 bpm; Rhythm: regular; P waves: upright, consistent, normal; P-R interval: Between 0.12-0.20 seconds and shortens with increasing heart rate; QRS Complex: Less than 0.12 seconds, consistent, and normal; Most often results from increased sympathetic stimulation (ex: pain, fever, increased O2 demand, hypovolemia); usually has a narrow QRS; It can produce angina if the cardiac output decreases to the point of reducing coronary circulation; Treatment: aimed at relieving sympathetic stimulation, imagery, distraction, calm environment, drugs such as sedatives, tranquilizers, antianxiety agents, analgesics and antipyretics

Premature Ventricular Contractions (PVCs)

premature ventricular beats that originate in an irritable ventricle before the next sinus beat is due; P wave: not present since the electrical stimulus originates outside the atria; Wave form is usually HIGHER and is also bizarre ; there is a characteristic of a compensatory pause; they warrant close observation b/c they are assoc. with development of ventricular tachycardia (VT) and ventricilar fibrillation (VF); they can be bigeminy (a pattern of 1 normal SA node initiated beat followed by 1 PVC) or trigeminy (a pattern of 2 normal beats followed by 1 PVC); Treatment: occasional PVC do not warrant treatment. The nurse needs to pay attention to low K+ / Mg+ (means myocardial irritability) - if low, give K+ and correct hypoxia with O2; Amiodarone is the most commonly med given in the setting if a pt is symptomatic (hypotension)

Sinus Rhythm

regular rhythm; bpm: 60-100; QRS is often narrow with upright P waves;

2nd degree AV block

the SA node impulse is conducted with a delay or it is completely blocked in the AV nodal area; P wave: present but the PR interval is irregular or not measurable b/c its missing QRS complexes; there are 2 patterns: Mobitz type 1 (PR interval lengthens progressively before dropping the QRS complex and is more common than type 2) and Mobitz type 2 (QRS complexes are wide b/c the block is usually in the bundles, is more serious b/c it is assoc. with 3rd degree AV block); Nurse mgt: a patient with type 2 2nd degree block whether symptomatic or asymptomatic will likely receive a pacemaker. Regardless of the type of 2nd degree AV block, if the pt. experiences symptoms Atropine is administered. Dopamine and epinephrine are used in severe symptomatic bradycardia

1st degree AV block

there is a delay in conduction through the AV node and is denoted by a prolonged PR interval; P wave and QRS have a 1:1 relationship; the rest of the ECG is normal; patient is usually asymptomatic and no treatment is necessary. However, the presence of an acute MI or CAD c there is a delay in conduction through the AV node and is denoted by a prolonged PR interval; P wave and QRS have a 1:1 relationship; the rest of the ECG is normal; patient is usually asymptomatic and no treatment is necessary. However, the presence of an acute MI or CAD can delay and increase into a 2nd degree or 3rd degree, requiring more treatment

Countershock (cardioversion)

used to treat SVT (supraventricular tachycardia) that is resistent to meds; unstable patient may have hypotension, dyspnea or complain of chest pain or may have symptoms of a MI; Analgesia is provided before the electric shock; Nurse: obtain an ECG strip before cardioversion, during and after. Informed consent is obtained, IV access is confirmed before procedure, pt. will likely given a sedative, any electrolyte abnormalities will be reported to dr (esp. Ca2+/Mg/K+); O2 and all metallic objects are removed from the patient and conductive pads are placed on the patient's chest below the right clavical and in the mid-axillary line on the left. No one should be touching patient or bed and CPR is resumed immediately after shock. After 5 cycles of CPR, the pulse and rhythm are checked. If indicated, shock and meds continue.

AV Block

when there is a delay that occurs at the AV node area; it is associated with MI and chronic blocks are assoc. with CAD; they are classified as 1st degree, 2nd degree, and 3rd degree