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1. How many boxes long is the QRS interval?
2. How long is the PR interval on the EKG strip?
3. How long is the QT interval on the strip?

1. QRS interval is no more than 2 small boxes.
2. PR interval is 3-5 small boxes.
3. QT interval is usually less that 1/2 of the RR interval (about 2 large boxes on the EKG strip)

A fib

irregularly irregular with absence of P waves

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Ventricular fibrillation

Unattainable rate; undiscernable P waves; QRS not apparent; chaotic

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Premature ventricular contractions (PVCs)

QRS = wide; bigger than 3 small boxes

(ST & T wave may be opposite)

Rhythym = irregular

P wave = usually obscured by QRS, PST, or T wave of PVC

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sinus rhythm with uniform PVCs

Atrial flutter

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P wave not present; usually a saw-tooth pattern present

Symptoms: palpitations, rapid heart rate, chest pain, shortness of breath, lightheadedness, fatigue, and low blood pressure.

Rhythm: usually regular, but can be irregular if the AV block varies.

1. Count # of complexes in 6 sec strip & multiply by 10
2. Count # of large boxes between 2 complexes & divide into 300
3. Count # of small squares between complexes & divide into 1500

Ways to determine HR on ECG strip:

Preload

Degree of myocardial stretch at end of diastole. Indicates how hard heart will push blood out. 

Afterload

Resistance; This will increase when arteries are occluded (harder to push blood through). 

Hypercalcemia

Electrolyte imbalance that causes increased contractility, ventricular dysrhythmias.

S&S = decreased DTR's, arrhythmias, decreased HR, decreased RR, decreased LOC, N&V, muscle weakness

TX: phosphorous, steroids, fluids, MOVE!

Hypocalcemia

Normal Ca+ = 9.0 - 10.5 mg/dl

Electrolyte imbalance that causes decreased contractility, decreased sensitivity to Digoxin, & cardiac insufficiency.

S&S: increased DTRs, tight/rigid muscles, stridor/laryngospasm, arrythmias, unpredictable mind changes

TX: Vitamin D, Renagel, Oscal, IV Ca+

Hyperkalemia

Normal potassium: 3.5 - 5 meq/L

Electrolyte imbalance that causes slowed conduction of impulses

S&S: muscle twitching -> weakness -> flaccid paralysis

***life threatening arrythmias***

ECG: bradycardia, tall/peaked T waves, prolonged PR intervals, flat or absent P waves, widened QRS conduction, blocks ventricular fibrillation

TX: dialysis, calcium gluconate, glucose & insulin, kayexalate

Hypokalemia

Normal potassium levels: 3.5 - 5 meq/L

Electrolyte imbalance that causes prolonged cardiac repolarization and decreased muscle strength; potentiates Digoxin toxicity

S&S: muscle cramps, weakness ***life threatening arrythmias*** ECG: u waves, PVCs, ventricular tachycardia

TX: Give k+, aldactone, eat k+ rich foods

Asystole

ventricular standstill

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5th Intercostal space

best place to hear/assess S1 (Lubb)

2nd Intercostal space

Best place to hear/assess S2 (Dubb)

4th Intercostal space; 

commonly heard with HF, close after S2 in early diastole

bigger deal if hearing this in someone over 40 years old

Best place to hear S3

When would you hear this?

When would this be of most concern?

Heart at apex; late diastole (before S1)

(scarring after MI, htn)

Best place to assess for S4:

What might cause you to hear S4?

Cardiac output is the amount of blood ejected from the L ventricle into the aorta per MINUTE

Equation:

CO = SV x HR

What is Cardiac Output?

How is it determined?

Stroke volume is the amount of blood ejected into the aorta by L ventricle per BEAT

SV = End diastolic volume - End systolic volume

***usually 70 mls/beat***

what is stroke volume?

How is it determined? Average Stroke volume is?

Ejection fraction measures L ventricular function;

Decreased ejection fraction = L ventricular FAILURE

SV divided by End diastolic volume = Ejection Fraction

{{55-60% is a healthy Ejection Fraction}}

What does ejection fraction measure?

How is it determined?

P Waves

Contraction of the atrium (atrial depolarization) is represented by what wave on the ECG?

the QRS complex

contraction of the ventricles are represented by what wave(s) on the ECG?

T wave

ventricular repolarization is represented by what on the ECG?

• Pt symptoms
• diet
• med hx
• w/abnormal EKG ask, "Is this new?"

Priority assessment in pt with dysrhythmia(s)?

• evaluate bp, LOC, CO (baseline?)
• show them how to check pulse (check frequently)
• evaluate for presence of hemodynamic deterioration
• assess for angina, hypotension, HF, decreased cerebral & renal perfusion
• consider causes of dysrhythmias
• education: avoid alcohol, smoking, caffeine
• Reg bp checks

NSG care of elderly with dysrhythmias:

• Eliminate underlying cause if possible
• Evaluate severity of problem
• Med: antiarrhythmic (i.e., Lidocaine); if also bradycardic, may give atropine to speed things up

TX for PVC:

• relieve hypoxia
• anticoag. tx
• cardioversion (pharmacologic & electrical)

TX for A fib:

• Observe ECG closely!! Look for prolonging of PR interval, QRS complex or QT, RR intervals.
• If QT interval prolongs more than one half the RR - HOLD the drug and report
• Monitor for Torsades De Pointes - be prepared to treat to slow down rate if it occurs
• Monitor for S&S of GI effects (N&V, Diarrhea)

Nursing implications with Class I antidysrhythmics

(effect the Na+ channel and cardiac action potentials...declining in use)

Torsades De Pointes

a variant type of ventricular tachycardia:

P wave: obscured, if present

QRS: wide & bizarre morphology

Rhythm: irrregular

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Class IA

s/e: diarrhea, N&V, abdominal cramping, anorexia

Side effects of Class IA drugs:

Examples:

procainamide (pronestyl, procan)

disopyramide (Norpace)

Class 1B

s/e: drowsiness, light-headedness, paresthesia, hypotension, bradycardia, possible lidocaine toxicity

Side effects of Class 1B drugs:

Examples:

Lidocaine (IV, short duration)

phenytoin

tocainide

mexiletene (Mexitil)

Class 1C

s/e: palpitation, SOB, chest pain, HF, MI

What class are Flecanide (Tambocor) and Propafenone (Rythmol) in?

Side effects?

• Monitor HR, Bp, ECG: HOLD if low HR and Bp
• Assess QRS duration: HOLD if expands 25%
• Monitor electrolytes
• assess for respiratory effects
• usually not used in HF
• Do not abruptly stop: may cause lethal rhythms, angina symptoms or precipitate MI (in pts w/coronary artery disease)
• teach pts to watch for symptoms of fluid retention (wt gain, edema, SOB)
• teach pts to limit fluid & Na+ intake to minimize fluid retention

Nursing Implications for Class II antidysthythmics:

Examples: propranolol (Inderal)

metoprolol (Lopressor)

• monitor ECG when starting tx
• do not administer sotolol unless pt is unresponsive to others (sotolol is used for atrial or ventricular tachyarrhthmias)
• see special instructions for specific meds:
  • Ibutilide: acute conversion of A fib to sinus rhythm
  • Bretylium: acute VF
  • Amiodarone: refractory VT or VF, cardiomyopathy and A fib (to maintian NSR)

Nursing implications for class III antidysrythmics:

Examples:

bretylium (bretylol)

amiodarone (Cordarone)

ibutilide (Corvert)

Sotolol (betapace)

Side effects: AV block, bradycardia, ventricular arrhythmias, bronchospasm, hypotension

• monitor bp & HR: hold med if HR below 60 & systolic bp below 90
• monitor bp & ECG continuously if pt is rec'g. IV verapamil
• teach pt to rise/change position slowly (minimize orthostatic hypotension)
• encourage to increase fiber intake to prevent constipation
• assess dizziness: may need dose changed

NOTE: grapefruit juice increases therapeutic effects & risk of toxicity!

Other interactions: Digoxin (dig toxicity); beta blockers (risk of bradycardia & HF); antihypertensives: additive hypotension; verapimil decreases lithium levels

Nursing implications with Class IV antidysrhythmics:

Examples:

verapamil (Calan)

diltiazem (Cardiazem)

Nifedapine (procardia)

*slows HR in fast rhythms, decreases contractility (lowers bp)

S/E: dizziness, hypotension, bradycardia, edema, constipation, HF, AV block, ventricular asystole, V Fib, Nausea

Class 5 antidysrhythmics

What class are these drugs?

Examples: adenosine (adenocard)

used for: paroxysmal SVT (unresponsive to vagal man.)

s/e: transient arrhythmias, dyspnea, facial flushing

*do not use: AV block, A fib, A flutter, V tach

Atropine (anticholinergic)

s/e: hallucinations, tachycardia, dry mouth, constipation

Use for: sinus bradycardia (symptomatic) & bradyarryth.

*do not use: glaucoma, urine retention or ileus

• Monitor Dig levels
• Monitor for Dig toxicity
  • abnormal heart rhythms, visual disturbances, N&V, diarrhea
• Monitor for conditions that increase toxicity
• w/HOLD if Dig toxicity is suspected
• W/HOLD if HR below 60

Nursing implications with Digoxin:

(Class V: cardiac glycoside)

used for: HF (improves contractility and CO); can be used to slow fast cardiac rhythms; A fib; A flutter

S/E: Dig toxicity, bradycardia, hypotension

• hypokalemia
• hypercalcemia
• renal impairment
• advanced age
• acute hypoxia
• hypothyroidism
• drug use of: amphotericin B, quinidine, amiodarone, diltiazem, captopril, furosemide, erythromycin, ibuprofen, nifedipine, and/or verapamil 
• Herbal use of: cascara sagrada bark, ginseng, pleurisy root, ephera, ephedrine, sarsaparilla

Conditions that increase Dig toxicity are:

• elevate lower extremities above heart level
• infuse a bolus of IV fluid
• IV atropine (TX for bradycardia)

NSG interventions after cardiac cath...to prevent vasovagal response:

What causes vasovagal response?

• increase activity gradually
• diet: No fat, low salt, no cholesterol
• no isometric exercisis (increases workload of heart)
• no valsalva
• no straining, no suppository (Docusate/Colace)
• Walking is best exercise
• S&S of HF are: wt gain, ankle edema, SOB, Confusion
• Sex can be resumed when they can walk up flight of stairs or around block w/out SOB (safest time: morning, when well rested)

What are discharge activity guidelines for cardiac clients?

• Avoid IM injections 
• monitor for dysrhythmias
• bleeding precautions/S&S
• blood typing (have blood "on hand")
• Monitoring pain w/angina