Dysrhythmias occur when there is a disturbance in the normal electrical conduction system of the heart, resulting in abnormal heart rates and inefficient pumping of blood. They can be caused by abnormal pacemaker cells firing irregularly or blockages interfering with normal conduction pathways. Diagnosis involves ECG, telemetry, Holter monitoring and lab tests. Treatment goals are to restore normal sinus rhythm and function while preventing recurrence of life-threatening dysrhythmias. Nursing care focuses on monitoring, assessment, education, and ensuring patients adhere to medication and lifestyle regimens.

1. Pharmacology
Dysrhythmias
Chapter 24

2. Dysrhythmias
• The electrical or conduction system controls
the sequence of muscle contraction for
optimal blood volume pumped from the heart
each beat

3. Dysrhythmias
• Sometimes called arrhythmia
• Occurs when there is a disturbance of the normal
electrical conduction
• Results in abnormal heart muscle contraction
• Results in abnormal heart rates
• The dangers is the frequency with which they
occur
• An inefficient pumping of adequate volume of
blood
• Certain type can produce additional dysrhythmias

4. Dysrhythmias
• Certain type can produce additional
dysrhythmias
– the heart stops pumping and still beat for a short
time--fibrillations

5. Dysrhythmias Classification
• Origin within heart tissue
– Electrical impulse sequence
– Obstruction of conduction pathway
– Combination
– Based on heart beat rate

6. Dysrhythmias
• Causes:
• Firing of abnormal pacemaker cells is when
something causes out of regularity of electrical
impulse (sequence)—irregular muscular
contraction
• Blockage of normal electrical pathways is a partial
obstruction of normal conduction pathway
causing an irregular pattern of muscle
contractions—reentrant dysrhythmia
• Combination of the both

7. Sequential Causes
• Above the Bundle of His—Supraventricular
– Atrial flutter
– Atrial fibrillation
– Premature atrial contraction PAC’s
– Sinus tachycardia
– Sinus bradycardia
– Paroxysmal supraventricular tachycardia

8. Sequential Causes
• Developing near or within the AV node are:
– Junctional dysrhythmias
• Developing below the Bundle of His are:
– Ventricular dysrhythmia
– Premature ventricular contractions—PVC’s
– Ventricular tachycardia—VT
– Ventricular fibrillation—VF

9. Obstruction Causes
• Described by location
• Supraventricular
• Ventricular
• Left or right bundle branches
• Atrio-ventricular blocks
– Sub-classifications
– 1st degree—partial block, delayed AV conduction
– 2nd degree—partial block, with occasional blocked
beats
– 3rd degree—complete block
• atria & ventricles function independent

10. Dysrhythmias: Diagnosis
• Physical examination
• History
• ECG pattern—underlying cause***

11. Treatment of Dysrhythmias
• The goal of therapy:
• Restore normal sinus rhythm
• Restore normal cardiac function
• Prevent recurrence of life-threatening
dysrhythmias

12. Dysrhythmias: Drug Therapy
• Anti-dysrhythmic are classified according to their
effect on the electrical conduction system
• Class Ia-IV
– Sodium Channel Blockers (intermediate acting)
– Sodium Channel Blockers (quick acting)
– Sodium Channel Blockers (slow acting)
– Beta Adrenergic Blockers
– Potassium Channel Blockers
– Calcium Channel Blockers
– Vagal Stimulators
– Conduction Slowers

13. Dysrhythmias: Drug Therapy
• Class
• Ia
• Ib
• Ic
• II
• III
• IV
• Misc.

14. Dysrhythmias: Drug Therapy
• Class I act as myocardial depressant by
inhibiting sodium ion movement

15. Dysrhythmias: Drug Therapy
• Class Ia prolong duration of the electrical
stimulation on cells & refractory time between
electrical impulses
• Sodium Channel Blockers (intermediate
acting)
• Quinidine
• Procainamide
• Disopyramine

16. Dysrhythmias: Drug Therapy
• Class Ib shorten the duration of electrical
stimulation & time between electrical
impulses
• Sodium Channel Blockers (quick acting)
• Lidocaine
• Mexiletine

17. Dysrhythmias: Drug Therapy
• Class Ic are the most potent myocardial
depressant & slow conduction rate through
atria and ventricles
• Sodium Channel Blocker (slow acting)
• Flecainide
• Propafenone

18. Dysrhythmias: Drug Therapy
• Class II are BAB agents that depress the
stimulation of beta cells of the SNS
• Beta Blockers
• Propranolol
• Esmolol
• metoprolol

19. Dysrhythmias: Drug Therapy
• Class III slow the rate of electrical conduction
& prolong the time interval between
contractions by blocking potassium channels
• Potassium Channel Blockers
• Amiodarone
• Sotalol
• Ibutilide
• dfetilide

20. Dysrhythmias: Drug Therapy
• Class IV block calcium ion flow, prolonging
duration of the electrical stimulation &
slowing AV node conduction
• Calcium Channel Blockers
• Verampamil
• Diltiazem

21. Dysrhythmias: Drug Therapy
• Misc Anti-dysrhythmia Agents
• Digoxin—vagal stimulator
• Adenosine—conduction slower

22. Nursing Process: Dysrhythmias
• Analysis & Diagnosis
• Assess ECG
• Telemetry in place as adjunct
• 24 hour ECG Holter monitor
• EPS - electrophysiologic studies
• Exercise electrocardiography
• Lab & DIAGNOSTIC TESTS: K+, Ca+, ABG, clotting: AST, ALT, CK-MB,
creatinine troponin, D-diameter, LDH, X-ray, cardiography, catherization
• Examine urinalysis & perform hourly I & O’s
• Report < 30-50mL urine output
• Monitor renal function—BUN and creatininte
• Medical history—meds prescribed
• 6 Cardinal Signs of CVD (dyspnea, chest pain, fatigue, edema, syncope,
palpitations
• Mental status: LOC, clarity of thought—cerebral perfusion
• VS: BP twice daily, record BP in both arm 5-10 mm Hg or more
reported, HR, RR, temperature, O2 sat, BrS
• Auscultation & Percussion for heart size and sounds

23. Nursing Process: Dysrhythmias
• Decreased Cardiac Output
• Activity Intolerance
• Risk for Decreased Cardiac Tissue Perfusion
• Fatigue
• Death Anxiety

24. Nursing Process: Dysrhythmias
• Planning:
• Order medication & place in the MAR
• History of 6 Cardinal Signs of CVD
• Basic Mental Status once per shift
• VS, Auscultation & Percussion schedule
consistent with client’s status
• Lab test order stat & subsequent labs; monitor
result
• Emergency treatment: “codes”—cardioversion
and defibrillation

25. Nursing Process: Dysrhythmias
• Implementation:
• Monitor ECG telemetry
• Perform physical assessment (Q4-8 hr)
• Assist with ADL’s, note the degree of impairment
or dyspnea w/or w/o exertion
• O2 as ordered or PRN
• Administer prescribed meds & ACLS protocol to
best alleviate symptom for maximum comfort
• Encourage physical activity
• Measure to reduce anxiety

26. Nursing Process: Dysrhythmias
• Education & Health Promotion:
• Identify modifiable factors
• Design approach to modify factors within
client’s control
• Teach, Discuss & Practice coping mechanism
to handle anxiety
• Teach to take pulse rate, blood pressure, signs
& symptoms

27. Nursing Process: Dysrhythmias
• Fostering Health Maintenance:
• Discuss med information & how it will benefit
• Discuss meds should be taken as prescribed
• Provide client & significant other w/important information
from drug monograph
• Teach drug adverse effects and how to respond
• Seek cooperation & understanding of:
• Name of med
• Dosage
• Route
• Times
• Common and Serious adverse effects

28. Nursing Process: Dysrhythmias
• Written Record:
• Enlist client’s aid in developing & maintaining
a written record
• Monitoring parameter to include like HR, BP,
degree of dyspnea & precipitating causes,
chest pain, edema
• Ensure client know how to use form
• Instruct client to bring completed form to
follow up visits