203 Exam 4
Specific Care of the Patient with Cardiac Dysrhythmias
An arrhythmia is a change in the rhythm of your heartbeat
• Can be too fast - tachycardia.
• Can be too slow - bradycardia.
• Can have irregular rhythm (skips a beat or has an extra beat)
• Arrhythmia (absence of a rhythm) / dysrhythmia used interchangeably
Arrythmia a/k/a Dysrhythmia:
• disorders of the regular rhythmic beating of the heart
• They're common — about 2.2 million Americans are living with atrial fibrillation (one
type of rhythm problem)
• can occur in a healthy heart and be of minimal consequence or may indicate a more
serious underlying problem
• Improper beating of the heart, whether irregular, too fast, or too slow. Cardiac arrhythmia
occurs when electrical impulses in the heart don't work properly. There may be no
symptoms. Or, symptoms may include a fluttering in the chest, chest pain, fainting, or
dizziness. If needed, treatment includes anti-arrhythmic drugs, medical procedures,
implantable devices, and surgery.
RHYTHMS YOU NEED TO IDENTIFY:
1. Normal Sinus Rhythm (SB & ST)
60-100 bpm SB = less than 60 bpm / ST = greater than 100 bpm
2. Asystole NO rhythm / no electrical activity/ flatline/Tx – activate EMS CPR
intubate/Treat underlying cause – Hs & Ts
3. V-Fibrillation
Most common in patients with cardiac arrest
Rapid, disorganized ventricular rhythm, causes ineffective quivering of the ventricles
No atrial activity seen on the ECG
Causes CAD and resulting acute MI***, untreated or unsuccessfully treated VT,
cardiomyopathy, valvular heart disease, several proarrhythmic medications, acid-base
and electrolyte abnormalities, and electrical shock
Rate: greater than 300 bpm
Rhythm: extremely irregular, without a specific pattern
QRS shape and duration: irregular, undulating waves with changing amplitudes. No
recognizable QRS complexes
4. V-tachycardia
3 or more PVC’s in a row occurring at a rate exceeding 100bpm.
Causes similar to those of PVC
Patients with larger MI’s and lower ejection fractions are at higher risk of lethal VT
Patient will be nearly unresponsive and pulseless
, Ventricular and atrial rate: Ventricular rate is 100 to 200 bpm; atrial rate depends
on the underlying rhythm (e.g., sinus rhythm).
Ventricular and atrial rhythm: Usually regular; atrial rhythm may also be regular.
QRS shape and duration: Duration is 0.12 seconds or more; bizarre, abnormal
shape.
P wave: Very difficult to detect, so the atrial rate and rhythm may be indeterminable.
PR interval: Very irregular, if P waves are seen
P:QRS ratio: Difficult to determine, but if P waves are apparent, there are usually
more QRS complexes than P waves.
5. Atrial fibrillation can cause clotting. An irregular, often rapid heart rate that
commonly causes poor blood flow. The heart's upper chambers (atria) beat out of
coordination with the lower chambers (ventricles). This condition may have no
symptoms, but when symptoms do appear they include palpitations, shortness of breath,
and fatigue. Treatments include drugs, electrical shock (cardioversion), and minimally
invasive surgery (ablation).
6. PVCs impulse that starts in a ventricle and is conducted through the ventricles before
the next normal sinus impulse.
Can occur in healthy people, especially with intake of caffeine, nicotine, or alcohol.
Caused by cardiac ischemia or infarction, increased workload on the heart (HF,
tachycardia), digitalis toxicity, hypoxia, acidosis, or electrolyte imbalances, especially
hypokalemia
the patient may feel nothing or may say that the heart “skipped a beat”. The effect of
a PVC depends on its timing in the cardiac cycle and how much blood was in the
ventricles when they contracted. Initial treatment is aimed at correcting the cause.
Ventricular and atrial rate: depends on the underlying rhythm
Rhythm: irregular due to early QRS, creating one RR interval that is shorter than the
others. The PP interval may be regular, indicating that the PVC did not depolarize the
sinus node.
QRS shape and duration:0.12 seconds or longer; shape is bizarre and abnormal.
P-wave: visibility of the P wave depends on the timing of the PVC; may be absent
(hidden in the QRS or T wave) or in front of the QRS. If the P wave follows the QRS,
the shape of the P wave may be different.
PR-interval: if the P wave is in front of the QRS, the PR interval is less than 0.12
seconds.
P:QRS ratio: 0:1; 1:1
Bigeminy every other complex is a PVC
Trigeminy every 3rd complex is a PVC
Quadrigeminy every 4th complex is a PVC
Factors Effecting Cardiac Output
PRELOAD
• the end diastolic filling volume of the ventricles
• a passive stretching force exerted on the ventricles at the end of diastole
• the more fibers that are stretched the greater the force of contraction