Alteration in Perfusion: Sinus Rhythms

Mechanism of Normal Sinus Rhythm

• The sinus node initiates regular impulses at a normal rate. Each impulse is conducted normally to the ventricles.

  • Pacemaker: sinus node 

  • Rates: 60-100 bpm 

  • Regularity: regular 

  • Conduction: normal; each impeller is conducted through to the ventricles

Rules for Normal Sinus Rhythm

• Regularity: Regular

• Rate: 60–100 bpm

• P Wave: Uniform shape; one P wave in front of every QRS complex

• PRI: 0.12–0.20 second and constant

• QRS: Less than 0.12 second

Rules for Normal Sinus Rhythm

• Regular, rate 90, P are upright (positive), sinus rhythm (60-100) 

• PR: 0.16 

• QRS: 0.08 

Mechanism of Sinus Bradycardia

• The sinus node is the pacemaker, firing regularly at a rate of less than 60 times per minute. Each impulse is conducted normally through the ventricles.

  • Pacemaker: sinus node 

  • Rates: <60 bpm 

  • Regularity: regular 

  • Conduction: normal; each impeller is conducted through to the ventricles 

Rules for Sinus Bradycardia

• Regularity: Regular

• Rate: Less than 60 bpm

• P Wave: Uniform shape; one P wave in front of every QRS complex

• PRI: 0.12–0.20 second and constant

• QRS: Less than 0.12 second

Sinus Bradycardia

• Cause:  vagal stimulation- causes decreased sinus node firing.  

• Can reflect normal, athletic heart

• Can be dangerous if suctioning patient.

Sinus Bradycardia can occur with

• Can occur with bowel movements (vasovagal), inferior wall MI, ocular pressure, hypothyroidism, increased intracranial pressure, carotid massage (pressing on both carotid) 

• May be related to Hs and Ts  

Hypoxia:

• low oxygen levels in the blood

Hypovolemia

• low amount of circulating blood

Hyperkalemia or hypokalemia

• and related disturbances of calcium or magnesium levels.

Hypothermia/Hyperthermia

body temperature not maintained

Hydrogen ions (Acidosis):

• Sodium bicarbonate or bronchodilators, vents

Hypoglycemia

Tension pneumothorax:

• increased pressure in the thoracic cavity, leading to decreased venous return to the heart

Tamponade

•  fluid or blood in the pericardium, compressing the heart

Toxic:

• chemicals, whether medication or poisoning

Thromboembolism and related mechanical obstruction

• (blockage of the blood vessels to the lungs or the heart by a blood clot or other material)

Assessment/Treatment

• Dizziness, syncope, confusion, hypotension, chest pain or SOB  

• ECG changes may occur 

• Treat causes: Oxygen, atropine 0.5 to 1 mg IV push (0.6 mg over 1 min) not slower

• If no response and HR < 45 bpm, prepare for temporary or permanent pacemaker

Mechanism of Sinus Tachycardia

• The sinus node is the pacemaker, firing regularly at a rate of greater than 100 bpm. Each impulse is conducted normally through the ventricles.

• Pacemaker: sinus node 

• Conduction normal, each impulse is conducted through to the ventricles

Rules for Sinus Tachycardia

• Regularity: Regular

• Rate: Greater than 100 bpm (usually does not exceed 160 bpm)

• P Wave: Uniform shape; one P wave in front of every QRS complex

• PRI: 0.12–0.20 second and constant

• QRS: Less than 0.12 second

Sinus Tachycardia

• Clinical associations 

  • Physiologic stressors

    • Exercise

    • Pain

    • Hypovolemia

    • Myocardial ischemia (can extend infarct) 

    • Heart failure (HF)

    • Fever

    • Anxiety

Sinus Tachycardia clincial manifestations

• Rapid, regular pulse

• Possibly asymptomatic

• Palpitations, dyspnea

• Dizziness and hypotension due to decreased CO

• Increased myocardial oxygen consumption may lead to angina

Sinus Tachycardia treating the underlying cause

•  administer pain meds, reduce fever, administer  oxygen 

• Clients on ventilators may need to be suctioned and oxygenated.  

Sinus Tachy: Medications to slow heart rate

• Beta blockers (olol)-propranolol, metoprolol

• Ca channel blockers –nifedipine, diltiazem

Mechanism of Sinus Arrhythmia

• The sinus node is the pacemaker, but impulses are initiated in an irregular pattern.

• The rate increases as the patient breathes in and decreases as the patient breathes out (has to be mentioned in the questions!!!). Each impulse is conducted normally through the ventricles.

• Normally in young people, can grow out of it

Rules for Sinus Arrhythmia

• Regularity: Irregular

• Rate: 60–100 bpm (usually)

• P Wave: Uniform shape; one P wave in front of every QRS complex

• PRI: 0.12–0.20 second and constant

• QRS: Less than 0.12 second

Sinus Arrhythmia

• Rate increases as the patient breathes in and decreases as the patient exhales.

• Cyclical speeding up and slowing down of rhythm

Sinus Arrhythmia monitor strips

• Monitor strip will show periods or short R-R intervals then long R-R intervals.

• rarely causes symptoms, Treated when it causes symptoms 

Sinus Arrhythmia is common in

• children, teenagers and  young adults

Collaborative Care Principles

• Arrhythmias are treated when they cause (or are likely to cause) clinical symptoms.

• Identify and correct hypoxia, acidosis, hypovolemia, etc.

All patients with arrhythmias (or the potential for them)

should be monitored, receive oxygen, and have a keep-open IV as a precaution.

why assess Perfusion

• Assess perfusion parameters (BP, pulses, skin, etc.) to determine impact on cardiac output. 

perfusion

• If the heart is going too fast it isn’t pulling blood out of the heart too slow has not enough blood to the body so perfusion is altered

• If there is not enough perfusion then there is not enough oxygen, nutrients, and electrolytes are missing

In addition to treating the specific arrhythmia, you may need to provide

ventilation, chest compression, and/or blood pressure support.

Matrix of Clinical Impact

A patient’s cardiac rhythm is sinus bradycardia with a heart rate of 34 beats/min. If the bradycardia is symptomatic, the nurse would expect the patient to exhibit:

A. Palpitations. 

B. Hypertension.

C. Warm, flushed skin.

D. Shortness of breath.