Sinus Tachycardia

Sinus Tachycardia

• In an adult is characterized by a sinus rate of more than 100 beats/minute

• Rate rarely exceeds 160 beats/minute except during strenuous exercise

• Each impulse follows the normal pathway of conduction resulting in atrial and ventricular depolarization

Sinus Tachycardia

• How it happens– Depends on the underlying cause • May be of no clinical significance

– May be the body’s response to exercise– May be the body’s response to high emotional state

• May also occur with hypovolemia, hemorrhage, or pain

– When the stimulus for the tachycardia is removed, the arrhythmia spontaneously resolves

Sinus Tachycardia

• Causes – Normal response to

• Exercise, pain, stress, fever, or strong emotions

– Certain cardiac conditions• Heart failure

– Medications• Epinephrine and atropine

– Substances• Caffeine, nicotine, and cocaine

– Other conditions• Anemia, respiratory distress, pulmonary embolism, sepsis, and

hyperthyroidism

Sinus Tachycardia

• Hard on the heart– Not good for those with heart conditions already– Considered a poor prognostic sign if follows MI• Is associated with massive heart damage

– Persistent tachycardia may signal impending heart failure or cardiogenic shock

– Consequences• Bring on an episode of chest pain in patients with CAD

Sinus Tachycardia

• What to look for– Look for a pulse rate of more than 100

beats/minute– Rhythm is regular

Symptomatic Tachycardia

• Pulse rate of more than 100 beats/minute but with regular rhythm– Usually patient is asymptomatic

Symptomatic Tachycardia

• If cardiac output falls and compensatory mechanisms fail– Will experience symptoms

• Hypotension• Syncope• Blurred vision• Chest pain and palpitations• Nervousness or anxiety• Heart failure

– JVD– crackles

Symptomatic Tachycardia

• Steps to take– Prompt recognition is vital so treatment can be

started– Provide the patient with a calm environment; help

to reduce fear and anxiety which can fuel the arrhythmia

– Tachycardia is commonly the first sign of pulmonary embolism

Symptomatic Tachycardia

• When to call for help and what to do until help arrives– Look at the patient and ask how they are doing– Call for help if heart rate is too fast and/or

symptomatic• Compare it their normal heart rate and rhythm

– Stay with the patient– If the patient is not breathing and does not respond

• Call code • ABCs/CPR

Sinus Tachycardia

• What to look for– Look for a pulse rate of more than 100

beats/minute– Rhythm is regular

Sinus Tachycardia

• Normal– P wave preceding each QRS complex – PR interval– QRS complex– T wave– QT interval

Sinus Tachycardia

• P wave– Normal size and shape and precedes each QRS,

but it may increase in amplitude– As the heart rate increases, the P wave may be

superimposed on the preceding T wave and difficult to identify

Sinus Tachycardia

• PR interval– Normal indicating that the impulse is following

normal conduction pathways• 0.12-0.20 seconds

Sinus Tachycardia

• QRS complex• Normal duration representing normal

ventricular impulse conduction and recovery– Less than 0.12 seconds

Sinus Tachycardia

• T wave– Upright in lead II, confirming that normal

repolarization has taken place

Sinus Tachycardia

• QT interval– Within normal limits • 0.36 to 0.44 seconds• QT normally shortens with tachycardia