Sinus Tachycardia

Exam Cram

• Sinus Tachycardia is the commonest cause of tachycardia

• Diagnosis: ECG- HR > 100, QRS < 120, regular, p waves present

• Broad range of causes from recent exercise, pain, anxiety, dehydration; infection, inflammatory response

• Management: DC shock if unstable, otherwise as per underlying cause

Outline

Assessment

History

• Recent movement/ exercise, pain, dehydration, 

• Infection, inflammatory condition, trauma, 

Examination

• Fluid status

• Infective screen

Investigations

• FBC, EUC, LFT with TFTs, calcium/ magnesium/ phosphate

• Septic screen- blood/ urine cultures; CXR, viral PCR; CRP/ PCT

• Weight

Diagnosis

Diagnostic criteria: ECG: (3/3)

• Heart rate > 100 bpm

• QRS < 120ms

• P waves present, regular QRS

Classification (aetiology):

• Exercise, pain, anxiety, dehydration

• Infection

• Cardiac: myocardial infarction, decompensated heart failure, pulmonary embolus, 

• Inflammatory conditions

• Endocrine: hyperthyroidism

Management

Acute 

1. Unstable

   • DC Cardioversion

   • Peri-arrest pager, senior support, HDU/ resus

2. Stable: 

   • Symptom control: analgesia, address concerns

   • Fluid status

     • Dehydration: fluids 

     • Overloaded: furosemide

   • Replace electrolytes

     • K+> 4.0

     • Mg > 1.0

   • Treat underlying cause

Resources and References

Written in 2024