Sinus Arrhythmia

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Welcome to our Sinus Arrhythmia reference page. This page provides a summary definition followed by introductions to our practice drills, quizzes, lessons and interactive guides.

Sinus Arrhythmia Definition

Sinus Arrhythmia, is a type of sinus rhythm where the P-P interval varies by greater than 10%. This variation occurs during inspiration and expiration. This is a normal condition and is often more noticeable in children. Non-respiratory arrhythmias can be abnormal and are covered in other pages on this website.

Sinus Arrhythmia ECG Features

The following table summarizes the key features of an sinus arrhythmia ECG strip.

Rhythm Irregular, varying with respiration
Rate Normal (60-100 bpm) and rate may increase during inspiration
P Wave Normal
PR Interval Normal (0.12-0.20 sec)
QRS Normal (0.06-0.10 sec)
Notes Heart rate frequently increases with inspiration, decreasing with expiration
sinus arrhythmia ecg strip

Sinus Arrhythmia Causes

Some common causes of abnormal heartbeats are:

  • Heart attack
  • Heart failure
  • Congenital heart disease
  • Abnormal potassium levels
  • Thyroid gland problems
  • Drugs, alcohol or caffeine
  • Medications
  • Nicotine

Sinus Arrhythmia Treatment

Several treatments are available to the clinician for treating arrhythmias. These include:

  • Medications
  • Pacemaker (short-term or longer)
  • Cardiac ablation
  • Implantable cardiac defibrillator

EKG Training - Introduction

A good starting point for learning EKG interpretation is our EKG Basics training course. The course provides training on the key features of an EKG tracing. These features include observing P-wave forms, measurement of EKG intervals and segments, assessment of rhythm, calculating heart rate, and the evaluation of other relevant wave segments. The arrhythmia practice drills allow students to build skills interactively.

EKG Basics

EKG Practice Drills

The heart arrhythmia practice drills provide a test EKG tracing and users are asked to identify the type of arrhythmia. Many of these drills include tachycardia EKG tracings. Each answer is immediately evaluated and the correct classification of the EKG tracing is provided, along with a detailed explanation. A directory of arrhythmias is also provided.

Arrhythmia Practice Drills

ECG Quiz

The quiz is structured like a classroom exam. The quiz present twenty EKGs. Users answer each question and at the end of the quiz, a fully graded report is provided. This graded report provides scoring as well as the correct answer to each question. Top scores and mean scores are also provided. This quiz draws its questions from a library of over 300 EKGs, allowing users to take the quiz multiple times.

ECG Quiz

ECG Monitor Challenge (beta version)

Try the beta version of our ECG monitor challenge. This quiz uses a simulated patient monitor with moving waveform instead of a paper tracing. As with the quiz described above, twenty questions are presented, then a graded report is available.

ECG Monitor Challenge