What is an Arrhythmia?
An arrhythmia occurs when the electrical impulses that coordinate heart rhythm are not working properly. This can lead to abnormal heart rhythms, causing the heart to beat too fast, too slow or irregularly.
Why Measure Arrhythmias?
Arrhythmias occur spontaneously in normal, healthy animals at a low incidence. Many arrhythmias are not harmful and have no clinical significance; however, some may have more serious effects and lead to cardiac arrest or sudden death. Changes in the incidence rate or type of arrhythmia may indicate disease progression or treatment effect. The underlying pathophysiology of arrhythmias is complex and still not fully understood. Animal models ranging from mice to pigs are frequently used in arrhythmia research, with dogs and primates being two of the most commonly used in treatment evaluations.
The tables below shows the most prevalent arrhythmias in the beagle dog and the cynomolgus monkey. Both the dog and the cynomolgus monkey can have prevalent occurrences of sinus rhythms to include bradycardia, tachycardia, sinus arrhythmia and premature ventricular complexes.
Incidence/prevalence of spontaneous arrhythmia: beagle dog1
| Arrhythmia |
Incidence Found |
Incidence Rate |
Sinus rhythms
|
2450 |
100%
|
Ventricular premature complexes
|
4 |
0.16%
|
Second degree AV block
|
14 |
0.57%
|
Bundle branch block (right)
|
1 |
0.04%
|
Ventricular pre-excitation and
Wolff-Parkinson-White syndrome
|
3
|
0.12%
|
Incidence/prevalence of spontaneous arrhythmia: cynomolgus monkey1
| Arrhythmia |
Incidence Found |
Incidence Rate |
Sinus rhythms
|
1563 |
100%
|
Atrial premature complexes
|
2 |
0.12%
|
Ventricular premature complexes
|
6 |
0.38% |
Ventricular tachycardia
|
1 |
0.06% |
Ventricular bigeminy
|
1 |
0.06%
|
Bundle branch block (right)
|
11 |
0.7% |
Ventricular escape rhythms
|
1 |
0.06% |
Factors that can Cause Arrhythmias
- Cardiac diseases
- Electrolyte imbalances
- Cardiomyopathy
- Injury from myocardial infarction
- Healing post cardiac surgery
- Smoking
- Drug abuse
- Stress or anxiety
- Medications
- Genetics
The most common arrhythmia types1
Classification of Cardiac Arrhythmias
|
Normal sinus impulse formation
|
Normal sinus rhythm
Sinus arrhythmia
Wandering sinus pacemaker |
Disturbances of sinus impulse formation
|
Sinus arrest/block
Sinus bradycardia
Sinus tachycardia |
Disturbances of supraventricular impulse formation
|
Atrial premature complexes
Atrial tachycardia
Atrial flutter
Atrial fibrillation
Atrioventricular junctional rhythm
Ventricular premature complexes |
Disturbances of ventricular impulse formation
|
Ventricular tachycardia
Ventricular asystole
Ventricular fibrillation
Sinoatrial block |
Disturbances of impulse conduction
|
Persistent atrial standstill
Atrial standstill
Ventricular pre-excitation
First degree AV block
Second degree AV block
Complete AV block
Bundle branch block
Sick-sinus syndrome
|
Disturbances of both the impulse formation and impulse conduction
|
Ventricular pre-excitation and Wolff-Parkinson-White syndrome
Atrial premature complexes with aberrant ventricular conduction |
Ventricular escape rhythms
|
Junctional escape rhythms
Ventricular escape rhythms
|
How are Arrhythmias Measured?
Arrhythmias are identified by looking at an electrocardiogram (ECG) signal and assessing the rate and regularity of the heartbeat. Typically, ECG is measured by placing two electrodes directly on the skin and reading the potential difference between them. The detected waveform features depend on the amount of cardiac tissue involved in the contraction, and well as the orientation of the electrode placement with respect to the heart. A number of different ECG lead configurations exist based on electrode location and configuration. DSI offers several technologies to record ECG, including implantable telemetry, external telemetry or hardwired options.
DSI implants are designed for monitoring and collecting data from conscious, freely moving animals. Implants are offered in different sizes to support a variety of animal species including mice, rats, dogs and non-human primates. Several telemetry models are capable of monitoring ECG and blood pressure.
Short durations of functional endpoints are collected non-invasively from chemically or physically restrained animals that are connected to external devices capable of monitoring surface ECG or blood pressure and recording directly into an acquisition and analysis computer system.
ECG and blood pressure signals are collected from conscious, freely moving animals wearing a jacket which contains and protects a small JET device capable of monitoring cardiovascular data and transmitting data to an acquisition and analysis computer system.
1100 Arrhythmia articles citing DSI in Google Scholar
Arrhythmia Detection and Analysis