**2. The continuous electrocardiographic in diagnosis support**

The most appropriate method to evaluate the heart rate in dogs is the CE system. This test allows assessment of rhythm for 24 hours, while conventional electrocardiography can only do about 0.2% of this period. Thus, this method allows the recognition of rhythm with the animal in different types of activity (sleep, exercise, feeding) and, consequently, under different physiological states.

Currently this method is most widely using the following conditions: a) confirmation of an arrhythmia as the cause of symptoms that occur during daily activities, b) prediction of future cardiac events, c) evidence of therapeutic efficacy of antiarrhythmic agents, d) detection of myocardial ischemia (MacKie et al., 2010).

There are some arrhythmias that occur at intervals greater than 24 hours, in such cases it is recommended either to repeat the exam, or use of cardiac event recorders (CER). When the owner presses a button on the device of CER, for example in the moment when the clinical

Continuous Electrocardiography in Dogs and Cats 143

The systems analysis should always allow classification of the forms of waves and broad

The two channels apparatus have five electrodes and the three channels have seven. When using two channels device, the electrodes are fixed to the skin on the chest of the animal,

Channel 1 - White electrode (negative): the sixth right intercostal space, two fingers above


Channel 2 - Brown electrode (negative): the sixth left intercostal space, two fingers above the


In equipment with four electrodes (Cardioflash® or Cardiolight®: www.cardios.com.br), the local standard ECG precordial examination can been adapted for CE as follows: position of red electrode in V2 place (sixth left intercostal space adjacent to the sternum), black in V4 (sixth left intercostal space in the costochondral junction location), orange electrode between black and red, and white electrode in the V1 position of conventional ECG (fifth right

Fig. 1. Left side of the figure - Animal with electrodes attached to the chest for the conduct of examination by equipment with four electrodes (See the text for more details). Note the shaved area with the setting of adhesives and the coupling of electrodes. Right side of the figure – Dog using cervical collar and being subjected to examination. Note that the device is


red and green electrodes positioned on the opposite side.

intercostal space near the sternum), as shown in figure 1.

packed in the side pocket of its waistcoat (arrows).

interaction with the device analyst for corrections and to eliminate possible artifacts.

according to the Ware scheme (1998):

the costochondral articulation;

costochondral articulation;

joint;

sign occurs, the device records the moments before, during and after the clinical signs which should be evaluated. The CER device is smaller and can be used for a week or more, but requires constant observation of the animal, although there are some devices that can function as EC conventionally or as CER at the same time.

In humans, medicine is defined in three classes of indications to perform CE: Class I - there is a consensus that the CE is a useful tool and reliable examination, class II - CE is useful and reliable, but there was no consensus, class III – there is consensus that the CE is unnecessary. In all situations in which the role of CE is discussed, it should be taken in account the history and the physical examination of the patient, and the review of the usefulness of the test. The decision to conduct a CE examination and interpretation of their results cannot be performed independently.

The major use of this examination in dogs and cats is to identify the type and degree of cardiac arrhythmias.

Being the main indications:


In moments of bradycardia, usually myocytes specialized in electrical conduction, trigger stimulus that can result in repeated arrhythmias. Therefore, due to the fact that some arrhythmias begin in a moment of great parasympathetic stimulation, it is logical to think that in an examination that is performed for 24 hours, with the animal performing its daily activities, it would be superior to the classic ECG in which the animal is contained on a clinic table. However, the ECG provides a panoramic view of the heart in ten different views (leads), not being replaced by the CE examination.
