Electrocardiography (ECG) is a widely used diagnostic tool for assessing cardiac arrhythmias, acute and old cardiac ischaemia, and for instance left ventricular hypertrophy. Further analysis allows differentiating between physiological and pathological brady- and tachycardia, as well as changes in conduction times (QT time or bundle branch block). As such, ECG continues to play an important role in many clinical trials.

Cardialysis has extensive experience in ECG analysis as Cardialysis started as a spin-off Holter analysis unit from the Erasmus Medical Center. To date the ECG Core Lab has been involved in over 60 trials with more than 60,000 patients and has extensive experience in working together with different ECG monitoring device vendors.

ECG Analysis, Advice and Logistics

Cardialysis provides independent ECG data analysis and interpretation for cardiac arrhythmias, heart rate measurement, cardiac ischaemia and infarction. Based on our years of experience in electrocardiography, we can provide you with tailor-made advice for consistent, efficient, and comprehensive ECG data collection for the purpose of endpoint adjudication. We can also advise you on how to to select the appropriate ECG monitoring strategy, and we can manage all related logistical aspects.

At the ECG Core Lab, interpretation and analysis is performed by well-trained in-house analysts under the supervision of a cardiologist and according to the trial protocol definitions.

We have established experience in:


We offer the possibility to analyze ICD read-outs from all companies, under the supervision of a trained specialist. This offers the possibility to classify arrhythmias as they are stored in ICDs. Given the fact that ICDs are more and more used to record events, this has an important potential for clinical trials.

Holter Electrocardiography

This non-invasive tool is particularly suitable for detecting and/or monitoring cardiac arrhythmias in (ambulant) patients over time and in particular during the administration of new investigational drugs or pre or post AF ablation. In addition, Holter Electrocardiography can be used to measure cardiac rhythm, ST deviation, and QT segment interval analysis and heart rate variability.

Transtelephonic Monitoring and Event Monitoring

Arrhythmia monitoring can be performed with the use of non-continuous ECG monitoring tools such as: transtelephonic recorders, patient-activated and automatically activated devices, and external loop recorders. The choice of method depends on individual needs and consequences of arrhythmia detection.

Implantable Loop Recorder

Continuous ECG monitoring for arrhythmia monitoring can also be facilitated by the use of implantable devices. More intensive monitoring is associated with a greater likelihood of detecting both symptomatic and asymptomatic AF.

Resting 12-lead ECG

For safety analysis in cardiac and non-cardiac trials, 12-lead ECGs are analyzed qualitatively. This analysis consists of arrhythmia diagnosis, heart rate measurement and diagnosis of infarction and ischaemia. For efficacy analysis, a more detailed quantitative analysis is performed in which all abnormalities are diagnosed and coded. This analysis includes the measurement of PR, QRS and QT intervals.

Exercise Tolerance Test

The exercise electrocardiogram, or ECG stress test, is used for detecting cardiac ischaemia or arrhythmias while the heart is undergoing strain imposed by a standardized exercise protocol.

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