Tqt QTc Measurement and Analysis

In partnership with Richmond Pharmacology, Prof Camm’s group, based within St George’s Hospital Medical School, London, offer clients two main approaches in QT interval measurement and analysis:

In fully manual over-read the QT interval is measured by a highly trained and experienced cardiologist on screen using electronic callipers (MUSE CV® Interval Editor, GE Marquette Medical Systems) with sufficient magnification allowing the measurement precision equal to the storage frequency of 500 MHz, i.e. ±1 ms. Whilst the details of the analysis can be discussed and agreed with our clients at the study design stage, as a matter of routine, in each ECG the QT interval is measured in all 12 leads. The median QT interval of all measurable beats from the 12 leads is then taken as valid for that particular ECG.

Alternatively, if this better suits client’s needs we also offer regulatory compliant semi-automated QT interval measurements. In this method, interval markers derived by MUSE CV® Interval Editor are assessed for accuracy by an experienced and fully trained cardiologist. The degree of cardiologist input may vary to meet the client needs.

In line with the current regulatory requirements and at least every six months, all cardiologists working for or with Richmond Pharmacology undertake intra- and inter-reader variability tests under blinded conditions to ensure that our measurements are as accurate and reproducible as possible. Furthermore, systematic in–process QC checks are performed by a senior cardiologist during a specific study analysis. All QC checks and any corrective actions are reconciled and fully documented.

The measured and verified QT intervals are corrected for heart rate using conventional population-derived formulae (e.g. Fridericia) or an individually derived formula. The QT/QTc interval data are then subjected to a statistical analysis in accordance with the current regulatory guidelines which also includes input and interpretation of the results from experienced cardiological scientists.

Case studies

The thorough approach to QTc studies ("Your perfect partner for conducting definitive thorough QT studies, all under one roof")

Timelines, Tight Timelines and Even Tighter Timelines in a Phase I Environment (We know we can help your business. We always rise to the challenge)