The management of patients with LQTS or BS or their relatives very often requires acquisition of continuous ECG recordings (ideally in 12-leads) under ambulatory conditions. This project seek to comprehensively assess static and dynamic features of ventricular repolarisation in patients with congenital LQTS and BS using high-resolution 12-lead ambulatory Holter recordings and standard 12-lead (or 15-lead, in case of BS) ECGs. What inspired this investigation is the presence in Hospital of a specialised clinic for Inherited Cardiac Conditions (ICC) of Dr which is attended by several hundred patients annually, many of them with congenital LQTS or BS, and an ECG laboratory with very modern ECG and Holter equipment.
Materials and Methods
Data of approximately 150 patients with BS (including relatives of patients and asymptomatic carriers of Brugada ECG pattern) and the same number of patients with congenital LQTS will be analysed over a period of 3 years.
A standardized protocol of ECG investigations has been implemented to be applied to all patients with congenital LQTS and BS. It includes an ambulatory 24-hour 12-lead Holter recording, a series of digital 12-lead (15-lead in case of BS - 12 standard leads plus leads V1 to V3 from one intercostal space higher than usual), a signal-averaged ECG and a diagnostic provocative test for BS.
Therefore, all data, including continuous ambulatory 12-lead ECG (Holter) recordings, standard-resting ECGs recording and signal-averaged ECGs to be used in this project will strictly be part of the standard management of the patients. No clinical, ECG or other data, which are not part of the standard patients' management, will be collected during the project.
Data analysis Data will be analysed using the GETEMED CardioDay ECG System available in the ECG laboratory of the Division of Cardiac and Vascular Sciences.
Analysis of the Holter ECG data will include the following:
Analysis of data collected will be done using the latest version of SPSS or SAS. Comparisons between different groups shall be done with the X² test of independence for qualitative variables, and the ANOVA or t test for quantitative variables
A Standard Visual Assessment, computerized analysis of the ECG waves, principle component analysis, analysis of T wave morphology, Signal-Averaged ECG and dynamic changes, heart rate variability, T wave Alternans, Beat-to-Beat variability, variability of the ECG changes will be used to demonstrate how the ECG is used for the diagnosis and risk stratification (prognosis) in cardiovascular disease. Genotype/Phenotype Relations in BS, epinephrine test in LQTS, autonomic provocative testing in LQTS (postural changes) will be conducted to try and address the current Problems with the Electrocardiographical Diagnosis and Risk Stratification of the Inherited Cardiac Arrhythmic Syndromes. It is hoped that the findings of this project will be useful in developing new or further investigate available ECG-based methods aimed to improve the diagnosis and risk stratification of inherited cardiac arrhythmic syndromes.