Analysis of multichannel ECG recordings (body surface maps (BSMs) and intracardial maps) requires special software. We created a software package and a user interface on top of a commercial data analysis package (MATLAB) by a combination of high-level and low-level programming. Our software was created to satisfy the needs of a diverse group of researchers.… (More)
To estimate conduction velocities from activation times in myocardial tissue, the "average vector" method computes all the local activation directions and velocities from local activation times and estimates the fastest and slowest propagation speed from these local values. The "single vector" method uses areas of apparent uniform elliptical spread of… (More)
The sequences of activation and recovery of the heart have physiological and clinical relevance. We report on progress made over the last years in the method that images these timings based on an equivalent double layer on the myocardial surface serving as the equivalent source of cardiac activity, with local transmembrane potentials (TMP) acting as their… (More)
BACKGROUND Paroxysmal atrial fibrillation in patients is often initiated by foci in the pulmonary veins. The mechanism of these initiating arrhythmias is unknown. The aim of this study was to determine electrophysiological characteristics of canine pulmonary veins that may predispose to initiating arrhythmias. METHODS AND RESULTS Extracellular recordings… (More)
Monomorphic ventricular tachycardia and ventricular extrasystoles have a specific exit site that can be localized using the multichannel surface electrocardiogram (ECG) and a database of paced ECG recordings. An algorithm is presented that improves on previous methods by providing a continuous estimate of the coordinates of the exit site instead of… (More)
BACKGROUND Thoracoscopic pulmonary vein isolation (PVI) and ganglionated plexus ablation is a novel approach in the treatment of atrial fibrillation (AF). We hypothesize that meticulous electrophysiological confirmation of PVI results in fewer recurrences of AF during follow-up. METHODS AND RESULTS Surgery was performed through 3 ports bilaterally.… (More)
— A 3D reconstruction of a 197-lead multiterminal electrode in the shape of the left atrial cavity of a dog heart was made using a CT scan and software was designed to interactively determine local activation times and display these onto a 3D representation of the multiterminal electrode .
— By means of Karhunen-Lò eve transformation it is possible to represent electrocardiographic body surface QRS integral maps using only two coefficients while retaining more than 80% of information. These coefficients are computed for a number of mean paced QRS integral maps , which were acquired from well-defined ventricular segments and are contained in a… (More)
Introduction The 'nondipolar content' of body surface qrst integral maps has been used for over two decades for diagnosing ventricular repolarization disorders. The algorithm for computing nondipolar content uses a Karhunen-Lò eve transform that is usually created from the covariance matrix of a large set of recordings.
— Exit sites of monomorphic ventricu-lar tachycardia and focal sites of ventricular ex-trasystoles can be localized using an endocardial catheter in conjunction with a multichannel surface ECG, in order to find a suitable site for abla-tion. For this procedure, as well as for the diagnosis of these types of arrhythmia it is desirable to know the relation… (More)