In patients without spontaneous VT, programmed stimulation was performed from the RV apex, RV outflow tract, and right atrium at drive trains of 2 different cycle lengths (500 or 400 ms and 330 ms), with ≤3 extra stimuli, with and without the use of isoproterenol (1 3 μg/min).
Each participant was assigned a personal computer on which the EQ-VT program was started up.
Before starting, they were briefed by an investigator, who explained the concept of TTO and demonstrated how the EQ-VT program works.
Some patients also had VT therapy programmed off with detection programmed as monitoring-only, up to the first arrhythmic event.
Histomorphometry was performed with the "VT-Master-Morphology" program (VideoTest, Russia, St .Petersburg).
The control of stimuli and recording of responses were managed by a SmartCtrl Package 8-In/16-Out with additional interfacing by MED-PC for Windows (Med Associates Inc., St . Albans VT) using custom programming (performed by RS).
In contrast, triggering of VT persisted following programmed electrical stimulation in 6 of 12 (50%), one of eight (12.5%), but six of eight (75%) Scn5a+/Δ hearts perfused with 0, 0.1 and 1 μ m propranolol respectively in parallel with corresponding alterations in repolarization gradients, reflected in action potential duration (ΔAPD90) values.
The numbers of Nissl-stained or TH-immunoreactive neurons in the substantia nigra pars compacta were counted using the optical fractionator method in the Stereo Investigator (v 4.35) software program (Microbrightfield, Burlington, VT).
The distribution of the cholinergic neurons in various coronal sections of the striatum was drawn with the Neurolucida program (MicroBrightField, Colchester, VT, USA), attached to a Zeiss microscope (Zeiss, Göttingen, Germany).
Patients implanted with an ICD for primary prophylaxis of sudden cardiac death are often programmed with empiric VT and VF zones based on age and physician preference.
VT allows debugging mixed-signal test programs in a simulation environment if a fast and sufficiently accurate chip model can be made available several weeks before first silicon.
