Characteristics of IVF patients with J point elevation in the
3rd intercostal space
There is a strong male dominance in IVF, early repolarization syndrome,
and BrS.15, 16 Similar to these diseases characterized
by risk of VF unassociated with structural heart diseases, majority of
patients with J point elevation in the 3rd ICS were men (93%). In this
study, VF occurred less frequently during exercise in IVF patients with
J point elevation in the 3rd ICS than those without J point elevation in
right ICS, suggesting that increased vagal tone is associated with risk
of VF in patients with J point elevation in the 3rd ICS. In BrS, VF is
associated increased vagal tone and often develops at rest and during
sleep.17, 18 The characteristic J point and ST-segment
elevation is often pronounced in the 3rd and 2nd ICS in BrS. Although
Type I Brugada ECG was not observed in patients with J point elevation
in the 3rd ICS at rest and during sodium channel blocker test, IVF with
J point elevation in the 3rd ICS and BrS share clinical and
electrophysiological characteristics, suggesting the presence of common
arrhythmogenic substrate between two disorders.
Kamakura et al.16 reported that the frequency
of VF recurrences is higher in ERS patients with J point elevation in
standard and/or high right ICS (58%) than those without J point
elevation in right ICS (11%). In this study, the frequency of VF
recurrences was also higher in IVF patients with J point elevation in
high right ICS (36%) than those without J point elevation in right ICS
(11%). Taken together, J point elevation in 3rd ICS may be an
electrographic risk factor for VF recurrence in patients with VF
unassociated with structural heart diseases.