The correct answer is increase the dose of Nadelol and monitor. I will say that this is a clinical judgment call. The observation here is that she has stress-induced polymorphic PDCs in the setting of what is most likely CPVT. In fact, in genetic testing of this woman, she carried the same pathologic or likely pathologic mutation as her sister who died suddenly. It certainly is a reasonable option with monitoring the density of PDCs to increase the dose of Nadelol for the remainder of her pregnancy, and in fact, in the postpartum period, considering more definitive therapy if risk dictates. Now, if Nadelol doesn't work, limited use of flecainide in pregnancy has been described. But it does appear to be safe, particularly if started later in pregnancy, and certainly in the postpartum period, and this could be added if increasing the beta blocker is not effective. Because of adverse hemodynamic effects on the fetus, calcium channel blockers should be avoided. Finally, in the absence of symptoms at this point in the pregnancy, it's probably best to avoid conventional or subcutaneous ICD implantation. Although if it's needed, certainly could be done with acceptable risk to the fetus. I'll also point out that the use of the ICD and CPPT is not straightforward because it can serve as a trigger as well as a therapy. This raises the question of the use of and the management of heritable arrhythmias in pregnancy. I will admit there's not lots of data here because of the relative infrequency particularly for CPPT, and much of what we do is driven by observations related to long QT syndrome during pregnancy and peripartum period. In fact, there are increases in adverse effects in long QT syndrome, but remarkably, many of those are observed in the postpartum period, not so much during pregnancy. The recommendation is really to continue beta blockers without interruption during pregnancy and after delivery, and it looks like about nine months to a year postpartum is when the risk appears to go back to baseline. As I mentioned, in the case of CPPT, a much rarer condition, there is very little data, but we generally tend to follow the medical treatment recommendations of long QT syndrome. As in this case, we actually have something that we can monitor, and that is the density of PVCs. Whether or not that's definitive in terms of preventing adverse events is unclear.

CPVT

Nadolol

pregnancy

heritable arrhythmias

long QT syndrome