Study patients
HF Patients hospitalized at Shaare Zedek Medical Center between the
years 2007-2017 for de novo ICD or CRTD implant and who were followed at
our hospital’s device clinic were included.
Inclusion criteria were therefore:
Primary prevention implant of an ICD or CRTD
At least 4 device clinic visits during the study follow up period.
Exclusion criteria were:
- Device upgrade during the study follow-up period
- Implant at another center (incomplete device interrogation data)
- Previous sustained VA or cardiopulmonary resuscitation.
Eligible patient’s data were reviewed by a senior cardiologist that
confirmed their indication for primary prevention ICD/CRTD according to
current guidelines (21-23) and the absence of exclusion criteria.
Medical treatment was determined based on medical prescriptions in the
discharge letter of the index hospitalization (hospitalization in which
ICD/CRTD was implanted). Guideline-recommended disease modifying HF
medications were grouped according to mechanism of action as beta
adrenergic blockers (BB), angiotensin antagonists (AngA) including
angiotensin receptor blockers (ARB) or angiotensin conversion enzyme
inhibitors (ACE-I), and mineralocorticoid receptor antagonist (MRA). All
anti-arrhythmic drugs (AAD) used were documented as well. The prevalence
of each medication group among study patients was noted. The proportion
of each HF medication dose to the guideline recommended target dose (23)
was calculated and reported as % target dose.
As previous studies suggested beneficial survival effects for taking
>50% target dose of AA and BB (20,24), we initially
planned to examine and compare medication dose effect by 50% target
dose cutoff. However, since the median dose for all 3 medication groups
in our study was 25% of target dose with relatively few patients taking
>50%, we used the median dose cutoff to examine the effect
of medications’ dose on study outcomes.