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.