Data collection
Demographic and clinical variables including history of diabetes
mellitus, hypertension, chronic kidney disease (CKD), lung disease,
malignancy, alcohol/ drug abuse, renal functions and echocardiographic
findings including type and severity of valve pathologies were recorded.
The left ventricular ejection fraction (LVEF) at implant and at the last
follow-up was recorded. History of CAD, myocardial infarction (MI),
percutaneous coronary intervention (PCI; history of bypass surgery,
valve replacement; documented atrial and ventricular arrhythmias; list
of anti-arrhythmic and heart failure medications; symptoms of syncope or
sudden cardiac arrest (SCA); history of radiofrequency ablation (RFA)
for VT in relation to the time of ICD implant was collected. The
following device characteristics were collected: information on clinical
interrogation during a scheduled clinic visit or remote transmission,
type of ICD, the programming zones of the ICD, date of first and second
therapy from the device, verification of the type of tachyarrhythmia and
the type of therapies delivered verified with the stored intracardiac
electrograms (EGMs), change in the programming parameters, ventricular
tachyarrhythmia (VT) storms, minimum cycle length of the recorded VT
(1st and 2nd episode was taken into
account), date and number of generator changes, therapies after
generator change. The survival characteristics were collected from the
NDI.