Occurrence of implantable defibrillator events in patients with syncope and nonischemic dilated cardiomyopathy

2012 ACCF/AHA/HRS Focused Update Incorporated Into the ACCF/AHA/HRS 2008 Guidelines for Device-Based Therapy of Cardiac Rhythm Abnormalities

“…16,224,333,[369][370][371][372][373][374][375][376][377][378][379] Observational studies suggest that up to 30% of deaths in patients with DCM are sudden. 380 Mortality in medically treated patients with DCM and a prior history of syncope may exceed 30% at 2 years, whereas those treated with an ICD experience a high frequency of appropriate ICD therapy.…”

“…380 Mortality in medically treated patients with DCM and a prior history of syncope may exceed 30% at 2 years, whereas those treated with an ICD experience a high frequency of appropriate ICD therapy. 16,372,373 CAT (Cardiomyopathy Trial) enrolled patients with recently diagnosed DCM with randomization to medical therapy versus medical therapy with an ICD. 377 The study was terminated before the primary end point was reached because of a lower-than-expected incidence of all-cause mortality.…”

Syncope

“…59 Noninducibility is less predictive with nonischemic dilated cardiomyopathy. [61][62][63] EPS is relatively insensitive for identifying bradyarrhythmia, especially paroxysmal AV block. 59,[64][65][66] The finding of a baseline H-V interval >100 ms or infra-Hisian block during incremental atrial pacing is predictive of progression to heart block.…”

AHA/ACCF Scientific Statement on the Evaluation of Syncope

“…27 A similar study found a high proportion of appropriate defibrillator therapies in a group of patients with NIDCM and syncope who had no inducible arrhythmias. 28 At least 2 additional studies that reported the outcome of patients with NIDCM treated with an implantable defibrillator for secondary prevention of sudden cardiac death included patients who presented with syncope. 29,30 In 1 study, 10 patients presented with syncope resulting from ventricular tachycardia.…”