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Which Patients Are Not Suitable for a Subcutaneous ICD: Incidence and Predictors of Failed QRS‐T‐Wave Morphology Screening
Author(s) -
OLDE NORDKAMP LOUISE R.A.,
WARNAARS JOPPE L.F.,
KOOIMAN KIRSTEN M.,
GROOT JORIS R.,
ROSENMÖLLER BOUDEWIJN R.A.M.,
WILDE ARTHUR A.M.,
KNOPS REINOUD E.
Publication year - 2014
Publication title -
journal of cardiovascular electrophysiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.193
H-Index - 138
eISSN - 1540-8167
pISSN - 1045-3873
DOI - 10.1111/jce.12343
Subject(s) - medicine , qrs complex , cardiology , supine position , lead (geology) , geomorphology , geology
T‐Wave Analysis for the Subcutaneous ICD Background The subcutaneous cardioverter‐defibrillator (S‐ICD) relies on a pre‐implantation QRS‐T morphology screening (TMS) of the ECG to assure that it reliably detects the QRS complexes and T waves. The prevalence and clinical characteristics of the patients who fail this TMS is unknown. Methods and Results QRS‐TMS was done in 230 consecutive ICD outpatients (75% male, age 57 ± 15 years) without an indication for cardiac pacing, using an ECG simulating the 3 sensing vectors of the S‐ICD (TMS‐ECG). Patients were defined suitable when at least 1 sensing vector was considered appropriate in both supine and standing position. In total, 7.4% of patients, who were all male, were considered not suitable for a S‐ICD according to the TMS‐ECG. Independent predictors for TMS failure were hypertrophic cardiomyopathy (HCM; odds ratio [OR] 12.6), a heavy weight (OR 1.5), a prolonged QRS duration (OR 1.5) and a R:T ratio <3 in the lead with the largest T wave on a standard 12‐lead surface ECG (OR 14.6). Conclusion In patients without an indication for pacing, 7.4% would have been not suitable for a S‐ICD according to the TMS. HCM, a heavy weight, a prolonged QRS duration and a R:T ratio <3 in the ECG lead with the largest T wave were independently associated with TMS failure. These data might alert physicians that selection of patients for a S‐ICD should be considered with special caution in certain patient groups, because they may not satisfy ECG criteria for adequate sensing.