Author + information
- Received June 6, 2016
- Revision received August 11, 2016
- Accepted August 18, 2016
- Published online February 20, 2017.
- Daniel Cortez, MDa,b,c,d,
- Waseem Barham, MDc,
- Emily Ruckdeschel, MDe,
- Nandita Sharma, MDd,
- Anthony C. McCanta, MDf,
- Johannes von Alvensleben, MDa,b,
- William H. Sauer, MDb,
- Kathryn K. Collins, MDa,b,
- Joseph Kay, MDa,b,
- Sonali Patel, MDa,b and
- Duy T. Nguyen, MDb,∗ ()
- aDepartment of Cardiology, Children’s Hospital of Colorado, Aurora, Colorado
- bDepartment of Cardiology, University of Colorado, Aurora, Colorado
- cDivision of Cardiovascular Sciences, Lund University, Lund, Sweden
- dDepartment of Electrophysiology, Penn State Milton S. Hershey Medical Center, Hershey, Pennsylvania
- eDepartment of Adult and Pediatric Cardiology, Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania
- fDepartment of Cardiology, CHOC Children’s, Orange, California
- ↵∗Address for correspondence:
Dr. Duy T. Nguyen, University of Colorado, Denver, Anschutz Medical Campus, 12401 East 17th Avenue, B-132, Aurora, Colorado 80045.
Objectives This study sought to test the hypothesis that a vectorcardiographic parameter, the QRS vector magnitude (QRSVm), can risk stratify those patients at risk for sustained spontaneous ventricular arrhythmias (VAs) or ventricular arrhythmia inducibility (VAI) in a large cohort of patients with tetralogy of Fallot (TOF).
Background Patients with TOF have an increased risk of VAs, but predicting those at risk can often be challenging.
Methods Blinded retrospective analyses of 177 TOF patients undergoing pulmonary valve replacement (PVR) between 1997 and 2015 were performed. VAI was evaluated by programmed electrical stimulation in 48 patients. QRS intervals and QRSVm voltage measurements were assessed from resting 12-lead electrocardiograms, and risk of VA was determined. Clinical characteristics, including imaging and cardiac catheterizations, were used for other modality comparisons.
Results Sustained spontaneous VA occurred in 12 patients and inducible VA in 18 patients. Age and QRSVm were significant univariate predictors of VA. QRSVm was the only independent predictor of VAI (p < 0.001). Using a root mean square QRS value of 1.24 mV, the positive and negative predictive values were 47.9% and 97.8%, respectively, for spontaneous sustained VA. For VAI, using a QRSVm cutoff of 1.31 mV, positive and negative predictive values were 63.0% and 95.3%, respectively.
Conclusions In TOF patients undergoing PVR, older age was associated with increased spontaneous VA risk. Lower QRSVm predicted spontaneous VA or VAI risk with high negative predictive values. QRSVm is the only independent predictor of VAI. These clinical features may help further risk stratify TOF patients requiring therapies to prevent sudden death.
Drs. Sauer and Nguyen receive significant research grants from Biosense Webster and CardioNXT; and educational grants from St. Jude Medical, Boston Scientific, and Medtronic. Dr. Nguyen has a provisional patent on partially insulated focused catheter ablation; and has non–public equity interests/stock options in CardioNXT. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose.
All authors attest they are in compliance with human studies committees and animal welfare regulations of the authors' institutions and Food and Drug Administration guidelines, including patient consent where appropriate. For more information, visit the JACC: Clinical Electrophysiology author instructions page.
- Received June 6, 2016.
- Revision received August 11, 2016.
- Accepted August 18, 2016.
- 2017 American College of Cardiology Foundation