Rapid Fire Abstracts
Naser Alqahtani, MD
pediatric cardiac MRI fellow.
University of Alberta, Canada
Naser Alqahtani, MD
pediatric cardiac MRI fellow.
University of Alberta, Canada
Shanti Chidambarathanu, MD
Clinical fellow
University of Alberta, Canada
Edythe B. Tham, etham@ualberta.ca
Associate Professor of Pediatrics
Stollery Children's Hospital/University of Alberta, Canada
Kumaradevan Punithakumar, PhD
Associate Professor
University of Alberta, Canada
Michelle Noga, MD
Professor
University of Alberta, Canada
Joseph J. Pagano, MD, PhD
Assistant Professor
Stollery Children's Hospital/University of Alberta, Canada
Patients with repaired tetralogy of Fallot (TOF) often have progressive, adverse biventricular remodeling. Most of the focus has been on ventricular dilation and systolic dysfunction, while diastolic function is typically underappreciated. Observations from left ventricular (LV) diastolic strain analysis in patients with normal LV ejection fraction noted distinct strain patterns; in particular, the presence of prominent mid-diastolic strain (M-peak). We aimed to identify clinical and imaging factors associated with the presence or absence of prominent mid-diastolic strain (M-peak) in patients with repaired TOF.
Methods:
Retrospective single centre cohort study, where patients with repaired TOF and a CMR performed between 2006-2020 were included. CMR images were analysed and strain data, derived from in-house semi-automated deformation tracking software (Figure 1) [1], were collected. Strain rate time curves were generated (Figure 2) and assessed for the presence of an early strain peak (E-peak), late strain peak (A-peak), and/or triphasic strain pattern, by identification of a prominent mid-diastolic peak (M-peak) at least 20% of the E-peak (Figure 3). Clinical, limited echocardiographic data, and standard measures of CMR volumes, function, and pulmonary regurgitation (PR) were collected for study. Association between clinical and imaging parameters were assessed using logistic regression.
Results:
Of the 124 subjects included in this study, an M-peak was found in 38% of subjects (n=47), of which 62% were males. An M-peak was more prevalent with age (p=0.003) and increasing pre-CMR interventions (p=0.009), but no association was found with age at complete repair (p=0.918). There was no difference between those with and without an M-peak in regard to type of complete repair, reinterventions after CMR, arrhythmia, or RBBB QRS morphology. Subjects with an M-peak had smaller right and left ventricular volumes (p=0.004 & p=0.013, respectively), with no difference in ejection fractions (p=0.518 & p=0.965, respectively). Pulmonary regurgitation fraction is smaller in those with an M-peak (p=0.041). The presence of symptoms was associated with the presence of an M-peak (p=0.006). Multivariate analysis revealed significant correlation between the presence of an M-peak and age at CMR, LVEDVi, and RV longitudinal strain.
Conclusion:
A novel atypical diastolic strain pattern is found in subjects with repaired TOF, with a prominent mid diastolic peak. The M-peak was associated with smaller ventricular volumes, smaller pulmonary regurgitant fractions, and reduced early filling peak strain rates. Most significantly, the presence of an M-peak was associated with a higher incidence of symptoms. Further studies exploring the association between the presence of an M-peak and measures of diastology and functional status is warranted.
