An observational study in Hypertrophic Cardiomyopathy, sponsored by University Health Network, Toronto. Not yet recruiting. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-10-14.
Sponsored by University Health Network, Toronto · Observational
Mitral regurgitation (MR) following septal myectomy for hypertrophic obstructive cardiomyopathy may persist despite relief of systolic anterior motion and left ventricular outflow tract obstruction. Clinical observations suggest that a subset of postoperative MR may be transient and related to posterior leaflet restriction rather than structural mitral valve abnormality.
The investigators will perform a retrospective single-centre cohort study of patients undergoing septal myectomy between 2022 and 2025. Intraoperative post-bypass transesophageal echocardiograms and predischarge transthoracic echocardiograms will be independently reviewed to assess MR severity and mechanism.
The investigators hypothesize that a substantial proportion of moderate-or-greater postoperative MR resolves before discharge, supporting a conservative approach to mitral valve intervention and improving intraoperative echocardiographic decision-making.
Hypertrophic obstructive cardiomyopathy (HOCM) is characterized by asymmetric septal hypertrophy and dynamic LVOT obstruction. Septal myectomy is the standard surgical therapy for symptomatic patients refractory to medical management.
Mitral regurgitation (MR) in HOCM is classically related to systolic anterior motion (SAM) of the anterior leaflet. Following myectomy, relief of LVOT obstruction typically reduces SAM-associated MR. However; intraoperative transesophageal echocardiography (TEE) frequently demonstrates persistent or new MR following separation from cardiopulmonary bypass.
Clinical observation suggests that a subset of this MR may be due to transient posterior leaflet restriction, potentially related to incomplete myocardial protection in hypertrophied myocardium. This may result in MR that resolves prior to discharge without requiring mitral valve intervention. Misinterpretation of this transient phenomenon may lead to unnecessary surgical procedures.
There is currently limited systematic evaluation of the mechanism and natural history of MR observed immediately following myectomy. This study aims to address this knowledge gap using retrospective echocardiographic review.
363 studies on the registry are indexed under Cardiomyopathy, Hypertrophic; 116 are open to participants now.
This study's planned enrollment of 150 is below the median of 259 across 174 observational studies indexed under Cardiomyopathy, Hypertrophic.
Browse Cardiomyopathy, Hypertrophic studies →University Health Network, Toronto is the lead sponsor of 1,438 studies on the registry; 297 are open to participants now.
Of its 17 completed or terminated interventional studies of FDA-regulated products, 3 (18%) have results posted.
Counted across the registry records on this site, refreshed daily.
The investigators will be enrolling all patients who are ≥18 years and underwent Septal Myectomy surgery between January 1, 2020 and December 31, 2025
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Exclusion Criteria:
The investigators will enroll into the study all patients who underwent septal myectomy at Toronto General Hospital between January 1, 2020 and December 31, 2025.
≥ moderate MR on intraoperative post-bypass TEE that improves to ≤ mild MR on predischarge transthoracic echocardiography (TTE)
To determine the proportion of patients with ≥ moderate MR on intraoperative post-bypass TEE that improves to ≤ mild MR on predischarge transthoracic echocardiography (TTE).
Time frame: From January 1, 2022 to December 31, 2025
No study locations are listed for this record.
Plan to share: Undecided — The investigators may decided to share in the future
Start is estimated for Oct 2026; primary completion for Jul 2027, 9 months later.
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From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
This study is not yet recruiting, as verified in Oct 2026. You cannot join it, but the record below documents what was studied.
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Cardiomyopathy, Hypertrophic →
University Health Network, Toronto →