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QT dispersion as a marker of risk in patients awaiting heart transplantation
D J Pinsky1, R R Sciacca, J S Steinberg
1Department of Medicine, Columbia-Presbyterian Medical Center, New York, New York 10032, USA. djp5@columbia.edu
Insights
QT dispersion measured by electrocardiogram (ECG) effectively predicts cardiac death risk in heart transplant candidates awaiting surgery. This helps prioritize patients most in need of life-saving organ transplantation.
Area of Science:
- Cardiology
- Transplant Medicine
- Medical Diagnostics
Background:
- Heart transplantation is a critical, limited resource.
- Identifying high-risk patients awaiting transplantation is crucial for optimizing organ allocation.
- Predicting mortality during the waiting period is essential for patient management.
Purpose of the Study:
- To evaluate the prognostic value of signal-averaged electrocardiogram (SAECG) and QT interval variability on ECG for predicting cardiac death in heart transplant candidates.
- To identify clinical, ECG, or SAECG variables that predict mortality during the waiting period for heart transplantation.
Main Methods:
- Prospective study of 80 consecutive patients placed on a heart transplant waiting list.
- Standard 12-lead ECG and SAECG recorded at wait-listing.
- QT dispersion measured using maximal-minimal QT interval (QTDISP) and coefficient of variation of QT intervals (QTCV).
Main Results:
- Mortality rate was 27% per year, with equal rates of heart failure and sudden cardiac death.
- QTDISP > 140 ms and QTCV >= 9% significantly predicted increased mortality risk (4.1-fold increase for both).
- No clinical variables predicted mortality; however, normal SAECG was associated with no sudden cardiac deaths.
Conclusions:
- QT dispersion indexes are valuable for stratifying mortality risk in patients awaiting heart transplantation.
- These measurements can aid in prioritizing patients on the heart transplant waiting list.
- SAECG may offer additional prognostic information, particularly regarding sudden cardiac death.
Objectives:
The objectives of this study were to determine whether a signal-averaged electrocardiogram (SAECG) or measurement of interlead variability of QT intervals on an electrocardiogram (ECG) obtained at the time of wait-listing could provide prognostic value with respect to cardiac death during the waiting period.
Background:
Because heart transplantation is a life-saving but limited resource, there remains an urgent need to identify those patients at greatest risk of dying while awaiting heart transplantation as part of the strategy to optimize the allocation of donor organs to those in greatest need. This study was undertaken to prospectively identify clinical, ECG or SAECG variables that might predict mortality during the waiting period.
Methods:
Of 108 consecutive patients referred for heart transplant evaluation, 80 were placed on a waiting list, at which time a standard 12-lead ECG and a SAECG were recorded. In this cohort of 80 patients, QT dispersion was characterized from the 12-lead ECG as either the maximal-minimal QT interval (QTDISP) or as the coefficient of variation of all QT intervals (QTCV).
Results:
During the 25-month follow-up period (mean time on waiting list, 201 days), the mortality rate was 27%/year, divided equally between heart failure and sudden deaths. No clinical variable identified at entry predicted mortality. QTDISP and QTCV were strong mortality predictors, with a 4.1-fold increase in mortality in patients with QTDISP > 140 ms compared with those patients with QTDISP < or = 140 ms (95% CI 1.1 to 14.9), whereas a QTCV > or = 9% also predicted a 4.1-fold increased risk of death (95% CI 1.4 to 11.8). Although 88% of all SAECGs were abnormal, no patient with a normal SAECG died suddenly during the waiting period.
Conclusions:
Indexes of QT dispersion provide a means of stratifying a patient's risk of dying while awaiting heart transplantation and may help to establish priority on a heart transplant waiting list.