Determinants of QRS duration in patients with tetralogy of Fallot after pulmonary valve replacement

Longitudinal ECG changes in tetralogy of Fallot and association with surgical repair

Background

ECG abnormalities have been linked to adverse changes in right ventricular (RV) morphology and poor clinical outcomes in repaired Tetralogy of Fallot (rTOF). Our aim was to describe how ECG changes progress in early and intermediate follow-up and whether types of surgical strategy at the time of primary repair affected these changes.

Methods

We studied patients with rTOF born 2000-2018 operated at our institution. Seven time points in relation to primary repair, follow-up, and pulmonary valve replacement (PVR) were identified. Patients correct with valve sparing repair (VSR), trans-annular patch (TAP) including with a monocusp valve (TAP + M) and with at least 3 ECGs were included. PQ interval, QRS duration, dispersion, and fragmentation, QTc duration and dispersion, JTc as well as presence of a right bundle branch block (RBBB) were analyzed. Medical records were reviewed for demographic and surgical data.

Results

Two hundred nineteen patients with 882 ECGs were analyzed with a median follow-up time of 12.3 years (8.4, 17) with 41 (19%) needing PVR during the study period. QRS duration increased at time of primary repair to discharge from 66 msec (IQR 12) to 129 msec (IQR 27) (p < 0.0001) and at 1- and 6- year follow-up but showed only a modest and temporary decrease after PVR. QTc increased at the time of primary repair as well as prior to PVR. PQ interval showed a small increase at the time of primary repair, was at its highest prior to PVR and decreased with PVR. Type of surgical repair affected mainly QTc and JTc and was consistently longer in the TAP + M group until PVR. In VSR, QTc and JTc were prolonged initially compared to TAP but were similar after 1 year. After PVR, there were no differences in adverse ECG changes between surgical groups.

Conclusions

PQ interval and QRS duration best correspond to the assumed volume load whereas the relationship with QTc and JTc is more complex, suggesting that these represent more complex remodeling of the myocardium. Before PVR, QTc and JTc are longer in the TAP + M group which may be due to a longer surgical incision.

Right ventricular dilatation score: a new assessment to right ventricular dilatation in adult patients with repaired tetralogy of Fallot

BACKGROUND

Patients with repaired tetralogy of Fallot (rTOF) experience long-term chronic pulmonary valve regurgitation resulting in right ventricular (RV) dilatation. According to current guidelines, the evaluation of patients with rTOF for RV dilatation should be based on cardiac magnetic resonance (CMR). However, for many asymptomatic patients, routine CMR is not practical. Our study aims to identify screening methods for CMR based on echocardiographic data, with the goal of establishing a more practical and cheap method of screening for severity of RV dilatation in patients with asymptomatic rTOF.

METHODS

Thirty two rTOF patients (mean age, 21(10.5) y, 21 males) with moderate to severe pulmonary regurgitation (PR) were prospectively recruited. Each patient received CMR and echocardiogram examination within 1 month prior to operation and collected clinical data, and then received echocardiogram examination at discharge and 3-6 months post-surgery.

RESULTS

RV moderate-severe dilatation was defined as right ventricular end-diastolic volume index (RVEDVI) ≥ 160 ml/m2 or right ventricular end-systolic volume index (RVESVI) ≥ 80 ml/m2 in 15 of 32 patients (RVEDVI, 202.15[171.51, 252.56] ml/m2, RVESVI, 111.99 [96.28, 171.74] ml/m2). The other 17 (RVESDI, 130.19 [117.91, 139.35] ml/m2, RVESVI = 67.91 [63.35, 73.11] ml/m2) were defined as right ventricle mild dilatation, i.e., RVEDVI < 160 ml/m2 and RVESVI < 80 ml/m2, and the two parameters were higher than normal values. Compared with the RV mild dilatation group, patients of RV moderate-severe dilatation have worse cardiac function before surgery (right ventricular ejection fraction, 38.92(9.19) % versus 48.31(5.53) %, p < 0.001; Left ventricular ejection fraction, 59.80(10.26) versus 66.41(4.15), p = 0.021). Patients with RV moderate-severe dilatation faced longer operation time and more blood transfusion during operation (operation time, 271.53(08.33) min versus 170.53(72.36) min, p < 0.01; Intraoperative blood transfusion, 200(175) ml versus 100(50) ml, p = 0.001). Postoperative RV moderate-severe dilatation patients have poor short-term prognosis, which was reflected in a longer postoperative hospital stay (6.59 [2.12] days versus 9.80 [5.10] days, p = 0.024) and a higher incidence of hypohepatia (0[0] % versus 4[26.7] %, p = 0.023). Patients with RV dilatation score > 2.35 were diagnosed with RV moderate-severe dilatation (AUC = 0,882; Sensitivity = 94.1%; Specificity = 77.3%).

CONCLUSIONS

RV moderate-severe dilatation is associated with worse preoperative cardiac function and short-term prognosis after PVR in rTOF patients with moderate to severe PR. The RV dilatation score is an effective screening method. When RV dilatation score > 2.35, the patient is indicated for further CMR examination and treatment.

Outcomes of Transcatheter Pulmonary Valve Replacement and Surgical Pulmonary Valve Replacement: A Cohort Analysis

Background

Transcatheter pulmonary valve replacement (TPVR) has become an alternative to surgical pulmonary valve placement (SPVR) for patients after tetralogy of Fallot repair. This study compared the outcomes of TPVR with those of SPVR.

Methods

We reviewed data from patients who underwent pulmonary valve replacement with a median of 2 years of follow-up.

Results

Between 2010 and 2021, 215 patients underwent pulmonary valve replacement (72 TPVR and 143 SPVR). The median size of the right ventricular end-diastolic volume index in the TPVR group was 165 mL/m2 (IQR, 136-190) and 184 mL/m2 (IQR, 163-230) in the SPVR group (P = .001). The median value of the maximum landing zone at the right ventricular outflow tract (RVOT) in patients with native RVOT was 26 mm (IQR, 24-28) in the 43 patients in the TPVR group and 31 mm (IQR, 28-34) in the 101 patients in the SPVR group (P < .001). The median size of the pulmonary valve implant for the native RVOT in the TPVR group was 29.0 mm (IQR, 26.0-29.0) and 24.0 mm (IQR, 24.0-24.0) in the SPVR group (P < .001). There were no deaths in the TPVR group and 8 deaths in the SPVR group (P = .041). Major complications and the length of hospitalization were lower in the TPVR group (P = .001). After 2 years, the mean decrease in QRS duration was 5 milliseconds (IQR, 1-14) in the TPVR group and 1 millisecond (IQR, -4 to 10) in the SPVR group (P = .006).

Conclusions

TPVR allows for larger implants, resulting in lower mortality, shorter hospital stays, and fewer major cardiac events. SPVR may be preferable in patients with larger (>30 mm) native RVOT and in those who require concomitant surgical procedures.

What Is the Importance of Electrocardiography in the Routine Screening of Patients with Repaired Tetralogy of Fallot?

Background: In patients following complete repair of the tetralogy of Fallot, the duration of the QRS complex is associated with the size and mechanical function of the right ventricle, which are contemporarily assessed by cardiac magnetic resonance (CMR). Methods: 38 patients aged 18.0–54.9 years (median age 24.9 years) who had undergone complete repair of the tetralogy of Fallot were examined using CMR and concomitant 24 h ambulatory electrocardiography monitoring. We used statistical analysis to investigate the correlations between electrocardiographic parameters (heart rate, HR; PQ interval, PQ; QRS duration, QRS; and corrected QT interval, QTc) and CMR results (right ventricular ejection fraction, RVEF; right ventricular end-diastolic volume index, RVEDVI; and right ventricular end-systolic volume index, RVESVI) for patients after early and late repair. Results: The ECG-based parameters were not correlated with time since repair. There were significant correlations between QRS duration and RVEF (r = −0.61), RVEDVI (r = 0.56), and RVESVI (r = 0.54) for early operated patients but not for late-operated patients. No other substantial correlations were reported. Conclusion: Despite its role in screening for arrhythmias, electrocardiography has a limited role as a predictor of morphology and function of the right ventricle in patients after repair of the tetralogy of Fallot.