AHA/ACCF/HRS Recommendations for the Standardization and Interpretation of the Electrocardiogram

Development of atrioventricular and intraventricular conduction disturbances in patients undergoing transcatheter aortic valve replacement with new generation self-expanding valves: A real world multicenter analysis

BACKGROUND

High degree cardiac conduction disturbances (HDCD) remain a major complication after transcatheter aortic valve replacement (TAVR), especially with self-expandable valves (SEV). Our aim was to investigate peri-procedural and in-hospital modification of atrioventricular and intracardiac conduction associated to new generation SEV implantation, and the development of new HDCD resulting in permanent pacemaker implantation (PPM) in patients undergoing TAVR.

METHODS AND RESULTS

Three-hundred forty-four consecutive patients with severe aortic stenosis who underwent TAVR with a new generation SEV [Evolut-R/Pro (n = 130), Acurate-neo (n = 79), Portico (n = 75) and Allegra (n = 60)] were included. An analysis of baseline, post-TAVR and pre-discharge ECG and procedural aspects were centrally performed. A significant increase in baseline PR interval (169.6 ± 28.2 ms) and QRS complex width (101.7 ± 25.9 ms) was noted immediately post-TAVR (188.04 ± 34.49; 129.55 ± 30.02 ms), with a partial in-hospital reversal (179.4 ± 30.1; 123.06 ± 30.94 ms), resulting in a net increase at hospital discharge of 12.6 ± 38.8 ms and 21.4 ± 31.6 ms (p < 0.001), respectively. The global incidence of new onset persistent HDCD at hospital discharge was 46.3%, with 17.7% of patients requiring PPM. Independent predictors of new onset HCDC at hospital discharge were valve recapture (OR: 2.8; 95% IC: 1.1-7.2, p = 0.033) and implantation depth ≥ 6 mm (OR: 1.9 05% IC 1.1-3.3, p = 0.015), while higher implantation (<3 mm (OR: 0.3, 95% IC 0.1-0.7, p = 0.014) and use of Acurate-Neo valve (OR: 0.4; 95% IC 0.2-0.8, p = 0.009) were protective factor.

CONCLUSIONS

New generation self-expanding aortic valves were associated with a significant increase in PR and QRS interval at hospital discharge leading to a very high rate of HDCD. While valve recapture and implantation depth were independent predictors for the occurrence of HDCD, use of Accurate-Neo valve was a protective factor.

Electrocardiographic variables associated with underlying Brugada syndrome or drug-induced Type 1 Brugada pattern in patients with slow/fast atrioventricular nodal reentrant tachycardia

Background

The coexistence of clinical atrioventricular nodal reentrant tachycardia (AVNRT) and drug-induced type 1 Brugada pattern (DI-Type 1 BrP) has been previously reported. The present study was designed to determine the 12-lead ECG characteristics at baseline and during AVNRT and to identify a subset of 12-lead ECG variables of benefit associated with underlying Brugada syndrome (BrS)/DI-Type 1 BrP among patients with slow/fast AVNRT.

Methods

A total of 40 (11 numerical/29 categorical) 12-lead ECG parameters were analyzed and compared between patients with (n = 69) and without (n = 104) BrS/DI-Type1-BrP matched for age, female gender, body mass index, left ventricular ejection fraction and comorbid conditions. Five distinct types of ECG pattern (Type A/B/C/D/E) in V1-V2 leads during AVNRT were defined.

Results

A total of nine electrocardiographic variables, four at baseline, and five during AVNRT were identified. At baseline, patients with BrS/DI-Type 1 BrP had higher prevalence of interatrial block, leftward shift of frontal plane QRS axis, the absence of normal QRS pattern (the presence of rSr' pattern or type 2/3 Brugada pattern) in V1-V2 and QRS fragmentation in inferior leads compared to patients without BrS/DI-Type 1 BrP. During AVNRT, patients with BrS/DI-Type 1 BrP had higher prevalence of Type A ECG pattern ("coved-type" ST-segment elevation) in V1-V2, Type C ECG pattern (pseudo-r' deflection in V₁ and "RBBB-like" pattern in V₂), pseudo-r' deflection in V₁, QRS fragmentation in inferior leads and "isolated" QRS fragmentation/notching/slurring in aVL compared to patients without BrS/DI-Type 1 BrP.

Conclusions

We identify several electrocardiographic variables that point to an underlying type 1 BrP among patients with slow/fast AVNRT.

Influence of Capture Selectivity and Left Intrahisian Block on QRS Characteristics During Left Bundle Branch Pacing

OBJECTIVES

This study sought to examine QRS and intracardiac characteristics during selective (S) and nonselective (NS) left bundle branch pacing (LBBP) from direct left septal recordings.

BACKGROUND

Criteria for S-LBBP and NS-LBBP have not been validated with intracardiac mapping.

METHODS

Pacing was performed from multielectrode Purkinje recordings below the left-sided His. S-LBBP and NS-LBBP were performed in patients with narrow QRS (n = 9), right bundle branch block (n = 3), intraventricular conduction delay (n = 5), and left bundle branch block (n = 10). QRS duration was measured from stimulus onset (QRS_st) and from the intrinsicoid deflection of the R-wave in V₁-V₂ (QRS_id) to QRS end. Retrograde left bundle branch conduction was assessed by stimulus-to-retrograde His intervals.

RESULTS

Among 27 patients analyzed, 20 demonstrated both NS- and S-LBBP and were studied in paired comparisons. NS-LBBP resulted in narrower QRS compared to S-LBBP (QRS_st: 163 ms [interquartile range (IQR): 144-179 ms] vs 181 ms [IQR: 173-203 ms]; P < 0.001; QRS_id: 125 ms [IQR: 117-142 ms] vs 150 ms [IQR: 135-157 ms]; P < 0.001). Left ventricular activation time was also significantly shorter for NS-LBBP compared to S-LBBP (88 ms [IQR: 75-111 ms] vs 97 ms [IQR: 82-123 ms]; P = 0.019). Left intrahisian block was bidirectional in 10 patients with long retrograde stimulus-to-His intervals. QRS_st duration was significantly longer in patients with complete conduction block compared to those with intact Purkinje activation during NS-LBBP (181 ms [IQR: 162-195 ms] vs 157 ms [IQR: 139-168 ms]; P = 0.022).

CONCLUSIONS

In contrast to His-bundle pacing, S-LBBP predominantly yields a wide QRS as a result of delayed RBB synchronization, whereas NS-LBBP results in shorter QRS duration because of recruitment of the basal right ventricular septum. A wider-paced morphology of LBBP was noted in patients with complete conduction block caused by bidirectional left intrahisian block. Achievement of narrow QRS during LBBP is predicated upon capture nonselectivity or programmed atrioventricular fusion, rather than intrinsic physiologic synchrony from left bundle branch stimulation.

Cusp-overlapping TAVI technique with a self-expanding device optimizes implantation depth and reduces permanent pacemaker requirement

INTRODUCTION AND OBJECTIVES

This study aimed to determine the safety and efficacy of modifying the classic implantation technique for aortic transcatheter heart valve (THV) implantation to a cusp-overlap-projection (COP) technique to achieve a higher implantation depth and to reduce the burden of new permanent pacemaker implantation (PPMI) at 30 days. Aortic self-expanding THV carries an elevated risk for PPMI. A higher implantation depth minimizes the damage in the conduction system and may reduce PPMI rates.

METHODS

From March 2017, 226 patients were consecutively included: 113 patients were treated using the COP implantation technique compared with the previous 113 consecutive patients treated using the classic technique. In all patients, implantation depth was assessed by 3 methods (noncoronary cusp to the THV, mean of the noncoronary cusp and the left coronary cusp to the THV, and the deepest edge from the left coronary cusp and the noncoronary cusp to the THV).

RESULTS

The COP group had a lower implantation depth than the group treated with the classic technique (4.8 mm± 2.2 vs 5.7 mm± 3.1; P=.011; 5.8 mm± 3.1 vs 6.5 mm± 2.4; P=.095; 7.1 mm± 2.8 vs 7.4 mm±3.2; P=.392). Forty patients (17.7%) required a new PPMI after the 30-day follow-up but this requirement was significantly lower in the COP group (12.4% vs 23%, P=.036). The COP implantation technique consistently protected against the main event (OR, 0.45; 95%CI, 0.21-0.97; P=.043), with similar procedural success rates and complications.

CONCLUSIONS

The COP implantation technique is a simple modification of the implantation protocol and provides a higher implantation depth of self-expanding-THV with lower conduction disturbances and PPMI rates.

Dispersion of repolarization increases with cardiac resynchronization therapy and is associated with left ventricular reverse remodeling

PURPOSE

Cardiac resynchronization therapy (CRT) reduces ventricular activation times and electrical dyssynchrony, however the effect on repolarization is unclear. In this study, we sought to investigate the effect of CRT and left ventricular (LV) remodeling on dispersion of repolarization using electrocardiographic imaging (ECGi).

METHODS

11 patients with heart failure and electrical dyssynchrony underwent ECGi 1-day and 6-months post CRT. Reconstructed epicardial electrograms were used to create maps of activation time, repolarization time (RT) and activation recovery intervals (ARI) and calculate measures of RT, ARI and their dispersion. ARI was corrected for heart rate (cARI).

RESULTS

Compared to baseline rhythm, LV cARI dispersion was significantly higher at 6 months (28.2 ± 7.7 vs 36.4 ± 7.2 ms; P = 0.03) but not after 1 day (28.2 ± 7.7 vs 34.4 ± 6.8 ms; P = 0.12). There were no significant differences from baseline to CRT for mean LV cARI or RT metrics. Significant LV remodeling (>15% reduction in end-systolic volume) was an independent predictor of increase in LV cARI dispersion (P = 0.04) and there was a moderate correlation between the degree of LV remodeling and the relative increase in LV cARI dispersion (R = -0.49) though this was not statistically significant (P = 0.12).

CONCLUSION

CRT increases LV cARI dispersion, but this change was not fully apparent until 6 months post implant. The effects of CRT on LV cARI dispersion appeared to be dependent on LV reverse remodeling, which is in keeping with evidence that the risk of ventricular arrhythmia after CRT is higher in non-responders compared to responders.

Automatic Multichannel Electrocardiogram Record Classification Using XGBoost Fusion Model

There is an increasing demand for automatic classification of standard 12-lead electrocardiogram signals in the medical field. Considering that different channels and temporal segments of a feature map extracted from the 12-lead electrocardiogram record contribute differently to cardiac arrhythmia detection, and to the classification performance, we propose a 12-lead electrocardiogram signal automatic classification model based on model fusion (CBi-DF-XGBoost) to focus on representative features along both the spatial and temporal axes. The algorithm extracts local features through a convolutional neural network and then extracts temporal features through bi-directional long short-term memory. Finally, eXtreme Gradient Boosting (XGBoost) is used to fuse the 12-lead models and domain-specific features to obtain the classification results. The 5-fold cross-validation results show that in classifying nine categories of electrocardiogram signals, the macro-average accuracy of the fusion model is 0.968, the macro-average recall rate is 0.814, the macro-average precision is 0.857, the macro-average F1 score is 0.825, and the micro-average area under the curve is 0.919. Similar experiments with some common network structures and other advanced electrocardiogram classification algorithms show that the proposed model performs favourably against other counterparts in F1 score. We also conducted ablation studies to verify the effect of the complementary information from the 12 leads and the auxiliary information of domain-specific features on the classification performance of the model. We demonstrated the feasibility and effectiveness of the XGBoost-based fusion model to classify 12-lead electrocardiogram records into nine common heart rhythms. These findings may have clinical importance for the early diagnosis of arrhythmia and incite further research. In addition, the proposed multichannel feature fusion algorithm can be applied to other similar physiological signal analyses and processing.

Risk Stratification and Management of Advanced Conduction Disturbances Following TAVI in Patients With Pre-Existing RBBB

Background

Pre-existing right bundle branch block (RBBB) is a strong predictor of increased need for a permanent pacemaker (PPM) following transcatheter aortic valve implantation (TAVI). Yet, further risk stratification and management remain challenging in patients with pre-existing RBBB owing to limited data. Therefore, we sought to investigate the incidence, predictors, and management of advanced conduction disturbances after TAVI in patients with pre-existing RBBB.

Methods

We retrospectively reviewed 261 consecutive patients with pre-existing RBBB (median age 81 years; 28.0% female; 95.0% received a balloon-expandable valve) without a pre-existing PPM who underwent TAVI at our institution in 2015-2019. Outcomes were high-degree atrioventricular block/complete heart block (HAVB/CHB) and PPM requirement.

Results

Overall, the 30-day HAVB/CHB rate was 28.0%, of which 76.7% occurred during the TAVI procedure. The delayed HAVB/CHB rate was 8.3%. Implantation depth below aortic annulus (per 1-mm increase) was significantly associated with increased risk of procedural HAVB/CHB (adjusted odds ratio = 1.25, 95% confidence interval = 1.07-1.46), delayed HAVB/CHB (1.34 [1.01-1.79]), and 30-day PPM (1.32 [1.11-1.55]). Predilation was associated with delayed HAVB/CHB (4.02 [1.22-13.23]). The combination of no predilation and implantation depth of ≤2.0 mm had lower rates of procedural HAVB/CHB (11.2% vs. 26.7%-30.4%, p = 0.011), delayed HAVB/CHB (2.1% vs. 7.6%-28.1%, p < 0.001), and 30-day PPM (10.3% vs. 20.0%-43.5%, p < 0.001) than the other strategies of valve deployment. Complete HAVB/CHB recovery after PPM implantation was uncommon at 7.1%.

Conclusions

In patients with pre-existing RBBB, the majority of HAVB/CHB events occurred during the TAVI procedure. Avoidance of predilation coupled with high valve deployment may result in relatively low rates of procedural and delayed HAVB/CHB, along with 30-day PPM rates.

Advantages and disadvantages of drug challenge during electrophysiological study in patients with new left bundle branch block after transaortic valve implantation

Aims

Electrophysiological study (EPS) is recommended in case of new-onset persistent left bundle branch block (NOP-LBBB) after transaortic valve implantation (TAVI) to identify patients at high risk of delayed atrioventricular block (D-AVB). We evaluated the added value of drug challenge, after normal baseline EPS, to predict D-AVB in such patients.

Methods

We conducted a comparative single-centre study of two successive periods, during which we used baseline EPS alone (first period) or drug challenge in case of normal baseline EPS (second period), for patients with NOP-LBBB after TAVI. The primary endpoint was a composite of pacemaker use, documented D-AVB, cardiac syncope, sudden death, or delayed pacemaker implantation.

Results

Among 736 patients with TAVI implantation between January 2016 and September 2019, 64 with NOP-LBBB were included. During the first period, 4/22 (18.2%) presented with a positive baseline EPS. After a mean (standard deviation [SD]) of 15.6 (8.3) months, 7/22 (31.8%) reached the primary endpoint. During the second period, 19/42 (45.2%) presented with a positive EPS. After a mean (SD) of 12.8 (3.5) months, 8/42 (19.0%) reached the primary endpoint. There was a tendency to increased sensitivity (42.9–87.5%; P = 0.12) and negative predictive value (77.8–95.7%; P = 0.15) of the EPS, respectively during the first to the second period. However, the specificity decreased (93.3–64.7%; P = 0.04).

Conclusion

Diagnostic yield improved with drug challenge in case of normal baseline EPS. However, the decrease in specificity led to a high rate of unnecessary pacemaker implantation.

Early Resolution of New-Onset Left Bundle Branch Block After Transcatheter Aortic Valve Implantation With the SAPIEN 3 Valve

New-onset left bundle branch block (LBBB) is common after transcatheter aortic valve implantation (TAVI) but can resolve in the post-TAVI period. We sought to examine the incidence, predictors, and outcomes of early resolution of new-onset LBBB among TAVI recipients with a SAPIEN 3 (S3) valve. Among 1,203 S3-TAVI recipients without a pre-existing pacemaker or wide QRS complex at our institution between 2016 and 2019, we identified 143 patients who developed new-onset LBBB during TAVI and divided them according to the resolution or persistence of LBBB by the next day post-TAVI to compare high-degree atrioventricular block (HAVB) and permanent pacemaker (PPM) rates. Patients with resolved LBBB (n = 74, 52%), compared with those with persistent LBBB, were more often women and had a shorter QRS duration at baseline and post-TAVI, with a smaller S3 size and a shallower implantation depth. A multivariable logistic regression model demonstrated significant associations of post-TAVI QRS duration (per 10 ms increase, odds ratio = 0.60 [95% confidence interval = 0.44 to 0.82]) and implantation depth (per 1-mm-depth-increase, 0.77 [0.61 to 0.97]) with a lower likelihood of LBBB resolution. No patient with resolved LBBB developed HAVB within 30 days post-TAVI. Meanwhile, 8 patients (11.6%) with persistent LBBB developed HAVB. The 2-year PPM rate was significantly higher after persistent LBBB than after resolved LBBB (30.3% vs 4.5%, log-rank p <0.001), mainly driven by higher 30-day PPM rate (18.8% vs 0.0%). In conclusion, about half of new-onset LBBBs that occurred during S3-TAVI resolved by the next day post-TAVI without HAVB. In contrast, new-onset persistent LBBB may need follow-up with ambulatory monitoring within 30 days because of the HAVB risk.

Evaluation of the 2021 European Society of Cardiology guidelines in pre-existing right bundle branch block patients undergoing transcatheter aortic valve implantation with a balloon-expandable valve

Aims

The 2021 European Society of Cardiology guidelines recommend early pacemaker implantation in pre-existing right bundle branch block (RBBB) patients who develop PR prolongation or QRS axis change after transcatheter aortic valve implantation (TAVI). We aimed to evaluate this recommendation in TAVI recipients with a balloon-expandable valve (BEV).

Methods and results

We retrospectively reviewed 188 pre-existing RBBB patients without pre-existing permanent pacemaker (PPM) who underwent TAVI with a BEV at our institution in 2015–19. Patients who developed high-degree atrioventricular block (HAVB) during TAVI or within 24 h post-TAVI were excluded. Eligible patients were divided according to the guideline-directed criteria (ΔPR interval ≥20 ms and/or QRS axis change). Patients who met the criteria (n = 102, 54.3%), compared with those who did not (n = 86), had a higher prevalence of baseline right axis deviation and were more likely to have received a larger valve with greater oversizing. The 30-day delayed HAVB rate did not differ significantly between the groups (3.9% vs. 4.7%, P = 1.00; odds ratio = 0.84, 95% confidence interval = 0.20–3.45). There was also no significant difference in terms of death (5.0% vs. 8.4% at 1 year; overall log-rank P = 0.94) or a composite of death or PPM implantation (14.8% vs. 16.6% at 1 year; overall log-rank P = 0.94) during follow-up post-TAVI. The majority of PR prolongations (79.4%) and QRS axis changes (52.0%) regressed within the following 24 h.

Conclusion

The present data did not demonstrate an association of significant changes in PR interval or QRS axis with heightened delayed HAVB risk in BEV recipients with pre-existing RBBB. Prospective studies are warranted to confirm these findings.

QRS Narrowing Following CRT Implantation: Predictors, Dynamics, and Association with Improved Long-Term Outcome

Background: Heart failure (HF) patients with wide QRS often benefit from cardiac resynchronization therapy (CRT), although QRS narrowing does not always occur. The current study investigates the incidence and predictors for QRS narrowing following CRT and its long-term impact on clinical outcomes. Methods: Among individuals undergoing clinically indicated CRT, pre-and post-implantation electrocardiographs were meticulously analyzed for QRS duration change. All-cause mortality and the composite of mortality and HF hospitalizations were retrieved. Results: For 104 patients, mean age 67 years, 25% females, QRS narrowed within days by 20.2 ± 24.7 ms. In 55/104 (53%) QRS narrowed by ≥20 ms (“acute narrowing”). Female gender and baseline QRS predicted acute narrowing. Acute narrowing persisted for 1−6 weeks in 18/20 (90%) and 3−12 months in 21/31 (68%) of patients. During the average follow-up of 41 months, 29/104 (28%) died and 50/104 (48%) met the composite outcome. In a multivariable analysis including comorbidities and cardiac history, prolonged baseline PR interval (HR 1.015, CI 1.008−1.021, p < 0.001) and acute narrowing < 20 ms (HR 3.243, CI 1.593−6.603, p = 0.001) were significant and independent predictors for the composite outcome. Conclusions: Post-CRT acute QRS narrowing ≥ 20 ms is independently associated with favorable long-term outcomes and might be considered as a novel measure for procedural success.

High-sensitivity cardiac troponin I after coronary artery bypass grafting for post-operative decision-making

AIMS

Current troponin cut-offs suggested for the post-operative workup of patients following coronary artery bypass graft (CABG) surgery are based on studies using non-high-sensitive troponin assays or are arbitrarily chosen. We aimed to identify an optimal cut-off and timing for a proprietary high-sensitivity cardiac troponin I (hs-cTnI) assay to facilitate post-operative clinical decision-making.

METHODS AND RESULTS

We performed a retrospective analysis of all patients undergoing elective isolated CABG at our centre between January 2013 and May 2019. Of 4684 consecutive patients, 161 patients (3.48%) underwent invasive coronary angiography after surgery, of whom 86 patients (53.4%) underwent repeat revascularization. We found an optimal cut-off value for peak hs-cTnI of >13 000 ng/L [>500× the upper reference limit (URL)] to be significantly associated with repeat revascularization within 48 h after surgery, which was internally validated through random repeated sampling with 1000 iterations. The same cut-off also predicted 30-day major adverse cardiovascular events and all-cause mortality after a median follow-up of 3.1 years, which was validated in an external cohort. A decision tree analysis of serial hs-cTnI measurements showed no added benefit of hs-cTnI measurements in patients with electrocardiographic or echocardiographic abnormalities or haemodynamic instability. Likewise, early post-operative hs-cTnI elevations had a low yield for clinical decision-making and only later elevations (at 12-16 h post-operatively) using a threshold of 8000 ng/L (307× URL) were significantly associated with repeat revascularization with an area under the curve of 0.92 (95% confidence interval 0.88-0.95).

CONCLUSION

Our data suggest that for hs-cTnI, higher cut-offs than currently recommended should be used in the post-operative management of patients following CABG.

Long-term outcomes of left bundle branch area pacing versus biventricular pacing in patients with heart failure and complete left bundle branch block

Left bundle branch area pacing (LBBAP) has developed in an effort to improve cardiac resynchronization therapy (CRT). We aimed to compare the long-term clinical outcomes between LBBAP and biventricular pacing (BIVP) in patients with heart failure (HF) and complete left bundle branch block (CLBBB). Consecutive patients with HF and CLBBB requiring CRT received either LBBAP or BIVP were recruited at the Second Affiliated Hospital of Nanchang University from February 2018 to May 2019. We assessed their implant parameters, electrocardiogram (ECG), clinical outcomes at implant and during follow-up at 1, 3, 6, 12, and 24 months. Forty-one patients recruited including 21 for LBBAP and 20 for BIVP. Mean follow-up duration was 23.71 ± 4.44 months. LBBAP produced lower pacing thresholds, shorter procedure time and fluoroscopy duration compared to BIVP. The QRS duration was significantly narrower after LBBAP than BIVP (129.29 ± 31.46 vs. 156.85 ± 26.37 ms, p = 0.005). Notably, both LBBAP and BIVP significantly improved LVEF, LVEDD, NYHA class, and BNP compared with baseline. However, LBBAP significantly lowered BNP compared with BIVP (416.69 ± 411.39 vs. 96.07 ± 788.71 pg/ml, p = 0.007) from baseline to 24-month follow-up. Moreover, patients who received LBBAP exhibited lower number of hospitalizations than those in the BIVP group (p = 0.019). In addition, we found that patients with moderately prolonged left ventricular activation time (LVAT) and QRS notching in limb leads in baseline ECG respond better to LBBAP for CLBBB correction. LBBAP might be a relative safe and effective resynchronization therapy and as a supplement to BIVP for patients with HF and CLBBB.

Membranous septum morphology and risk of conduction abnormalities after transcatheter aortic valve implantation

BACKGROUND

There are limited data on the association of membranous septum (MS) morphology and transcatheter heart valve (THV) implantation depth, and the development of new conduction abnormalities (CA) after transcatheter aortic valve implantation (TAVI).

AIMS

The aim of this study was to describe the morphology of the MS and predict the risk of new CA after TAVI based on the MS morphology and THV implantation depth.

METHODS

Based on preprocedural CT scans, the MS depth was measured for every 25% of the entire MS width in 272 TAVI patients without preprocedural bundle branch block (BBB) or pacemaker. Post-procedural CT scans for THV implantation depth assessment were available in 130 of these patients.

RESULTS

The MS depth was a median of 2.5 mm (IQR 1.4-3.8) deeper at the posterior edge when compared to the anterior edge of the MS. New CA developed in 7.1% of patients in whom the THV did not cross the lower MS border at its anterior edge (3.6% with new BBB and high degree CA, respectively), in 18.8% of patients (15.6% with new BBB and 3.1% with new high-degree CA) where the THV overlapped the lower MS border by <2.5 mm and in 47.1% of patients (24.3% with new BBB and 22.9% with new high-degree CA) with THV overlap of the lower MS border by ≥2.5 mm.

CONCLUSIONS

The difference of the MS depth and THV implantation depth measured at the anterior edge of the MS predicted new CA after TAVI.

Association of Electrocardiographic Signs of Right Ventricular Hypertrophy and Clot Localization in Chronic Thromboembolic Pulmonary Hypertension

The role of electrocardiography (ECG) in chronic thromboembolic pulmonary hypertension (CTEPH) diagnosis and prognosticating has not been yet established. We aimed to assess the relationships of the recommended ECG criteria of right ventricular hypertrophy (RVH) with clot localization in CTEPH patients. ECG patterns of RVH according to the American College of Cardiology Foundation were assessed in patients with newly diagnosed CTEPH. We enrolled 58 (45.3%) patients with proximal and 70 (54.7%) with distal CTEPH. Receiver-operating characteristics curves analysis indicated that the following ECG abnormalities predicted proximal CTEPH localization: R_V1 > 6 mm—AUC 0.75 (CI: 0.66–0.84, p < 0.00001); S_V6 > 3 mm—AUC 0.70 (CI: 0.60–0.79, p < 0.00001); S_I > R_I wave—AUC 0.67 (CI: 0.58–0.77, p = 0.0004); R_V1:S_V1 > 1.0—AUC 0.66 (CI: 0.56–0.76, p = 0.0009); R_V1 peak > 0.035 s (QRS < 120 ms)—AUC 0.66 (CI: 0.56–0.75, p = 0.0016); R_V1:S_V1 > R_V3(V4):S_V3(V4)—AUC-0.65 (CI: 0.54–0.75, p = 0.0081); R_aVR > 4 mm—AUC 0.62 (CI: 0.52–0.71, p = 0.002) and P_II > 2.5 mm—AUC 0.62 (CI: 0.52–0.72, p = 0.00162). Pulmonary vascular resistance significantly correlated with amplitudes of R_V1 (r = 0.34, p = 0.008), S_V6 (r = 0.53, p = 0.000027) and P_II (r = 0.44, p = 0.00007). In patients with CTEPH, only 8 out of 23 ECG RVH criteria were useful for differentiating between proximal and distal CTEPH localization and we found that R_V1 and S_V6 may contribute as potential discriminators.

Electrocardiographic features and need for pacemaker in cardiac amyloidosis: Analysis of 58 cases

AIM

Amyloidosis is a disease in which amyloid fibrils can be deposited in different cardiac structures, and several electrocardiographic abnormalities can be produced by this phenomenon. The objective of this study was to describe the most common basal electrocardiographic alterations in patients diagnosed with cardiac amyloidosis (CA) and to determine if these abnormalities have an impact on the need of pacemaker.

METHODS

This retrospective study included patients who had an established diagnosis of CA [light-chain cardiac amyloidosis (LA-CA) or transthyretin cardiac amyloidosis (TTR-CA)] between January 2013 and March 2021. The baseline heart rate, the percentage of patients with a pseudo-infarct pattern, low-voltage pattern or cardiac conductions disturbances, and the impact of these factors on the need of pacemaker were analysed.

RESULTS

Fifty-eight patients with CA (20 with LA-CA and 38 with TTR-CA) were included, and the majority were male (69.0%). Twenty-one patients had atrial fibrillation (AF) at diagnosis. Thirty-five patients had a pseudo-infarct pattern, 35% had a low-voltage pattern, and 22% had criteria for ventricular hypertrophy. Two hirds had a conduction disorder: 18 patients with first degree atrioventricular block, 12 right bundle branch block, 3 left bundle branch block and 25 with a branch hemiblock. There were no differences between LA-CA and TTR-CA. Patients with TTR-CA had a greater need for pacemakers in the folow-up (39±40 meses). Bundle branch block was a predictor of the need for a permanent pacemaker (HR: 23.43; CI 95%: 4.09.134.09; P=.01).

CONCLUSIONS

Electrocardiographic abnormalities in patients diagnosed wich CA are heterogeneus. Most frecuent is the presence of conduction disorders, the pseudoinfarction pattern, followed by the low voltage pattern. Patients with any bundle branch block at the baseline electrocardiogram need more frecuent to require a pacemaker during follow-up, especially in TTR-CA.

Myositis-Specific Autoantibodies and QTc Changes by ECG in Idiopathic Inflammatory Myopathies

OBJECTIVES

The aim of this study was to investigate cardiac involvement detected by electrocardiography (ECG) in patients with idiopathic inflammatory myopathies (IIM) and to evaluate possible associations between autoantibody profile and ECG changes in these patients.

METHODS

In a Scandinavian cross-sectional study, patients were included from two Danish centres and one Swedish centre. Resting 12-lead ECG was investigated in 261 patients with IIM compared with 102 patients with systemic sclerosis (SSc) and 48 healthy controls (HCs). ECG changes were correlated to clinical manifestations and myositis-specific (MSAs) and myositis-associated (MAAs) autoantibodies.

RESULTS

Patients with IIM had longer mean QTc duration and more frequently presented with prolonged QTc (≥ 450 ms; p= 0.038) compared with HCs. Longer QTc duration was recorded in SSc compared with IIM (433 ± 23 ms vs 426 ± 24 ms, p= 0.011), yet, no significant difference in the fraction with prolonged QTc (SSc: 22%, IIM: 16%; p= 0.19). In multivariable regression analyses, anti-Mi2 (p= 0.01, p= 0.035) and anti-Pl-7 (p= 0.045, p= 0.014) were associated with QTc duration and prolonged QTc in IIM. Elevated CRP was associated with prolonged QTc (p= 0.041).

CONCLUSION

Presence of QTc abnormalities was as common in patients with IIM as in patients with SSc, including prolonged QTc seen in almost one fifth of the patients. Anti-Mi2, anti-Pl-7, and elevated CRP may serve as biomarkers for cardiac disease in IIM, but needs to be confirmed in a larger prospective study.

Cardiovascular abnormalities and its correlation with genotypes of children with osteogenesis imperfecta

BACKGROUND AND OBJECTIVES

Osteogenesis imperfecta (OI) is a rare disorder of abnormal production or modification of type I collagen, which is caused by mutations in COL1A1, COL1A2 or other genes. We investigate the cardiac abnormalities and its correlation with pathogenic mutations in OI children.

METHODS

A cross-sectional comparative study was completed in a relatively large sample of OI children, who were matched in body surface area (BSA) with healthy controls. All echocardiography was performed by experienced cardiologists using Vivid 7 equipment (GE Medical Systems, Horton, Norway). The resting standard 12-lead electrocardiogram (ECG) were obtained in OI patients by FX-8600 machine. Skeletal phenotypes of OI patients were evaluated, including information of bone fractures, deformities, motility, and bone mineral density (BMD). Pathogenic mutations of OI were detected by a next-generation sequencing panel and confirmed by Sanger sequencing.

RESULTS

A total of 69 OI children and 42 healthy children matched in BSA were enrolled. Abnormalities of echocardiography were found in 6 OI children, including enlarged left atrium (n=5), increased internal diameter of the left ventricle (n=1), who all carried the COL1A1 mutation. Mild regurgitation of mitral or tricuspid valves was observed in 26 OI patients. Abnormal ECG manifestations were found in 8 OI children, including deep Q wave, T wave change, premature ventricular complexes, short P-R interval, incomplete bundle branch block and high voltage of left ventricular. Compared with healthy controls, OI children had significant larger values in the main pulmonary artery (1.84 vs 1.60 cm, P < 0.01), left atrial diameter (2.58 vs 2.11 cm, P < 0.001), left ventricular internal dimension at end-diastolic (LVEDd) (3.85 vs 3.50 cm, P < 0.05) and lower left ventricular ejection fraction (LVEF) (68.40% vs 71.74%, P < 0.01). Moreover, OI patients with COL1A1 mutation tended to have greater main pulmonary artery, larger diameters of left atrial and LVEDd, and lower LVEF than healthy controls. COL1A1 mutation was correlated to dilated MPA (β = 1.557, P < 0.01), LAD (β = 3.915, P < 0.001), and LVEDd (β = 2.714, P < 0.01), and decreased LVEF (β = -3.249, P < 0.01).

CONCLUSIONS

Cardiovascular alterations were identified in OI children, including increased dimensions of the main pulmonary artery and left chamber, and low LVEF. The cardiovascular abnormalities seemed to be correlated to COL1A1 mutation and defects of type I collagen, which expanded our understandings of the cardiac phenotypes of OI children.

Use of handheld electrocardiograph (SnapECG) for the remote monitoring of arrhythmias

Objective

To investigate the value of a SnapECG monitoring in diagnosing arrhythmias compared with the conventional management.

Methods

In the first phase, the SnapECG and 12-lead electrocardiogram (ECG) were simultaneously adopted to detect arrhythmias in 439 hospitalized patients. The accuracies of the SnapECG in detecting different arrhythmias were assessed. In the second phase, 62 patients with palpitations were randomized to receive the SnapECG monitoring or conventional management for 3 months. The diagnosis rate, time of diagnosis, episodes before diagnosis, associated expenses, and scores of the modified European Heart Rhythm Association (EHRA), Self-rating Anxiety Scale (SAS), and the 36-item short-form health survey questionnaire (SF-36) were compared between groups.

Results

In the first phase, the SnapECG monitoring showed a sensitivity of 83.55% and specificity of 96.79% in identifying tachyarrhythmias, and a sensitivity of 95.29% and specificity of 97.54% in identifying bradyarrhythmias. In the second phase, 1642 ECGs were recorded by the SnapECG, among which 290 abnormal ECGs were identified. Compared with the conventional management, the SnapECG monitoring increased the diagnosis rate of symptomatic arrhythmias (70.97% vs. 19.35%, P < 0.05), shortened the time of diagnosis (48.26 ± 36.78 days vs. 71.45 ± 30.01 days, P < 0.05) and consequently reduced the episodes of symptomatic arrhythmias prior to establishing diagnosis. The scores of modified EHRA, SAS, SF-36 significantly improved at 3-month compared with their baseline levels in the SnapECG group.

Conclusions

Remote monitoring with the SnapECG can achieve early diagnosis of symptomatic arrhythmias. However, its sensitivity in identifying P-wave-related arrhythmias warrants further improvement.

Arrhythmias and Intraventricular Conduction Disturbances in Patients Hospitalized With Coronavirus Disease 2019

Cardiac arrhythmias have been observed in patients hospitalized with coronavirus disease (COVID-19). Most analyses of rhythm disturbances to date include cases of sinus tachycardia, which may not accurately reflect true cardiac dysfunction. Furthermore, limited data exist regarding the development of conduction disturbances in patients hospitalized with COVID-19. Hence, we performed a retrospective review and compared characteristics and outcomes for patients with versus without incident arrhythmia, excluding sinus tachycardia, as well as between those with versus without incident conduction disturbances. There were 27 of 173 patients (16%) hospitalized with COVID-19 who developed a new arrhythmia. Incident arrhythmias were associated with an increased risk of intensive care unit admission (59% vs 31%, p = 0.0045), intubation (56% vs 20%, p <0.0001), and inpatient death (41% vs 10%, p = 0.0002) without an associated increase in risk of decompensated heart failure or other cardiac issues. New conduction disturbances were found in 13 patients (8%). Incident arrhythmias in patients hospitalized with COVID-19 are associated with an increased risk of mortality, likely reflective of underlying COVID-19 disease severity more than intrinsic cardiac dysfunction. Conduction disturbances occurred less commonly and were not associated with adverse patient outcomes.

Myval versus alternative balloon- and self-expandable transcatheter heart valves: A central core lab analysis of conduction disturbances

BACKGROUND

Several studies have compared surface electrocardiographic changes following different self-expandable (SE) (Evolut (Medtronic, USA); Acurate (Boston Scientific, USA); Portico (Abbott, USA); and Allegra (NVT, Germany)) and balloon-expandable (BE) Sapien-3 (Edwards Lifesciences, USA) transcatheter heart valves. We aimed to compare these prosthesis with the novel Myval BE prosthesis (Meril Life, India).

METHODS

Academic European registry of consecutive patients with severe aortic stenosis who received any of the 6 aforementioned valves. Baseline, post-procedural, and discharge 12‑leads electrocardiograms (ECG) were centrally analyzed and compared.

RESULTS

A total of 1131 patients were included: 135 Myval (11.9%), 290 Sapien-3 (25.6%), 298 Evolut (26.3%), 180 Acurate (15.9%), 125 Portico (11.1%), and 103 Allegra (9.1%). There were no baseline differences in intraventricular conduction disturbances rate. Compared to the novel BE Myval, there were similar procedural and in-hospital outcomes. Similar rates of early new permanent pacemaker implant (PPI) were observed amongst Myval (7.4%), Sapien-3 (13.4%), and Acurate (9.1%), but Evolut, Portico, and Allegra presented significantly higher rates (18.5%, p = 0.003; 29.5% p < 0.001 and 22%, p = 0.001, respectively). Central analysis of ECGs, unraveled significant prolongation of the PR segment with Evolut, Portico and Allegra whereas Evolut, Acurate, and Portico showed significant QRS widening compared to Myval. However, at discharge no differences in PR segment duration were observed while, Evolut, and Portico- but not Acurate, Allegra or Sapien-3 - still presented significant widening of QRS segment compared to Myval.

CONCLUSIONS

After blinded central ECG analysis, the novel Myval balloon-expandable prosthesis was associated with a low rate of early conduction disturbances.

ECG pathology and its association with death in critically ill COVID-19 patients, a cohort study

BACKGROUND

We investigated the prevalence of ECG abnormalities and their association with mortality, organ dysfunction and cardiac biomarkers in a cohort of COVID-19 patients admitted to the intensive care unit (ICU).

METHODS

This cohort study included patients with COVID-19 admitted to the ICU of a tertiary hospital in Sweden. ECG, clinical data and laboratory findings during ICU stay were extracted from medical records and ECGs obtained near ICU admission were reviewed by two independent physicians.

RESULTS

Eighty patients had an acceptable ECG near ICU-admission. In the entire cohort 30-day mortality was 28%. Compared to patients with normal ECG, among whom 30-day mortality was 16%, patients with ECG fulfilling criteria for prior myocardial infarction had higher mortality, 63%, odds ratio (OR) 9.61 (95% confidence interval (CI) 2.02-55.6) adjusted for Simplified Acute Physiology Score 3 and patients with ST-T abnormalities had 50% mortality and OR 6.05 (95% CI 1.82-21.3) in univariable analysis. Both prior myocardial infarction pattern and ST-T pathology were associated with need for vasoactive treatment and higher peak plasma levels of troponin-I, NT-pro-BNP (N-terminal pro-Brain Natriuretic Peptide), and lactate during ICU stay compared to patients with normal ECG.

CONCLUSION

ECG with prior myocardial infarction pattern or acute ST-T pathology at ICU admission is associated with death, need for vasoactive treatment and higher levels of biomarkers of cardiac damage and strain in severely ill COVID-19 patients, and should alert clinicians to a poor prognosis.

Impact of sigmoid septum on periprocedural outcomes following transcatheter aortic valve implantation using current-generation valves

The role of sigmoid septum (SS) observed using preprocedural transthoracic echocardiography (TTE) in patients undergoing transcatheter aortic valve implantation (TAVI) remains unknown. This study aimed to compare clinical outcomes of TAVI using the current-generation transcatheter heart valves in patients with and without SS. We divided 140 consecutive patients, excluding four patients who underwent pacemaker implantation before TAVI, into two groups (those with and without SS) and compared the periprocedural outcomes, including new pacemaker implantation, within 30 days post-TAVI. Thirty-five patients (25%; 32 female patients) had SS before TAVI. The body surface area and aortic annulus area measured using computed tomography were significantly smaller in patients with SS than in those without SS (1.40 m² vs. 1.48 m², P = 0.03; and 372 mm² vs. 409 mm², P < 0.01; respectively). Device success was achieved in all patients with SS. Postprocedural TTE on 30 days post-TAVI showed no significant differences in the valvular hemodynamics between patients with and without SS. No severe prosthesis-patient mismatch was noted on TTE, although the transcatheter heart valve size tended to be smaller in patients with SS. Within 30 days of the TAVI, three (8.6%) and eight (7.6%) patients with and without SS, respectively, had new pacemaker implantation (P = 0.86). The presence of SS was not associated with periprocedural outcomes following TAVI in patients without pre-existing pacemakers. No specific assessment or treatment strategy is required for the TAVI in patients with SS using the current-generation devices.

Q waves are the strongest electrocardiographic variable associated with primary prophylactic implantable cardioverter-defibrillator benefit: a prospective multicentre study

AIM

The association of standard 12-lead electrocardiogram (ECG) markers with benefits of the primary prophylactic implantable cardioverter-defibrillator (ICD) has not been determined in the contemporary era. We analysed traditional and novel ECG variables in a large prospective, controlled primary prophylactic ICD population to assess the predictive value of ECG in terms of ICD benefit.

METHODS AND RESULTS

Electrocardiograms from 1477 ICD patients and 700 control patients (EU-CERT-ICD; non-randomized, controlled, prospective multicentre study; ClinicalTrials.gov Identifier: NCT02064192), who met ICD implantation criteria but did not receive the device, were analysed. The primary outcome was all-cause mortality. In ICD patients, the co-primary outcome of first appropriate shock was used. Mean follow-up time was 2.4 ± 1.1 years to death and 2.3 ± 1.2 years to the first appropriate shock. Pathological Q waves were associated with decreased mortality in ICD patients [hazard ratio (HR) 0.54, 95% confidence interval (CI) 0.35-0.84; P < 0.01] and patients with pathological Q waves had significantly more benefit from ICD (HR 0.44, 95% CI 0.21-0.93; P = 0.03). QTc interval increase taken as a continuous variable was associated with both mortality and appropriate shock incidence, but commonly used cut-off values, were not statistically significantly associated with either of the outcomes.

CONCLUSION

Pathological Q waves were a strong ECG predictor of ICD benefit in primary prophylactic ICD patients. Excess mortality among Q wave patients seems to be due to arrhythmic death which can be prevented by ICD.

Frequency and Significance of Right Bundle Branch Block and Subclinical Coronary Atherosclerosis in Asymptomatic Individuals

Limited data exist regarding the association between right bundle branch block (RBBB) and subclinical coronary atherosclerosis. This study investigated the influence of RBBB on subclinical coronary atherosclerosis detected by coronary computed tomographic angiography (CCTA) in an asymptomatic population. We retrospectively analyzed 7,205 asymptomatic individuals (mean age 54.4 ± 7.9 years and 4,695 men [65.2%]) with no prior history of coronary artery disease who voluntarily underwent CCTA and 12-lead electrocardiographic evaluation as part of a general health examination. The degree and extent of subclinical coronary atherosclerosis were evaluated by CCTA, and ≥50% diameter stenosis was defined as significant. The association between RBBB and subclinical coronary atherosclerosis was determined by logistic regression and propensity score matching analyses. Of study participants, 116 (1.6%) had RBBB. After adjustment for cardiovascular risk factors, there were no statistically significant differences in the adjusted odds ratios of RBBB for any atherosclerotic plaque (0.87, 95% confidence interval [CI] 0.57 to 1.32), calcified plaque (0.78, 95% CI 0.51 to 1.19), noncalcified plaque (1.44, 95% CI 0.77 to 2.69), mixed plaque (1.12, 95% CI 0.52 to 2.39), and significant coronary artery stenosis (0.92, 95% CI 0.48 to 1.74). Similarly, in the 5: 1 propensity score-matched population (n = 696), there were no statistically significant differences in the odds ratios for any subclinical coronary atherosclerosis between participants with and without RBBB (p for all >0.05). In conclusion, through this large cross-sectional study of asymptomatic individuals who underwent CCTA and electrocardiography evaluation, individuals with RBBB were not associated with an increased risk of subclinical coronary atherosclerosis compared with those without RBBB.

Re-worsening left ventricular ejection fraction after response to cardiac resynchronization therapy

BACKGROUND

Although cardiac resynchronization therapy (CRT) provided functional and clinical improvement in patients with heart failure (HF) and electrical intraventricular conduction disturbances, some patients had re-worsening left ventricular (LV) function after a favorable CRT response. We analyzed the clinical variables and cardiac outcomes associated with this re-worsening LV function after CRT.

METHODS

In this study, 71 patients with CRT response who received CRT between 2006 and 2017 were included. CRT response was defined as a "≥ 10% improvement in LV ejection fraction (LVEF) on follow-up." Patients were classified into two groups: (i) persistent: (n = 48, 68%), defined as those with a CRT response and (ii) re-worsening: (n = 23, 32%), consisting of those who fell out of the definition of a CRT response after an initial CRT response.

RESULTS

Half of the patients in the re-worsening group failed to maintain a CRT response from two years upwards. A longer duration from HF diagnosis to CRT implantation, nonspecific intraventricular conduction delay (NIVCD) on electrocardiogram at CRT implantation, and a lower increased LVEF at initial CRT response were independent predictors for the re-worsening group. Patients in the re-worsening group had a higher incidence rate for HF hospitalization and cardiac deaths, compared with those in the persistent group.

CONCLUSION

One-third of CRT responders experienced re-worsening LVEF, which was associated with poor outcomes. CRT responders with NIVCD, longer HF duration, and a lower increased LVEF at initial CRT response should be monitored with caution.

Fascicular heart blocks and risk of adverse cardiovascular outcomes: Results from a large primary care population

BACKGROUND

Fascicular heart blocks can progress to complete heart blocks, but this risk has not been evaluated in a large general population.

OBJECTIVE

The purpose of this study was to investigate the association between various types of fascicular blocks diagnosed by electrocardiographic (ECG) readings and the risk of incident higher degree atrioventricular block (AVB), syncope, pacemaker implantation, and death.

METHODS

We studied primary care patients referred for ECG recording between 2001 and 2015. Cox regression models were used to estimate hazard ratios (HRs) as well as absolute risks of cardiovascular outcomes.

RESULTS

Of 358,958 primary care patients (median age 54 years; 55% women), 13,636 (3.8%) had any type of fascicular block. Patients were followed up to 15.9 years. We found increasing HRs of incident syncope, pacemaker implantation, and third-degree AVB with increasing complexity of fascicular block. Compared with no block, isolated left anterior fascicular block (LAFB) was associated with 0%-2% increased 10-year risk of developing third-degree AVB (HR 1.6; 95% confidence interval [CI] 1.25-2.05), whereas right bundle branch block combined with LAFB and first-degree AVB was associated with up to 23% increased 10-year risk (HR 11.0; 95% CI 7.7-15.7), depending on age and sex group. Except for left posterior fascicular block (HR 2.09; 95% CI 1.87-2.32), we did not find any relevant associations between fascicular block and death.

CONCLUSION

We found that higher degrees of fascicular blocks were associated with increasing risk of syncope, pacemaker implantation, and complete heart block, but the association with death was negligible.

Speckle tracking strain and ECG heterogeneity correlate in transcatheter aortic valve replacement-induced left bundle branch blocks and right ventricular paced rhythms

Objective

Transcatheter aortic valve replacement (TAVR) complications include left bundle branch block (LBBB) and right ventricular paced rhythm (RVP). We hypothesised that changes in electrocardiographic heterogeneity would correlate better with speckle tracking strain measures than with left ventricular ejection fraction (LVEF) on transthoracic echocardiogram (TTE) among patients with TAVR-induced conduction abnormalities.

Methods

We reviewed medical records of 446 consecutive patients who underwent TAVR at our institution. Of the 238 patients with 12-lead electrocardiograms (ECGs) that met our inclusion criteria, 58 had pre-TAVR and post-TAVR TTEs adequate for strain assessment. We compared patients who did not have an LBBB or RVP pre-TAVR and post-TAVR (controls, n=11) with patients who developed LBBBs (n=11) and who required RVPs (n=10) post-TAVR. In our study population (n=32, 41% female, mean age 85.8 years), we evaluated QRS complex duration, R-wave heterogeneity (RWH), T-wave heterogeneity (TWH), LVEF, global longitudinal strain (GLS) and mechanical dispersion (MD).

Results

TAVR-induced changes on ECG did not correlate with LVEF. TAVR-induced changes in MD and QRS complex duration correlated among all patients (r=0.4, p=0.04). GLS and RWH correlated among RVP patients (r=0.7, p=0.00003). MD and TWH correlated among LBBB patients (r=0.7, p=0.00004).

Conclusions

In this convenience sample of patients with TAVR-induced conduction abnormalities, RWH and TWH correlated with strain measures but not with LVEF. Strain measures, RWH and TWH may offer additional insights for pre-TAVR evaluation and post-TAVR clinical management.

Association between vectorcardiographic QRS area and incident heart failure diagnosis and mortality among patients with left bundle branch block: A register-based cohort study

BACKGROUND

QRS duration and morphology including left bundle branch block (LBBB) are the most widely used electrocardiogram (ECG) markers for assessing ventricular dyssynchrony and predicting heart failure (HF). However, the vectorcardiographic QRS area may more accurately identify delayed left ventricular activation and HF development.

OBJECTIVE

We investigated the association between QRS area and incident HF risk in patients with LBBB.

METHODS

By crosslinking data from Danish nationwide registries, we identified patients with a first-time digital LBBB ECG between 2001 and 2015. The vectorcardiographic QRS area was derived from a 12‑lead ECG using the Kors transformation method and grouped into quartiles. The endpoint was a composite of HF diagnosis, filled prescriptions for loop diuretics, or death from HF. Cause-specific multivariable Cox regression was used to compute hazard ratios(HR) with 95% confidence intervals(CI).

RESULTS

We included 3316 patients with LBBB free from prior HF-related events (median age, 72 years; male, 40%). QRS area quartiles comprised Q1, 36-98 μVs; Q2, 99-119 μVs; Q3, 120-145 μVs; and Q4, 146-295 μVs. During a 5-year follow-up, 31% of patients reached the composite endpoint, with a rate of 39% in the highest quartile Q4. A QRS area in quartile Q4 was associated with increased hazard of the composite endpoint (HR:1.48, 95%CI:1.22-1.80) compared with Q1.

CONCLUSIONS

Among primary care patients with newly discovered LBBB, a large vectorcardiographic QRS area (146-295 μVs) was associated with an increased risk of incident HF diagnosis, filling prescriptions for loop diuretics, or dying from HF within 5-years.

Premature atrial contractions with multiple patterns of aberrant conduction followed by torsade de pointes in a patient with polymyalgia rheumatica: A case report

RATIONALE

Recent studies have shown that QT interval prolongation is associated with disease severity and predicts mortality in systemic inflammatory diseases, particularly rheumatoid arthritis. Systemic pro-inflammatory cytokines released from synovial tissues in rheumatoid arthritis, such as interleukin (IL)-1β, IL-6, and tumor necrosis factor-α, could have direct effects on cardiac electrophysiology, particularly changes in the expression and function of potassium and calcium channels, resulting in QT interval prolongation on surface electrocardiogram (ECG) and an increased predisposition to develop lethal ventricular arrhythmias. However, reports on torsade de pointes (TdP) due to acquired long QT syndrome in patients with polymyalgia rheumatica (PMR) are limited.

PATIENT CONCERNS

An 85-year-old Japanese woman with active PMR developed first syncope.

DIAGNOSIS

Frequent premature atrial contractions (PACs) with multiple patterns of aberrant conduction, QT interval prolongation, and morphological T-U wave variability followed by TdP were documented. PACs were the first beat of TdP.

INTERVENTIONS

Amiodarone, together with magnesium and potassium, was intravenously administered. However, TdP resulted in a ventricular arrhythmic storm, for which sedation with mechanical ventilatory support, temporary overdrive cardiac pacing, and intravenous landiolol administration in addition to multiple direct current shocks were effective.

OUTCOMES

Approximately 2 years later, the patient was treated with amiodarone, propranolol, and prednisolone. She did not undergo implantable cardioverter-defibrillator implantation and was quite well, with no recurrence of ventricular tachyarrhythmia.

LESSONS

IL-6 hyperproduction in inflamed tissues has been widely confirmed in PMR. Frequent PACs with various patterns of aberrant conduction, QT interval prolongation, and morphological T-U wave variability followed by TdP, for which IL-6-mediated enhancement of L-type Ca2+ current and inhibition of the rapid component of the delayed rectifier K+ current are the most likely mechanisms, were documented in an elderly Japanese woman with PMR. ECG may be recorded once in patients with active PMR even when these patients do not complain of palpitation or syncope. If QT interval prolongation or arrhythmia, including even PACs, is observed, follow-up ECG may be warranted, particularly for patients with some risk factors for QT prolongation that could lead to TdP, such as advanced age, female sex, hypopotassemia, and polypharmacy.

Prevalence, clinical and instrumental features of left bundle branch block-induced cardiomyopathy: the CLIMB registry

AIMS

Although increasingly recognized as a distinct pathological entity, left bundle branch block-induced cardiomyopathy (LBBB-ICMP) is not included among the possible aetiologies of acquired dilated cardiomyopathies (DCM). While diagnostic criteria have been proposed, its recognition remains principally retrospective, in the presence of clinical and instrumental red flags. We aimed to assess the prevalence and clinical and instrumental features of LBBB-ICMP in a large cohort of patients with DCM.

METHODS AND RESULTS

We analysed a cohort of 242 DCM patients from a two-centre registry. Inclusion criteria were age > 18, non-ischaemic or non-valvular DCM, and LBBB on electrocardiogram. LBBB-ICMP was defined according to previously proposed diagnostic criteria: (i) neither family history nor clinically identifiable potential causes for DCM; (ii) negative genetic testing; (iii) echocardiographic features including non-severe chamber dilation, normal absolute and relative wall thickness, marked dyssynchrony, and normal right ventricular function; and (iv) absence of late gadolinium enhancement (LGE) on cardiac magnetic resonance (CMR). From the entire cohort, we identified 30 subjects (similar in terms of New York Heart Association class I or II in 80% vs. 75%, P = 0.56; QRS width of 150 ± 22 vs. 151 ± 24 ms, P = 0.82; and cardiac remodelling of baseline end-diastolic diameter 66 ± 8 vs. 65 ± 10 mm, P = 0.53) with a comprehensive dataset including CMR and genetic testing, required to verify the presence of the diagnostic criteria proposed for LBBB-ICMP. The main characteristics of this subgroup were 73% males, age 45 ± 13 years, left ventricular ejection fraction (LVEF) 30 ± 10%, LGE in 38% of patients, and QRS complex of 150 ± 22 ms. Patients were under guideline-directed medical therapy, and 57% of them were treated with cardiac resynchronization therapy (CRT). Two patients (6.67%, 50% males, age 53 ± 13 years) fulfilled the diagnostic criteria proposed for LBBB-ICMP. After a follow-up of 44 (12-76) months, LVEF was normal and QRS width significantly reduced (from 154 ± 25 to 116 ± 52 ms) in patients with LBBB-ICMP. Both patients were under optimal medical treatment, and one was implanted with CRT-D. Neither of the two patients experienced death, malignant ventricular arrhythmia, or heart failure hospitalization at follow-up.

CONCLUSIONS

Left bundle branch block-induced cardiomyopathy emerges as a distinct pathological entity, promptly identifiable in a minority but not negligible proportion of patients with newly diagnosed DCM and LBBB, using a series of diagnostic criteria including CMR and genetic testing. Further studies are needed to better elucidate the clinical course of LBBB-ICMP.

Assessment of QTc and Risk of Torsades de Pointes in Ventricular Conduction Delay and Pacing: A Review of the Literature and Call to Action

BACKGROUND

Assessment of the heart rate-corrected QT-interval on the 12-lead electrocardiogram when prescribing medications known to increase the risk of Torsades de Pointes has become a common part of consultation-liaison psychiatry practice.

OBJECTIVES

Highlighted by a patient who experienced psychiatric decompensation due to inaccurate interpretation of QTc prolongation in the setting of a wide QRS complex, we aimed to describe the approach to QTc interpretation in patients with ventricular conduction delay.

METHODS

We reviewed the current literature on the approach to assessment of prolonged repolarization in patients with ventricular conduction delay due to bundle branch block (BBB) and ventricular pacing.

RESULTS

Physicians of any specialty may perform initial electrocardiogram interpretation and should be proficient in the definition, recognition, and understanding of the basic pathophysiology of electrocardiographic abnormalities. We discuss current approaches to assessment of the QT-interval in patients with a wide QRS complex due to bundle branch block and ventricular pacing, including bivariate QTc modification, univariate QT-interval modifications, and use of the JT-interval.

CONCLUSIONS

The QT-interval is prolonged ipso facto in patients with a wide QRS complex from ventricular conduction delay/ventricular pacing and must be adjusted for QRS duration. Multiple formulae have been proposed to account for wide QRS complex in this setting with no single universally accepted methodology. We suggest the use of either the Bogossian formula or JT-interval followed by Hodges or Framingham heart-rate correction to adjust for a wide QRS complex. It is critical that the C-L psychiatrist be able to identify a wide QRS complex on the electrocardiogram, understand implications for accurate assessment of prolonged depolarization, and apply an appropriate correction methodology.

Deleterious Rare Desmosomal Variants Contribute to Hypertrophic Cardiomyopathy and are Associated With Distinctive Clinical Features

BACKGROUND

Deleterious rare variants in genes encoding desmosome proteins have been identified as the essential basis of arrhythmogenic cardiomyopathy (ACM) and detected in dilated cardiomyopathy, but the relationship between deleterious rare desmosomal variants and hypertrophic cardiomyopathy (HCM) remains unknown.

METHODS

Whole exome sequencing was performed in 1000 HCM patients and 761 non-HCM controls to search for deleterious rare variants in genes encoding desmosomal proteins including PKP2, JUP, DSC2, DSG2, and DSP. Clinical phenotypes were assessed in HCM patients, and patients with deleterious rare desmosomal variants underwent evaluation of ACM revised Task Force Criteria.

RESULTS

A total of 27 deleterious rare desmosomal variants were present in 24 (2.4%) HCM patients and 5 (0.66%) controls. The variants were more prevalent in the HCM patients than in the controls (P=0.004). The majority of patients possessing deleterious rare desmosomal variants could not be diagnosed as ACM. Moreover, the patients with deleterious rare desmosomal variants possessed several distinctive clinical features comparing to patients without such variants, including a higher incidence of non-sustained ventricular tachycardia (29.2% vs. 4.5%, P<0.001), left bundle branch block (33.3% vs. 1.6%, P<0.001), and right ventricular involvement for an HCM phenotype (29.2% vs. 0.30%, P<0.001).

CONCLUSIONS

We screened deleterious rare desmosomal variants in a large HCM case-control cohort, and found deleterious rare desmosomal variants can be relevant to HCM. Moreover, our data indicated deleterious rare desmosomal variants were associated with distinctive clinical features of HCM. These findings require validation in other HCM cohorts.

Cardiac manifestations in Finnish gelsolin amyloidosis patients

INTRODUCTION

Finnish gelsolin amyloidosis (AGel amyloidosis) is an inherited systemic amyloidosis with well-known ophthalmological, neurological and cutaneous symptoms. Additionally, cardiomyopathies, conduction disorders and need of cardiac pacemakers occur in some patients. This study focuses on electrocardiographic (ECG) findings in AGel amyloidosis and their relation to cardiac magnetic resonance (CMR) changes. We also assessed whether ECG abnormalities were associated with pacemaker implantation and mortality.

MATERIALS AND METHODS

In this cohort study, 51 genetically verified AGel amyloidosis patients (mean age 66 years) without cardiac pacemakers underwent 12-lead ECG and CMR imaging with contrast agent in 2017. Patients were followed-up for 3 years.

RESULTS

Conduction disturbances were found in 22 patients (43%). Nine (18%) presented with first-degree atrioventricular block, six (12%) with left anterior hemiblock, seven (14%) with left or right bundle branch block and two (4%) with non-specific intraventricular conduction delay. Low QRS voltage was present in two (4%) patients. Late gadolinium enhancement (LGE) concentrating on the interventricular septum and inferior parts of the heart was present in 19 (86%) patients with conduction abnormalities. During the follow-up, only one patient received a pacemaker, and one patient died.

DISCUSSION

Conduction disorders and septal LGE are common in AGel amyloidosis, whereas other ECG and CMR findings typically observed in most common cardiac amyloidosis types were rare. Septal pathology seen in CMR may interfere with the cardiac conduction system in AGel amyloidosis, explaining conduction disorders, although pacemaker therapy is rarely required.

Impact of conduction disturbances on left ventricular mass regression and geometry change following transcatheter aortic valve replacement

Our study aimed to compare the difference of LV mass regression and remodeling in regard of conduction disturbances (CD) following transcatheter aortic valve replacement (TAVR). A prospective analysis of 152 consecutive TAVR patients was performed. 53 patients (34.9%) had CD following TAVR, including 30 (19.7%) permanent pacemaker implantation and 23 (15.2%) new left bundle branch block. In 123 patients with 1-year follow-up, significant improvement of LV ejection fraction (LVEF) (baseline vs 12-month: 65.1 ± 13.2 vs 68.7 ± 9.1, P = 0.017) and reduced LV end-systolic volume (LVESV) (39.8 ± 25.8 vs 34.3 ± 17.1, P = 0.011) was found in non-CD group (N = 85), but not in CD group (N = 38). Both groups had significant decrease in LV mass index (baseline vs 12-month: 148.6 ± 36.9 vs. 136.4 ± 34.7 in CD group, p = 0.023; 153.0 ± 50.5 vs. 125.6 ± 35.1 in non-CD group, p < 0.0001). In 46 patients with 3-year follow-up, only non-CD patients (N = 28) had statistically significant decrease in LV mass index (Baseline vs 36-month: 180.8 ± 58.8 vs 129.8 ± 39.1, p = 0.0001). Our study showed the improvement of LV systolic function, reduced LVESV and LV mass regression at 1 year could be observed in patients without CD after TAVR. Sustained LV mass regression within 3-year was found only in patients without CD.

Efficacy of His Bundle Pacing on LV Relaxation and Clinical Improvement in Heart Failure and LBBB

OBJECTIVES

This study aimed to compare acute hemodynamic improvements and responses to His bundle pacing (HBP) and conventional biventricular pacing (BVP).

BACKGROUND

HBP can correct left bundle branch block (LBBB) and may be an alternative cardiac resynchronization therapy (CRT) to BVP.

METHODS

Fourteen consecutive patients with heart failure (HF) and typical LBBB who required CRT were enrolled. The acute hemodynamic responses during HBP and BVP were compared using a micromanometer-tipped catheter inserted into the left ventricle (LV) before CRT. Each configuration was compared with AAI mode. A permanent HBP device was implanted when LBBB correction threshold was ≤1.5 V at 1.0 ms, and remaining patients were treated with BVP. Clinical and echocardiographic improvements were assessed during a 12-month follow-up period.

RESULTS

The LV contractile index (positive maximal rate of LV pressure rise [dP/dt_max]) increased similarly during HBP and BVP (18.8 ± 6.4% vs 18.0 ± 10.2%; P = 0.810). LV relaxation indices (negative dP/dt_max and tau) were significantly improved during HBP compared with BVP (negative dP/dt_max: 14.3% ± 5.5% vs 3.1% ± 8.1%; P < 0.001; tau: 7.2% ± 4.3% vs -0.8% ± 8.1%; P = 0.001). Nine (64%) patients received permanent HBP devices, while 5 patients were treated with BVP. The New York Heart Association functional class, LV ejection fraction, LV end-systolic volume, and B-type natriuretic peptide level improved in patients treated with HBP and BVP (all P < 0.05 vs baseline). Patients treated with HBP exhibited earlier and greater improvements of the LV ejection fraction and LV end-systolic volume than did those with BVP.

CONCLUSIONS

HBP improves systolic function and LV relaxation in patients with HF and LBBB. CRT via HBP produced earlier and greater clinical responses than BVP.

Prophylactic permanent pacemaker strategy in patients with right bundle branch block undergoing transcatheter aortic valve replacement

OBJECTIVES

To report on the experience with a selective prophylactic permanent pacemaker (PPx-PPM) implantation strategy in patients with pre-existing right bundle branch block (RBBB) undergoing transcatheter aortic valve replacement (TAVR).

BACKGROUND

Pre-existing RBBB is an independent predictor for PPM after TAVR and has been linked to increased mortality.

METHODS

Hospital patient flow and longer-term clinical endpoints were compared for TAVR patients with pre-existing RBBB treated in a period with and without selective PPx-PPM strategy (2013-2020).

RESULTS

A total of 260 patients were included: 170 in the early period without PPx-PPM strategy and 90 patients in the late period with selective PPx-PPM strategy. A PPx-PPM was implanted in 44% of patients in the late period. Overall, 69% versus 80% of all patients in the early versus late period ended up with a PPM (p = .06). Streamlined transfemoral TAVR was routinely used from 2017-in this series of patients, both TAVR procedural time and hospital length of stay (LoS) were significantly shorter in the late versus early period (mean procedural time: 70 vs. 83 min and LoS ≥5 days: 15% vs. 40%; p < .05). No difference in all-cause/cardiovascular mortality was observed between both strategies, whereas cardiac rehospitalization was significantly higher for patients treated in the early versus late period (hazard ratio 2.33 [1.04-5.26]; p = .042)-this mainly due to (sub)acute PPM-implantation early after discharge.

CONCLUSIONS

Selective prophylactic PPM implantation in TAVR candidates with pre-existing RBBB results in shorter TAVR procedural time and hospital LoS and prevents early cardiac rehospitalization related to complete heart block.

Arrhythmic burden in patients with new-onset persistent left bundle branch block after transcatheter aortic valve replacement: 2-year results of the MARE study

AIMS

We determined the incidence and type of arrhythmias at 2-year follow-up in patients with new-onset persistent left bundle branch block (LBBB) following transcatheter aortic valve replacement (TAVR).

METHODS AND RESULTS

Multicentre prospective study including 103 consecutive patients with new-onset persistent LBBB post-TAVR (SAPIEN XT/3: 53; CoreValve/Evolut R: 50). An implantable cardiac monitor (Reveal XT, Reveal Linq) was implanted before hospital discharge and patients had continuous monitoring for up to 2 years. Arrhythmic events were adjudicated in a central core lab. 1836 new arrhythmic events (tachyarrhythmias: 1655 and bradyarrhythmias: 181) occurred at 2 years. Of these, 283 (15%) occurred beyond 1 year (tachyarrhythmias 212, bradyarrhythmias 71) in 33 (36%) patients, without differences between valve type. Most late (>1 year) arrhythmic events were asymptomatic (94%) and led to a treatment change in 17 (19%) patients. A total of 71 late bradyarrhythmias [high-degree atrioventricular block (HAVB): 3, severe bradycardia: 68] were detected in 17 (21%) patients. At 2 years, 18 (17%) patients had received a permanent pacemaker (PPM) or implantable cardiac-defibrillator. PPM implantation due to HAVB predominated in the early phase post-TAVR, with only 1 HAVB event requiring PPM implantation after 1 year.

CONCLUSION

Patients with new-onset LBBB post-TAVR exhibited a very high burden of arrhythmic events within the 2 years post-procedure. While new tachyarrhythmic events were homogeneously distributed over time, the vast majority of new HAVB episodes leading to PPM implantation occurred early after the procedure. These results should help to guide the management of this challenging group of patients. (clinicaltrials.gov: NCT02153307).

Human model of IRX5 mutations reveals key role for this transcription factor in ventricular conduction

AIMS

Several inherited arrhythmic diseases have been linked to single gene mutations in cardiac ion channels and interacting proteins. However, the mechanisms underlying most arrhythmias, are thought to involve altered regulation of the expression of multiple effectors. In this study, we aimed to examine the role of a transcription factor (TF) belonging to the Iroquois homeobox family, IRX5, in cardiac electrical function.

METHODS AND RESULTS

Using human cardiac tissues, transcriptomic correlative analyses between IRX5 and genes involved in cardiac electrical activity showed that in human ventricular compartment, IRX5 expression strongly correlated to the expression of major actors of cardiac conduction, including the sodium channel, Nav1.5, and Connexin 40 (Cx40). We then generated human-induced pluripotent stem cells (hiPSCs) derived from two Hamamy syndrome-affected patients carrying distinct homozygous loss-of-function mutations in IRX5 gene. Cardiomyocytes derived from these hiPSCs showed impaired cardiac gene expression programme, including misregulation in the control of Nav1.5 and Cx40 expression. In accordance with the prolonged QRS interval observed in Hamamy syndrome patients, a slower ventricular action potential depolarization due to sodium current reduction was observed on electrophysiological analyses performed on patient-derived cardiomyocytes, confirming the functional role of IRX5 in electrical conduction. Finally, a cardiac TF complex was newly identified, composed by IRX5 and GATA4, in which IRX5 potentiated GATA4-induction of SCN5A expression.

CONCLUSION

Altogether, this work unveils a key role for IRX5 in the regulation of human ventricular depolarization and cardiac electrical conduction, providing therefore new insights into our understanding of cardiac diseases.

The value of septal rebound stretch analysis for the prediction of volumetric response to cardiac resynchronization therapy

AIMS

Patient selection for cardiac resynchronization therapy (CRT) may be enhanced by evaluation of systolic myocardial stretching. We evaluate whether systolic septal rebound stretch (SRSsept) derived from speckle tracking echocardiography is a predictor of reverse remodelling after CRT and whether it holds additive predictive value over the simpler visual dyssynchrony assessment by apical rocking (ApRock).

METHODS AND RESULTS

The association between SRSsept and change in left ventricular end-systolic volume (ΔLVESV) at 6 months of follow-up was assessed in 200 patients. Subsequently, the additive predictive value of SRSsept over the assessment of ApRock was evaluated in patients with and without left bundle branch block (LBBB) according to strict criteria. SRSsept was independently associated with ΔLVESV (β 0.221, P = 0.002) after correction for sex, age, ischaemic cardiomyopathy, QRS morphology and duration, and ApRock. A high SRSsept (≥optimal cut-off value 2.4) also coincided with more volumetric responders (ΔLVESV ≥ -15%) than low SRSsept in the entire cohort (70.0% and 56.4%), in patients with strict LBBB (83.3% vs. 56.7%, P = 0.024), and non-LBBB (70.7% vs. 46.3%, P = 0.004). Moreover, in non-LBBB patients, SRSsept held additional predictive information over the assessment of ApRock alone since patients that showed ApRock and high SRSsept were more often volumetric responder than those with ApRock but low SRSsept (82.8% vs. 47.4%, P = 0.001).

CONCLUSION

SRSsept is strongly associated with CRT-induced reduction in left ventricular end-systolic volume and holds additive prognostic information over QRS morphology and ApRock. Our data suggest that CRT patient selection may be improved by assessment of SRSsept, especially in the important subgroup without strict LBBB.

CLINICAL TRIAL REGISTRATION

The MARC study was registered at clinicaltrials.gov: NCT01519908.

Increasing modified CHA2DS2-VASc risk score is associated with acute cardiac injury in hospitalised COVID-19 patients

BACKGROUND

Prediction of hospital mortality in patients with COVID-19 by the CHA2DS2VASc (M-CHA2DS2VASc) has been recently shown. Because COVID-19 patients with acute cardiac injury have higher mortality compared to those without, we assumed that this risk score may also predict acute cardiac injury in these patients.

METHODS

In this retrospective, single centre cohort study, we included 352 hospitalised patients with laboratory-confirmed COVID-19 and divided into three groups according to M-CHA2DS2VASc risk score which was created by changing gender criteria of the CHA2DS2VASc from female to male (Group 1, score 0-1 (n = 142); group 2, score 2-3 (n = 138) and group 3, score ≥4 (n = 72)).

RESULTS

As the M-CHA2DS2VASc risk score increased, acute cardiac injury was also significantly increased (Group 1, 11.3%; group 2, 48.6%; group 3, 76%; p < 0.001). The higher M-CHA2DS2VASc tertile had higher prevalence of arrhythmias compared to lower tertile. The multivariate logistic regression analysis showed that M-CHA2DS2VASc risk score, admission to intensive care unit and invasive mechanical ventilation were independent predictors of acute cardiac injury (p = 0.001, odds ratio 1.675 per scale for M-CHA2DS2VASc). In receiver operating characteristic analysis, M-CHA2DS2VASc risk score was able to predict acute cardiac injury (Area under the curve value for acute cardiac injury was 0.80; p < 0.001).

CONCLUSION

Admission M-CHA2DS2VASc risk score was associated with acute cardiac injury in hospitalised patients with COVID-19.

Occurrence and Persistency of Conduction Disturbances during Transcatheter Aortic Valve Implantation

Background and Objectives: Conduction disturbances such as left bundle branch block (LBBB) and complete atrio-ventricular block (cAVB) are relatively frequent complications following trans-catheter aortic valve implantation (TAVI). We investigated the dynamics of these conduction blocks to further understand luxating factors and predictors for their persistency. Materials and Methods: We prospectively included 157 consecutive patients who underwent a TAVI procedure. Electrocardiograms (ECGs) were obtained at specific time points during the TAVI procedure and at follow-up until at least six months post-procedure. Results: Of the 106 patients with a narrow QRS complex (nQRS) before TAVI, ~70% developed LBBB; 28 (26.4%) being classified as super-transient (ST-LBBB), 20 (18.9%) as transient (T-LBBB) and 24 (22.6%) as persistent (P-LBBB). Risk of LBBB was higher for self-expandable (SE) than for balloon-expandable (BE) prostheses and increased with larger implant depth. During the TAVI procedure conduction disturbances showed a dynamic behavior, as illustrated by alternating kinds of blocks in 18 cases. Most LBBBs developed during balloon aortic valvuloplasty (BAV) and at positioning and deployment of the TAVI prosthesis. The incidence of LBBB was not significantly different between patients who did and did not undergo BAV prior to TAVI implantation (65.3% and 74.2%, respectively (p = 0.494)). Progression to cAVB was most frequent for patients with preexisting conduction abnormalities (5/34) patients) and in patients showing ST-LBBB (6/28). Conclusions: During the TAVI procedure, conduction disturbances showed a dynamic behavior with alternating types of block in 18 cases. After a dynamic period of often alternating types of block, most BBBs are reversible while one third persist. Patients with ST-LBBB are most prone to progressing into cAVB. The observation that the incidence of developing LBBB after TAVI is similar with and without BAV suggests that a subgroup of patients has a substrate to develop LBBB regardless of the procedure.

Impact of electrophysiological features acquired after anatomical repair of congenital corrected transposition of the great arteries on late mortality and ventricular dysfunction

OBJECTIVES

In patients with anatomically repaired congenitally corrected transposition of the great arteries, the impact of electrophysiological features on postoperative ventricular dysfunction remains less well known. Our goal was to investigate the role of fragmented QRS and QRS duration in mortality and systemic ventricular dysfunction after anatomical repair of corrected transposed great arteries.

METHODS

Consecutive patients who underwent anatomical repair in our institution from January 2005 to December 2017 were enrolled in this retrospective analysis. Fragmented QRS was defined as ≥1 discontinuous deflections in narrow QRS complexes, and ≥2 in wide QRS complexes, in 2 contiguous electrocardiogram leads. The primary end point was a composite of all-cause mortality and systemic ventricular dysfunction.

RESULTS

A total of 74 patients were included. Among them, 30, 15 and 29 underwent the Senning arterial switch, the Senning Rastelli and the hemi-Mustard/bidirectional Glenn/Rastelli procedures, respectively. The primary end point occurred in 9 (12.2%) patients and included 7 late deaths and 2 cases of late-onset systemic ventricular dysfunction. Fragmented QRS and QRS prolongation were noted in 19 (25.7%) and 21 (28.4%) patients, respectively. In patients with the primary end point, QRS fragmentation (6/9 vs 10/65; P < 0.001) and QRS prolongation (6/9 vs 15/65; P = 0.013) were noted more frequently than in patients without the primary end point. No statistical differences in these electrocardiogram findings were found among patients treated with 3 surgical strategies.

CONCLUSIONS

Appearance of QRS fragmentation or QRS prolongation is associated with death or ventricular dysfunction in anatomically repaired corrected transposition of the great arteries. Although there is a trend that QRS fragmentation and QRS prolongation appear more frequently in patients who had the Senning-arterial switch operation, there is no statistically significant difference associated with these electrocardiogram features among varied procedures.