CineECG for visualization of changes in ventricular electrical activity during ischemia

BACKGROUND

CineECG offers a visual representation of the location and direction of the average ventricular electrical activity throughout a single cardiac cycle, based on the 12‑lead ECG. Currently, CineECG has not been used to visualize ventricular activation patterns during ischemia.

PURPOSE

To determine the changes in ventricular activity during acute ischemia with the use of CineECG, and relating this to changes in the ECG.

METHODS

Continuous ECG's during percutaneous coronary intervention with prolonged balloon inflation from the STAFF III database were analyzed with CineECG at baseline and every 10 s throughout the first 150 s of balloon inflation. The CineECG direction was determined for the initial QRS-complex, terminal QRS-complex, ST-segment and T-wave. Changes in the CineECG were quantified by calculating the Δangle between the direction at baseline and the direction at every 10 s of inflation. Additionally, the root mean square amplitude (rmsA) of the ST-segment was computed.

RESULTS

94 patients were included. At start inflation, the median Δangle was 14.7° [7.5-33.4], 21.8° [11.4-34.2], 20.6° [8.0-43.9], and 23.5° [11.8-48.0] for the initial QRS-complex, terminal QRS-complex, ST-segment and T-wave, respectively. Meanwhile, the median rmsA increased from 0.039 mV [0.027-0.058] at baseline to 0.045 mV [0.033-0.075] at start of inflation.

CONCLUSIONS

CineECG was able to detect immediate changes in ventricular electrical activity during induced ischemia, while changes in the ST-segment of the ECG were still subtle. Therefore, CineECG might support the early detection of acute ischemia, even before distinct ECG changes become visible.

Modeling ventricular repolarization gradients in normal cases using the equivalent dipole layer

Background Electrical activity underlying the T-wave is less well understood than the QRS-complex. This study investigated the relationship between normal T-wave morphology and the underlying ventricular repolarization gradients using the equivalent dipole layer (EDL). Methods Body-surface-potential-maps (BSPM, 67‑leads) were obtained in nine normal cases. Subject specific MRI-based anatomical heart/torso-models with electrode positions were created. The boundary element method was used to account for the volume conductor effects. To simulate the measured T-waves, the EDL was used to apply different ventricular repolarization gradients: a) transmural, b) interventricular c) apico-basal and d) all three gradients (a-c) combined. The combined gradient (d) was optimized using an inverse procedure (Levenberg-Marquardt). Correspondence between simulated and measured T-waves was assessed using correlation coefficient (CC) and relative difference (RD). Results Realistic T-waves were simulated if repolarization times of: (a) the epicardium were smaller than the endocardium; (b) the left ventricle were smaller than the right ventricle and (c) the apex increased towards the base. The apico-basal gradient resulted in the highest correspondence between measured and simulated T-waves (CC = 0.84(0.81-0.91);RD = 0.68(0.60-0.71)) compared to a transmural gradient (CC = 0.77(0.71-0.80);RD = 1.46(0.82-1.75)) and an interventricular gradient (CC = 0.71(0.67-0.80);RD = 0.85(0.75-0.87)). All three gradients combined further improved the correspondence between measured and simulated T-waves (CC = 0.83(0.82-0.89);RD = 0.60(0.51-0.63)), especially after optimization (CC = 0.96(0.94-0.98);RD = 0.27(0.22-0.34)). Conclusion The application of all repolarization gradients combined resulted in the largest agreement between simulated and measured T-waves, followed by the apico-basal repolarization gradient. With these findings, we will optimize our EDL-based inverse procedure to assess repolarization abnormalities.

Novel CineECG to identify disease onset and progression in pathogenic plakophilin-2 mutation carriers

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Dutch Heart Foundation

Introduction

Arrhythmogenic cardiomyopathy (ACM) is a heterogeneous progressive disease. Identification of patients at risk for malignant ventricular arrhythmias is challenging, making extensive cardiac follow-up necessary. CineECG provides insight in the average cardiac pathway of cardiac electrical activity. In previous studies, CineECG proved useful to detect disease progression.

Objective

Evaluate the applicability of CineECG to monitor disease progression in plakophilin-2 (PKP2) pathogenic mutation carriers.

Methods

To compute the CineECG, a 3D heart/torso model and 12 lead ECG is used. From 68 PKP2 pathogenic mutation carriers, all raw ECGs were extracted from the patient database. In pathogenic mutation carriers with definite ACM, the ECG ±2 years before (ECG1), at (ECG2) and ±2 years after (ECG3) diagnosis were selected. In pathogenic mutation carriers without definite ACM, the most recent ECG (ECG2) and the ECG ±2 years before (ECG1) were selected. CineECGs were computed for the QRS complex and the distance between CineECG location at end QRS was determined per subject for subsequent CineECGs.

Results

In 53 pathogenic mutation carriers ≥2 ECGs were available. 33 pathogenic mutation carriers were diagnosed with definite ACM of whom 4 had an ECG before, at and after diagnosis. Average distance between CineECG location at end QRS was 7.8±6.8 mm. In pathogenic mutation carriers with definite ACM, CineECG before and at diagnosis (figure, example 1&2) were different whereas CineECG at and after diagnosis did not always change. In pathogenic mutation carriers without definite ACM, in 14/19 changes in CineECG were observed (figure, example 3), whereas in the others (figure, example 4) not.

Conclusion

Our preliminary results show that CineECG provides additional insight in the changes of cardiac activation in ACM patients and may enable detection of disease progression. Further analysis will also include cardiac repolarization.

Endocardial and epicardial ECG imaging during sinus rhythm to detect local conduction delay in arrhythmogenic cardiomyopathy

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Dutch Heart Foundation

Introduction

We recently optimized our ECG imaging (ECGi) method for the estimation of endo- and epicardial activation during sinus rhythm. In patients with arrhythmogenic cardiomyopathy, late gadolinium enhancement (LGE)-CMR can identify regional myocardial injury and the combination of structural and electrical information may provide valuable insight in disease progression and risk stratification. However, the effect of structural disease and local conduction delay on the ECGi estimation of ventricular activation has not been studied.

Purpose

Evaluate the relation between LGE-CMR and non-invasively estimated local conduction velocity (CV).

Methods

8 pathogenic mutation carriers (PKP2/PLN) underwent LGE-CMR for clinical follow up and 67 lead body surface mapping. Subject specific triangulated surface heart/torso/lung meshes were created. ECGi activation sequences were used to determine local CV with the triangulation method. The LGE location was identified according to the AHA 17 segment model. Per segment, variation in CV was computed and local activation timing maps and CV maps were constructed.

Results

Isochronal crowding was observed in subjects in segments with LGE (figure, red boxes) and locally, conduction velocity decreased. Variation in conduction velocity per segment in subjects with extensive LGE presence (>9 segments) was higher 0.031±0.018 vs. 0.026±0.013 m/s/cm2 in subjects without.

Conclusion

Our preliminary results indicate the ability of the ECGi method to identify regions with higher variation in local CV. This increase in CV variability might be used to assess the vulnerability to cardiac arrhythmia. Analysis will be extended towards the RV and subsequently, more subjects will be included.

Change in QRS area by cardiac resynchronization therapy is associated with clinical outcomes and echocardiographic response

Background

Cardiac Resynchronization Therapy (CRT) is the cornerstone of treatment in patients with dyssynchronous heart failure. Recently, baseline QRS area proved to predict outcomes after CRT better than QRS duration and morphology.

Purpose

It was the aim of the study to investigate whether the change in QRS area (ΔQRS area) by CRT-pacing further improves the prediction of CRT outcomes.

Methods

We conducted a retrospective analysis on 1,299 patients, who were included in a CRT-registry from three Dutch University hospitals with both pre- (baseline) and post-implantation 12-lead ECGs. ΔQRS area and ΔQRS duration were defined as the decrease in their respective values after CRT. Optimal cut offs for ΔQRS area and ΔQRS duration by means of Youden indices were found at 62μVs and −11ms, respectively. Primary endpoint was a combination of all-cause mortality, heart transplantation, and left ventricular assist device implantation. Secondary endpoint was the relative reduction in left ventricular end-systolic volume (LVESV), and echocardiographic response being defined as ≥15% LVESV reduction.

Results

The primary endpoint occurred in 408 patients (31%). ΔQRS area was superior to ΔQRS duration for the primary and secondary endpoints. Primary endpoint analysis showed a lower risk in the ΔQRS area ≥62μVs than in the <62μVs group (HR 0.43; 0.33–0.56, p<0.001). In the multivariable analysis, both baseline QRS area and ΔQRS area remained significantly associated with both primary and secondary endpoints. Clinical outcome (left panel of figure) and echocardiographic response (right panel) were significantly worse in patients with baseline QRS area <109μVs (group 3) than in those with QRS area ≥109μVs. Within the latter group, outcomes were significantly better in patients with ΔQRS area ≥62μVs (group 1) as compared to ΔQRS area <62μVs (group 2) (figure). Baseline QRS duration and ΔQRS duration were not independently associated with both clinical outcome and echocardiographic response.

Conclusion

The combination of baseline QRS area and ΔQRS area has a stronger association with CRT response than baseline QRS area alone, and (Δ)QRS duration. These results suggest that especially in patients with a good electrical substrate (large baseline QRS area) it is worthwhile to adjust CRT to achieve the largest decrease in QRS area.

Funding Acknowledgement

Type of funding source: None

The AirSeal® insufflation device can entrain room air during routine operation

Background

Surgical procedures that use insufflation carry a risk of gas embolism, which is considered relatively harmless because of the high solubility of carbon dioxide. However, an in vitro study suggested that valveless insufflation devices may entrain non-medical room air into the surgical cavity. Our aim was to verify if this occurs in actual surgical procedures.

Methods

The oxygen percentage in the pneumoperitoneum or pneumorectum/pneumopelvis of eight patients operated with use of the AirSeal® was continuously measured, to determine the percentage of air in the total volume of the surgical cavity.

Results

Basal air percentage in the surgical cavity was 0–5%. During suctioning from the operative field air percentage increased to 45–65%.

Conclusions

The AirSeal® valveless insufflation device maintains optimal distension of the surgical cavity not only by insufflating carbon dioxide, but also by entraining room air, especially during suctioning from the operative field. This may theoretically lead to air embolism in patients operated on with this device.

P566Activated amyloid-beta pathways in patients with atrial fibrillation and heart failure, a pathway analysis in BIOSTAT

Funding Acknowledgements

European Commission [FP7-242209-BIOSTAT-CHF], European Union’s Horizon 2020 under the Marie Skłodowska-Curie grant agreement No 754425

Background. Atrial fibrillation (AF) and heart failure (HF) are two growing epidemics that frequently co-exist, share clinical risk factors, and predispose to each other. There is limited understanding of the underlying pathophysiology of the combination of both conditions.

Purpose. To perform pathway analyses of circulating plasma proteins and evaluate whether patients with both HF and AF have different activated pathways compared to those with HF without AF.

Methods. We performed pathway overrepresentation analyses of differentially expressed plasma proteins in HF, with reduced (HFrEF) and preserved (HFpEF) ejection fraction, with AF versus sinus rhythm on ECG at enrolment in BIOSTAT-CHF, using 92 cardiovascular biomarkers. Pathway analyses were performed based on existing knowledge using Gene Ontology, REACTOME, and KEGG, to study underlying activated biological pathways. Resulting pathways were corrected by Bonferroni method.

Results. We studied 2,839 patients with HF irrespective of their ejection fraction of whom 1,116 (39%) had AF and 1,723 (61%) were in sinus rhythm. HF patients with AF were older (76 ± 10 vs. 70 ± 12, p < 0.001), were less women (28% vs. 34%, p < 0.001), had history of stroke (16% vs. 10%, p < 0.001), renal disease (39% vs. 31%, p < 0.001) and less history of coronary artery disease (40% vs. 53%, p < 0.001). There were no significant differences in patients with hypertension (62% vs. 60 %, p = 0.22), diabetes (32% vs. 31%, p = 0.51) and COPD (18% vs. 16%, p = 0.20). A total of 1,661 (59%) had HFrEF and 432 (15%) had HFpEF. Pathway overrepresentation analyses revealed three amyloid-related pathways statically significant in  total HF group, and in HFrEF and HFpEF respectively, with AF compared with those in sinus rhythm: amyloid-beta formation (p < 4.0E-4, p < 7.4E-6), amyloid-beta metabolic process (p < 1.0E-3, p < 1.9E-5), and amyloid precursor protein catabolic process (p < 9.1E-4, p < 1.6E-5). The key proteins related to these processes were spondin-1 (SPON-1), insulin-like growth factor binding protein 1 (IGFBP-1) and 7 (IGFBP-7). After adjusting for sex and age and correcting for multiple testing with fall discovery rate (FDR), SPON-1 (FDR < 6.3E-6), IGFBP-1 (FDR < 6.6E-3) and IGFBP-7 (FDR < 2.5E-9) remained statically significant in HFrEF patients with AF vs. sinus rhythm; whereas only SPON-1 (FDR < 7.3 E-3) and IGFBP-7 (FDR < 1.9E-3) remained in HFpEF patients with AF vs. sinus rhythm.

Conclusion. Pathway analyses revealed activation of amyloid-beta pathways in HF patients with AF versus sinus rhythm with SPON-1, IGFBP-1 and IGFBP-7 overrepresented proteins. Amyloid-beta pathways may play a role in the pathophysiology of the combination of HF and AF, which needs to be replicated and validated in additional cohorts. 

Figure. Pathway analysis of activated proteins in patients with HF, HFrEF (A) and HFpEF (B) and AF versus sinus rhythm. Proteins are represented as dots and pathways as circumferences.

Abstract Figure. Pathway overrepresentation analysis

[Cardiac resynchronization therapy: who is a candidate and who is not?]

- Cardiac resynchronisation therapy (CRT) is a treatment for patients with impaired cardiac pump function (left ventricular ejection fraction ≤ 35%) and a wide QRS complex who, despite maximum tolerated medical therapy, remain symptomatic.- In addition to reducing symptoms, CRT can reduce hospital admissions and improve survival.- Selection of patients for CRT remains difficult. Despite the fact that predicting and influencing success of CRT has improved, ~30% of patients do not respond to the therapy.- Optimizing therapy and follow-up of patients after implantation requires a multidisciplinary approach tailored to the individual patient.- Cardiac rehabilitation with life style advices and structured exercise training maximizes patient benefit from CRT.