Myocardial scarring and recurrence of ventricular arrhythmia in patients surviving a ventricular fibrillation out of hospital cardiac arrest

Introduction

Prediction of ventricular arrhythmia recurrence in survivors of ventricular fibrillation out of hospital cardiac arrest (VF-OHCA) is important, but currently difficult. Risk of recurrence may be related to presence of myocardial scarring and dedicated late gadolinium enhancement cardiac magnetic resonance (LGE-CMR) software allows for characterization of left ventricular scarring, including differentiation between core, border zone (BZ) and BZ channels that represent potential electrical circuits of slow conductivity responsible for ventricular arrhythmic events.

Purpose

Our study aims to characterize myocardial scarring as defined by LGE-CMR in survivors of a VF-OCHA and investigate its potential role for the risk of new ventricular arrhythmia.

Methods

Between 2018 and 2021, a total of 130 VF-OHCA patients had CMR, of which we included 28 patients with LGE-CMR before ICD implantation for secondary prevention. A total of 15 (54%) patients had signs of acute or chronic ischemic heart disease (IHD); and 13 (46%) patients had arrhythmogenic cardiomyopathy (ACM). Scar tissue including core, BZ and BZ channels were automatically detected by specialized investigational software. To differentiate BZ from healthy tissue and BZ from core, thresholds of 40% ± 5% and 60% ± 5% of the maximum signal intensity were applied. A BZ channel in the LGE-CMR reconstruction was defined as a continuous corridor of BZ between 2 core areas or between a core area and a valve annulus (Figure 1A+B).

Results

The median age was 56 years; 86% were men and the median left ventricular ejection fraction was 50±11%. A total of 16 (57%) patients had an inferior scar on LGE-CMR, and 8 (29%) patients with IHD were incompletely revascularized. After a median follow-up of 98 days, 9 (32%) patients (6/9 with IHD, including 5/6 incompletely revascularized; 3/9 with ACM) had recurrence of ventricular arrhythmia (6/9 monomorphic ventricular tachycardia (VT)). A significantly higher number of patients with BZ channels had recurrence of ventricular arrhythmia compared with patients without BZ channels (7/11 vs. 2/17; P=0.01) (Figure 2). The number of BZ channels (3±1 vs. 2±1; P=0.13); scar mass (21±8g vs. 14±11g; P=0.21); core mass (7±4g vs. 4±5g; P=0.14); and BZ mass (11±5g vs. 9±7g; P=0.42) were insignificantly higher in patients with recurrent ventricular arrhythmia compared with patients without.

Conclusion

Borderzone channels analyzed by LGE-CMR were associated with subsequent recurrence of ventricular arrhythmia in patients with out of hospital cardiac arrest caused by ventricular fibrillation.

Funding Acknowledgement

Type of funding sources: None.

Scar related border zone channels assessed with cardiac MRI are associated with ventricular arrhythmia in patients with ST-segment elevation myocardial infarction

Funding Acknowledgements

Type of funding sources: None.

Introduction

Prediction of scar-related ventricular arrhythmia in ST-Segment Elevation Myocardial Infarction (STEMI) is important, but currently difficult. Late gadolinium enhancement cardiac magnetic resonance (LGE-CMR) permits characterization of left ventricular (LV) ischemic scars, including differentiation between core, border zone (BZ) and BZ channels. The latter represents potential electrical circuits of slow conductivity responsible for ventricular arrhythmic events. We hypothesized that detailed BZ channel characterization potentially serves as a risk marker for ventricular arrhythmia, therefore contributing to risk stratification following STEMI.

Purpose

The aim of this study was to assess scar-related arrhythmic BZ channels with advanced CMR in STEMI patients developing subsequent ventricular arrhythmia compared with controls.

Methods

This is a CMR sub-study of the DANAMI-3 STEMI multicenter trial (year 2011, n=1234) and Danegaptide phase II proof-of-concept clinical trial (year 2013, n=591). All patients were admitted for primary PCI in all primary PCI centers in Denmark. A total of 779 patients had a 3-month follow-up CMR. Of these, 21 patients subsequently experienced ventricular arrhythmia during 68 months of follow-up and were randomly matched 1:2 with 42 controls, who constituted the study population. Matching were based on left ventricular ejection fraction (LVEF), infarct location, culprit vessel, and revascularization status in patients with multivessel disease. Ischemic scar tissue including core, BZ and BZ channels were automatically detected by a specialized investigational software (1). To differentiate BZ from healthy tissue and BZ from core, thresholds of 40% ± 5% and 60% ± 5% of the maximum signal intensity were applied. A BZ channel in the LGE-CMR reconstruction was defined as a continuous corridor of BZ between 2 core areas or between a core area and a valve annulus (Figure 1).

Results

We included 63 patients (median age: 58.0 years; 84% men; median LVEF: 45 ± 10%), of whom 30 (48%) patients had an anterior located infarction, and 45 (71%) patients were completely revascularized. The median time from STEMI to a ventricular arrhythmic event was 3 ± 2 years. A significantly higher number of patients with ventricular arrhythmia had BZ channels (n=16 (76%) vs. n=18 (43%), P=0.02) including an increased number of BZ channels (2 ± 2 vs. 1 ± 1, P=0.02) compared with controls. Patients with subsequent ventricular arrhythmia had a larger scar mass (core mass + BZ mass) (27 ± 17g vs. 19 ± 11g; P=0.03), core mass (9 ± 8g vs. 6 ± 5g; P=0.06) and BZ mass (18 ± 10g vs. 13 ± 7g; P=0.01).

Conclusion(s)

Border zone channels visualized by LGE-CMR were associated with subsequent development of ventricular arrhythmia in patients with STEMI and may serve as risk stratification following STEMI.

Left atrial remodeling and cerebrovascular disease assessed by magnetic resonance imaging in patients undergoing continuous heart rhythm monitoring

Background

Atrial remodeling and atrial fibrillation (AF) have both been associated with cerebrovascular lesions. We wished to investigate the possible direct association between atrial remodeling and cerebrovascular disease including white matter lesions and lacunar infarcts in patients with and without atrial fibrillation (AF) as documented by implantable loop recorder (ILR).

Methods

Cardiac and cerebral MRI scans were acquired in a cross-sectional study including participants ≥70 years of age with stroke risk factors (history of hypertension, diabetes mellitus, congestive heart failure and/or previous stroke) but without known AF. Cerebrovascular disease was visually rated using the Fazekas scale and number of lacunar strokes. Left atrial (LA) (see figure) and ventricular volumes and function were analyzed, and associations between atrial remodeling and cerebrovascular disease were assessed with logistic regression models. Multivariable models were adjusted for sex, age, diabetes, hypertension, heart failure and history of stroke/transient ischemic attack. The analyses were stratified according to sinus rhythm or any AF during three months of continuous ILR monitoring to account for subclinical AF.

Results

Of 200 participants investigated, 87% had a Fazekas score≥1 and 45% had ≥1 lacunar infarct. Within three months of ILR implantation, AF was detected in 28 (14%) participants, while 172 (86%) had sinus rhythm only. Results are summarized in table. For participants with sinus rhythm, lower LA passive emptying fraction was associated with Fazekas score after multivariable adjustment, while LA total emptying fraction was borderline significant, and increased LA maximum and minimum volumes were associated with lacunar infarcts. There were no significant associations in patients with AF.

Sensitivity analyses showed similar results with longer screening periods for AF.

Conclusions

In patients free from AF as documented by ILR monitoring, we found an independent association between LA passive emptying and Fazekas score, and between atrial volumes and lacunar infarcts. This supports that atrial remodeling alone without AF is associated with an increased risk of cerebrovascular lesions.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): The Innovation Fund, DenmarkThe Research Foundation for the Capital Region of Denmark

Left atrial late gadolinium enhancement is associated with atrial fibrillation as detected by continuous monitoring

Background

Left atrial late gadolinium enhancement (LA LGE) measured with cardiac magnetic resonance (CMR) imaging is emerging as a marker of atrial fibrosis and has been associated with worse outcomes in AF ablation procedures. However, the prognostic value of LA LGE for incident AF remains unknown.

Methods

CMR including measurement of left ventricular (LV) and LA volumes and function, as well as LV extracellular volume fraction and LA LGE, was acquired in 68 patients aged at least 70 years with risk factors for stroke. All included patients received and implantable loop recorder and were continuously monitored for previously unknown AF. Incident AF was adjudicated by senior cardiologists.

Results

Patients were monitored for AF with implantable loop recorder during a median of 41 [36; 43] months. AF episodes lasting ≥6 minutes were detected in 32 patients (47%) and 16 patients (24%) experienced AF episodes lasting ≥5.5-hour. In Cox regression analyses adjusted for sex, age and comorbidities, we found that LA volumes and function and LA LGE were independently associated with incident AF. For LA LGE, the hazard ratio for time to AF episodes lasting ≥6 minutes and ≥5.5 hours were 1.40 (1.03, 1.89) per 10 cm2 increase (p=0.03) and 1.63 (1.11, 2.40) per 10 cm2 increase (p=0.01), respectively. LA LGE was significantly associated with high burden of AF. The addition of LA LGE to a multivariable risk prediction model for incident AF significantly increased the predictive value.

Conclusions

Extent of LA fibrosis measured by LA LGE was significantly associated with incident AF detected by implantable loop recorder.

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): The Innovation Fund Denmark, The Research Foundation for the Capital Region of Denmark [no grant number]

P3096The cardioprotective effect of FFR-significant multivessel disease detected by cardiac magnetic resonance imaging in patients following ST-segment elevation myocardial infarction. Results from DANAMI3

Background

In patients with ST-segment elevation myocardial infarction (STEMI) treated with primary percutaneous coronary intervention (PCI), reperfusion injury accounts for a significant part of the final infarct size, which is directly related to patient prognosis. In animal studies brief periods of ischemia in non-infarct related coronary arteries protects the myocardium via remote ischemic perconditioning. Fractional flow reserve (FFR) measures functional significant coronary stenosis which may offer remote ischemic perconditioning of the myocardium. It has not previously been investigated if FFR-significant stenosis in non-culprit myocardium offers cardioprotection following STEMI.

Purpose

To investigate cardioprotective effect of FFR-significant multivessel disease (MVD) on final infarct size and myocardial salvage in a large contemporary cohort of patients with ST-segment elevation myocardial infarction (STEMI).

Methods and results

We included 509 patients with STEMI from the DANAMI-3 trial, divided into three groups: 388 (76%) patients had single vessel disease (SVD), 34 (7%) had non-FFR-significant MVD and 192 (17%) had FFR-significant MVD. CMR was performed at baseline and three months after primary PCI. There was no difference in final infarct size; mean infarct size (% left ventricular mass) SVD 9±3%; non-FFR-significant MVD 9±3%; and FFR-significant MVD 9±3%, p=0.95, or in myocardial salvage index (MSI) between groups, calculated as (area-at-risk – infarct size)/area-at-risk; mean index (%) SVD 67±23%; non-FFR-significant MVD 68±19%; and FFR-significant MVD 67±21%, p=0,99. In multivariable regression analyses FFR-significant MVD was not associated med larger MSI (p=0.84) or lower infarct size (p=0.60).

Figure 1. A. Late gadolinium (LGE) cardiac magnetic resonance (CMR) image of a mid-ventricular short-axis slice. Hyperintense signals (arrow) shows contrast enhancement in the anterior-septal segments, indicating myocardial infarction (MI). B. Same patient. T2-weighted image of the same mid-ventricular short-axis slice. Hyperintense signals (arrows) shows edema in the anterior-septal segments.

Conclusions

FFR-significant functional MVD of non-culprit myocardium does not offer cardioprotection in patients following STEMI.

Risk for contralateral breast cancer among carriers of the CHEK2*1100delC mutation in the WECARE Study

The protein encoded by the CHEK2 gene is involved in cellular repair of DNA damage. The truncating mutation, CHEK2^*1100delC, seems to increase the risk for breast cancer. We investigated whether the CHEK2^*1100delC mutation carrier status increases the risk for asynchronous contralateral breast cancer (CBC) and whether it interacts with radiation therapy (RT) or chemotherapy in regard to CBC risk. The germline mutation frequency was assessed in 708 women with CBC and 1395 women with unilateral breast cancer (UBC) in the Women's Environment, Cancer and Radiation Epidemiology (WECARE) Study whose first primary breast cancer was diagnosed before age 55 years and during 1985–1999. Seven women with CBC (1.0%) and 10 women with UBC (0.7%) were CHEK2^*1100delC variant carriers (rate ratio (RR)=1.8, 95% confidence interval (CI)=0.6–5.4 for CBC vs UBC). Carriers who received RT for their first breast cancer, compared with non-carriers not treated with RT, had an RR of developing CBC of 2.6 (95% CI=0.8–8.7). We found no significant associations between the CHEK2^*1100delC mutation and CBC overall or among those treated with RT. However, the sampling variability was such that modest increases in risk could not be excluded. Nonetheless, because this is a rare mutation, it is unlikely to explain a major fraction of CBC in the population.

Dynamics of 103K/N and 184M/V HIV-1 drug resistant populations: Relative comparison in plasma virus RNA versus CD45RO+T cell proviral DNA

BACKGROUND

Viral populations defined by 103K/N and 184M/V as linked or single mutations in the HIV-1 reverse transcriptase gene were investigated in plasma samples and compared with previous findings in the CD45RO(+)T cell compartment.

OBJECTIVE

To develop an ARMS assay for plasma virions and to investigate the expression of resistance mutations (103N and 184V) and dynamic interactions between proviral DNA and plasma virions.

STUDY DESIGN

A clinical cross-sectional study, including 11 patients on lamivudine efavirenz and/or nevirapine therapy. The viral populations were determined by an assay based on real-time PCR and amplification refractory mutation system (ARMS).

RESULTS

The 103N and 184V mutations were not detected in patients with stable low viremia. Patients previously exposed to mono or dual therapy often carried minor viral populations of either one or both mutations in plasma. The viral population with linked mutations (103N and 184V) was detected in two patients after more than 2 years of non-NNRTI HAART.

CONCLUSION

The ARMS assay is useful for detecting viral quasi-species containing efavirenz and lamivudine resistant mutations in plasma virions and in proviral DNA. Data suggest an unequal distribution of linked-mutation populations in plasma and CD45RO(+)T cells. Furthermore, the linked 103N-184V mutation may be more fit than the single 184V mutation and this linked population emerges rapidly under inadequate drug pressure.