BACKGROUND:Genetic variants in TNNI3K (troponin-I interacting kinase) have previously been associated with dilated cardiomyopathy (DCM), cardiac conduction disease, and supraventricular... Show moreBACKGROUND:Genetic variants in TNNI3K (troponin-I interacting kinase) have previously been associated with dilated cardiomyopathy (DCM), cardiac conduction disease, and supraventricular tachycardias. However, the link between TNNI3K variants and these cardiac phenotypes shows a lack of consensus concerning phenotype and protein function. METHODS:We describe a systematic retrospective study of a cohort of patients undergoing genetic testing for cardiac arrhythmias and cardiomyopathy including TNNI3K. We further performed burden testing of TNNI3K in the UK Biobank. For 2 novel TNNI3K variants, we tested cosegregation. TNNI3K kinase function was estimated by TNNI3K autophosphorylation assays. RESULTS:We demonstrate enrichment of rare coding TNNI3K variants in DCM patients in the Amsterdam cohort. In the UK Biobank, we observed an association between TNNI3K missense (but not loss-of-function) variants and DCM and atrial fibrillation. Furthermore, we demonstrate genetic segregation for 2 rare variants, TNNI3K-p.Ile512Thr and TNNI3K-p.His592Tyr, with phenotypes consisting of DCM, cardiac conduction disease, and supraventricular tachycardia, together with increased autophosphorylation. In contrast, TNNI3K-p.Arg556_Asn590del, a likely benign variant, demonstrated depleted autophosphorylation. CONCLUSIONS:Our findings demonstrate an increased burden of rare coding TNNI3K variants in cardiac patients with DCM. Furthermore, we present 2 novel likely pathogenic TNNI3K variants with increased autophosphorylation, suggesting that enhanced autophosphorylation is likely to drive pathogenicity. Show less
Kimura, Y.; Riva, M. de; Ebert, M.; Glashan, C.; Wijnmaalen, A.P.; Piers, S.R.; ... ; Zeppenfeld, K. 2023
Background: In dilated cardiomyopathy (DCM), outcome after catheter ablation of ventricular tachycardia (VT) is modest, compared with ischemic heart disease (IHD). Pleomorphic VT (PL-VT) has been... Show moreBackground: In dilated cardiomyopathy (DCM), outcome after catheter ablation of ventricular tachycardia (VT) is modest, compared with ischemic heart disease (IHD). Pleomorphic VT (PL-VT) has been associated with fibrotic remodeling and end-stage heart failure in IHD. The prognostic role of PL-VT in DCM is unknown. Methods: Consecutive IHD (2009-2016) or DCM (2008-2018) patients undergoing ablation for monomorphic VT were included. PL-VT was defined as >= 1 spontaneous change of the 12-lead VT-morphology during the same induced VT episode. Patients were followed for VT recurrence and mortality. Results: A total of 247 patients (86% men; 6313 years; IHD n=152; DCM n=95) underwent ablation for monomorphic VT. PL-VT was observed in 22 and 29 patients with IHD and DCM, respectively (14% versus 31%, P=0.003). In IHD, PL-VT was associated with lower LVEF (28 +/- 9% versus 34 +/- 12%, P=0.02) and only observed in those with LVEF<40%. In contrast, in DCM, PL-VT was not related to LVEF and induced in 27% of patients with LVEF>40%. During a median follow-up of 30 months, 79 (32%) patients died (IHD 48; DCM 31; P=0.88) and 120 (49%) had VT recurrence (IHD 59; DCM 61; P<0.001). PL-VT was associated with mortality in IHD but not in DCM. In IHD, VT recurrence was independently associated with LVEF, number of induced VTs, and procedural noncomplete success. Of note, in DCM, PL-VT (HR, 2.62 [95% CI, 1.47-4.69]), pathogenic mutation (HR, 2.13 [95% CI, 1.16-3.91]), and anteroseptal VT substrate (HR, 1.75 [95% CI, 1.00-3.07]) independently predicted VT recurrence. Conclusions: In IHD, PL-VT was associated with low LVEF and mortality. In DCM, PL-VT was not associated with mortality but a predictor of VT recurrence independent from LVEF. PL-VT in DCM may indicate a specific arrhythmic substrate difficult to control by current ablation techniques. Show less
BACKGROUND Nonischemic cardiomyopathy patients referred for catheter ablation of ventricular arrhythmias (VAs) typically have either inferolateral (ILS) or anteroseptal (ASS) VA substrate locations... Show moreBACKGROUND Nonischemic cardiomyopathy patients referred for catheter ablation of ventricular arrhythmias (VAs) typically have either inferolateral (ILS) or anteroseptal (ASS) VA substrate locations, with poorer outcomes for ASS. Sympathetic denervation is an important determinant of arrhythmogenicity. Its relation to nonischemic fibrosis in general and to the different VA substrates is unknown.OBJECTIVES This study sought to evaluate the association between VA substrates, myocardial fibrosis, and sympa-thetic denervation. METHODS Thirty-five patients from the Leiden Nonischemic Cardiomyopathy Study, who underwent electroanatomic voltage mapping and iodine-123 metaiodobenzylguanidine imaging between 2011 and 2018 were included. Late gadolinium-enhanced cardiac magnetic resonance data were collected when available. The relation between global cardiac sympathetic innervation and area-weighted unipolar voltage (UV) as a surrogate for diffuse fibrosis was evalu-ated. For regional analysis, patients were categorized as ASS or ILS. The distribution of low UV, sympathetic denervation, and late gadolinium enhancement (LGE) scar were compared using the 17-segment model.RESULTS Median area-weighted UV was 12.3 mV in patients with normal sympathetic innervation and 8.7 mV in patients with sympathetic denervation. Global sympathetic denervation correlated with diffuse myocardial fibrosis (R = 0.53; P = 0.02). ILS (n = 13) matched with low UV, sympathetic denervation, and LGE scar in all patients, whereas ASS (n = 11) matched with low UV in all patients, with LGE scar in 63% (P = 0.20), but with sympathetic denervation in only 27% of patients (P = 0.0002).CONCLUSIONS Global cardiac sympathetic denervation is related to fibrosis in nonischemic cardiomyopathy patients with VA. The mismatch between regional fibrosis and preserved innervation for ASS may contribute to a VA substrate difficult to control by catheter ablation. (J Am Coll Cardiol EP 2022;8:1234-1245)(c) 2022 by the American College of Cardiology Foundation. Show less
Ebert, M.; Wijnmaalen, A.P.; Riva, M. de; Trines, S.A.; Androulakis, A.F.A.; Glashan, C.A.; ... ; Zeppenfeld, K. 2020
OBJECTIVES This study aimed to assess the frequency of (likely) pathogenic variants (LP/Pv) among dilated cardiomyopathy (DCM) ventricular tachycardia (VT) patients referred for CA and their impact... Show moreOBJECTIVES This study aimed to assess the frequency of (likely) pathogenic variants (LP/Pv) among dilated cardiomyopathy (DCM) ventricular tachycardia (VT) patients referred for CA and their impact on procedural outcome and long-term prognosis.BACKGROUND The prevalence of genetic variants associated with monomorphic VT among DCM is unknown.METHODS Ninety-eight consecutive patients (age 56 +/- 15 years; 84% men, left ventricular ejection fraction [LVEF] 39 12%) referred for DCM-VT ablation were included. Patients underwent electroanatomical mapping and testing of >= 55 cardiomyopathy-related genes. Mapping data were analyzed for low-voltage areas and abnormal potentials. LP/Pv-positive (LP/Pv+) patients were compared with LP/Pv-negative (LP/Pv-) patients and followed for VT recurrence and mortality.RESULTS In 37 (38%) patients, LP/Pv were identified, most frequently LMNA (n = 11 of 37, [30%]), 17N (n = 6 of 37, [16%]), PLN (n = 6 of 37, [16%]), SCN5A (n = 3 of 37, [8%]), RBM20 (n = 2 of 37, [5%]) and DSP (n = 2 of 37, [5%]). LP/Pv+ carriers had tower LVEF (35 + 13% vs. LP/Pv-: 42 11%; p 0.005) and were less often men (n 27 [73%] vs. n 55 [90%] p 0.03). After a median follow-up of 2.4 years (interquartile range: 0.9 to 4.4 years), 63 (64%) patients had VT recurrence (LP/Pv+: 30 of 37 [81%] vs. LP/Pv-: 33 of 61 [54%]; p = 0.007). Twenty-eight patients (29%) died (LP/Pv +: 19 of 37 [51%] vs. LP/Pv-: 9 of 61 [15%]; p < 0.001). The cumulative 2-year VT-free survival was 41% in the total cohort (LP/Pv+: 16% vs. LP/Pv-: 54%; p 0.001). The presence of LP/Pv (hazard ratio: 1.9; 95% confidence interval: 1.1 to 3.4; p = 0.02) and unipolar low-voltage area size/cm(2) increase (hazard ratio: 2.5; 95% confidence interval: 1.6 to 4.0; p < 0.001) were associated with a decreased 2-year VT-free survival.CONCLUSIONS In patients with DCM-VT, a genetic cause is frequently identified. LP/Pv+ patients have a tower LVEF and more extensive VT substrates, which, in combination with disease progression, may contribute to the poor prognosis. Genetic testing in patients with DCM-VT should therefore be recommended. (C) 2020 by the American College of Cardiology Foundation. Show less
Dilated cardiomyopathy (DCM) is defined by the presence of left ventricular or biventricular dilatation and systolic dysfunction in the absence of abnormal loading conditions or coronary artery... Show moreDilated cardiomyopathy (DCM) is defined by the presence of left ventricular or biventricular dilatation and systolic dysfunction in the absence of abnormal loading conditions or coronary artery disease sufficient to explain these changes. This is a heterogeneous disease frequently having a genetic background. Imaging is important for the diagnosis, the prognostic assessment and for guiding therapy. A multimodality imaging approach provides a comprehensive evaluation of all the issues related to this disease. The present document aims to provide recommendations for the use of multimodality imaging according to the clinical question. Selection of one or another imaging technique should be based on the clinical condition and context. Techniques are presented with the aim to underscore what is 'clinically relevant' and what are the tools that 'can be used'. There remain some gaps in evidence on the impact of multimodality imaging on the management and the treatment of DCM patients where ongoing research is important. Show less
Bijl, P. van der; Bootsma, M.; Hiemstra, Y.L.; Marsan, N.A.; Bax, J.J.; Delgado, V. 2019
Aims Genetic, dilated cardiomyopathy (DCM) can be caused by a large variety of mutations. Mutation carriers are often asymptomatic until DCM is well established, presenting with heart failure,... Show moreAims Genetic, dilated cardiomyopathy (DCM) can be caused by a large variety of mutations. Mutation carriers are often asymptomatic until DCM is well established, presenting with heart failure, arrhythmias, or sudden cardiac death. Preventive strategies can only be applied if DCM can be detected early. Echocardiographic, left ventricular (LV) global longitudinal strain (GLS) is a promising tool for early diagnosis, i.e. before a decrease in LV ejection fraction (EF) has occurred. We, therefore, investigated the role of LV GLS as an early disease marker in genetic DCM.Methods and results Genetic DCM patients and genotyped family members were evaluated. The study population was grouped as (i) genotype-positive, phenotype-positive (GPFP) patients with a pathogenic mutation and LVEF <55% (ii) genotype-positive, phenotype-negative (GPFN) individuals with a pathogenic mutation and LVEF >= 55%, and (iii) genotype-negative, phenotype-negative (GNFN) individuals without a pathogenic mutation and LVEF >= 55%. One hundred and fifteen individuals (53 +/- 15 years, 51% male) were analysed: 28 (24%) were classified as GNFN, 50 (44%) as GPFN, and 37 (32%) as GPFP. Various mutations were represented: 39 (34%) titin, 14 (12%) lamin A/C, 13 (11%) sarcomeric, and 21 (18%) less frequent mutations (grouped together). The mean LVEF was 58 +/- 14% for all subjects. The mean LV GLS in the GNFN group was -21.7 +/- 1.5% vs. -19.7 +/- 3.5% for the GPFN group (P = 0.036). The mean LV GLS was -12.9 +/- 4.3% for the GPFP category (P < 0.001 vs. GPFN and GNFN).Conclusion Decreased LV GLS discriminates GPFN individuals from normal controls, which may permit early institution of therapy for genetic DCM. Show less
