Filmin-c mutations in arrhythmogenic cardiomyopathy: a peculiar association with left dominat variant and high risk of sudden death

Introduction

Arrhythmogenic cardiomyopathy (AC) is characterized by myocyte necrosis and progressive fibro-fatty substitution. Recently, truncated mutations on Filamin C gene have been correlated with AC and a peculiar phenotype characterized by a prominent left ventricular fibrosis and high risk of sudden death.

Purpose

To evaluate clinical and instrumental features of subjects affected by AC in whom genetic study identified presence of truncating and missense mutations on FLNC gene.

Materials and methods

A population of 192 probands affected by AC according to 2010 Task Force Criteria or McKenna's proposed criteria for left dominant AC were evaluated for FLNC variants. In positive probands and families anamnestic and clinical data (ECG, echocardiographic and cardiac magnetic resonance (CMR), twenty-four-hours ECG monitoring) were evaluated.

Results

A total of 19 subjects (9 probands and 10 family members) were identified as carrier of nine different FLNC mutations (5 truncating and 4 missense). In 3 patients (23%) clinical onset was characterized by major arrhythmic episodes and in one (8%) by sudden death. In 6 (46%) ECG was unremarkable and the most common abnormalities were low QRS voltages in peripheral leads (85%), followed by T wave inversion in lateral (15%) and in inferior leads (16%). Twenty-four-hours ECG monitoring revealed a high arrhythmic burden (PVC >500/die) in 6 cases (46%). CMR was performed in all patients. Four of them (31%) showed a LV dilatation, while in 2 cases (15%) a RV dilatation was present. In 8 (61%) a fatty infiltration was detected mainly affecting the left ventricle (6 cases, 46%). Moreover, late enhancement was present in 8 cases (62%), with a LV distribution.

Conclusions

This is the first studied population in which both truncating and missense variants were evaluated as causative of AC, confirming that FLNC gene mutations are rare (4% of probands without known AC causative mutations) and the prevalent clinical expression is a left dominant phenotype with a high degree of electrical instability and recurrence of sudden familial cardiac death.

Funding Acknowledgement

Type of funding source: None

Predictors of death and heart transplantation in biopsy-proven myocarditis: a machine-learning approach

Background

Risk stratification for death and heart transplantation (HTx) in myocarditis is complex. A random forest (RF) is a tree-based machine learning technique (MLT) which is being increasingly used for clinical data analysis; it allows the detection of complex relationships between the outcome of interest and the covariates, overcoming the limits of traditional statistical analysis (i.e. regression approaches). Purpose To assess the potential role of clinical and diagnostic features at presentation as predictors of death and HTx in biopsy (Bx)-proven myocarditis using RF. Methods From January 1993 to August 2019, we consecutively enrolled 357 patients with Bx-proven myocarditis (65% male, median age 39 years, interquartile range (IQR) 26–51). An RF approach for survival data was used. Variables included in the analysis were: histology type by Bx, NYHA, type of presentation (infarct-like, arrhythmia, heart failure), viral genome detection on Bx, serum antiheart (AHA), antiintercalated disk (AIDA), anticardiac endothelial cells (AECA), antinuclear (ANA) autoantibodies, immunosuppressive therapy, cardiac catheterisation (left ventricular enddiastolic volume (LVEDV), mean capillary wedge pressure, right and left ventricular enddiastolic pressure) and 2-D echocardiographic measures (LVEDV, left ventricular ejection fraction (LVEF) at presentation and at follow-up, right ventricular fractional area change (FAC%), right ventricular diastolic area). Results The median follow-up time was of 1352 days (IQR 423.25–2535.75). At the end of follow-up, 42 patients were dead or transplanted. The 1-year, 5-year, and 10-year survival probabilities were of 0.928, 0.854, and 0.817, respectively. The most relevant predictors of death or HTx identified by the RF algorithm (according to the variable importance measure) were histological type, NYHA, clinical presentation, LVEF, and FAC%. Among the circulating auto-antibodies AECA were found to be the most important. Histological type was the strongest predictor of death/HT (100% relative importance, (RI)), giant cell myocarditis having a lower survival probability compared to other types. The next stronger predictors were advanced (III-IV) NYHA and heart failure presentation with lower survival probabilities (90% and 84% RI respectively). AECA-positive patients had lower survival probability compared to AECA negative ones (20% RI). The RF algorithm revealed an excellent predictive performance in the correct identification of all alive patients, with only 5 dead patients being misclassified (balanced accuracy 94%).

Conclusions

Autoimmune features, i.e Giant cell myocarditis and AECA, as well as severity of heart failure and of left ventricular disfunction at presentation were the strongest predictors of dismal prognosis. Our RF approach provides a new automated powerful tool for accurate risk stratification for death/HTx in Bx-proven myocarditis.

Funding Acknowledgement

Type of funding source: Public Institution(s). Main funding source(s): Budget Integrato per la Ricerca dei Dipartimenti (BIRD, year 2019), Padova University, Padova, Italy (project Title: Myocarditis: genetic background, predictors of dismal prognosis and of response to immunosuppressive therapy.)

Cardiac magnetic resonance features of left dominant arrhythmogenic cardiomyopathy: differential diagnosis with myocarditis

Objectives

To identify potential imaging features at cardiac magnetic resonance (CMR) specific for left-dominant arrhythmogenic cardiomyopathy (LDAC) diagnosis.

Materials and methods

Between January 2011 and May 2016, we considered 36 consecutive stable patients with a recent diagnosis of significant VA and ECG morphology consistent with a LV origin, detection of potential LV arrhythmic substrate at CMR, undergoing a clinically-indicated LV endomyocardial biopsy. Exclusion criteria were history of known cardiac disease, contraindications to CMR and impaired CMR image quality. After application of these criteria, in 9 patients endomyocardial biopsy showed tissue abnormalities consistent with the diagnosis of LDAC. From the same CMR-endomyocardial biopsy registry, a second group of 9 consecutive patients with a histological diagnosis of previous myocarditis were identified.

Results

Mid-wall LGE in the interventricular septum was detected in 5 myocarditis, without findings in LDAC group (p=0.03), whereas subepicardial LGE at the level of posterolateral wall of LV was detected in 8 cases of LDAC vs. 2 cases of myocarditis (p=0.02). Fat infiltration, and particularly subepicardial posterolateral fat infiltration, was found in all LDAC patients vs. one myocarditis only (p<0.01). No differences in other CMR findings or in any clinical or echocardiographic parameters were found between patients with a biopsy consistent with LDAC vs. patients in whom biopsy suggested myocarditis.

Conclusions

In patients with significant VA and ECG morphology consistent with a LV origin, identification of morpho-functional involvement of the subepicardial layer of LV posterolateral wall at CMR (LGE, fat infiltration, wall dyskinesis) is consistent with a diagnosis of LDAC.

Funding Acknowledgement

Type of funding source: None

Role of endomyocardial biopsy guided by electroanatomic voltage mapping for the diagnosis of cardiomyopathies in patients with arrhythmic presentation

Background

A myocardial substrate assessment through percutaneous endomyocardial biopsy (EMB) represents an important additional diagnostic test for cardiomyopathies when uncertainties remain after non-invasive evaluation. Yet, extensive application of EMB has been limited by the low sensitivity of biopsies. Electroanatomic voltage mapping (EVM) is a promising modality for guiding Endomyocardial biopsies (EMB).

Aim

The aim of our study is to evaluate the diagnostic yield of EVM-guided EMB and the role of histological analysis in the diagnosis of patients with suspected cardiomyopathies and arrhythmic presentation.

Methods

One-hundred and sixty-two consecutive patients undergoing EMB at our Institution from 2010 to 2019 were included. Demographics, clinical data, CMR data and peri-procedural complications were retrospectively retrieved. All procedures were guided by endo-cavitary EVM. According to non-invasive data collected before proceeding with EMB a suspected clinical diagnosis was expressed and compared to histological diagnosis

Results

One-hundred and sixty-two patients were included in the study. Mean age of the cohort resulted 40.9±14.7 years, with 26.5% of the included patients being females. ECG alterations were present in 51.3% of the population, with the most common abnormality being T wave inversion. Sustained or non-sustained ventricular tachycardia was registered in 51 (31.5%) of the patients, while 44 (27.2%) patients were referred for frequent isolated premature ventricular complex (PVC), and 19 (11.7%) after an episode of an arrhythmogenic syncope or resuscitated cardiac arrest. Suspected ARVC (41.6%) together with acute/chronic myocarditis (28.0%) were the main clinical diagnosis leading to an invasive approach. The sampling site was the right ventricle in 116 (72.5%), the left ventricle in 31 (19.4%), and both ventricles in 13 (8.1%) patients. Biopsy samplings were judged appropriate for histological analysis in 141 (87.0%) patients. Among the analyzed samples, a diagnosis was reached in 120 patients (74.1%). In the remaining 21 cases (25.9%), the analysis yielded nonspecific histologic findings, inconclusive results, or sampling error. The biopsy allowed to confirm the clinical diagnosis in 72 (60.0%) patients, while a different diagnosis was reached in 48 (39.0%) cases (Reclassification are showed Figure 1).In particular of 67 (41.6%) patients suspected for ARVC, only 32 (22.7) reached a confirmation. Conversely, the number of patients with acute/chronic myocarditis augmented from 45 (28.0%) to 47 (33.3%).

Conclusion

EMB guided by EVM reached a diagnostic yield as high as 74.1%. EMB proved to be a useful tool in the clinical management of patients, as it allowed to correctly reclassify a significant number of patients who would have been misdiagnosed based only on non-invasive assessment.

Sankey Diagram

Funding Acknowledgement

Type of funding source: None

Immunosuppression and outcomes of myocarditis patients presenting with ventricular arrhythmias

Background

Effects of immunosuppressive therapy (IST) on ventricular arrhythmias (VA) have not been reported in immune-mediated biopsy-proven myocarditis patients. Furthermore, myocarditis arrhythmic risk is still unpredictable. The aim of our study was to evaluate effectiveness of IST on VA in myocarditis patients, and stratify their arrhythmic risk, using clinical and diagnostic features, including serum organ-specific anti-heart (AHA) and antiintercalated-disk autoantibodies (AIDA).

Methods

From a cohort of 498 consecutive patients, we enrolled 255 cases with biopsy-proven virus-negative myocarditis and evidence of VA (VF, VT, NSVT, and Lown's grade ≥2 PVC) at index hospitalization. Serum AHA and AIDA were detected by a standardised indirect immunofluorescence technique. Whenever accepted and non-contraindicated, IST was started. Controls (IST-) were chosen after 1:1 matching to IST+ cases by age, gender, ethnicity, left ventricular ejection fraction, VA type, and treatment. Prospective follow-up (FU), occurred at defined timepoints.

Results

58 matched patient couples (42±13 y, 67% males, 50% IST+) were analyzed in the main study cohort. Overall, 28 (24%) had VT, and 62 (53%) were discharged with ICD. IST duration was 12±1 months. No patients died and no serious complications from IST occurred. By 24-month FU, major VA occurred in 6 IST+ vs. 10 IST- patients (p=0.420), with no cases of VT following IST termination. As compared to IST- ones, IST+ patients showed a significant reduction in NSVT and PVC burden, as well as an improvement in clinical, laboratory and imaging findings (all p<0.05). Major VA onset and positive AIDA status were independently associated with major VA at FU (HR 14.2, 95% CI 2.9–68.7, and 8.0, 95% CI 2.6–25.2, respectively, both p<0.001). Furthermore, in the whole study population (N=255), IST played as an independent protective factor from major VA (HR 0.3, 95% CI 0.2–0.7, p=0.005) at 38±21 months FU.

Conclusions

In immune-mediated virus-negative myocarditis patients presenting with VA, IST is feasible and effective on NSVT and PVC burden, as well as on structural, laboratory and imaging endpoints. Short-term effects are limited on major VA, which were independently associated with major arrhythmic onset and positive AIDA, in keeping with the proposed etiopathogenetic involvement of autoimmunity in virus-negative myocarditis.

Funding Acknowledgement

Type of funding source: None

P3684Detecting true left dominant arrhythmogenic cardiomyopathy: cardiac magnetic resonance imaging and an invasive diagnostic assessment to go beyond current diagnostic criteria

Background

Left-dominant arrhythmogenic cardiomyopathy (LDACM) represents an underdiagnosed subtype of the classical right-dominant ACM, with a fibro-fatty infiltration of the left ventricle ab disease initio. To date, ACM diagnosing criteria do not include any paradigm for LDACM and no shared consensus or position statement has been issued yet.

Purpose

To analyse the diagnostic work-up needed to reach a definite diagnosis in LDACM patients (pts).

Methods

All pts with a high clinical suspicion of ACM admitted at our institution were evaluated. Disease and familiar history, and both baseline ECG and cardiac ultrasound (US) were retrieved in all pts. Before invasive evaluation, all pts underwent cardiac magnetic resonance imaging (MRI) for morphology assessment and tissue characterization by late gadolinium enhancement (LGE). An invasive evaluation with an electrophysiological study (EPS) and an endo-cavitary electro-anatomical mapping (EAM) was then subsequently performed; EAM-guided endo-myocardial biopsy (EMB) was performed at physician discretion, for direct histological evaluation of myocardial substrate.

Results

30 ACM pts (53±6 y.o.; 66% male) were defined as LDACM; 22 (73%) pts presented unspecific ECG abnormalities, with 8 (27%) pts instead presenting negative t-waves in V4-V6. Cardiac US resulted unremarkable in 27 (90%) pts. Sustained ventricular arrhythmia with right bundle brunch block were experienced in 4 (14%) pts, while frequent premature ventricular beats with the same morphology in 10 (33%).

LDACM diagnosis was mainly suspected upon MRI evaluation: all 30 pts presented a late gadolinium enhancement (LGE) pattern revealing an isolate left ventricle fibro-fatty infiltration, with normal biventricular contractility (LV and RV ejection fraction 57±9% and 53±2%, respectively).

Right ventricular, left ventricular and biventricular endo-cavitary EAM was performed in 10 (33%), 11 (37%) and 9 (30%) pts respectively, revealing pathologically low unipolar voltages in 7 (23%) and both unipolar and bipolar low voltages in 15 (50%) pts. In 18 (60%) pts an EMB was performed, revealing in 15 (83%) a fibro-fatty infiltrate and a fibro-fatty infiltrated with a superimposed viral myocarditis in a single pt. Genetic testing was performed in 16 (53%) pts, of which 10 (33%) showed causative mutation of desmosomal genes.

If strictly adhering to the existing criteria, only 7 (23%) LDACM definite diagnosis would have been reached, even when using EMB and genetic testing.

LDACM EAM with late potentials

Conclusion

LDACM is an underestimated ACM subtype that require MRI evaluation and an invasive work-up for definite diagnosis. Although EMB and genetic testing being the most effective diagnostic tools currently at disposal adhering to existing criteria, a definite diagnosis could be reached only in a fraction of patient population. Existing diagnostic criteria should be revised, mainly to take in consideration EAM specific role and to properly define the LDACM entity.

P3682Myocardial structural abnormalities in nonischemic patients presenting with ventricular arrhythmias

Background

The diagnosis of concealed cardiomyopathies in patients with ventricular arrhythmias (VAs) is one of the major challenging issues faced by physicians.

Purpose

We aimed at reporting the cardiomyopathic substrate in patients with recurrent arrhythmias of ventricular origin.

Methods

Consecutive patients with unexplained VAs underwent a complete diagnostic work-out, including endomyocardial biopsy (EMB).

Results

Ninety-seven patients were enrolled (76.3% male, age 39.7±13.3 yrs). The presenting arrhythmic manifestation was aborted cardiac arrest in 30 (30.9%) patients, sustained ventricular tachycardia (VT) in 9 (9.3%), nonsustained VT in 15 (15.5%) and frequent premature ventricular complexes in 43 (44.3%). Overall, 350 biopsies were collected (3.6/patient). The incidence of procedure-related complications was 5.1% (n=5): 4 major complications (1 rupture of a tricuspid chorda tendinea w/o hemodynamic impairment, 1 dissection of right external iliac artery treated with stent, 1 thrombotic occlusion of left superficial femoral artery which required surgical treatment, 1 TIA) and 1 minor complication (groin hematoma) occurred. The final diagnosis was arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) (n=41; 42.3%), followed by myocarditis (n=20; 20.6%), dilated cardiomyopathy (n=6; 6.2%), cardiac sarcoidosis (n=6; 6.2%), and myocarditis in ARVD/C (n=5; 5.1%). Among the 25 patients whose final diagnosis was consistent with myocarditis, an acute stage of the disease was documented in 7 (7.2%), while a chronic myocarditis in 18 (18.5%). Additionally, according to medical history and diagnostic workout, in 2 of the 6 patients the dilated cardiomyopathy had a likely post-inflammatory etiology. Absence of myocardial abnormalities was documented in 15 (15.5%) patients: this group included 1 case of methadone-induced torsade de pointes. The remaining 4 (4.1%) patients were diagnosed with a cardiac hypertrophy (n=2, 2.1%, secondary to exercise or Fabry disease), a dilated mitochondrial cardiomyopathy (n=1, 1.0%), a dilated cardiomyopathy in Emery-Dreifuss muscular dystrophy (n=1; 1.0%).

Conclusion

In our series, approximately 45% of patients with unexplained VAs had a final diagnosis of ARVD/C.

P5557Cardiac autoantibodies and ventricular arrhythmias in patients with biopsy-proved myocarditis

Background

Cardiac autoandibodies have been associated with dilatative cardiomyopathy in subjects with inflammatory heart disease. However, their association with ventricular arrhythmias (VA) in patients with autoimmune myocardits has never been investigated so far.

Purpose

To evaluate the association between cardiac autoantibodies and both baseline and FU VA in patients with a de novo diagnosis of biopsy-proved autoimmune myocarditis.

Methods

We enrolled 44 consecutive patients (59% males, mean age 44±13y, mean LVEF 50±10%) presenting with symptomatic VA (VF, VT, NSVT, >1ehz746.0501 PVC/24h) and a de novo diagnosis of biopsy-proved autoimmune myocarditis according to the ESC criteria. Serum anti-heart (AHA) and anti-intercalated disk (AIDA) autoantibodies were assessed at a referral center at the time of the index hospitalization. Complete baseline data, including ECG, arrhythmia telemonitoring, echocardiogram, cardiac magnetic resonance (CMR) and blood biomarkers (T-troponin, NT-proBNP) were collected. The endpoint of the study was the occurrence of major VA (VT, VF, appropriate ICD shocks) at 5y FU, as assessed by 2/y Holter ECG monitoring and (when applicable) ICD interrogation.

Results

At baseline evaluation, 24 (55%) and 23 patients (52%) were AHA+ and AIDA+, respectively. Clinical onset with major VA was documented in 24 patients (55%): 9 AHA+ vs. 15 AHA- (p=0.017) and 13 AIDA+ vs. 11 AIDA- (p=0.547). At presentation, no significant differences were found between AHA+ vs. AHA- and AIDA+ vs. AIDA- patients in LVEDV, LVEF, T-troponin and NT-proBNP values (all p=n.s.). Positive (2/3) Lake Louise criteria at CMR were found in 33 patients (75%; p=n.s. among different subgroups). Before discharge, 27 subjects (61%) underwent ICD implant. Optimal medical treatment was started in all of the cases, with no significant differences in betablockers, antiarrhythmic drugs and immunsuppressive therapy, among different subgroups (all p=n.s.). Overall, 10 patients (23%) experienced major VA by 5y FU: 3 AHA+ vs. 7 AHA- (p=0.147) and 9 AIDA+ vs. 1 AIDA- (p=0.013). In particular, 18 events were documented (range 1–3 episodes per patient at 2.2±1.7 y mean FU), including 3 VT episodes and 15 appropriate ICD shocks. Taking together baseline and FU data, multiple (>1) major VA episodes occurred in 8 patients: 3 AHA+ vs. 5 AHA- (p=0.436) and 8 AIDA+ vs. 0 AIDA- (p=0.005). Of note, 3/3 AHA+ patients with multiple major VA espisodes were also AIDA+ (double positivity).

Conclusion

In biopsy-proved autoimmune myocarditis presenting with VA, major VA occurrence by 5y FU, as well as arrhythmias recurrences, are more common among AIDA+ patients. By converse, none of the isolated AHA+ cases experienced multiple episodes of major VA. These findings may suggest distinct pathophysiological mechanisms involving the different molecular targets of cardiac autoimmunity.

Acknowledgement/Funding

None

4252Additional value of stress testing for evaluation of ventricular arrhythmias in athletes undergoing preparticipation screening

Introduction

The optimal protocol of athletes pre-participation screening is a matter of debate. The aim of this study is to test the additional value of exercise testing (ET) for evaluation of ventricular arrhythmias (VA) in athletes with otherwise normal findings.

Methods

The study included 10,975 competitive athletes who underwent preparticipation screening including ECG and stress testing. Athletes with ≥3 isolated premature ventricular beats or ≥1 repetitive VA underwent second-line investigations (echocardiography and 24-hour ambulatory ECG monitoring with a training session) and, in case of frequent, complex or exercise-induced VA or echocardiographic abnormalities, also cardiac magnetic resonance (CMR).

Results

451 (4,1%) athletes were excluded for abnormalities at history, physical examination and baseline ECG. Among the remaining 10524 athletes, 524 (5%)showed VA at ET, 87 of whom underwent CMR.Echocardiography identified major cardiac abnormalities in 5 athletes and regional ventricular systolic dysfunction in 7, which were confirmed by CMR in 6. Other 12 patients with normal echocardiography had a positive CMR. In particular, in 16 subjects the CMR showed left ventricular late gadolinium enhancement suggesting myocardial fibrosis with a non-ischemic distribution. At multivariate analysis, VA observed at high work load at ET, the presence of complex VA at ET and the presence of a morphology other than infundibular or fascicular predicted an underlying pathological myocardial substrate while the presence of frequent (>500/24-hour) premature ventricular beats did not.

Predictors of underlying pathological myocardial substrate Substrate Univariate Multivariable YES (n=23) NO (n=501) OR (95% IC) P OR (95% IC) P Age 17 [13–43] 15 [14–17] 1.03 [0.98 -1.06] 0.18 – Male gender 15 (65%) 184 (37%) 3.2 [1.3–7.7] <0.001 1.6 [0.7–4.8] 0.28 >500 PVBs/24-hour 7 (30%) 98 (20%) 1.8 [0.7–4.5] 0.21 – VA at high work-load 10 (44%) 78 (16%) 4.2 [1.8–9.8] <0.001 1.6 [1.1–4.7] 0.02 Couplets/NSVT at ET 14 (61%) 117 (23%) 6.2 [2.5–15] <0.001 8.5 [2.5–29] 0.01 PVBs other than infundibular/fascicular 17 (74%) 118 (24%) 6.1 [2.4–16] <0.001 3.9 [1.4–11] 0.008

Conclusions

VA at ET may represent the only sign of a pathological myocardial abnormalities, such as the “isolated nonischemic left ventricular scar”, that could be the substrate for life-threatening ventricular arrhythmias. Addition of ET to baseline ECG may increase the sensitivity of PPE of competitive athletes.

P3687Abnormal voltage recordings in patients with ventricular arrhythmias: comparison between right and left cardiomyopathy

Background

Arrhythmogenic Cardio-Myopathy (ACM) is characterized by epi-endocardial fibro-fatty replacement. Depending on the most affected ventricle, right dominant (RDACM) or left dominant (LDACM) phenotypes can be defined. RDACM voltage mapping characteristics have already been described, with late potentials strongly correlating with arrhythmia recurrence risk; LDACM voltage features have not been described yet.

Purpose

To analyze voltage map characteristics in LDACM patients (pts) and compare them with RDACM; to assess if there is any correlation between late potentials and recurrence rate in LDACM as well.

Methods

We retrospectively enrolled all consecutive ACM patients treated c/o our center and diagnosed according to the 2010 Task Force Criteria. Procedural and follow up data were collected. Patient were sorted by ventricular involvement lateralization. Recurrence rates were evaluated and linearly regressed for the presence of late potentials.

Results

89 ACM patients were enrolled (67 RDACM, 22 LDACM; 76% males, 69±4 y.o.) in our study. All patients underwent endocardial voltage mapping; procedurally, 43 (48%) pts underwent catheter ablation, while 46 (52%) were managed conservatively with anti-arrhythmic drugs.

Bipolar pathological potentials were found in 43 (64%) and 13 (59%), unipolar pathological potentials in 45 (67%) and 14 (63%), while late potentials in 19 (31%) and 8 (36%) in the RDACM and LDACM group respectively [p = 0.66, p=0.63, and p=0.33].

The average follow-up was 18 months [14–48]; 15 (22%) in the RDACM and 9 (40%) in LDACM arrhythmic recurrences were respectively encountered; recurrences in both groups were regressed for the presence of late potentials. Results were as follows: the presence of late potentials correlated with recurrences with an 4,3 [1.15–16.1; p=0.03] OR and with an 11 [0.4–85; p=0.022] OR in the RDACM and LDACM group respectively.

Conclusion

Pathologically low unipolar, bipolar and late potentials can be found in comparable % both in RDACM and LDACM; like in RDACM, late potentials represent an important risk factor for arrhythmic recurrence in LDACM as well.

P3828Zebrafish models for arrhythmogenic cardiomyopathy type 8: a starting platform for exercise stress test and drug treatment

Background

Arrhythmogenic Cardiomyopathy (AC) is an inherited heart disease characterized by progressive substitution of the myocardium with fibro-fatty tissue, leading to electrical instability and high risk of sudden death, particularly in young subjects and athletes. In recent years, our laboratory has produced zebrafish (zf) mutant lines modelling AC type 8, an AC form linked to mutations in the junctional protein Desmoplakin (Dsp). Mutations in the DSP gene have been identified in both dominant and recessive AC cases, characterized by left-dominant and biventricular forms of the disease. Sports medicine has highlighted that they are the most dangerous forms, being less easily identifiable by ECG.

Purpose

Taking advantage of our zf Dsp mutant lines, we aim to fully characterize the pathological phenotype, analyze the perturbation of cell communication pathways, evaluate the role of the physical exercise, and test the efficacy of candidate drugs.

Methods

Among our zf lines we have identified double mutant animals, bearing both zf dspa and dspb mutations in heterozygous condition, as the best model able to recapitulate the human AC phenotype. This model underwent physical stress tests in the presence/absence of candidate drug treatment. Phenotyping included heart rhythm measurement, gene expression analysis using Real Time PCR and signaling pathway transgenes, immune-histochemistry, whole-mount in situ hybridization, standard histology and ultrastructural TEM analysis.

Results

Preliminary results from mutant phenotyping indicate alterations in heart rate, sudden cardiac death, structural alterations of the myocardium associated with junctional disorganization and, in parallel, dysregulation of Wnt, Hippo and TGFbeta pathways. Specifically, Dsp mutant animals can range from an 8% decrease to a 14% increase of heart rhythm compared to the physiological range (120–140 beats per minute in zf larvae). At the adult stage, about 1% of the fish mutant population dies suddenly. The histological examination shows a 50% reduction of the myocardial cell mass, in parallel with a 50% decrease of Dsp signal, detected by TEM, associated with the so-called “pale desmosome” phenotype. Signaling dysregulation includes an 80% loss of Wnt/Beta-catenin, a 300% increase of TGFbeta and a 500% increase of Hippo/YAP-TAZ signaling in the cardiac tissue. Physical stress tests and pathway-directed drug treatment have clarified that these factors can modulate the pathological phenotype, as preliminarily evidenced by the rescue of Wnt signal decrease to normal levels through SB216763 treatment of Dsp-deficient individuals at rest.

Conclusion

Preliminary evidences corroborate the zf organism as a suitable model for AC cellular and molecular phenotyping, exploitable for the dissection of the genetic events leading to the onset and progression of the disease, and applicable to the analysis of chemical and mechanical modulators of AC-associated features.

Acknowledgement/Funding

Cariparo 2017 SHoCD; TRANSAC; CPDA133979/13; RP-2014-ehz745.06700394

P4652Magnetic resonance and electroanatomical guided endomyocardial biopsy as a diagnostic tool in the clinician's box: a 5 year experience

Background

Percutaneous endo-myocardial biopsy (EMB) is an invasive diagnostic test used to reach or confirm a diagnosis when structural or substrate anomalies are suspected, such as in cardiomyopathies or myocarditis evaluation. In recent years, cardiac magnetic resonance imaging (MRI) and endo-cavitary electro-anatomical mapping (EAM) have been used to localize the most significant myocardial area to sample, therefore increasing EMB overall effectiveness and reliability.

Purpose

To describe and characterize safety, feasibility and anatomical findings of a large cohort of patients (pts) undergoing diagnostic EMB and to assess its impact on the treatment decision making algorithm.

Methods

A cohort of all pts undergoing a percutaneous EMB at our Institution from January 2014 to January 2019 was analyzed. All EMB procedures were guided by a pre-procedural cardiac MRI radiological alteration analysis and an endo-cavitary EAM. Intra-cardiac echography (ICE) was used in all procedures, to directly visualize the sample area and to evaluate in real time post-EBM complications. Demographics, clinical data, MRI data, pathological EMB features, and peri-procedural data were systematically retrieved.

Results

One-hundred and eleven pts were enrolled (78% male, 47±4 y.o., 33% athletes). EMB indication was abnormal MRI findings in 94 (85%), pathological EMB voltages in 10 (9%) and clinical suspect and patient history in 7 (6%) pts.

EMB sample area was determined by both MRI and EAM pathological area analysis in 92 (83%) pts, while by EAM alone in 19 (17%) pts (n=6 pathological unipolar EAM; n=13 bipolar and unipolar pathological EAM). The sample site was the right ventricle in 89 (80%), the left ventricle in 20 (18%), and both in 3 (2%) pts.

In 103 (93%) pts a concomitant electrophysiological induction study was performed (40% positive for sustained ventricular arrhythmias) and 35 (32%) pts underwent a trans-catheter ablation (TCA) (n=8 epicardial TCA; n=2 endo-epicardial TCA; n=25 endocardial ATC). Only 2 (2%) peri-procedural adverse events were witnessed, specifically femoral pseudo-aneurysms, requiring surgical repair. EMB analysis allowed to confirm 58 (52%) pre-procedural diagnosis and to reach 32 (29%) new diagnosis, while resulting inconclusive or non-specific in the diagnostic process only in 21 (19%) cases [Figure1]. A total of 33 (30%) intra-cardiac devices (ICDs) were implanted contextually in the cohort, of which 9 (8%) solely upon EMB indication; in 4 (4%) other patients, biopsy represented a strong decisional factor in the multi-modality decision process for abstaining from ICD implant.

Dashed lines: diagnosis changed upon EMB

Conclusion

MRI and EAM guided EMBs allowed to finely define a large cohort of patients by representing a disease defining parameter in over 80% of the enrolled pts while and a decision shifting parameter in ICD implant algorithm in a high % of pts.

P5695Catheter ablation of ventricular tachycardia in patients with acute vs. previous myocarditis

Background

Ventricular tachycardias (VT) may occur late after myocarditis, as well as in the acute inflammatory phase of the disease. However, the role of catheter ablation (CA) in preventing VT recurrences in patients with acute (AM) vs. previous myocarditis (PM) has never been investigated so far.

Purpose

To evaluate the results of CA performed in patients presenting with VA and biopsy-proved myocarditis at different inflammatory stages.

Methods

We enrolled 46 consecutive patients (74% males, mean age 43±12y, mean LVEF 46±9%) with myocarditis and VT at index hospitalization. Based on endomyocardial biopsy and cardiac magnetic resonance (CMR) results, the patients were divided into AM and PM groups: in AM group, myocarditis was biopsy-proved, according to the ESC criteria; PM patients had a history of biopsy-proved myocarditis more than 12 months before, with no current signs of active inflammation (negative biopsy according to the ESC criteria; nonischaemic LGE at CMR with negative Lake-Louise criteria; absence of unexplained troponin abnormalities). ICD were implanted upon clinical indications. All of the patients underwent electroanatomical mapping (EAM) and VT CA. During 3 (2.5–3.5)y FU, VT recurrences were evaluated by 2/y Holter ECG and ICD interrogation.

Results

At baseline, 23 patients (50%) had AM, and 23 PM. Overall, 16 AM and 21 PM patients underwent ICD implant (p=n.s.). The clinical VT was monomorphic in 22 AM and 23 PM patients, respectively (p=n.s.) with a dominant right-bundle branch block with superior axis (RS) morphology in both groups (16 AM vs. 17 PM cases, p=n.s.). However, RS morphology was associated with left ventricular inferoposterior LGE at CMR in 9/16 AM vs. 17/17 PM patients (p=0.003). Similarly, inferoposterior localization of low-voltage areas at EAM was found in 11/16 AM vs. 17/17 PM patients (p=0.018). Furthermore, CMR showed a greater LGE transmural extension in AM patients (65±19%) as compared to PM ones (40±25%, p<0.001). Epicardial EAM and CA were performed in 14 AM vs. 15 PM patients, with endocardial-only approach adopted in the remaining cases (p=n.s.). VT CA was defined as successful (class A) in all of the subjets. However, during FU VT recurrences were documented in 7/23 AM vs. 0/23 PM patients (p=0.009). Four AM cases underwent redo CA late after myocarditis (1.5±0.3y after index hospitalization), with no further VT recurrences in FU.

Conclusion

In myocarditis patients presenting with VT, CA results are significantly better in PM cases as compared to AM ones. These findings are consistent with the different underlying substrate, and suggest the best role for ablation strategy after myocarditis healing.

Acknowledgement/Funding

None

P5560Assessing etiology in a cohort of patients with myocarditis presenting with complex ventricular arrhythmias: can the percutaneous endomyocardial biopsy help?

Background

Myocarditis represents a common but often under-diagnosed disease, with a wide range of clinical presentations; diagnosis is often presumptive and a clear etiology leading to a specific therapeutic approach is usually not identified.

Purpose

To describe and assess disease etiology in a cohort of myocarditis patients (pts) with arrhythmic presentation undergoing an invasive diagnostic work-up.

Methods

All pts with myocarditis presenting with ventricular arrhythmias undergoing an electro-anatomical mapping (EAM) guided endo-myocardial biopsy (EMB) at our institution were enrolled. All enrolled pts also underwent cardiac magnetic resonance imaging (MRI) and an electrophysiological study (EPS). Demographics, arrhythmic presentation, MRI data, arrhythmic inducibility at EPS, EAM and EMB biopsy data were retrieved and analyzed. Molecular biology testing for cardio-tropic virus genome as well as leukocyte immunohistochemical typization were routinely performed on all EMB samples.

Results

Twenty-six pts were enrolled (85% male, 39±6 y.o.). Clinical presentation was an organized ventricular arrhythmia in 16 (62%) pts (n=3 non-sustained ventricular arrhythmia; n=9 sustained ventricular arrhythmia; n=4 ventricular fibrillation) while frequent (>10.000) premature ventricular complexes (PVCs) in the remaining 10 (38%) pts.

MRI showed a late gadolinium enhancement (LGE) pattern consistent with myocarditis in all pts (35% left LGE; 65% right LGE). At the EPS, 10 (38%) pts showed inducibility for SVTs and underwent an intra-cardiac defibrillator (ICD) implant, while 4 (16%) more were implanted for secondary arrhythmic prevention.

EAM was performed in 18 (70%), 6 (22%) and 2 (8%) pts in the right, left and in both ventricle respectively; in all cases, abnormal myocardial voltages were retrieved in the area showing LGE at MRI. Extensive myocardial scarring was detected in 7 (27%) pts.

All EMB were performed without peri-procedural complications; inflammatory infiltrate and substrate alteration consistent with myocarditis were retrieved in 100% of the bioptic samples. Viral genome was identified in 13 (50%) samples (n=5 Human Herpes Virus 6; n=2 Parvovirus B 19; n=3 Adenovirus; n=1 Ebstein Barr Virus; n=1 Cytomegalovirus; n=1 Rhinovirus) and specific human immunoglobulin treatment was undergone by a single pt; eosinophilic infiltration was found in 2 (8%) patients; lymphocite invasion and auto-antibodies consistent with auto-immune myocarditis were detected in 2 (8%) patients and appropriate immunosuppressive therapy was started, while a myocardial band contraction pattern typical of toxic myocarditis was found in a single (4%) patient [Figure 1].

Different Myocarditis Etiology Rates

Conclusion

In our myocarditis cohort, EMB confirmed viruses to represented the first myocarditis etiological agent. Despite an invasive work-out, 31% of the cohort etiology still remains unclear.

P307Magnetic resonance, electroanatomical mapping, and endomyocardial biopsy to solve the diagnostic and sport eligibility dilemma in a cohort of competitive athletes with ventricular arrhythmias

Background

Ventricular arrhythmias (VAs) are a frequent finding in agonist athletes (athl) at routine sport medicine visits. VAs impact on sport eligibility, their management, and the sudden arrhythmic death risk evaluation in athletes currently represents one of the greatest challenges across both the cardiology and sport medicine field.

Purpose

To describe how an advanced multi-methodical evaluation allowed diagnosis, risk stratification, targeted therapy and sport eligibility reassessment in a competitive athl cohort with ventricular arrhythmias and pathological findings at magnetic resonance (MR).

Methods

All consecutive competitive athl with denied sport eligibility due to ventricular arrhythmias that underwent an advanced invasive evaluation at our institute were enrolled.

A baseline and stress ECG, and late gadolinium enhanced evaluation (LGE) at MR were performed prior to invasive evaluation in all athl.

Invasive evaluation performed in all athl comprised of an electrophysiological study (EPS) to assess arrhythmic inducibility, an endo-cavitary electro-anatomical mapping (EAM), and a EAM and MR guided endo-myocardial biopsy (EMB). A defined diagnosis was postulated in all cases, specific therapeutic interventions were started and sport eligibility status reassessed after 6 months from discharge.

Results

Thirty-two competitive athl were enrolled in our study (32±6 y.o.; 77% male; 4±1 1h-training session/week); 26 (81%) athl practiced a mixed aerobic-anaerobic, 5 (16%) a pure-aerobic, while only 1 (3%) a pure anaerobic sport.

Arrhythmic presentation leading to sport eligibility revoke was: in 13 (40%) athl frequent (>2000/day) premature ventricular contractions (PVCs) at rest, in 2 (6%) PVCs during stress ECG, in 6 (18%) non-sustained ventricular tachycardia (VT), in 8 (25%) sustained VT, and in 3 (11%) ventricular fibrillation/cardiac arrest during sport practice.

MR alterations were described in all cases, and LGE at MR was found in 31 (87%) athl; a definite radiological diagnosis was obtained in 13 (40%) athl.

A normal myocardium at EMB was found only in 3 (8%) pts; in 15 (45%) a leukocyte infiltrate pattern compatible with myocarditis, in 11 (39%) fibro-fatty replacement, in 2 (5%) a mitochondrial disease and in 1 (3%) a sarcoidosis were proven, and diagnosis were consequently postulated.

EPS showed complex VAs inducibility in 8 (25%) cases, while a trans catheter ablation was performed in 10 (31%) athl. A total of 9 (28%) implantable cardioverter devices (ICDs) were implanted, for primary or secondary prevention.

According to invasive diagnostic findings and sport medicine guidelines, 8 (25%) athl had their sport eligibility statuts re-instated.

Conclusion

An invasive multi-methodical assessment allowed in all cases to reach a diagnosis and to start a targeted therapy in a cohort of competitive athl with VA and a pathological MR, granting in a significant (25%) percentage sport eligibility status re-instatement.

P5563Biopsy proven myocarditis: clinical and instrumental predictors of adverse prognosis at presentation

Background

Myocarditis is an insidious and potentially fatal illness with different clinical presentations and an unpredictable course. Prompt recognition of high risk patients is of paramount importance in preventing major adverse events.

Purpose

To identify predictors of dismal prognosis in a large cohort of patients with biopsy proven myocarditis.

Methods

Univariate analysis was used to identify predictors of death and heart transplant in a prospective cohort of 366 patients with biopsy proven myocarditis (aged 38±17, male 66%) using student's test and contingency tables as appropriate.

Results

At the time of follow up 46 patients (13%) were dead or received heart transplant (DHTX), 283 (77%) were alive (A) and 37 (10%) lost at follow up. Age at presentation was 33±20 y in DHTX v.s 39±15 in A cohort (p=0.057). Clinical features predicting adverse prognosis included female gender (p=0.002), heart failure at presentation (p=0.000), NYHA class II to IV (p=0.000). Clinical and radiographic signs of both left and right heart failure suggested worse outcome (p=0.000) as well as ongoing anticoagulation therapy (p=0.009). On ECG right (R) or left (L) axis deviation was a strong predictor of events (p=0.000). From an echocardiography perspective the presence of mild to severe mitral regurgitation (p=0.03), reduced left ventricular systolic function (FE) (p=0.000), reduced right ventricular fractional area change (FAC) (p=0.035) was strongly correlated to death or heart transplant. On cardiac catheterization the variables predicting unfavourable outcome included reduced left ventricular systolic pressure (LVSP) (p=0.000), reduced mean aortic pressure (mAP) (p=0.002), increased mean right atrial pressure (RAP) (p=0.001), FE on angiography (p=0.000). On cardiac biopsy (Bx) negative predictors were giant cell histology type (p=0.000) and PCR positive for viral genome (p=0.02) particularly for parvovirus B19 (p=0.04), adenovirus (p=0.04), and Epstein Barr virus (EBV) (p=0.03). See Tab 1

Table 1

Conclusion

Female gender, HF like presentation, reduced LV and RV systolic function, R or L axis deviation on ECG, presence of viral PCR or giant cell histology on Bx, reduced LVSP and mAP; increased RAP may be useful parameters to identify high risk patients on presentation. This may increase clinical efforts and surveillance in this subgroup in order to reduce the incidence of major adverse events.

P5556Impact of viral genome detection in endo-myocardial biopsy of arrhythmogenic cardiomyopathy substrate

Background

Arrhythmogenic cardiomyopathy (ACM) is a genetically inherited cardiomyopathy characterized by myocardial fibro-fatty replacement. A pathogenetic role of viral myocardial infections in ACM natural history has been proposed over the years, although no definitive conclusion has been reached yet.

Purpose

To describe viral genome presence into a cohort of ACM biopsy proven patients (pts) and its impact on clinical features and outcome.

Methods

A cohort of all ACM pts undergoing an invasive third level evaluation at our institution was enrolled. All pts underwent a cardiac magnetic resonance (MR), an invasive electrophysiological study (EPS) with endo-cavitary electro-anatomical mapping (EAM), and a EAM guided endo-myocardial biopsy (EMB). Viral genome research through molecular biology techniques was performed on all biopsied samples.

According to arrhythmic risk evaluation, a trans-catheter ablation (TCA) and/or an internal cardioverter device (ICD) implant was performed. Clinical arrhythmic presentation, MR data, arrhythmia inducibility at EPS, EAM and EMB characteristic, and arrhythmic events at a 12-month follow up visit were retrieved in all pts and compared between the viral genome positive (v+ACM) and negative group (v-ACM).

Results

Forty-five pts were enrolled in our study (48±13 years; 66% male); the EMB samples of 7 (15%) pts presented a lymphocytic infiltrate and tested positive for viral genome (n=3 B19 Parvovirus; n=2 for Citomegalovirus; n=2 for Ebstein-Bar Virus) [Figure1].

At arrhythmic presentation, complex ventricular arrhythmias (NSVT, SVT and FV) were more frequent in the v+ACM group (86% vs 50%; p=0.039). Both left and right ventricular ejection fraction at MR resulted more depressed in the v+ACM group (44±7 vs 52±2 and 47±2 vs 52±2; p=0.047 and p=0.041). Complex ventricular arrhythmia inducibility at EPS was more frequent in v+ACM (72% vs 34%; p=0.032), while no differences in pathological potentials rate and extension at unipolar and bipolar EAM were found. TCA was performed in 55% and 57% and an ICD was implanted in 29% and 42% in the v+ACM and v-ACM group respectively. No differences in 12-months arrhythmic event rates (39% vs 42%) between the two groups were described.

EBM at different magnifications/stains

Conclusion

In our cohort a viral infection super-imposed to the fibrofatty infiltration was found in 15% of the patients. ACM pts testing positive for viral genome at the EMB had a more severe arrhythmic disease presentation, a more impaired heart function, and a higher rate of complex ventricular arrhythmias at disease presentation, but seemed to respond as well as viral genome negative ACM to ablative and pharmacological treatment