Electrocardiogram analysis in Anderson-Fabry disease: a valuable tool for progressive phenotypic expression tracking

Background

Electrocardiogram (ECG) has proven to be useful for early detection of cardiac involvement in Anderson-Fabry disease (AFD); however, little evidence is available on the association between ECG alterations and the progression of the disease.

Aim and Methods

To perform a cross sectional comparison of ECG abnormalities throughout different left ventricular hypertrophy (LVH) severity subgroups, providing ECG patterns specific of the progressive AFD stages. 189 AFD patients from a multicenter cohort underwent comprehensive ECG analysis, echocardiography, and clinical evaluation.

Results

The study cohort (39% males, median age 47 years, 68% classical AFD) was divided into 4 groups according to different degree of left ventricular (LV) thickness: group A ≤ 9 mm (n = 52, 28%); group B 10-14 mm (n = 76, 40%); group C 15-19 mm (n = 46, 24%); group D ≥ 20 mm (n = 15, 8%). The most frequent conduction delay was right bundle branch block (RBBB), incomplete in groups B and C (20%,22%) and complete RBBB in group D (54%, p < 0.001); none of the patients had left bundle branch block (LBBB). Left anterior fascicular block, LVH criteria, negative T waves, ST depression were more common in the advanced stages of the disease (p < 0.001). Summarizing our results, we suggested ECG patterns representative of the different AFD stages as assessed by the increases in LV thickness over time (Central Figure). Patients from group A showed mostly a normal ECG (77%) or minor anomalies like LVH criteria (8%) and delta wave/slurred QR onset + borderline PR (8%). Differently, patients from groups B and C exhibited more heterogeneous ECG patterns: LVH (17%; 7% respectively); LVH + LV strain (9%; 17%); incomplete RBBB + repolarization abnormalities (8%; 9%), more frequently associated with LVH criteria in group C than B (8%; 15%). Finally, patients from group D showed very peculiar ECG patterns, represented by complete RBBB + LVH and repolarization abnormalities (40%), sometimes associated with QRS fragmentation (13%).

Conclusions

ECG is a sensitive tool for early identification and long-term monitoring of cardiac involvement in patients with AFD, providing "instantaneous pictures" along the natural history of AFD. Whether ECG changes may be associated with clinical events remains to be determined.

Diagnostic pathways leading to arrhythmogenic left ventricular cardiomyopathy in a single center cohort

Background

Despite major advances, the recognition of arrhythmogenic left ventricular cardiomyopathy (ALVC) remains challenging, since this clinical entity is often concealed in different clinical settings both in terms of clinical onset and imaging phenotype, resulting in significant delays in diagnosis with prognostic implications.

Purpose

To describe a single Center cohort of ALVC patients, focusing on the spectrum of clinical presentation and diagnostic pathways.

Methods

Patients were retrospectively evaluated between January 2012 and January 2022. Diagnosis was based on 1) ≥3 contiguous segments with subepicardial/midwall LGE in the LV at cardiac magnetic resonance (CMR) plus a likely pathogenic/pathogenic arrhythmogenic cardiomyopathy (ACM) associated genetic mutation and/or familial history of ACM and/or red flags for ALVC (i.e, negative T waves in V4–6/aVL, low voltages in limb leads) or 2) pathology examination of explanted hearts/autoptic cases suffering from sudden cardiac death (SCD). Patients with significant right ventricular involvement were excluded.

Results

Sixty-six patients were evaluated for suspected ALVC: 8 phenocopies were excluded (6 acute myocarditis and 2 sarcoidosis) after a comprehensive clinical and multi-modality instrumental evaluation. The final study cohort was composed by 56 patients (55% males, median age 45 years), from 36 families. Diagnostic pathways leading to diagnosis were: SCD in 4 (7%), ventricular arrhythmias in 11 (20%), chest pain in 9 (16%), heart failure in 7 (12%), and familial screening in 25 (45%) (Figure 1). An echocardiogram was available for all but 2 patients with SCD: 25 (46%) had normal phenotype, 17 (32%) had a hypokinetic non dilated cardiomyopathy, and 12 (22%) had a dilated cardiomyopathy (DCM). Of the 49 tested patients, 31 (63%) had a pathogenic/likely pathogenic DNA variant: desmoplakin (DSP, N=21), filamin C (FLNC, N=4), SCN5A (N=3) were the most frequently involved genes; 8 patients had a double gene mutation. Twenty-four patients (43%) had previously received a diagnosis other than ALVC: 10 idiopathic DCM, 9 acute myocarditis, 4 post-myocarditis DCM, 2 acute myocardial injury/non-ST elevated myocardial infarction. In 13 patients ALVC was diagnosed with the introduction of CMR in the diagnostic work-up of a DCM, in 2 cases the diagnosis was done with the pathology examination after heart transplantation. The median diagnostic delay was of 8 years, with a maximum of 20 years. It is worth nothing that patients from the same family might have different diagnostic pathways and phenotypes of ALVC (Figure 2).

Conclusions

ALVC is a challenging diagnosis, hidden in different clinical scenarios. Five main clinical pathways leading to ALVC diagnosis may be identified: ventricular arrhythmias, chest pain, heart failure, SCD at first presentation, and clinical/instrumental familial screening.

Funding Acknowledgement

Type of funding sources: None.

Impact on clinical outcomes of right ventricular response to percutaneous correction of secondary mitral regurgitation

Funding Acknowledgements

Type of funding sources: None.

Background. Right ventricular function (RVF) is a strong determinant of prognosis in patients with reduced ejection fraction heart failure (HFrEF) and secondary mitral regurgitation (SMR). Percutaneous mitral valve repair (pMVR) can promote the recovery of RVF.

Purpose. We sought to characterize the RV response to pMVR in HFrEF with SMR and to assess the influence of improved RVF after pMVR in this specific setting of patients.

Methods. We included all the patients with HFrEF and SMR≥3+ successfully treated with pMVR between April 2012 and January 2020 in two tertiary care centers for HF. Improved RVF was defined as DRVFAC≥5% at early follow-up (median time 4 months). The primary endpoint was a composite of death/heart transplant (D/HT).  

Results. In total, 110 patients were included. Mean age was 67 ± 12 years, mean LVEF was 31 ± 8% and mean RVFAC was 31 ± 10%. DRVFAC≥5% occurred in 54 (49%) patients and was independent from the measures of left ventricle recovery. During a median follow-up of 36 months (IQR 19-52), 40 patients (36%) died or were transplanted.  After adjustment for other significant covariates, DRVFAC≥5% was significantly associated with lower risk of D/HT (HR 0.49, 95% CI 0.24 – 0.98 p &lt; 0.042) along with M2+ at follow-up (HR 0.36; 95% CI 0.17-0.74 p 0.005).

Conclusions. In patients with HFrEF and SMR, the improvement of RVF is frequent after pMVR and is associated with better long-term survival free from HT.

Abstract Figure.

P6455Differences in cardiac phenotype and natural history of laminopathies with and without neuromuscular presentation

Aim

To look for differences in cardiac phenotype and natural history of patients affected by laminopathy, according to the presence or less of neuromuscular involvement at clinical presentation.

Methods

We prospectively analyzed 47 consecutive pts with a genetic diagnosis of laminopathy followed at a single centre between 1994 and 2017. Additionally, reports of clinical and instrumental evaluations before referral at our centre were retrospectively evaluated.

Results

Neuromuscular presentation, mainly as Emery-Dreifuss muscular dystrophy (EDMD), was present in 21 (46%) cases (14 LMNA and 7 EMD gene mutations). These pts had symptoms earlier (9 vs 39 years, p<0.001) in life compared to pts without neuromuscular onset (26 LMNA gene mutations), and clinical manifestations anticipated the first evidence of cardiac disease by a mean time of 15±8 years (maximum time gap of 38 years). Despite a similar prevalence of atrial fibrillation/flutter (AF) (71% vs 65%, p=0.758) and atrio-ventricular blocks (48% vs 65%, p=0.250), pts with neuromuscular onset experienced AF and pace-maker implantation at a significantly younger age (27 vs 41 yrs, p=0.015 and 23 vs 44 yrs, p=0.027 respectively). Differently a higher prevalence of sinus node dysfunction (33% vs 4%; p=0.015) and atrial paralysis (14% vs 4%; p=0.311) was reported in pts with neuromuscular onset. Prevalence of cardiomyopathy (CMP) (73% vs 33%, p=0.008) and sustained ventricular tachyarrhythmias were higher among pts with cardiac onset (23% vs 4%, p=0.111) whereas the prevalence of heart transplantations and median age of recipients were similar in the two groups (24% vs 20%, p=1.000 and 46 vs 43, p=0.592 years respectively). All pts with neuromuscular onset who received a diagnosis of CMP had a previous history of rhythm disturbance except 2 cases, where a concomitant diagnosis of the 2 disorders was formulated. On the contrary a strict temporal progression from rhythm disturbances to CMP (or viceversa) was not appreciable in the other group: AF and AVBs could precede the diagnosis of CMP be diagnosed at the same time or later.

Conclusions

In pts affected by laminopathy neuromuscular involvement, when present, was most often the first clinical manifestation and preceded cardiological involvement, with a long time frame in some cases. Except for sinus node dysfunction, much more frequent in patients with EDMD, a similar prevalence of rhythm disturbances was reported, although pts with neuromuscular clinical onset were younger at diagnosis of AF and at PM implantation. Pts without neuromuscular presentation had a higher prevalence of CMP and ventricular arrhythmias, albeit a similar rate of heart transplantation. In pts with neuromuscular onset, cardiac involvement was characterized by a stepwise progression from rhythm disturbances to CMP, where a strict temporal progression from rhythm disturbances to CMP was not observed in the group of pts without neuromuscular clinical onset.

P900Electrocardiographic findings in Anderson-Fabry disease versus sarcomeric hypertrophic cardiomyopathy

Background

Cardiac involvement is one of the most frequent and disabling organ damage in Anderson-Fabry (AF) disease, causing hypertrophic cardiomyopathy (HCM), conduction disturbances, arrhythmias and coronary disease. Differential diagnosis from sarcomeric HCM is often very challenging, especially for patients with exclusive cardiac involvement.

Purpose

To gain new insights from standard electrocardiogram (ECG) in AF disease, and identify ECG differences from sarcomeric HCM.

Methods

Sixty-two consecutive patients (27 males, mean age: 62±16 years) with definite diagnosis of AF disease from 2 Italian centres were evaluated for ECG analysis and divided in 2 groups, according to the presence (Group A, N=39) or the absence (Group B, N=26) of cardiac involvement [hypertrophy detected at echocardiogram or cardiac magnetic resonance (CMR)]. All ECGs were analysed by 2 independent investigators. For Group A, when CMR was performed, a correlation between CMR and ECG was assessed. Patients with cardiac involvement were matched with 78 sarcomeric HCM patients according to sex, age and septal wall thickness on echocardiogram.

Results

Two AF patients out 39 with cardiac involvement (5%) had normal ECG. Short PR and I degree atrio-ventricular (AV) block were both reported in 6 (15%) cases. Twenty-six (67%) patients showed left ventricular hypertrophy and the majority (85%) had abnormal repolarization. CMR was performed in 22 patients (56%); the 11 (50%) patients with replacement fibrosis had a higher mean Sokolow-Lyon score (4.1±1.8 vs 2.9±1.0 mV; p=0.05), more frequent ST segment depression (82 vs 27%; p=0.03) and negative T waves (91 vs 36%; p=0.027; sensitivity: 90%; specificity: 63%), compared with the 11 without replacement fibrosis.

When compared with sarcomeric HCM, AF patients with cardiac involvement had a significantly wider QRS (120±30 vs 100±16 msec; p<0.0001), a higher frequency of right bundle branch block (RBBB) (18 vs 3%; p=0.01), ST segment depression (54 vs 20%; p<0.0001) and negative T waves (72 vs 46%; p=0.01), typically in the inferior leads (44 vs 14%; p<0.0001). No significant differences in terms of pseudo-necrosis and QRS voltages were found.

Among Group B AF patients (26, mean age: 36±12 years), 4 had short PR and 5 incomplete RBBB. Four had an abnormal ECG (1 left atrial enlargement, 2 unspecific repolarization abnormalities, 1 Sokolow score of 3.5 mV).

Conclusions

Standard ECG can detect cardiac involvement in AF disease. A good correlation was reported between repolarization abnormalities and replacement fibrosis on CMR. Wide QRS and RBBB were more frequent among AF patients compared to age-sex-matched sarcomeric HCM ones, probably due to the different aetiology of the diseases (infiltrative disease vs pure hypertrophy).