Cardiac [99mTc]Tc-hydroxydiphosphonate uptake on bone scintigraphy in patients with hereditary transthyretin amyloidosis: an early follow-up marker?

PURPOSE

There is a need for early quantitative markers of potential treatment response in patients with hereditary transthyretin (ATTRv) amyloidosis to guide therapy. This study aims to evaluate changes in cardiac tracer uptake on bone scintigraphy in ATTRv amyloidosis patients on different treatments.

METHODS

In this retrospective cohort study, outcomes of 20 patients treated with the transthyretin (TTR) gene silencer patisiran were compared to 12 patients treated with a TTR-stabilizer. Changes in NYHA class, cardiac biomarkers in serum, wall thickness, and diastolic parameters on echocardiography and NYHA class during treatment were evaluated.

RESULTS

Median heart/whole-body (H/WB) ratio on bone scintigraphy decreased from 4.84 [4.00 to 5.31] to 4.16 [3.66 to 4.81] (p < .001) in patients treated with patisiran for 29 [15-34] months. No changes in the other follow-up parameters were observed. In patients treated with a TTR-stabilizer for 24 [20 to 30] months, H/WB ratio increased from 4.46 [3.24 to 5.13] to 4.96 [ 3.39 to 5.80] (p = .010), and troponin T increased from 19.5 [9.3 to 34.0] ng/L to 20.0 [11.8 to 47.8] ng/L (p = .025). All other parameters did not change during treatment with a TTR-stabilizer.

CONCLUSION

A change in cardiac tracer uptake on bone scintigraphy may be an early marker of treatment-specific response or disease progression in ATTRv amyloidosis patients.

Phenotypic variability of FLNC-related cardiomyopathy: insights from a novel Dutch founder variant

Background

Truncating variants in filamin C (encoded by the FLNC gene) are an important cause of dilated cardiomyopathy (DCM). Recently, a new pathogenic FLNC variant c.6864_6867dup, p.(Val2290Argfs*23) was identified in a number of families with DCM in the south of the Netherlands.

Objectives

The aim of this study was to: (i) investigate whether this FLNC variant is a founder variant; and (ii) to evaluate the clinical phenotype of the affected individuals.

Material and methods

Genetic and clinical data from these FLNC carriers were retrospectively collected. To determine a possible founder effect, haplotypes were reconstructed. The geographical distribution and age of the variant were determined. Clinical characteristics and outcomes were retrieved from electronic medical records. Cardiac magnetic resonance imaging (CMR) studies were reviewed.

Results

In total 33 individuals from 9 families carrying this FLNC variant were identified. A shared haplotype spanning 2.1 Mb was present in all subjects that were haplotyped. The variant appears to have originated in the south of the Netherlands between 275 and 650 years ago.

Median age was 53 years (range 20–79). Nine (27%) individuals were male. The clinical presentation is heterogeneous, ranging from the presence of DCM with heart failure with reduced ejection fraction in 11 (33%) subjects (median age 57, range 36–79 years), to presentation with sudden cardiac death (SCD) in 1 subject at 28 years of age with LV dilation and fibrosis on pathology, without prior symptoms. Seven subjects (21%) had left ventricular (LV) dilation with normal LV function, and one had midrange LV function without dilation. Nine (27%) subjects had no cardiac abnormalities, with a median age of 56 (range 26–70).

CMR was available in 18 subjects and showed late gadolinium enhancement (LGE), indicating fibrosis, in 11 subjects (61%), including 2 with preserved LV function. The LGE was extensively present in epicardial and infrequently in the subepicardial LV segments, with ring-like distributions being observed in 4 (22%) of the assessed patients.

During follow-up 1 subject experienced SCD and 3 developed end-stage heart failure and underwent heart transplantation. Six (18%) subjects had asymptomatic non-sustained ventricular arrhythmias detected by Holter monitoring, and 4 (12%) subjects received an implantable cardioverter defibrillator for primary prevention and 1 for secondary prevention.

Conclusion

The c.6864_6867dup, p.(Val2290Argfs*23) pathogenic FLNC variant is a founder variant originating from the south of the Netherlands. The phenotype is characterized by extensive myocardial fibrosis, even in subjects with preserved LV function, making subjects prone to both arrhythmias and heart failure.

Funding Acknowledgement

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

Multi-omics integration identifies key upstream regulators of pathomechanisms in hypertrophic cardiomyopathy due to truncating MYBPC3 mutations

BACKGROUND

Hypertrophic cardiomyopathy (HCM) is the most common genetic disease of the cardiac muscle, frequently caused by mutations in MYBPC3. However, little is known about the upstream pathways and key regulators causing the disease. Therefore, we employed a multi-omics approach to study the pathomechanisms underlying HCM comparing patient hearts harboring MYBPC3 mutations to control hearts.

RESULTS

Using H3K27ac ChIP-seq and RNA-seq we obtained 9310 differentially acetylated regions and 2033 differentially expressed genes, respectively, between 13 HCM and 10 control hearts. We obtained 441 differentially expressed proteins between 11 HCM and 8 control hearts using proteomics. By integrating multi-omics datasets, we identified a set of DNA regions and genes that differentiate HCM from control hearts and 53 protein-coding genes as the major contributors. This comprehensive analysis consistently points toward altered extracellular matrix formation, muscle contraction, and metabolism. Therefore, we studied enriched transcription factor (TF) binding motifs and identified 9 motif-encoded TFs, including KLF15, ETV4, AR, CLOCK, ETS2, GATA5, MEIS1, RXRA, and ZFX. Selected candidates were examined in stem cell-derived cardiomyocytes with and without mutated MYBPC3. Furthermore, we observed an abundance of acetylation signals and transcripts derived from cardiomyocytes compared to non-myocyte populations.

CONCLUSIONS

By integrating histone acetylome, transcriptome, and proteome profiles, we identified major effector genes and protein networks that drive the pathological changes in HCM with mutated MYBPC3. Our work identifies 38 highly affected protein-coding genes as potential plasma HCM biomarkers and 9 TFs as potential upstream regulators of these pathomechanisms that may serve as possible therapeutic targets.

Incremental value of cardiovascular magnetic resonance imaging in family screening for hypertrophic cardiomyopathy

Funding Acknowledgements

Type of funding sources: None.

Genetic testing in relatives of hypertrophic cardiomyopathy (HCM) patients can lead to early identification of carriers of pathogenic DNA variants (G+), before onset of left ventricular hypertrophy (LVH). Repeated evaluation by electrocardiography (ECG) and transthoracic echocardiography (TTE) is recommended to detect HCM during follow-up. Cardiovascular magnetic resonance (CMR) imaging has become valuable in the work-up of HCM, although its role in G+ subjects has not been extensively evaluated. In this study, we investigated the value of CMR in the G+/LVH- population.

We included 55 G+ subjects who underwent CMR in addition to ECG and TTE, with a maximal wall thickness (MWT) &lt;15mm on TTE. The CMR imaging protocol consisted at least of steady state free procession imaging and 2-dimensional late gadolinium enhancement (LGE) images. ECGs were considered abnormal in case of pathologic Q waves, T wave inversion or signs of LVH (by voltage criteria including Sokolow-Lyon and a Romhilt-Estes score ≥4). TTEs were abnormal in case of LVH (defined as MWT≥10mm). For both modalities, the diagnosis of HCM was based on a MWT≥13mm. The yield of CMR relative to ECG/TTE was assessed by comparing the proportion of HCM diagnoses and the presence of other phenotypic features. Forward step logistic regression was used to assess whether the presence of TTE/ECG abnormalities could predict reclassifications or abnormalities (crypts and LGE) on CMR.

An overview of ECG/TTE and CMR findings is shown in the Figure. Two of 16 (13%) subjects diagnosed with HCM on TTE were reclassified as having no HCM on CMR, and 8 of 39 (21%) subjects without HCM on TTE were reclassified as HCM on CMR. These 8 subjects had a mean MWT of 15.4 ± 2.6 mm on CMR and a mean MWT difference of 4.5 ± 2.9 mm (range 1.7-9.4) compared to TTE, which in 3 cases was explained by a hook-shaped thickening of the basal anterior wall in the 2 chamber view, not visible on TTE. Compared to subjects without HCM on both modalities, the reclassified group had a significantly higher QRS duration (104 ± 14 vs 93 ± 11 ms, p = 0.03) and anterior mitral valve leaflet length (30 ± 4 vs 26 ± 3 mm, p = 0.01). Of the 13 subjects with normal ECG/TTE results, none were reclassified as HCM using CMR.

The proportion of additional CMR abnormalities was large in subjects with and without abnormal ECG/TTE results (57% vs 38%, p = 0.24). Subjects with poor TTE image quality were equally likely to be reclassified compared to those with sufficient image quality (10% vs 24%, p = 0.19). Logistic regression demonstrated that the presence of TTE/ECG abnormalities (odds ratio [OR] 8.7 [1.3-59.0], p = 0.03) and age (OR 1.1 [1.0-1.2], p &lt; 0.01) independently predicted reclassifications or presence of abnormalities using CMR.

Additional CMR imaging reclassifies 18% of subjects. Subjects with normal ECG and TTE results are not diagnosed as HCM on CMR, but the prevalence of HCM-related abnormalities on CMR was high in subjects with and without ECG/TTE abnormalities.

Abstract Figure. Diagnostic approach and CMR findings

Differences in left ventricular mass and morphology and right ventricular function differentiate phenotype-negative sarcomere gene mutation carriers from healthy volunteers

Funding Acknowledgements

Type of funding sources: None.

Carriers of pathogenic DNA variants (G+) causing hypertrophic cardiomyopathy (HCM) can be identified by genetic testing, before manifestation of left ventricular hypertrophy (LVH). These G+/LVH- subjects are routinely monitored for phenotypic expression, which, alongside LVH, can include other HCM-related abnormalities, including crypts and myocardial fibrosis. Cardiovascular magnetic resonance (CMR) imaging has emerged as a valuable technique in diagnosing and follow-up of HCM. In this study, we identified clinical features of subclinical HCM in a G+/LVH- population compared to healthy subjects.

We studied 33 G+ subjects with CMR and a maximal wall thickness (MWT) &lt;13mm, and compared them to an age- and gender-matched group of 35 healthy controls  (44 ± 14 vs 48 ± 10 y, p = 0.17; 11 (33%) vs 12 (34%) men, p = 0.93). The CMR imaging protocol consisted of 1) steady state free procession cine imaging, 2) 2-dimensional late gadolinium enhancement (LGE) images in the G+ patients and 3) pre-contrast T1 mapping using a modified look-locker inverse recovery sequence. We assessed CMR examinations for features of HCM. Forward logistic regression analysis was performed to determine which of the CMR characteristics were predictive of G+ status.

G+ subjects had a higher MWT (10.9 ± 1.6 vs 10.2 ± 1.3 mm, p = 0.04), a similar interventricular septal wall (IVS) thickness (8.8 ± 1.6 vs 8.7 ± 1.6 mm, p = 0.85), a smaller posterior wall (PW) and a higher IVS/PW ratio (6.6 ± 1.2 vs 7.7 ± 1.3mm, p &lt; 0.001; 1.4 ± 0.3 vs 1.1 ± 0.2, p = 0.001). Indexed left ventricular (LV) mass was significantly lower in the G+ group (Table). LV function was similar (63 ± 6 vs. 61 ± 5%, p = 0.12), but right ventricular (RV) function was higher in the G+ group. They often had a characteristic hook-shaped thickening of the basal anterior wall (7 (21%) vs 0, p &lt; 0.004; Figure) and  more frequently exhibited myocardial crypts. Midwall LGE was present in 3 (9%) G+ subjects. Native septal T1 values were elevated in G+ patients compared to controls, although mostly within the normal range (986 ± 31 vs 963 ± 28 ms, p &lt; 0.01). Crypts, indexed LV mass and RV ejection fraction were significant predictors of G+ status in logistic regression analysis (Table).

CMR demonstrates significant morphological differences between the G+/LVH- population and healthy controls. Further studies are needed to assess the prognostic significance of these morphological features.

Predictors of genotype-positive status Variables G+ subjects (n = 33) Controls (n = 35) P value OR for G+ status P value Left ventricular mass/BSA (g/m&sup2;) 45 ± 7.4 53 ± 7.9 &lt;0.001 0.86 [0.78-0.95] 0.003 Right ventricular ejection fraction (%) 58 ± 6 53 ± 4 &lt;0.001 1.15 [1.00-1.32] 0.047 Crypts 17 (55%) 4 (11%) &lt;0.001 9.62 [1.93-48.00] 0.006 G+: genotype-positive, OR: odds ratio Abstract Figure. CMR findings

BIO FOr CARE: biomarkers of hypertrophic cardiomyopathy development and progression in carriers of Dutch founder truncating MYBPC3 variants-design and status

BACKGROUND

Hypertrophic cardiomyopathy (HCM) is the most prevalent monogenic heart disease, commonly caused by truncating variants in the MYBPC3 gene. HCM is an important cause of sudden cardiac death; however, overall prognosis is good and penetrance in genotype-positive individuals is incomplete. The underlying mechanisms are poorly understood and risk stratification remains limited.

AIM

To create a nationwide cohort of carriers of truncating MYBPC3 variants for identification of predictive biomarkers for HCM development and progression.

METHODS

In the multicentre, observational BIO FOr CARe (Identification of BIOmarkers of hypertrophic cardiomyopathy development and progression in Dutch MYBPC3 FOunder variant CARriers) cohort, carriers of the c.2373dupG, c.2827C > T, c.2864_2865delCT and c.3776delA MYBPC3 variants are included and prospectively undergo longitudinal blood collection. Clinical data are collected from first presentation onwards. The primary outcome constitutes a composite endpoint of HCM progression (maximum wall thickness ≥ 20 mm, septal reduction therapy, heart failure occurrence, sustained ventricular arrhythmia and sudden cardiac death).

RESULTS

So far, 250 subjects (median age 54.9 years (interquartile range 43.3, 66.6), 54.8% male) have been included. HCM was diagnosed in 169 subjects and dilated cardiomyopathy in 4. The primary outcome was met in 115 subjects. Blood samples were collected from 131 subjects.

CONCLUSION

BIO FOr CARe is a genetically homogeneous, phenotypically heterogeneous cohort incorporating a clinical data registry and longitudinal blood collection. This provides a unique opportunity to study biomarkers for HCM development and prognosis. The established infrastructure can be extended to study other genetic variants. Other centres are invited to join our consortium.

Cardiovascular disease in non-classic Pompe disease: A systematic review

Pompe disease is a rare inherited metabolic and neuromuscular disorder, presenting as a spectrum, with the classic infantile form on one end and the more slowly progressive non-classic form on the other end. While being a hallmark in classic infantile Pompe disease, cardiac involvement in non-classic Pompe disease seems rare. Vascular abnormalities, such as aneurysms and arterial dolichoectasia, likely caused by glycogen accumulation in arterial walls, have been reported in non-classic Pompe patients. With this first systematic review on cardiovascular disease in non-classic Pompe disease, we aim to gain insight in the prevalence and etiology of cardiovascular disease in these patients. Forty-eight studies (eight case-control studies, 15 cohort studies and 25 case reports/series) were included. Fourteen studies reported cardiac findings, 25 studies described vascular findings, and nine studies reported both cardiac and vascular findings. Severe cardiac involvement in non-classic Pompe disease patients has rarely been reported, particularly in adult-onset patients carrying the common IVS1 mutation. There are indications that intracranial dolichoectasia and aneurysms are more prevalent in non-classic Pompe patients compared to the general population. To further investigate the prevalence of cardiovascular disease in non-classic Pompe patients, larger case-control studies that also study established cardiovascular risk factors should be conducted.

Cardiac sarcoidosis: frequency, diagnostic approach and follow-up in a tertiary center

Background

Cardiac sarcoidosis (CS) is associated with poor prognosis, making early diagnosis and treatment important. The aim of this study is to evaluate our diagnostic results and follow-up for the diagnosis of CS in a tertiary center.

Methods

We studied 188 patients with proven extra-cardiac sarcoidosis referred to our outpatient clinic for evaluation of cardiac involvement. Eight patients were excluded because electrocardiogram (ECG) and/or transthoracic echocardiography (TTE) was missing. Cardiac magnetic resonance (CMR) and/or positron emission tomography (PET) was performed in 66% and 37% of the patients, respectively. Median follow-up duration was 2.9 [1.2–5.3] years. The diagnosis of CS was based on the Heart Rhythm Society criteria.

Results

Cardiac symptoms defined as palpitations, angina, dyspnea and (near)-syncope were present in 156 of 180 (87%) patients. Any abnormality on ECG (bundle branch blocks, atrioventricular blocks, sinus tachycardia or atrial fibrillation) and/or TTE (left ventricular ejection fraction &lt;55%, presence of regional wall abnormalities or myocardial hypertrophy) was found in 92/180 (51%) patients. CS was diagnosed in 42 of 180 (23%) patients, of whom 31 (74%) had any ECG and/or TTE abnormalities. However, ECG and/or TTE abnormalities were also present in 44% of the patients without cardiac involvement. Patients with CS showed a second type II or third degree AV-blocks in 3/42 (7%), a left ventricular ejection fraction &lt;35% on TTE in 9/42 (21%), late gadolinium enhancement by CMR consistent with CS in 28/34 (82%), and myocardial FDG uptake by PET in 19/31 (61%). In 84 of the 138 patients without cardiac involvement, CMR was performed. In 15 patients an alternative diagnosis was found (i.e. myocardial infarction or other non-ischemic cardiomyopathy). The estimated 8-year cumulative event rate composite endpoint of sustained ventricular tachycardia, ventricular fibrillation, aborted sudden cardiac death, heart transplantation and all-cause mortality was 41% in the CS patients and 12% in the patients without CS (Figure 1, p&lt;0.001).

Conclusions

In our study, 23% of the patients with proven extra-cardiac sarcoidosis was diagnosed with CS. Cardiac symptoms, ECG and TTE were of limited diagnostic value for screening for CS. CMR provided a good diagnostic yield and identified other cardiac diseases in a substantial number of patients.

Figure 1. KMCurve_CompositeEndpoint

Funding Acknowledgement

Type of funding source: None

[A young man with a skin lesion after chemotherapy]

Ecthymagangrenosum is a painful node that rapidly progresses to a necrotic ulcer and occurs as a result of a local infection or hematogenous spread. It has a high mortality rate when treatment is delayed. We describe a 19-year-old male with neutropenic fever due to ecthymagangrenosum caused by Pseudomonas aeruginosa without bacteremia.

P1825 Myocardial bridging and coronary artery disease in hypertrophic cardiomyopathy: a matched case control study

Funding Acknowledgements

None.

Introduction

The etiology of chest pain in hypertrophic cardiomyopathy (HCM) is diverse and includes coronary artery disease (CAD) as well as HCM-specific causes. Myocardial bridging (MB) has been associated with HCM, chest pain, and accelerated atherosclerosis. To investigate differences in the presence of MB and CAD, we compared HCM patients with age-, gender- and CAD pre-test probability (PTP)-matched outpatients presenting with chest pain.

Methods

We studied 84 HCM patients who underwent cardiac computed tomography and compared these with 168 matched controls (age 54 ± 11 years, 70% men, PTP 12% [5%–32%]). MB, calcium score, plaque morphology and presence and extent of CAD were assessed for each patient. Linear mixed models were used to assess differences between cases and controls.

Results

Differences between HCM patients and controls are described in the table. In summary, MB was more often seen in HCM patients (50% vs. 25%, p &lt; 0.001), who were also more likely to have &gt;1 segment affected (14% vs. 2%, p &lt; 0.05). In the HCM group, MB was associated with pathogenic mutation status. Calcium score and the presence of obstructive CAD were similar in both groups (9 [0-225] vs. 4 [0-82] and 18% vs. 19%; p &gt; 0.05 for both).

Conclusion

MB was twice as prevalent in the HCM group. However, in a matched analysis, the prevalence and extent of CAD was equal among patients with and without HCM. These finding illustrate that despite a higher prevalence of MB, the prevalence of CAD is similar between groups, also demonstrating satisfactory performance of pre-test risk prediction in HCM patients.

Assessment of CAD by CT HCM group(n = 84) Control group (n = 168) p-value Agatston score 9 [0-225] 4 [0-82] 0.22 No. of pts with score* 0.07 0-399 31 (89%) 149 (91%) &gt;400 8 (11%) 15 (9%) Obstructive CAD 15 (18%) 32 (19%) 0.82 No. of pts with MB 42 (50%) 42 (25%) &lt;0.001 No. of vessels with MB &lt;0.001 1 34 (40%) 39 (23%) 2 8 (10%) 3 (2%) No. of pts with &gt;1 segment with MB 12 (14%) 4 (2%) &lt;0.001 Abbreviations CAD = Coronary artery disease, MB = Myocardial bridging, pts = patients *Only measured in 73/84 HCM patients and in 164/168 control patients

P802 Delayed time to peak left ventricular outflow tract velocity is associated with symptomatic status in patients with hypertrophic obstructive cardiomyopathy

Funding Acknowledgements

None.

The presence and magnitude of left ventricular outflow tract (LVOT) obstruction in hypertrophic obstructive cardiomyopathy (HOCM) patients is weakly associated with presence of symptoms. The factors underlying this are not well understood. We hypothesize that time to peak velocity (TPV) of LVOT flow is associated with symptomatic status.

We included 136 HOCM patients (58% men, mean age 55 ± 14 years) with peak gradients ≥30 mmHg at rest or during Valsalva without aortic valve stenosis. At rest and during Valsalva, continuous wave Doppler tracings from 3 consecutive beats were used to assess peak velocity (PV), left ventricular ejection time (LVET) and TPV, which was defined as the time interval between the onset of flow over the LVOT and the moment of PV. Differences were compared between asymptomatic and symptomatic patients (defined as New York Heart Association class I vs. II-IV). The relation between symptom status and TPV was investigated using logistic regression models. A random sample of 20 patients was examined by 2 observers and reproducibility was assessed using the intraclass correlation coefficient (ICC).

Symptomatic patients were more often female (table) and had significantly higher mean TPV values (figure). In multivariable logistic regression models, TPV was an independent predictor of symptomatic status after correction for PV, LVOT diameter, heart rate and age (odds ratio 1.02 per 1 ms, p &lt; 0.001). The ICC was 0.99 with a mean difference of 0.28 ± 8.5 ms.

Delayed TPV is associated with symptomatic status in HOCM patients, after adjustment for heart rate, peak velocity, LVOT diameter and age, and is an easily measured echocardiographic variable with excellent inter-reader reproducibility. The clinical implications of delayed TPV, particularly in the context risk prediction and clinical decision making, remain to be determined.

Characteristics per group Asymptomatic HOCM patients n = 47 Symptomatic HOCM patients n = 89 p value Age, y 55 ± 14 55 ± 14 0.99 Male gender 34 (72%) 45 (51%) 0.01 Body mass index, kg/m&sup2; 27 ± 5 28 ± 5 0.08 Left atrial diameter, mm 46 ± 7 47 ± 7 0.64 Septal wall thickness, mm 18 ± 4 19 ± 5 0.58 LV outflow tract diameter, mm 22 ± 3 21 ± 3 0.001 Peak velocity, cm/s 403 ± 86 434 ± 79 0.03 LV ejection time, ms 316 ± 44 340 ± 42 0.002 Time to peak velocity, ms 157 ± 32 178 ± 32 &lt;0.001 HOCM = hypertrophic obstructive cardiomyopathy, LV = left ventricular.

Abstract P802 Figure. Time to peak velocity per NYHA class

Effect of body surface area and gender on wall thickness thresholds in hypertrophic cardiomyopathy

BACKGROUND

Family screening for hypertrophic cardiomyopathy (HCM) is based on genetic testing and clinical evaluation (maximal left ventricular wall thickness (MWT) ≥15 mm, or ≥13 mm in first-degree relatives of HCM patients). The aim of this study was to assess the effect of gender and body size on diagnosis of HCM and prediction of clinical outcome.

METHODS

This study includes 199 genotype-positive subjects (age 44 ± 15 years, 50% men) referred for cardiac screening. Gender-specific reference values for MWT indexed by body surface area (BSA), height and weight were derived from 147 healthy controls. Predictive accuracy of each method for HCM-related events was assessed by comparing areas under the receiver operating characteristic curves (AUC).

RESULTS

Men had a higher absolute, but similar BSA- and weight-indexed MWT compared with women (14.0 ± 3.9 mm vs 11.5 ± 3.8 mm, p < 0.05; 6.8 ± 2.1 mm/m² vs 6.6 ± 2.4 mm/m²; 0.17 ± 0.06 mm/kg vs 0.17 ± 0.06 mm/kg, both p > 0.05). Applying BSA- and weight-indexed cut-off values decreased HCM diagnoses in the study group (48% vs 42%; 48% vs 39%, both p < 0.05), reclassified subjects in the largest, lightest and heaviest tertiles (≥2.03 m²: 58% vs 45%; ≤70 kg: 37% vs 46%; ≥85 kg: 53% vs 25%, all p < 0.05) and improved predictive accuracy (AUC 0.76 [95% CI 0.69-0.82] vs 0.78 [0.72-0.85]; and vs 0.80 [0.74-0.87]; both p < 0.05).

CONCLUSIONS

In genotype-positive subjects referred for family screening, differences in MWT across gender are mitigated after indexation by BSA or weight. Indexation decreases the prevalence of HCM, particularly in larger men, and improves the predictive accuracy for HCM-related events.

P2881Eligibility for a subcutaneous defibrillator based on standard 12-lead electrocardiogram

Background

Currently, the eligibility for a subcutaneous implantable defibrillator (S-ICD) system relies on a pre-implant vector screening based on the automated screening tool (AST).

Objective

To determine 12-lead ECG characteristics associated with eligibility for an S-ICD in a heterogeneous population at risk for sudden cardiac death (SCD). The goal is to determine patient eligibility for S-ICD using the standard 12-lead ECG, thereby avoiding additional AST screening.

Methods

We prospectively evaluated the eligibility for an S-ICD in 254 consecutive patients at risk for SCD. We identified 12-lead ECG parameters which were independently associated with AST passing (≥1 vector) using multivariable logistical regression analysis in our derivation cohort. The final model was tested in a separate validation cohort.

Results

The overall passing rate was 92% in our derivation cohort. Independent 12-lead ECG characteristics associated with AST passing were QRS≤130 ms, absence of QRS/T discordance in lead II and R/T-ratio ≥3.5 in lead II (Table). Eighty-three of 254 patients (33%) fulfilled these three criteria and had a passing rate of 100%. Of the validation cohort, 37 of 60 patients (62%) fulfilled all three criteria and also had a passing rate of 100%. The interobserver agreement for applying the ECG model was 90% (Cohen's Kappa=0.80).

Table 1 Variables Univariable Multivariable OR (95% CI) P-value OR (95% CI) P-value QRS ≤130 ms 9.65 (3.66–25.43) <0.01 8.09 (2.88–22.77) <0.01 QTc ≤450 ms 3.33 (1.18–9.54) 0.02 Absence of T-wave inversion in lead I 2.74 (1.03–7.25) 0.04 Absence of T-wave inversion in lead II 3.65 (1.29–10.33) 0.02 Absence of QRS/T-wave discordance in lead II 5.05 (1.98–12.92) <0.01 4.19 (1.49–11.74) <0.01 Absence of QRS/T-wave discordance in lead aVF 3.95 (1.53–10.19) <0.01 R/T-ratio ≥3.5 in lead II 3.58 (1.27–10.01) 0.02 4.21 (1.27–13.95) 0.02 R/T-ratio ≥3.5 in lead aVF 3.16 (1.18–8.42) 0.02 OR = odds ratio; CI = confidence interval.

Figure 1

Conclusion

Using the standard 12-lead ECG, we developed a simple screening model with a high specificity for S-ICD eligibility. Our results suggest that patients who fulfill the three ECG criteria do not need additional AST-screening. Therefore, we developed a simple flowchart to determine eligibility for an S-ICD that can be easily implemented in daily clinical practice (Figure).

P1244Survival after septal myectomy in male and female patients with hypertrophic obstructive cardiomyopathy

In recent years, studies have debated the impact of gender on the presentation and clinical course of HCM, with research showing that at time of myectomy, women are older, have worse diastolic function and more advanced cardiac remodeling. The clinical impact of these differences is unknown.

We included 221 HCM patients (57% men) who underwent septal myectomy and are followed in our center. Time to treatment was calculated in relation to symptom onset. Pre- and post-operative clinical and echocardiographic data were collected. Gender differences were assessed at baseline and in survival analyses for the composite endpoint of all-cause mortality, cardiac transplantation, re-intervention and aborted sudden cardiac death.

Women were older at time of myectomy, but time until treatment was similar (table). Pre-operative echocardiographic indices were comparable among groups, but were significantly higher in women when correcting for body surface area. At three months, no differences were found in clinical and echocardiographic results. After 6.1 [2.9–10.1] years, 24% of women and 23% of men had reached the composite endpoint (p=0.30, figure).

Gender comparison pre- and post-myectomy Men (n=125) Women (n=96) p value Age 49±14 54±17 0.02 Maximal wall thickness, mm 19.9±4.7 19.8±5.8 0.97 Indexed maximal wall thickness, mm/m2 9.8±2.5 11.5±4.5 0.001 Left atrial diameter, mm 48.1±7.3 45.9±7.3 0.06 Indexed left atrial diameter, mm/m2 23.5±3.5 26.5±7.5 0.002 LV end-diastolic diameter, mm 45.4±7.6 42.8±5.6 0.04 Indexed LV end-diastolic diameter, mm/m2 22.1±3.7 23.6±3.0 0.02 Gradient reduction, %* 75.1±25.0 72.9±28.6 0.63 Improvement in symptoms*† 97 (95%) 64 (89%) 0.34 MWT = maximal wall thickness; LV = left ventricle. *At three months follow-up; †Defined as a reduction of ≥1 NYHA class, measured in 102 men and 72 women.

Survival after myectomy

Although women present later in life and seem to have more advanced disease at time of myectomy, time to treatment is similar and survival after myectomy is excellent for both men and women.

Extra energy for hearts with a genetic defect: ENERGY trial

Aims

Previous studies have shown that hypertrophic cardiomyopathy mutation carriers have a decreased myocardial energy efficiency, which is thought to play a key role in the pathomechanism of hypertrophic cardiomyopathy (HCM). The ENERGY trial aims to determine whether metabolic drugs correct decreased myocardial energy efficiency in HCM mutation carriers at an early disease stage.

Methods

40 genotype-positive, phenotype-negative MYH7 mutation carriers will be treated for two months with trimetazidine or placebo in a double-blind randomised study design. Directly before and after treatment, study subjects will undergo an [¹¹C]-acetate positron emission tomography/computed tomography (PET/CT) and cardiac magnetic resonance (CMR) scan to measure myocardial energy efficiency. Myocardial efficiency will be calculated as the amount of oxygen the heart consumes to perform work.

Conclusion

The ENERGY trial will be the first proof of concept study to determine whether metabolic drugs are a potential preventive therapy for HCM. Given that trimetazidine is already being used in clinical practice, there is large potential to swiftly implement this drug in HCM therapy.

Management of an LCHADD Patient During Pregnancy and High Intensity Exercise

In this report we describe a female Long-Chain 3-Hydroxyacyl-CoA Dehydrogenase Deficiency (LCHADD) patient who suffered from severe exercise intolerance. At age 34, the patient became pregnant for the first time. After an uneventful first 32 weeks of pregnancy she developed sinus tachycardia (resting heart rate 120-134 bpm) and lactate and creatinine kinase levels increased (3.3 mmol/L and 264 U/L, respectively). Increasing MCT supplementation (dose and frequency of administration) lowered heart rate and improved biochemical parameters. At 34 weeks the heart rate rose again and it was decided to deliver the child by caesarean section. Postpartum both mother and child did well.Prior to pregnancy, she performed exercise tests with different doses of medium chain triglycerides (MCTs) to establish a safe and effective exercise program (baseline test, second test with 10 g MCTs and third test with 20 g of MCTs). In the MCT supplemented tests the maximal power output was 23% (second test) and 26% (third test) higher, while cardiac output at maximal power output was the same in all three tests (~15.8 L/min).In conclusion, this is the first report of pregnancy in an LCHADD patient, with favourable outcome for both mother and child. Moreover, in the same patient, MCT supplementation improved cardiac performance and metabolic parameters during high intensity exercise. Using impedance cardiography, we got a clear indication that this benefit was due to improved muscle energy generation at high intensity exercise, since at the same cardiac output a higher power output could be generated.

Platelet function alterations in dengue are associated with plasma leakage

Severe dengue is characterised by thrombocytopenia, plasma leakage and bleeding. Platelets are important for preservation of endothelial integrity. We hypothesised that platelet activation with secondary platelet dysfunction contribute to plasma leakage. In adult Indonesian patients with acute dengue, we measured platelet activation status and the response to the platelet agonist TRAP using flow cytometer-based assays. Patients were monitored daily for plasma leakage by ultrasonography. Acute dengue was associated with platelet activation with an increased expression of the activated fibrinogen receptor (αIIbβ3), the lysosomal marker CD63 and the alpha-granule marker CD62P (P-selectin). Upon maximal platelet activation by TRAP, platelet function defects were observed with a significantly reduced maximal activated αIIbβ3 and CD63 expression and reduced platelet-monocyte and platelet-neutrophil complexes. Patients in the lowest tertile of activated αIIbβ3 and CD63 expression had an odds ratio for plasma leakage of 5.2 (95% confidence interval [CI] 1.3-22.7) and 3.9 (95% CI 1.1-13.7), respectively, compared to the highest tertile. Platelet-derived serotonin has previously been related to plasma leakage and we found increased intra-platelet serotonin concentrations in our patients. In conclusion, platelet activation with platelet function alterations can be found in patients with acute dengue and this may contribute to dengue-associated plasma leakage.

Clinical usefulness of SonoVue contrast echocardiography: the Thoraxcentre experience

Although other imaging techniques, such as magnetic resonance imaging and computer tomography, are becoming more and more important in cardiology, two-dimensional echocardiography is still the most used technique in clinical cardiology. Quantification of left ventricular function and dimensions is important because therapeutic strategies, for example implanting an ICD after myocardial infarction, are based on ejection fraction measurements. Because of the sometimes low quality of echocardiographic images we started to use an ultrasound contrast agent and in this article we describe our experiences with SonoVue, a second-generation contrast agent, over a threeyear period in the Thoraxcentre. (Neth Heart J 2007;15:55-60.).

Recurrent and founder mutations in the Netherlands: cardiac Troponin I (TNNI3) gene mutations as a cause of severe forms of hypertrophic and restrictive cardiomyopathy

BACKGROUND

About 2-7% of familial cardiomyopathy cases are caused by a mutation in the gene encoding cardiac troponin I (TNNI3). The related clinical phenotype is usually severe with early onset. Here we report on all currently known mutations in the Dutch population and compared these with those described in literature.

METHODS

TheTNNI3 gene was screened for mutations in all coding exons and flanking intronic sequences in a large cohort of cardiomyopathy patients. All Dutch index cases carrying a TNNI3 mutation that are described in this study underwent extensive cardiological evaluation and were listed by their postal codes.

RESULTS

In 30 families, 14 different mutations were identified. Three TNNI3 mutations were found relatively frequently in both familial and non-familial cases of hypertrophic cardiomyopathy (HCM) or restrictive cardiomyopathy (RCM). Haplotype analysis showed that p.Arg145Trp and p.Ser166Phe are founder mutations in the Netherlands, while p.Glu209Ala is not. The majority of Dutch TNNI3 mutations were associated with a HCM phenotype. Mean age at diagnosis was 36.5 years. Mutations causing RCM occurred less frequently, but were identified in very young children with a poor prognosis.

CONCLUSION

In line with previously published data, we found TNNI3 mutations to be rare and associated with early onset and severe clinical presentation.

Founder mutations in hypertrophic cardiomyopathy patients in the Netherlands

In this part of a series on cardiogenetic founder mutations in the Netherlands, we review the Dutch founder mutations in hypertrophic cardiomyopathy (HCM) patients. HCM is a common autosomal dominant genetic disease affecting at least one in 500 persons in the general population. Worldwide, most mutations in HCM patients are identified in genes encoding sarcomeric proteins, mainly in the myosin-binding protein C gene (MYBPC3, OMIM #600958) and the beta myosin heavy chain gene (MYH7, OMIM #160760). In the Netherlands, the great majority of mutations occur in the MYBPC3, involving mainly three Dutch founder mutations in the MYBPC3 gene, the c.2373_2374insG, the c.2864_2865delCT and the c.2827C>T mutation. In this review, we describe the genetics of HCM, the genotype-phenotype relation of Dutch founder MYBPC3 gene mutations, the prevalence and the geographic distribution of the Dutch founder mutations, and the consequences for genetic counselling and testing. (Neth Heart J 2010;18:248-54.).

Coronary flow reserve in hypertrophic cardiomyopathy: relation with microvascular dysfunction and pathophysiological characteristics

BACKGROUND.: The decrease in coronary flow reserve (CFR) in hypertrophic cardiomyopathy (HCM) predisposes to myocardial ischaemia, systolic dysfunction and cardiac death. In this study we investigate to which extent haemodynamic, echocardiographic, and histological parameters contribute to the reduction of CFR. METHODS.: In ten HCM patients (mean age 44+/-14 years) and eight heart transplant (HTX) patients (mean age 51+/-6 years) CFR was calculated in the left anterior descending coronary artery. In all subjects haemodynamic, echocardiographic and histological parameters were assessed. The relationship between these variables and CFR was determined using linear regression analysis. RESULTS.: CFR was reduced in HCM compared with HTX patients (1.6+/-0.7 vs. 2.7+/-0.8, p<0.01). An increase in septal thickness (p<0.005), indexed left ventricular (LV) mass (p<0.005), LV end-diastolic pressure (p<0.001), LV outflow tract gradient (p<0.05) and a decrease in arteriolar lumen size (p<0.05) were all related to a reduction in CFR. CONCLUSION.: In HCM patients haemodynamic (LV end-diastolic pressure, LV outflow tract gradient), echocardiographic (indexed LV mass) and histological (% luminal area of the arterioles) changes are responsible for a decrease in CFR. (Neth Heart J 2007;15:209-15.).

The sensitivity of direct identification from positive BacT/ALERT™ (bioMérieux) blood culture bottles by matrix-assisted laser desorption ionization time-of-flight mass spectrometry is low

Recently, matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) has been presented as a novel method for the direct identification of bacteria from positive blood culture bottles. The rate of the MALDI TOF MS-based identification in the present study from positive BacT/ALERT (bioMérieux, Marcy l'Etoile, France) blood culture bottles was 30%, which is far below the previously reported sensitivities using the BACTEC (Becton Dickinson, Franklin Lakes, NJ, USA) system. We also found evidence that the Biotyper algorithm did not identify a second pathogen in cases of positive BacT/ALERT blood culture bottles containing two different species.