The Definition of Sarcomeric and Non-Sarcomeric Gene Mutations in Hypertrophic Cardiomyopathy Patients: A Multicenter Diagnostic Study Across Türkiye

Evaluation of potential links between phenotypic features and genetic variants in left ventricular outflow tract obstruction in hypertrophic cardiomyopathy using cardiovascular magnetic resonance imaging

This study aimed to identify the phenotypic features contributing to the development of left ventricular outflow tract obstruction (LVOTO) in patients with hypertrophic cardiomyopathy (HCM) and to evaluate the genotype‒phenotype relationship. This cross-sectional study included 96 patients diagnosed with HCM (mean age: 56.9 ± 13.5 years, 32.3% female). The patients were divided into hypertrophic nonobstructive cardiomyopathy (HNCM; n = 60) and hypertrophic obstructive cardiomyopathy (HOCM; n = 36) groups. All patients underwent CMR. Patients (n = 77) who had previously provided formal approval underwent a genetic examination that included 18 genes. The anterior mitral leaflet (AML) length/LVOT diameter ratio, posterior mitral leaflet (PML) length/LVOT diameter ratio, and anterolateral papillary muscle (AL-PM) mobility were associated with LVOTO, independent of the basal IVS thickness, abnormal chordal attachment, and bifid PM. An AML length/LVOT diameter ratio of ≥ 2.30, a PML length/LVOT diameter ratio of ≥ 1.83, and an AL-PM mobility of ≥ 57.7% were predictors of LVOTO, with good sensitivity and specificity. Positive variants (VUS, LP, and P) were detected in 37.7% (29 of 77) of the patients who underwent genetic testing. The LP/P variant was detected in 20.8% (16 of 77) of patients. Three groups (variant-negative, VUS, and LP/P groups) had significant differences in the LVOT diameter (median 14, 12, and 10 mm, respectively; p = 0.021), AML length (mean 25.3, 26.5, and 27.5 mm, respectively; p = 0.029), AML length/LVOT diameter ratio (median 1.74, 2.33, and 2.85, respectively; p = 0.006), PML length/LVOT diameter ratio (median 1.29, 1.82, and 2.10, respectively; p = 0.045), and abnormal chordal attachment (6.3%, not observed, and 31.3%, respectively; p = 0.009). The AML length/LVOT diameter ratio, PML length/LVOT diameter ratio, and AL-PM mobility were associated with LVOTO. In addition, genetic testing results may provide information regarding the phenotypic expression of patients with HCM.

Septal Myectomy in Patients with Hypertrophic Cardiomyopathy and Nonclassical Anderson-Fabry Disease

Anderson-Fabry disease (AFD) results from decreased enzyme activity of lysosomal enzymes and intralysosomal storage of nonhydrolyzed forms. Cardiovascular complications, mainly in the form of HCM, contribute substantially to AFD patient mortality. Here, we report three new cases of obstructive HCM (HOCM) in nonclassical presentations of AFD and isolated cardiac involvement. In all three cases, the diagnosis of AFD was made postoperatively by routine genetic and morphological testing. Together with previously published cases, this report illustrates the potential safety and beneficial effect of septal surgical myectomy in patients with AFD-HOCM, as well as underlines the need for more thorough screening for clinical signs of AFD-associated cardiomyopathy and GLA variants among patients with HOCM.

When Paying Attention Pays Back: Missense Mutation c.1006G>A p. (Val336Ile) in PRKAG2 Gene Causing Left Ventricular Hypertrophy and Conduction Abnormalities in a Caucasian Patient: Case Report and Literature Review

PRKAG2 cardiomyopathy is a rare genetic disorder that manifests early in life with an autosomal dominant inheritance pattern. It harbors left ventricular hypertrophy (LVH), ventricular pre-excitation and progressively worsening conduction system defects. Its estimated prevalence among patients with LVH ranges from 0.23 to about 1%, but it is likely an underdiagnosed condition. We report the association of the PRKAG2 missense variant c.1006G>A p. (Val336Ile) with LVH, conduction abnormalities (short PR interval and incomplete right bundle branch bock) and early-onset arterial hypertension (AH) in a 44-year-old Caucasian patient. While cardiac magnetic resonance (CMR) showed a mild hypertrophic phenotype with maximal wall thickness of 17 mm in absence of tissue alterations, the electric phenotype was relevant including brady-tachy syndrome and recurrent syncope. The same variant has been detected in the patient's sister and daughter, with LVH + early-onset AH and electrocardiographic (ECG) alterations + lipothymic episodes, respectively. Paying close attention to the coexistence of LVH and ECG alterations in the proband has been helpful in directing genetic tests to exclude primary cardiomyopathy. Hence, identifying the genetic basis in the patient allowed for familial screening as well as a proper follow-up and therapeutic management of the affected members. A review of the PRKAG2 cardiomyopathy literature is provided alongside the case report.

Sudden Cardiac Death, Post-Mortem Investigation: A Proposing Panel of First Line and Second Line Genetic Tests

Investigating the causes of Sudden cardiac death (SCD) is always difficult; in fact, genetic cardiac conditions associated with SCD could be "silent" even during autopsy investigation. In these cases, it is important to exclude other aetiology and assist to ask for genetic investigations. Herein, the purpose of this review is to collect the most-implicated genes in SCD and generate a panel with indications for first line and second line investigations. A systematic review of genetic disorders that may cause SCD in the general population was carried out according to the Preferred Reporting Item for Systematic Review (PRISMA) standards. We subsequently listed the genes that may be tested in the case of sudden cardiac death when the autopsy results are negative or with no evidence of acquired cardiac conditions. To make genetic tests more specific and efficient, it is useful and demanded to corroborate autopsy findings with the molecular investigation as evident in the panel proposed. The genes for first line investigations are HCM, MYBPC3, MYH7, TNNT2, TNNI3, while in case of DCM, the most implicated genes are LMNA and TTN, and in second line for these CDM, ACTN2, TPM1, C1QPB could be investigated. In cases of ACM/ARVC, the molecular investigation includes DSP, DSG2, DSC2, RYR2, PKP2. The channelopathies are associated with the following genes: SCN5A, KCNQ1, KCNH2, KCNE1, RYR2. Our work underlines the importance of genetic tests in forensic medicine and clinical pathology; moreover, it could be helpful not only to assist the pathologists to reach a diagnosis, but also to prevent other cases of SCD in the family of the descendant and to standardise the type of analysis performed in similar cases worldwide.

Short- and Mid-Term Outcomes of Early Alcohol Septal Ablation Therapy for Patients with Mildly Symptomatic Hypertrophic Obstructive Cardiomyopathy: A Tertiary Center Experience

Background: Left ventricular outflow tract obstruction (LVOTO) impairs survival and diminishes quality of life in patients with hypertrophic obstructive cardiomyopathy (HOCM). In this study, we aimed to investigate the safety and the efficacy of earlier alcohol septal ablation (ASA) in patients with HOCM. Methods: A total of 47 patients with mildly symptomatic HOCM (NYHA II) and having poor functional capacity despite maximal tolerated medical therapy were included. Results: The mean age of the patients was 55 ± 14, and 57% of the patients were male. All clinical endpoint targets including 30 d mortality (1% vs. 0% p < 0.01), 30 d adverse complications (10% vs. 0% p < 0.01), 30 d complete heart block resulting in need for permanent pacemaker (10% vs. 4.2% p < 0.01), more than moderate residual mitral regurgitation (5% vs. 2.1% p < 0.01), repeat procedure rate (10% vs. 4.2% p < 0.01), improvement of (NYHA) class (90% vs. 95.7% p < 0.01), rest and provoked (LVOT) gradient < 50 mmHg (90% vs. 97.8% p < 0.01) were significantly reached. Conclusions: In patients with mildly symptomatic HOCM (NYHA II), earlier ASA may be performed as an effective and safe procedure in experienced centers.

Current barriers and recommendations on the diagnosis of transthyretin amyloid cardiomyopathy: a Delphi study

Objectives

This study has been conducted to investigate the non-invasive diagnostic journey of patients with a transthyretin amyloid cardiomyopathy (aTTR-CM) in Turkey, identify the challenges and uncertainties encountered on the path to diagnosis from the perspectives of expert physicians, and develop recommendations that can be applied in such cases.

Methods

This study employed a three-round modified Delphi method and included 10 cardiologists and five nuclear medicine specialists. Two hematologists also shared their expert opinions on the survey results related to hematological tests during a final face-to-face discussion. A consensus was reached when 80% or more of the panel members marked the "agree/strongly agree" or "disagree/strongly disagree" option.

Results

The panelists unanimously agreed that the aTTR-CM diagnosis could be established through scintigraphy (using either 99mTc-PYP, 99mTc-DPD, or 99mTc-HMPD) in a patient with suspected cardiac amyloidosis (CA) without a further investigation if AL amyloidosis is ruled out (by sFLC, SPIE and UPIE). In addition, scintigraphy imaging performed by SPECT or SPECT-CT should reveal a myocardial uptake of Grade ≥2 with a heart-to-contralateral (H/CL) ratio of ≥1.5. The cardiology panelists recommended using cardiovascular magnetic resonance (CMR) and a detailed echocardiographic scoring as a last resort before considering an endomyocardial biopsy in patients with suspected CA whose scintigraphy results were discordant/inconclusive or negative but still carried a high clinical suspicion of aTTR-CM.

Conclusion

The diagnostic approach for aTTR-CM should be customized based on the availability of diagnostic tools/methods in each expert clinic to achieve a timely and definitive diagnosis.