A Normal Electrocardiogram Does Not Exclude Infra-Hisian Conduction Disease in Patients With Myotonic Dystrophy Type 1

Objectives: This study aimed to identify electrocardiographic (ECG) predictors of a prolonged His-ventricular (HV) interval in patients with type 1 myotonic dystrophy (DM1).\ud Background: Patients with DM1 have an increased risk of sudden cardiac death. The presence of His-Purkinje system disease/prolonged HV interval (≥70 ms) is associated with a higher risk of potentially life-threatening bradyarrhythmic events. Methods: Electrophysiology studies (EPSs) were performed in all DM1 patients referred to 2 tertiary centers for routine cardiac assessment. In a subgroup of patients, the EPS was repeated at varying intervals. Results: A total of 154 patients (mean age: 43.7 ± 13.3; 58.1% male) underwent 202 diagnostic EPSs. HV ≥70 ms was found on 58 EPSs (28.7%); 9 of 59 patients (15.2%) with PR <200 ms and QRS interval <110 ms on baseline ECG had an HV ≥70 ms on EPS. Among those with PR ≥200 ms and/or QRS interval ≥100 ms, only 33.9% had an HV ≥70 ms on EPS. There were 38 patients who underwent repeated EPS, in which 28.8% demonstrated a prolongation of the HV interval overall compared with baseline. QRS duration demonstrated the most powerful discriminative capacity for HV ≥70 ms (area under the receiver operating characteristic curve: 0.76; 95% confidence interval [CI]: 0.68 to 0.84; p < 0.001). On multivariate analysis, QRS interval ≥112 ms had the highest predictive value for HV ≥70 ms (odds ratio: 7.94; 95% CI: 3.85 to 16.37. Conclusions: ECG parameters have a poor predictive value for infra-Hisian conduction block in DM1 patients. QRS and PR intervals are normal in up to 15.2% of DM1 patients with prolonged HV, and 66.1% of those with PR ≥200 ms and/or QRS ≥100 ms do not have advanced His-Purkinje conduction system disease on EPS. Electrophysiology testing should be a mandatory part of screening for all patients to guide prophylactic pacemaker implantation

Andersen-Tawil Syndrome Presenting with Complete Heart Block

Andersen-Tawil syndrome (ATS) is a rare autosomal dominant neuromuscular disorder due to mutations in the KCNJ2 gene. The classical phenotype of ATS consists of a triad of periodic paralysis, cardiac conduction abnormalities and dysmorphic features. Episodes of either muscle weakness or cardiac arrhythmia may predominate however, and dysmorphic features may be subtle, masking the true breadth of the clinical presentation, and posing a diagnostic challenge. The severity of cardiac involvement varies but includes reports of life-threatening events or sudden cardiac death, usually attributed to ventricular tachyarrhythmias. We report the first case of advanced atrioventricular (AV) block in ATS and highlight clinical factors that may delay diagnosis

Whole body bone scintigraphy in osseous hydatosis: a case report

Hydatid disease is common in many parts of the world, and causes considerable health and economic loss. This disease may develop in almost any part of the body

An overview of heart rhythm disorders and management in myotonic dystrophy type 1

Myotonic dystrophy type 1 (DM1) is the most common adult form of muscular dystrophy, presenting with a constellation of systemic findings secondary to a CTG triplet expansion of the noncoding region of the DMPK gene. Cardiac involvement is frequent, with conduction disease and supraventricular and ventricular arrhythmias being the most prevalent cardiac manifestations, often developing from a young age. The development of cardiac arrhythmias has been linked to increased morbidity and mortality, with sudden cardiac death well described. Strategies to mitigate risk of arrhythmic death have been developed. In this review, we outline the current knowledge on the pathophysiology of rhythm abnormalities in patients with myotonic dystrophy and summarize available knowledge on arrhythmic risk stratification. We also review management strategies from an electrophysiological perspective, attempting to underline the substantial unmet need to address residual arrhythmic risks for this population

Andersen-Tawil Syndrome Presenting with Complete Heart Block

Andersen-Tawil syndrome (ATS) is a rare autosomal dominant neuromuscular disorder due to mutations in the KCNJ2 gene. The classical phenotype of ATS consists of a triad of periodic paralysis, cardiac conduction abnormalities and dysmorphic features. Episodes of either muscle weakness or cardiac arrhythmia may predominate however, and dysmorphic features may be subtle, masking the true breadth of the clinical presentation, and posing a diagnostic challenge. The severity of cardiac involvement varies but includes reports of life-threatening events or sudden cardiac death, usually attributed to ventricular tachyarrhythmias. We report the first case of advanced atrioventricular (AV) block in ATS and highlight clinical factors that may delay diagnosis

Thoracic Outlet Syndrome Caused by Hydatid Cyst of the First Rib-Rare But Important

Hydatid cysts are usually located in the liver and lungs. Skeletal echinococcosis is relatively rare and that of the rib is exceptional. Less than 50 cases of costal echinococcosis have been reported in the literature so far. To our knowledge, only one case report of thoracic outlet syndrome due to echinococcal cyst in the first rib was described in 1995. Accurate pre-operative diagnosis is important but may be challenging in some cases. Reported here is a case of echinococcosis of the first rib in a young adult who was presented with thoracic outlet syndrome. Plain chest radiograph, CT scan and MRI were performed. The imaging features were suggestive of a solitary aneurysmal bone cyst and the differential diagnosis included echinococcosis of the first rib. The lesion was completely resected and the histopathological examination confirmed the diagnosis of echinococcosis

New risk prediction score for life-threatening ventricular tachyarrhythmias in laminopathies

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