Cardiac involvement in myotonic dystrophy

Abstract

BackgroundMyotonic dystrophy (DM) is an inherited progressive muscle disorder caused by defects in muscle proteins. As the incidence of this condition is low, not many are familiar with the multisystem involvement. At times, cardiac disease may even be the predominant manifestation in the form of arrhythmias, conduction defects, and cardiomyopathies. The progression of the disease can lead to sudden, unpredictable death. Thus, it is important to identify this subgroup and treat accordingly.ObjectiveTo identify patients with DM and assess their risk for sudden cardiac death.MethodsNine patients previously diagnosed with muscular dystrophy were evaluated by cardiologists for various reasons, from a general follow-up to cardiac arrest. All of them had electrocardiograms (EKG) and 2-D echocardiograms, and seven of them had further electrophysiological (EP) studies.ResultsOf the nine patients with DM, eight had EKG evidence of conduction abnormalities ranging from first-degree heart block to complete heart block. Of the seven who had EP studies, five had inducible ventricular tachycardia requiring immediate cardioversion and implantable cardioverter defibrillator (ICD) implant. Two of them underwent permanent pacemaker placement due to complete heart block and infra-Hissian block. The remaining two patients opted for a conservative approach with yearly EKG monitoring.ConclusionBecause one-third of the cardiac deaths in patients with DM are sudden, there is a strong need to identify these patients and intervene in those at high risk. Prophylactic pacemaker placement is recommended even in those with minimal conduction system abnormality. However, the common practice is to identify patients at high risk of conduction abnormalities by EP studies and then provide them with prophylactic invasive strategies.

Symptomatic Trifascicular Block in Steinert’s Disease: Is It Too Soon for a Pacemaker?

“…A 12-lead EKG is an appropriate screening test and should be performed annually after the diagnosis of DM [ 11 ]. Radionucleotide imaging and echocardiography may reveal diastolic and systolic dysfunction in either ventricle [ 5 ].…”

Progression to Complete Heart Block in a Patient With Myotonic Dystrophy

“…Electrophysiological studies with prophylactic pacemaker placement and ICD is recommended for those at risk for severe bradycardia, high degree AV block or malignant ventricular arrhythmia. There is a class I recommendation for device placement for the high risk patients but unfortunately prophylactic pacing is rarely pursued, even though lower mortality and increased survival rates have been shown [7][8][9]. Patient with high risk EKGs, defined as PR interval greater than 200 ms and/or QRS duration greater than 100 ms, who underwent invasive implantation of a prophylactic pacing device showed a significant survival benefit of 9 years when compared to their non-invasive counterparts [9].…”

Rare neurological diseases and pregnancy

“…Наиболее частыми симптомами поражения сердца являются аритмии, атриовентрикулярные блокады, кардиомиопатия, застойная сердечная недостаточность, синкопальные состояния и внезапная смерть, причем каждая третья смерть является внезапной [8,9]. Наиболее частыми респираторными нарушениями у больных миотонической дистрофией являются гиповентиляция, аспирационная пневмония и апноэ во время сна.…”