Myotonic Dystrophy Type 1 and Type 1 Brugada pattern: Brugada phenocopy or Brugada syndrome?

Andrés Ricardo Pérez Riera
Andrés Ricardo Pérez Riera

Case presentation

A 42-year-old Caucasian Brazilian man referred by his ophthalmologist to evaluate the surgical risk for cataract surgery. He had clinical-genetic diagnosis of Steinert’s disease since 22 years of age. He complained of a long history of progressive muscular weakness and myotonic phenomenon predominantly in the distal leg, forearm, wrists, hand and fingers. Additionally, he reported dysphagia, mastication problem, constipation, diabetes, and progressive loss of visual acuity. It was not possible to know their family history as he was an adopted son. He denied any sign of cardiovascular involvement.

Physical: He had bilateral cataracts, droopy eyelids, nasal voice quality, blood pressure 135/80 mmHg, pulse rate 55 bpm. Absence of evidence of jugular venous distension in the neck. Palpation of the point of maximum impulse verified with 1 cm lateral shift at the left of the midclavicular line at the 5th intercostal space. Absence of thrills.

Normal physiological first (S1) and second sounds (S2) with physiological split, during inhalation. S3 heart sound that increased in intensity with exhalation and had gallop cadence. Absence of heart murmurs.

Lung: normal vesicular breath sounds. Inspiration/expiration ratio 3:1. Absence of crackles and wheezes.
A palpable and painful liver 2 cm from the right costal margin.

Absence of swelling in legs, ankles, or feet.

We performed electrocardiogram (ECG) (Figure 1), vectorcardiogram (VCG) (Figure 2A, Figure 3, Figure 4). He brought an ECG performed 3 years before (Figure 5). We requested: signal-averaged ECG (SAECG), heart rate variability (HRV), 24-hour Holter and ambulatory transthoracic echocardiogram (TTE), genetic screening for Brugada syndrome with a panel for 20 genes (SCN5A, ABCC9, CACNA1C, CACNB2, CACNA2D1 GPD1L, HCN4, KCND3, KCNE4, KCNE5, KCNJ8, PKP2, SCN10A, SCN1B, SCN2B, SCN3B, SCN5A, RANGRF, SLMAP and TRPM4) that was negative; and electrophysiology study (EPS).

Transthoracic echocardiogram (TTE): regional wall motion abnormality, minimal left atrial enlargement, minimal left ventricular hypertrophy, Doppler evidence of mild diastolic dysfunction and discrete impairment of ventricular systolic and diastolic functions. LVEF 50%, Signal-Averaged ECG (SAECG): positive late potentials.



1. What is the ECG/VCG diagnosis?
2. What is the clinical diagnosis?
3. What is the appropriate approach?
4. What is the ECG diagnosis of the Figure 5?

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Auspicios Institucionales
  • Sociedad Argentina de Cardiología
  • Federación Argentina de Cardiología
  • SIAC
  • Asociación Argentina de Cardiología
  • Latin American Heart Rhythm Society
  • Fundación Barceló - Facultad de Medicina