Holter Recordings at Initial Assessment for Long QT Syndrome: Relationship to Genotype Status and Cardiac Events

Figures

• 

  Figure 1. Holter-derived mean QTc (Panel (A)) and RTPc values (Panel (B)) from 101 subjects with long QT syndrome, values are mean ± SD (ms, milliseconds). “Girls”—females < 15 years and “Boys”—males < 15 years. Normative ranges are shown in grey shading. The central motif indicates the mean value.

• 

  Figure 2. The association of ECG and Holter recording measurements with symptoms and cardiac arrest among families presenting for assessment with long QT syndrome (101 patients with long QT syndrome and 28 gene negative family members). (A) Panel shows QTc values from the initial 12 lead ECG expressed as milliseconds above the age/sex-based reference values. Only 2/10 patients who had cardiac arrest (left side) and 7/24 symptomatic patients (right side) had a QTc exceeding 500 ms on their first ECG. (B) This panel shows Holter-derived mean RTPc values (R wave to peak T wave corrected for heart rate) expressed as milliseconds above the age/sex-based reference range. Results from 10 cardiac arrest survivors are shown on the left versus the rest, and on the right the symptomatic versus asymptomatic subjects are shown. Only one symptomatic patient had a value in the normal range. ms = milliseconds. Black circle—LQTS with symptoms, black square—LQTS with cardiac arrest, white circle—all subjects (gene positive and negative) without symptoms, white square—all subjects (gene positive and negative) without cardiac arrest.

• 

  Figure 3. Holter-derived mean QTc and RTPc values are shown from those less than 7 years of age. Normative controls (n = 16) are shown in grey, and those with long QT syndrome (n = 31) are shown in black. Values were rounded up or down to the nearest 10 ms.