Beat-to-beat T-wave amplitude variability in the long QT syndrome.

Aims: Long QT syndrome (LQTS) is a primary electrical disease characterized by QT prolongation and increased repolarization dispersion leading to T-wave amplitude beat-to-beat changes. We aimed to quantify beat-to-beat T-wave amplitude variability from ambulatory Holter recordings in genotyped LQTS patients.

Methods And Results: Seventy genotyped LQTS patients (mean age 23 +/- 15 years, 42 males, 50% LQT1, 39% LQT2, and 11% LQT3) and 70 normal matched control subjects underwent a 24-h digital Holter recording.

[Bidirectional ventricular tachycardias].

Bidirectional tachycardias are rare arrhythmias. Nevertheless in the sixties and seventies these arrhythmias prompted much work relating to their mechanism. Discussions about the supposed supra-ventricular origin of certain bidirectional tachycardias essentially rested on presumptive arguments based on electrocardiographic analysis.

[Brugada syndrome].

The Brugada syndrome is characterised clinically by the occurrence of syncope or sudden death due to ventricular arrhythmias in patients with structurally normal hearts and electrocardiographic signs of right bundle branch block and ST elevation in the right precordial leads (V1 to V3). The transmission of the condition is autosomal dominant with variable penetration. Mutations have been identified in a gene coding for the alpha sub-unity of the sodium channel (SCN5A) on chromosome 3 in only 30% of cases.

Spontaneous sequences of onset of torsade de pointes in patients with acquired prolonged repolarization: quantitative analysis of Holter recordings.

Objectives: This study investigated the cycle length changes preceding the spontaneous onset of torsade de pointes in patients with acquired prolonged ventricular repolarization.

Background: Torsade de pointes is a polymorphic ventricular tachycardia generally associated with prolonged ventricular repolarization. Because torsade de pointes is not inducible by programmed electrical stimulation, quantitative analysis of Holter recordings of spontaneous episodes may clarify the mechanisms favoring the onset of torsade de pointes in actual clinical conditions.

[Effects of sublingual nifedipine on the velocity of pulse wave evaluated by Doppler echocardiography of the thoracic aorta].

Sublingual nifedipine has a rapid and powerful hypotensive effect. Its action on arterial distensibility can be assessed by measurement of pulse wave velocity (PWV) by Doppler echocardiography (DE). Ten patients were used to evaluate intra-observer reproducibility (Group 1).