Giornale italiano di cardiologia
-
QT dispersion (maximal minus minimal QT interval calculated on a standard 12-lead electrocardiogram) has been suggested to reflect regional variations of ventricular repolarization and to provide a substrate for reentry ventricular arrhythmias. In this study we evaluate QT dispersion in patients with acute myocardial infarction and assess its relation with early severe ventricular arrhythmias. ⋯ Our data suggest that QT dispersion: 1) increases during acute myocardial infarction; 2) peaks in the early hours after symptom onset; 3) drops late after infarction in patients treated with thrombolytic agents; 4) is associated with early severe ventricular arrhythmias.
-
Review Case Reports
Unusual induction of slow-fast atrioventricular nodal reentrant tachycardia. Report of two cases.
Generally, the induction of typical atrioventricular nodal reentrant tachycardia (AVNRT) occurs with a premature atrial stimulus that blocks in the fast pathway and proceeds down the slow pathway slowly enough to allow the refractory fast pathway time to recover. We describe two cases in which a typical AVNRT was induced in an unusual fashion. ⋯ A rare manifestation of dual atrioventricular nodal pathways is a double ventricular response to an atrial impulse that may cause a tachycardia with an atrioventricular conduction of 1:2. In our first case, an atrial extrastimulus was simultaneously conducted over the fast and the slow pathway inducing an AVNRT. This nodal reentry implies two different mechanisms: 1) a retrograde block on the slow pathway impeding the activation of the slow pathway from the impulse coming down the fast pathway, and 2) a critical slowing of conduction in the slow pathway to allow the recovery of excitability of the fast pathway. Interestingly, in the second case, during an AVRT the atrial impulse suddenly proceeded alternately over the fast and the slow pathway. The progressive slowing of conduction over the slow pathway until a certain point which allows the recovery of excitability of the fast pathway determines the AVNRT. This is a case of "tachycardia-induced tachycardia" as confirmed by the fact that the ablation of the accessory pathway eliminated both tachycardias.
-
Randomized Controlled Trial Comparative Study Clinical Trial
ASSENCE (assessment of cost-effectiveness of several strategies of early diagnosis in patients with acute chest pain and non-conclusive electrocardiogram).
Clinical, economical, organizative, and medico-legal issues raised by management of citizens who come to Emergency Department with acute chest pain and non diagnostic electrocardiogram are well known. Data from the Italian Health Ministry show that, in 1996, 37,444 patients had been discharged from Italian hospitals with the main diagnosis of chest pain. To obtain this "non-diagnosis", it was needed a mean hospital stay of 4.2 days with estimated costs close to $57,000,000. ⋯ Costs will be assessed taking into account: hospital stay length, performed diagnostic procedures and treatments during index admission, in-hospital and 2-month follow-up events (cardiac death, myocardial infarction, definite unstable angina, coronary angioplasty, by-pass surgery, re-admission to hospital for chest-pain). A secondary ASSENCE study end-point will be to assess the effect on patient quality of life of the use of the 3 strategies tested. Sample size estimation calculated in order to detect an absolute difference of at least 10% and based on a 30% expected rate of events, was of 186 patients for each strategy tested.