QT prolongation after ampicillin anaphylaxis

Transient QT interval prolongation with inverted T waves indicates myocardial salvage on dual radionuclide single-photon emission computed tomography in acute anterior myocardial infarction

In patients with acute myocardial infarction (AMI), transient QT interval prolongation with a prominent negative T wave is frequently observed in cases of early spontaneous reperfusion and often indicates a good prognosis. Additionally, in nuclear cardiac imaging, technetium-99m/thallium-201 overlap on dual single-photon emission computed tomography (dual SPECT) in AMI patients indicates the presence of viable myocardium and early recanalization. To elucidate the clinical significance of this transient QT interval prolongation, 34 patients (64 +/- 8 years) admitted within 24h of the onset of anterior AMI were enrolled and classified into 2 groups according to the presence (group A, n=24) or absence (group B, n=10) of scintigraphic overlap on simultaneous dual SPECT imaging. The maximal QTc interval was 0.59 +/- 0.06 s in group A and 0.52 +/- 0.06 s in group B (p<0.01). The peak creatine kinase was lower in group A (2650 +/- 2160 IU/L) than in group B (3490 +/- 2060 IU/L). The left ventricular ejection fraction (LVEF) at discharge was 62 +/- 11% in group A and 49 +/- 14% in group B (p<0.01). The scintigraphic overlap group had a smaller infarct and better LVEF, which suggests that the QT interval prolongation that appears transiently in the acute phase of AMI indicates scintigraphically the presence of salvaged myocardium.

Electrocardiographic changes associated with anaphylaxis in a patient with normal coronary arteries

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Drug effects on the electrocardiogram. A review of their clinical importance

It is clear that many patients are now being treated with multiple pharmacological agents which may alter membrane function and ionic fluxes across membranes. Therefore, these agents will frequently influence the electrical behavioural of all excitable tissues including the myocardial cell. The changes in the myocardial cell are often reflected by changes, some subtle, some obvious, on the body surface electrocardiogram. Thus, the electrocardiogram provides the physician with a reasonably simple and inexpensive tool for monitoring drug effects and for detecting changes that may be toxic and/or life-threatening. For this reason, an appreciation of these changes by the noncardiologist has become increasingly important.

QT-interval prolonging drugs: mechanisms and clinical relevance of their arrhythmogenic hazards

The antiarrhythmic principle of drug-induced QT-interval prolongation is well known. However, with the widespread use of the presently known and new Class III antiarrhythmic agents under investigation, and the growing number of agents not primarily designed as antiarrhythmic drugs that potentially cause QT prolongation, we have also become aware of the proarrhythmic hazards associated with many of these agents. The proarrhythmic risk differs markedly from one agent to another and interferes with many individual clinical variables (e.g., hypokalemia, sinus bradycardia). This paper summarizes the present data on the proarrhythmic risk of drug-induced QT prolongation, including the value and problems of the rate-corrected QT interval, the mechanisms involved in the genesis of proarrhythmia, and the clinical cofactors that facilitate the occurrence of proarrhythmic events. In addition, an extensive database provides information on the known proarrhythmic risk of all currently used QT-prolonging agents.