The value of QTc dispersion in assessment of cardiac risk in elective aortic aneurysm surgery

Preoperative tests recommendations in adult patients for ambulatory surgery

Anesthetic assessment traditionally included a series of laboratory tests intended to detect undiagnosed diseases, and to ensure that the patient undergoes surgery following safety criteria. These tests, without a specific clinical indication, are expensive, of questionable diagnostic value and often useless. In the context of outpatient surgery, recent evidence suggests that patients of any age without significant comorbidity, ASA physical status gradei and grade ii, do not need additional preoperative tests routinely. The aim of the present recommendations is to determine the general indications in which these tests should be performed in ASA gradei and grade ii patients undergoing ambulatory surgery.

QTc variability in schizophrenia patients treated with antipsychotics and healthy controls

QTc prolongation is associated with the administration of some antipsychotics but the QTc interval is also known to vary physiologically. There is little published evidence about changes in QTc variability during treatment with antipsychotics. In this prospective investigation, we analyzed ECGs in 61 patients suffering from a schizophrenic disorder who were treated with different antipsychotics and 31 sex- and age-matched healthy controls. We found no differences in QTc intervals nor in QTc variability between patients and controls. Our results raise the question of the clinical relevance of a single ECG for diagnostics of cardiac complications in schizophrenia patients and suggest the need to conduct ECG monitoring in patients at high risk for cardiac complications during antipsychotic treatment.

QTc dispersion is prolonged in patients with early postoperative adverse cardiovascular events and those with silent myocardial ischemia

OBJECTIVE

To determine if increased QT interval dispersion (corrected and not corrected for heart rate) is associated with perioperative silent myocardial ischemia or postoperative adverse cardiovascular events.

DESIGN

Blinded retrospective observational study.

SETTING

University hospital.

PARTICIPANTS

One hundred eighty-one perioperative patients receiving general anesthesia for elective major vascular or orthopedic surgery.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

QT dispersion, corrected and uncorrected for heart rate, was prolonged in patients suffering significant myocardial ischemia up to 48 hours assessed by Holter ECG monitoring, for early cardiac morbidity and all early cardiac events (including mortality) up to 1 month postoperatively. There were no significant changes in patients showing early cardiovascular mortality or late cardiac morbidity or mortality between 1 and 12 months postoperatively. Morbidity and mortality were determined from clinical notes, laboratory investigations, and autopsy when available. QT dispersion performed poorly as a screening test to identify those who subsequently developed early adverse cardiovascular outcomes.

CONCLUSIONS

QT dispersion is prolonged in those at risk of early adverse cardiovascular events but is a poor screening tool.

Antipsychotics and QT prolongation

OBJECTIVE

To evaluate literature relating to cardiac QT prolongation and the use of antipsychotic drugs.

METHOD

Literature searches of EMBASE, Medline, PsychLIT were performed in December 2001 and reference sections of retrieved papers scrutinized for further relevant reports.

RESULTS

The Cardiac QTc interval is difficult to measure precisely or accurately but appears to be a useful predictor of risk of dysrhythmia (specifically torsade de pointes) and sudden death. It is less clear that drug-induced QTc prolongation gives rise to similar risks but data are emerging, linking antipsychotic use to increased cardiac mortality. Many antipsychotics have been clearly associated with QTc prolongation. Methodological considerations arguably preclude assuming that any antipsychotic is free of the risk of QTc prolongation and dysrhythmia.

CONCLUSION

Available data do not allow assessment of relative or absolute risk of dysrhythmia or sudden death engendered by antipsychotics but caution is advised. Risk of dysrhythmia can very probably be reduced by careful prescribing of antipsychotics in low doses in simple drug regimens which avoid metabolic interactions. Electrocardiographic monitoring may also help to reduce risk but review by specialist cardiologist may be necessary.