Heroin Addiction and Related Clinical Problems 2009; 11(4):5-10

QT Interval

Caldarola P., Cuonzo M.

Correspondence: Pasquale Caldarola, MD, Cardiologic Unit, "M. Sarcone" Hospital, Via P. Fiore, 153 - 70038 Terlizzi, Bari, Italy E-mail:bari4@cardionet.it

Summary: The electrocardiogram records the electrical activity of the heart, the depolarization and repolarization of the atria and ventricles. Deflections are all shown by the single features of the electrocardiogram: the P wave, the QRS complex, the T wave, the U wave, the PR interval and the QT. The QT interval represents the entire electrical activity of the left ventricle: it begins with the onset of ventricular depolarization (start of the Q wave) and is completed when ventricular repolarization ends (at the end of the T wave). Measurement of the QT interval is important because of the useful information it provides on the electrical activity of the heart; the length of the interval depends on various pathophysiological conditions, changes in electrolyte concentration, and the pharmacological action of toxic substances.

Publication Type: Seminar

 

Heroin Addiction and Related Clinical Problems 2009; 11(4):11-20

Psychoactive Drugs and Prolongation of the QT Interval

Deruvo G., Vendramin A., Di Sciascio G.

Correspondence: Gaetano Deruvo, MD - SerT AUSL BA/4 - Via Giovanna da Durazzo, 53 - 70032 Bitonto (BA), Italy  E-mail: <deruvogaetano@libero.it>

Summary: The links between psychiatry and cardiology that are pertinent to potential cardiovascular risks associated with the use of psychotropic drugs, especially antipsychotics, cannot be viewed as entirely new. In Italy, however, an important innovation was made when, on 28 February 2007, the Italian Medicines Agency (AIFA), issued a directive laying down provisions for the amendment of the printed papers that accompany various medicines, including haloperidol; that initiative has revived the relevance of the whole question. In particular, contraindications to the use of these drugs have been redefined. The primary ones are now listed as acute myocardial infarction, decompensated heart failure, arrhythmias treated with antiarrhythmic drugs belonging to special classes, the prolongation of the QT interval corrected for heart rate (QTc), the family history for arrhythmia or torsades de pointes, hypokalaemia and the concomitant use of drugs that prolong the QTc.

 

Publication Type: Seminar

 

Heroin Addiction and Related Clinical Problems 2009; 11(4):21-28

Opioid Treatment and “Long-QT Syndrome (LQTS)”: a Critical Review of the Literature

Pacini M., Maremmani A. G. I., Dell'Osso L., Maremmani I.

Correspondence: Matteo Pacini, MD, "G, De Lisio" Institute of Behavioural Sciences, Via di Pratale, 3 - 56127 Pisa, Italy E-mail: paciland@virgilio.it

Summary: The present review aims at perusing the available literature about QT-related cardiac safety during methadone treatment. On the whole, case reports, either single or multiple, do not seem a reasonable bases to draw conclusions about the weight of any putative risk factor for QT prolongation. On the other hand, systematic studies allow making some statements about the extension and weight of QT prolongation during methadone maintenance treatment for heroin addiction. No major concern about cardiac safety of methadone itself in the average addict seems to stand. Conditions at higher risk of multiple and polydrug treatments deserve some greater surveillance. No rationale for a dose-ceiling stands in a risk/benefit perspective.

Publication Type: Review

 

Heroin Addiction and Related Clinical Problems 2009; 11(4):29-34

Management of Cardiac Risk during Methadone Treatment: Focus on the QT Interval

Pani P. P.

Correspondence: Pier Paolo Pani, MD - Director Social-Health Service, Health District 8 (ASL 8), Cittadella della Salute, Padiglione C, Via Romagna, 16 - 09100 Cagliari, Italy, EU. Phone +39 070 47443701; E-mail: pallolo@tin.it

Summary: In recent years, methadone, along with various other drugs, has been implicated in the lengthening of the QT interval of the electrocardiogram (ECG) and in the onset of potentially fatal arrhythmias. The risk of prolonged QT in methadone-maintained subjects is estimated at between 2-4%, while the risks of torsades de pointes or sudden death are extremely low. Despite the diversities reported, the guidelines available to date indicate the need to implement preventive measures based on ECG screening.

The impact of these recommendations is, however, limited by the lack of a comparative risk/benefit assessment of specific procedures.

Publication Type: Seminar

 

Heroin Addiction and Related Clinical Problems 2009; 11(4):35-40

Cardiovascular Complications of Cocaine Use

Gambarana C.

Correspondence: Carla Gambarana, MD, Dept. Neuroscience, University of Siena, Via Aldo Moro, 4 - 53100 Siena, Italy E-mail: gambarana@unisi.it

Summary: As cocaine use has become prevalent, an increasing number of reports of cocaine-associated morbidity and mortality, largely because of central nervous system and cardiovascular toxicity, appeared. Cardiovascular toxicity is broad, and it may also lead to neurological, psychiatric and other organ-specific symptoms. Cocaine may induce myocardial ischemia by increasing myocardial oxygen demand while simultaneously decreasing myocardial oxygen supply. Most of the cardiovascular toxic effects elicited by cocaine are likely related to its ability to selectively bind to the L-type calcium channels and the potassium channels that modulate the Ikr current. In addition, cocaine may promote intracoronary thrombosis in the absence of coronary atherosclerosis. This article briefly reviews the current knowledge regarding the cardiovascular effects of cocaine, providing insight into some of the underpinning mechanisms.

Key Words: adrenergic receptors, monoamine uptake, L-type calcium channels, acute coronary events

Publication Type: Seminar