HIV and Long QT syndrome - Cause or coincidence? Puri R, Roberts-Thomson KC, Young GD. International Journal of Cardiology 2009 133;1:e9-e10
Dear Colleagues,
This may be the first article to formally describe the link between HIV and torsade de pointes tachycardia and at the same time to question the role of methadone. Their single case report has much in common with others in the literature: the 36 year old female with HIV was taking long term methadone for dependency and presented with recurrent syncope. The dose was only 70mg daily at the time of the torsade but importantly, had been 190mg daily 18 months previously – at which time ECG showed the QTc to be normal - and there were no cardiac symptoms. The authors proposed that their patient did not have methadone induced QT changes, but HIV-induced long QT (LQT) syndrome. The QTc was 540ms around the time of the torsade.
These authors go on to discuss the effects of HIV on the heart. Up to 60% apparently have positive cardiac findings at autopsy and 30% of cases may have asymptomatic prolonged QTc, largely in the absence of ‘culprit’ medications (citing Kocheril 1997). “Minor repolarisation abnormalities in HIV infecteds may therefore become clinically overt in the setting of concomitant predisposing drug therapies.”
The authors state in their introduction: “Methadone use has been associated with prolongation of the QTc and an increased risk of sudden cardiac death.” In fact after 40 years of widespread use there has been no such association with sudden cardiac deaths. Yet this statement well exemplifies the current popular mythology around the subject. Since Krantz and colleagues wrote the original case series (but not the first case) in 2002, there have been no confirmed or strongly suspected deaths due to torsade tachycardia from my reading. The only 2 or 3 deaths were either remote from the period of the torsade and/or else were due to another reported cause such as myocardial infarction. French reports from over 30 years ago quote a mortality from ‘torsade de pointes’ of around 16%. Since this was before modern mobile resuscitation and pacing technologies were widespread, the survival rate of 84% might have increased to something over 95%.
It is now clear that ‘torsade de pointes’ tachycardia rarely if ever occurs in new entrants to methadone treatment. The 103 reports in the literature and Justo’s excellent summary of the field in the Addiction journal inform us that simple clinical features can highlight risk and indicate the need for ECG monitoring where appropriate. Almost 50% of the ~100 reported cases in the literature had HIV infection. The author of the original FDA report, Ellen Pearson, has postulated that QT prolongation and torsade are ‘threshold events’ with numerous contributors based on the known risk factors.
The risk factors (not in order) are:
(1) long term methadone maintenance for addiction
(2) female sex
(3) age over 40
(4) doses over 150mg daily
(5) HIV infection
(6) concomitant use of drugs which either increase methadone levels and/or prolong QT interval
(7) metabolic disturbance
(8) structural heart disease
(9) alcohol
When used with supervision and adequate supports methadone treatment for heroin addiction reduces mortality substantially. It should be used with confidence as the benefits far outweigh even the most pessimistic views of the possible side effects.
Comments by Andrew Byrne ..
Clinic web page: http://www.redfernclinic.com/c/
Refs:
Kocheril AG, Bokhari SAJ, Batsford WP, et al. Long QTc and torsades de pointes in human immunodeficiency virus disease. Pacing Clin Electrophysiol 1997 20:2810-6
Krantz MJ, Lewkowiez L, Hays H, Woodroffe MA, D. Robertson AD, Mehler PS. Torsade de Pointes Associated with Very-High-Dose Methadone. Ann Intern Med. 2002 137:501-504
Dessertenne PF. La tachycardie ventriculaire a deux foyers opposes variables. Arch Mal Coeur 1966 59:263-72
Pearson EC, Woosley RL. QT prolongation and torsades de pointes among methadone users: reports to the FDA spontaneous reporting system. Pharmcoepidemiol Drug Safety. 2005 14;11:747-753
