The Impact of Opioids on Cardiac Electrophysiology

Opioid Agents and Cardiac Arrhythmia: A Literature Review

Opioids are compounds that cause similar effects to morphine by binding to its receptors. Opioids can be synthetic, semi-synthetic, or natural and can easily bind to the receptors of opioids in order to depict their effects, which may vary depending upon the exposure of the drug and its dose. However, several side effects of opioids can also be observed, with the most crucial being their impact on the heart's electrical activity. This review majorly focuses on opioids' impact on the prolongation of the QT curve and their arrhythmogenic susceptibility. Articles published up to the year 2022 in various databases were identified and searched with the use of keywords. Search terms included "cardiac arrhythmias," "QT interval," "opioids," "opioid dependence," and "torsade de pointes (TdP)". These terms highlight the impact of each opioid agent on the activity of the heart on an electrocardiogram. The results of the available data depict that opioids, such as methadone, pose higher risks, even when taken in smaller amounts, and have the capability for QT interval prolongation and TdP development. A variety of opioids, i.e., oxycodone and tramadol, are considered as intermediary risk drugs and can build long QT intervals and TdP in large doses. Several other opioids are considered low-risk drugs, including buprenorphine and morphine, which lead to no production of TdP and QT interval prolongation in daily routine doses. Evidence indicates a high risk of sinus bradycardia, atrial fibrillation, cardiac block, and supra-ventricular arrhythmias in opium consumers. This literature review will play a key role in determining the association between the use of opioids and cardiac arrhythmias. It will further highlight the practical implications of opioids for the management of cardiac issues based on their dose, frequency, and intensity. Moreover, it will also depict the adverse effects of opioids along with their dose-specific relationship. Opioids display disparate cardiac arrhythmogenicity, and methadone contains a greater ability to induce long QT intervals and hazardous arrhythmias at conventional doses. In order to reduce arrhythmogenic risk, opioids taken in large amounts should be monitored with a regular electrocardiogram in high-risk consumers, i.e., patients on opioid maintenance.

Prevention of heart failure, tachyarrhythmias and sudden cardiac death in HIV

PURPOSE OF REVIEW

To summarize the state-of-the-art literature on the epidemiology, disease progression, and mediators of heart failure, tachyarrhythmias, and sudden cardiac death in people living with HIV (PLWH) to inform prevention strategies.

RECENT FINDINGS

Recent studies corroborate the role of HIV as a risk enhancer for heart failure and arrhythmias, which persists despite adjustment for cardiovascular risk factors and unhealthy behaviors. Immune activation and inflammation contribute to the risk. Heart failure occurs more frequently at younger ages, and among women and ethnic minorities living with HIV, highlighting disparities. Prospective outcome studies remain sparse in PLWH limiting prevention approaches. However, subclinical cardiac and electrophysiologic remodeling and dysfunction detected by noninvasive testing are powerful disease surrogates that inform our mechanistic understanding of HIV-associated cardiovascular disease and offer opportunities for early diagnosis.

SUMMARY

Aggressive control of HIV viremia and cardiac risk factors and abstinence from unhealthy behaviors remain treatment pillars to prevent heart failure and arrhythmic complications. The excess risk among PLWH warrants heightened vigilance for heart failure and arrhythmic symptomatology and earlier testing as subclinical abnormalities are common. Future research needs include identifying novel therapeutic targets to prevent heart failure and arrhythmias and testing of interventions in diverse groups of PLWH.

Opioid-Associated Out-of-Hospital Cardiac Arrest: Distinctive Clinical Features and Implications for Health Care and Public Responses: A Scientific Statement From the American Heart Association

Opioid overdose is the leading cause of death for Americans 25 to 64 years of age, and opioid use disorder affects >2 million Americans. The epidemiology of opioid-associated out-of-hospital cardiac arrest in the United States is changing rapidly, with exponential increases in death resulting from synthetic opioids and linear increases in heroin deaths more than offsetting modest reductions in deaths from prescription opioids. The pathophysiology of polysubstance toxidromes involving opioids, asphyxial death, and prolonged hypoxemia leading to global ischemia (cardiac arrest) differs from that of sudden cardiac arrest. People who use opioids may also develop bacteremia, central nervous system vasculitis and leukoencephalopathy, torsades de pointes, pulmonary vasculopathy, and pulmonary edema. Emergency management of opioid poisoning requires recognition by the lay public or emergency dispatchers, prompt emergency response, and effective ventilation coupled to compressions in the setting of opioid-associated out-of-hospital cardiac arrest. Effective ventilation is challenging to teach, whereas naloxone, an opioid antagonist, can be administered by emergency medical personnel, trained laypeople, and the general public with dispatcher instruction to prevent cardiac arrest. Opioid education and naloxone distributions programs have been developed to teach people who are likely to encounter a person with opioid poisoning how to administer naloxone, deliver high-quality compressions, and perform rescue breathing. Current American Heart Association recommendations call for laypeople and others who cannot reliably establish the presence of a pulse to initiate cardiopulmonary resuscitation in any individual who is unconscious and not breathing normally; if opioid overdose is suspected, naloxone should also be administered. Secondary prevention, including counseling, opioid overdose education with take-home naloxone, and medication for opioid use disorder, is important to prevent recurrent opioid overdose.

Opium-associated QT Interval Prolongation: A Cross-sectional Comparative Study

Background

Toxicity and side effects of long-term use of opioids are well studied, but little information exists regarding electrophysiological disturbances of opium consumption. While natural opium has been regarded safe to a great extent among traditional communities, concerns are emerging owing to the available evidence of QT prolongation that have been exposed during recent outcome surveillance of patients under opioid use. Potential QT prolonging interactions would raise a higher level of such concern in opium users during COVID pandemic and warrant attention.

Materials and methods

This study was designed to detect the prevalence of QTc prolongation among opium users and nonusers. Two groups were compared with regard to gender, age, and median QTc interval. Normal and prolonged QTc intervals of user group were compared with respect to age, sex, dose of opium consumption, and duration of opium consumption.

Results

123 opium users and 39 controls were investigated. Median QTc interval in opium user and non-user group was 460 vs 386 milliseconds, respectively (p value < 0.001). In all, 59.3%, (95% CI: 50.51–67.62%) of cases and none of non-user had prolonged QTc interval (p value < 0.001). There was no significance between normal and prolonged QTc intervals with respect to dose and duration of opium use.

Conclusion

This study indicated that opium consumption is associated with QTc prolongation. This prolongation does not relate to dose and duration of opium use. Further study is propounded to assess the clinical significance of these results and to determine risk rating of opium compared to other opioids in this regard.

How to cite this article

Javadi HR, Mirakbari SM, Allami A, Yazdi Z, Katebi K. Opium-associated QT Interval Prolongation: A Cross-sectional Comparative Study. Indian J Crit Care Med 2021;25(1):43–47.

Disparity in the effect of morphine on eupnea and gasping in anesthetized spontaneously breathing adult rats

The goal of this study was to examine the effects of systemic morphine on the pattern and morphology of gasping breathing during respiratory autoresuscitation from transient anoxia. We hypothesized that systemic morphine levels sufficient to cause significant depression of eupnea would also cause depression of gasping breathing. Respiratory and cardiovascular variables were studied in 20 spontaneously breathing pentobarbital-anaesthetized adult male rats. Sham (saline) injections caused no significant change in resting respiratory or cardiovascular variables (n = 10 rats). Morphine, on the other hand, caused significant depression of eupneic breathing, with ventilation and peak inspiratory flow decreased by ∼30-60%, depending on the background condition (n = 10 rats). In contrast, morphine did not depress gasping breathing. Duration of primary apnea, time to restore eupnea, the number and amplitude of gasping breaths, average and maximum peak flows, and volume of gasping breaths were not significantly different postinjection in either condition. Blood pressures were all significantly lower following morphine injection at key time points in the process of autoresuscitation. Last, rate of successful recovery from anoxia was 80% in the morphine group (8/10 rats) compared with 100% (10/10 rats) in the sham group, postinjection. We conclude that the mechanisms and/or anatomic correlates underlying generation of gasping rhythm are distinct from those underlying eupnea, allowing gasping to remain robust to systemic morphine levels causing significant depression of eupnea. Morphine nevertheless decreases likelihood of recovery from transient anoxia, possibly as a result of decreased tissue perfusion pressures at critical time points during the process of respiratory autoresuscitation.

Prevalence of QTc Prolongation in Patients With Advanced Cancer Receiving Palliative Care-A Cause for Concern?

CONTEXT

Medications commonly used for symptom control along with other known risk factors have the potential to prolong ventricular repolarization as measured by the QT interval (the time from the start of the Q wave to the end of the T wave) on a standard electrocardiogram (ECG).

OBJECTIVES

To document the prevalence of a prolonged QT interval corrected for heart rate (QTc) interval in the palliative/oncology setting, compare automatic ECG QTc measurements with manual readings and identify any correlation between QTc prolongation and the use of drugs or other risk factors.

METHODS

A convenience sample of consecutive patients with cancer, admitted under or known to the palliative/supportive care teams in two metropolitan hospitals, and willing to provide an ECG recording and basic demographic information including QTc risk factors were included. Both automated and manually calculated QTc intervals were recorded. Multivariable analysis was used to determine risk factors independently associated with prolonged QTc intervals.

RESULTS

Of the 389 participants, there was a significant difference in mean QTc between sites using automated but not manual calculations. Manual readings were therefore used with predetermined cutoffs of 0.44 seconds (males) and 0.46 seconds (females). Seventy-two (18.5%) of the participants had a prolonged QTc with six (1.5%) having a prolongation of >0.50 seconds. At-risk drugs were being taken by 218 participants (56.0% of total cohort). Factors shown to be associated with QTc prolongation included age, gender, performance status, and hypocalcemia. No specific medication was associated with increased risk.

CONCLUSION

Although almost 20% of patients receiving palliative care had prolongation of QTc, the possibility of serious consequences appeared to be low despite the frequent occurrence of risk factors.

Effect of lofexidine on cardiac repolarization during treatment of opioid withdrawal

BACKGROUND

Lofexidine is a non-opioid treatment for opioid withdrawal syndrome. Its sympatholytic actions counteract the nor-adrenergic hyperactivity that occurs during abrupt opioid withdrawal.

METHODS

The effect of lofexidine 2.16 and 2.88 mg/day on QTcF (QT interval, heart-rate corrected, Fridericia formula) was studied as part of a large, double-blind, placebo-controlled trial (ClinicalTrials.gov identifier: NCT01863186). ECGs were time-matched to blood sampling for lofexidine concentration and were collected at prespecified timepoints over a 7-day inpatient period. Analyses included mean change-from-baseline QTcF and exposure-response modeling to predict QTcF at relevant lofexidine concentrations.

RESULTS

A total of 681 adult men and women received at least 1 dose of study drug; 566 qualified for inclusion in the concentration-QTcF analysis. Most subjects were withdrawing from heroin. During the first 24 h (Days 1-2) post-baseline, small increases in QTcF were observed in all groups: 4.7 ms for lofexidine 2.16 mg, 7.4 ms for lofexidine 2.88 mg and 1.4 ms for placebo. These increases were transient; by Day 4, when lofexidine levels had reached steady-state, QTcF increases were not present. By Day 7, QTcF was decreased from baseline in all groups. Exposure-response modeling predicted <10 ms increases in QTcF at lofexidine concentrations 3 times those obtained at maximal recommended dose.

CONCLUSIONS

Lofexidine was associated with small, transient QTcF increases. Decreases in QTcF that occurred with higher lofexidine concentrations argue for an indirect QTcF effect, potentially from changes in autonomic tone. Both opioid withdrawal and lofexidine's sympatholytic actions would be expected to alter sympathetic outflow over the 7-day withdrawal.

Predictors of electrocardiographic QT interval prolongation in men with HIV

OBJECTIVE

HIV-infected (HIV+) individuals may be at increased risk for sudden arrhythmic cardiac death. Some studies have reported an association between HIV infection and prolongation of the electrocardiographic QT interval, a measure of ventricular repolarisation, which could potentiate ventricular arrhythmias. We aimed to assess whether HIV+ men have longer QT intervals than HIV-uninfected (HIV-) men and to determine factors associated with QT duration.

METHODS

We performed resting 12-lead ECGs in 774 HIV+ and 652 HIV- men in the Multicenter AIDS Cohort Study (MACS). We used multivariable linear and logistic regression analyses to assess associations between HIV serostatus and Framingham corrected QT interval (QTc), after accounting for potential confounders. We also determined associations among QTc interval and HIV-related factors in HIV+ men. In a subgroup of participants, levels of serum markers of inflammation were also assessed.

RESULTS

After adjusting for demographics and risk factors, QTc was 4.0 ms longer in HIV+ than HIV- men (p<0.001). Use of antiretroviral therapy (ART), specific ART drug class use and other HIV-specific risk factors were not associated with longer QTc. Among the subgroup with inflammatory biomarker measurements, higher interleukin-6 (IL-6), intercellular adhesion molecule-1 (ICAM-1) and B-cell activating factor levels were independently associated with longer QTc and their inclusion partially attenuated the HIV effect.

CONCLUSIONS

HIV+ men had longer QTc, which was associated with higher levels of systemic inflammatory factors. This longer QTc may contribute to the increased risk for sudden arrhythmic cardiac death in some HIV+ individuals.