'Doubling Down' on Hydroxychloroquine QT Prolongation in COVID-19

Patrice Wendling

August 07, 2020

Editor's note: Find the latest COVID-19 news and guidance in Medscape's Coronavirus Resource Center.

A new analysis from Michigan's largest health system provides sobering verification of the risks for QT interval prolongation in COVID-19 patients treated with hydroxychloroquine and azithromycin (HCQ/AZM).

One in five patients (21%) had a corrected QT (QTc) interval of at least 500 msec, a value that increases the risk for torsade de pointes in the general population and at which cardiovascular leaders have suggested withholding HCQ/AZM in COVID-19 patients.

"One of the most striking findings was when we looked at the other drugs being administered to these patients; 61% were being administered drugs that had QT-prolonging effects concomitantly with the HCQ and AZM therapy. So they were inadvertently doubling down on the QT-prolonging effects of these drugs," senior author David E. Haines, MD, director of the Heart Rhythm Center at William Beaumont Hospital, Royal Oak, Michigan, said in an interview.

A total of 34 medications overlapped with HCQ/AZM therapy are known or suspected to increase the risk for torsade de pointes, a potentially life-threatening ventricular tachycardia. The most common of these were propofol coadministered in 123 patients, ondansetron in 114, dexmedetomidine in 54, haloperidol in 44, amiodarone in 43, and tramadol in 26.

"This speaks to the medical complexity of this patient population, but also suggests inadequate awareness of the QT-prolonging effects of many common medications," the researchers say.

The study was published August 5 in JACC Clinical Electrophysiology.

Both hydroxychloroquine and azithromycin increase the risk for QTc interval prolongation by blocking the KCHN2-encoded hERG potassium channel. Several reports have linked the drugs to a triggering of QT prolongation in patients with COVID-19.

For the present study, Haines and colleagues examined data from 586 consecutive patients admitted with COVID-19 to the Beaumont Hospitals in Royal Oak and Troy, Michigan, between March 13 and April 6. A baseline QTc interval was measured with 12-lead ECG prior to treatment initiation with hydroxychloroquine 400 mg twice daily for two doses then 200 mg twice daily for 4 days and azithromycin 500 mg once followed by 250 mg daily for 4 days.

Because of limited availability at the time, lead II ECG telemetry monitoring over the 5-day course of HCQ/AZM was recommended only in patients with baseline QTc intervals of at least 440 msec.

Patients without an interpretable baseline ECG or available telemetry/ECG monitoring for at least 1 day were also excluded, leaving 415 patients (mean age, 64 years; 45% female) in the study population. More than half (52%) were Black, 52% had hypertension, 30% had diabetes, and 14% had cancer.

As seen in previous studies, the QTc interval increased progressively and significantly after the administration of HCQ/AZM, from 443 msec to 473 msec.

The average time to maximum QTc was 2.9 days in a subset of 135 patients with QTc measurements prior to starting therapy and on days 1 through 5.

In multivariate analysis, independent predictors of a potentially hazardous QTc interval of at least 500 msec were:

  • age older than 65 years (odds ratio [OR], 3.0; 95% CI, 1.62 - 5.54)

  • history of congestive heart failure (OR, 4.65; 95% CI, 2.01 - 10.74)

  • admission creatinine of at least 1.5 mg/dL (OR, 2.22; 95% CI, 1.28 - 3.84)

  • peak troponin I level above 0.04 mg/mL (OR, 3.89; 95% CI, 2.22 - 6.83)

  • body mass index below 30 kg/m2 (OR for a BMI of 30 kg/m2 or higher, 0.45; 95% CI, 0.26 - 0.78).

Concomitant use of drugs with known risk for torsade de pointes was a significant risk factor in univariate analysis (OR, 1.73; P = .036), but fell out in the multivariate model.

No patients experienced high-grade arrhythmias during the study. In all, 112 of the 586 patients died during hospitalization, including 85 (21%) of the 415 study patients.

The change in QTc interval from baseline was greater in patients who died. Despite this, the only independent predictor of mortality was older age. One possible explanation is that the decision to monitor patients with baseline QTc intervals of at least 440 msec may have skewed the study population toward people with moderate or slightly long QTc intervals prior to the initiation of HCQ/AZM, Haines suggested. Monitoring and treatment duration were short, and clinicians also likely adjusted medications when excess QTc prolongation was observed.

Although it's been months since data collection was completed, in April, and the paper was written in record-breaking time, the study "is still very relevant because the drug is still out there," observed Haines. "Even though it may not be used in as widespread a fashion as it had been when we first submitted the paper, it is still being used routinely by many hospitals and many practitioners."

The use of hydroxychloroquine is "going through the roof" because of COVID-19, commented Dhanunjaya Lakkireddy, MD, medical director for the Kansas City Heart Rhythm Institute, HCA Midwest Health, Overland Park, Kansas, who was not involved in the study.

"This study is very relevant and I'm glad they shared their experience and it's pretty consistent with the data presented by other people. The question of whether hydroxychloroquine helps people with COVID is up for debate, but there is more evidence today that it is not as helpful as it was 3 months ago," said Lakkireddy, who is also chair of the American College of Cardiology (ACC) Electrophysiology Council.

He expressed concern for patients who may be taking HCQ with other medications that have QT-prolonging effects, and for the lack of long-term protocols in place for the drug.

In the coming weeks, however, the ACC and rheumatology leaders will be publishing an expert consensus statement that addresses key issues, such as how to best to use HCQ, maintenance HCQ, electrolyte monitoring, the optimal timing of electrocardiography and cardiac magnetic imaging, and symptoms to look for if cardiac involvement is suspected, Lakkireddy said.

Asked whether HCQ and AZM should be used in COVID-19 patients, Haines told theheart.org | Medscape Cardiology that the "QT-prolonging effects are real, the arrhythmogenic potential is real, and the benefit to patients is nil or marginal. So I think that use of these drugs is appropriate and reasonable if it is done in a setting of a controlled trial, and I support that. But the routine use of these drugs probably is not warranted based on the data that we have available."

Still, hydroxychloroquine continues to be dragged into the spotlight in recent days as an effective treatment for COVID-19, despite discredited research and the US Food and Drug Administration's June 15 revocation of its emergency-use authorization to allow use of HCQ and chloroquine to treat certain hospitalized COVID-19 patients.

"The unfortunate politicization of this issue has really muddied the waters because the general public doesn't know what to believe or who to believe. The fact that treatment for a disease as serious as COVID should be modulated by political affiliation is just crazy to me," said Haines. "We should be using the best science and taking careful observations, and whatever the recommendations derived from that should be uniformly adopted by everybody, irrespective of your political affiliation."

Haines has received honoraria from Biosense Webster, Farapulse, and Sagentia, and is a consultant for Affera, Boston Scientific, Integer, Medtronic, Philips Healthcare, and Zoll. Lakkireddy has served as a consultant to Boston Scientific, Biotronik, Medtronic, Biosense Webster, and Abbott. 

J Am Coll Cardiol EP. Published August 5, 2020. Abstract

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