Atrial fibrillation and reduced ventricular pumping are different cardiac findings. A lower frequency of one does not exclude the other as a possible contributor to embolic stroke. A 2024 retrospective study examined both in patients already admitted with acute ischemic stroke.
Who was included?
Lee and colleagues reviewed admissions at one medical center during 2019–2022. Of 973 consecutive patients, 35 were excluded for incomplete data, absent echocardiography, cocaine use or loss to follow-up, leaving 938. Forty-six were classified as having methamphetamine use; 892 were in the comparison group.
Classification used history or a urine drug screen. The methods identify the EMIT II Plus Amphetamines Assay, a class screen, rather than reporting quantitative confirmatory methamphetamine concentrations. Cardiomyopathy was operationally defined as left ventricular ejection fraction of 45% or less on the clinical echocardiography report.
What cardiac differences were observed?
Cardiomyopathy was found in 14/46 methamphetamine-classified patients, 30.4%, versus 125/892 comparison patients, 14.0%. Recorded atrial fibrillation showed the opposite pattern: 8.7% versus 33.4%. The methamphetamine group was substantially younger, with mean age 52.8 versus 69.7 years.
These percentages belong to people admitted with ischemic stroke. They are not estimates of cardiomyopathy or stroke frequency among all people who use methamphetamine. Starting with a diseased population changes the question and the denominator.
What did the regression estimate describe?
Methamphetamine-associated cardiomyopathy was associated with cardioembolic stroke classification in the adjusted model: odds ratio 1.79, 95% confidence interval 1.04–3.06. The modeled factor combined the exposure classification with the cardiac finding. It should not be relabeled as an odds ratio for all methamphetamine use causing any stroke.
An association with a classified stroke mechanism also differs from observing a drug-to-thrombus-to-brain sequence. The study did not experimentally establish that temporal pathway in each patient.
Why did poorer pumping coexist with better function?
Among patients with cardiomyopathy, the methamphetamine group had lower mean ejection fraction but more favorable three-month functional outcomes: modified Rankin score 0–2 in 9/14, versus 44/125 in the comparison cardiac group. The authors considered younger age and fewer comorbidities a likely explanation.
The corresponding three-month mortality difference was not statistically significant, p = 0.13. Better observed functional outcome therefore should not become a claim that methamphetamine was protective or that mortality was demonstrably lower.
What remains uncertain?
The investigators lacked detailed route, frequency and duration of methamphetamine use, and follow-up ended at three months. The retrospective design could not exclude alcohol use and other cardiac comorbidity as confounding influences or establish causation. Exposure classification itself also requires the distinction between history, screening and analytical confirmation.
The practical contribution is a reminder to keep cardiac phenotypes separate. Less recorded atrial fibrillation did not eliminate a cardiomyopathy-associated embolic pattern in this selected cohort. It did not create a diagnostic shortcut from a positive drug screen to the cause of an individual stroke.
Source
Lee SJ and colleagues. Cardiomyopathy in Patients With Acute Ischemic Stroke and Methamphetamine Use: Relevance for Cardioembolic Stroke and Outcome. Journal of the American Heart Association. 2024;13:e033667. DOI: 10.1161/JAHA.123.033667. Full text; bibliographic record.