Some Patients With Type 2 Diabetes Have Major ECG Abnormalities

Mitchel Zoler, PhD

March 02, 2021

Major ECG abnormalities were found in 13% of more than 8,000 unselected patients with type 2 diabetes, including a 9% prevalence in the subgroup of these patients without identified cardiovascular disease (CVD) in a community-based Dutch cohort. Minor ECG abnormalities were even more prevalent.

These prevalence rates were consistent with prior findings from patients with type 2 diabetes, but the current report is notable because "it provides the most thorough description of the prevalence of ECG abnormalities in people with type 2 diabetes," and used an "unselected and large population with comprehensive measurements," including many without a history of CVD, said Peter P. Harms, MSc, and associates noted in a recent report in the Journal of Diabetes and Its Complications.

The analysis also identified several parameters that significantly linked with the presence of a major ECG abnormality including hypertension, male sex, older age, and higher levels of hemoglobin A1c.

"Resting ECG abnormalities might be a useful tool for CVD screening in people with type 2 diabetes," concluded Mr. Harms, a researcher at the Amsterdam University Medical Center, and coauthors.

Findings "Not Unexpected"

Patients with diabetes have a higher prevalence of ECG abnormalities "because of their higher likelihood of having hypertension and other CVD risk factors," as well as potentially having subclinical CVD, said Fred M. Kusumoto, MD, so these findings are "not unexpected. The more risk factors a patient has for structural heart disease, atrial fibrillation (AFib), or stroke from AFib, the more a physician must consider whether a baseline ECG and future surveillance is appropriate," Kusumoto said in an interview.

But he cautioned against seeing these findings as a rationale to routinely run a resting ECG examination on every adult with diabetes.

"Patients with diabetes are very heterogeneous," which makes it "difficult to come up with a 'one size fits all' recommendation" for ECG screening of patients with diabetes, he said.

While a task force of the European Society of Cardiology and the European Association for the Study of Diabetes set a class I level C guideline for resting ECG screening of patients with diabetes if they also have either hypertension or suspected CVD, the American Diabetes Association has no specific recommendations on which patients with diabetes should receive ECG screening.

"The current absence of U.S. recommendations is reasonable, as it allows patients and physicians to discuss the issues and decide on the utility of an ECG in their specific situation," said Kusumoto, director of heart rhythm services at the Mayo Clinic in Jacksonville, Fla. But he also suggested that "the more risk factors that a patient with diabetes has for structural heart disease, AFib, or stroke from AFib the more a physician must consider whether a baseline ECG and future surveillance is appropriate."

Data From a Dutch Prospective Cohort

The new study used data collected from 8,068 patients with type 2 diabetes and enrolled in the prospective Hoorn Diabetes Care System cohort, which enrolled patients newly diagnosed with type 2 diabetes in the West Friesland region of the Netherlands starting in 1996. The study includes most of these patients in the region who are under regular care of a general practitioner, and the study protocol calls for an annual resting ECG examination.

The investigators used standard, 12-lead ECG readings taken for each patient during 2018, and classified abnormalities by the Minnesota Code criteria. They divided the abnormalities into major or minor groups "in accordance with consensus between previous studies who categorised abnormalities according to perceived importance and/or severity." The major subgroup included major QS pattern abnormalities, major ST-segment abnormalities, complete left bundle branch block or intraventricular block, or atrial fibrillation or flutter. Minor abnormalities included minor QS pattern abnormalities, minor ST-segment abnormalities, complete right bundle branch block, or premature atrial or ventricular contractions.

The prevalence of a major abnormality in the entire cohort examined was 13%, and another 16% had a minor abnormality. The most common types of abnormalities were ventricular conduction defects, in 14%; and arrhythmias, in 11%. In the subgroup of 6,494 of these patients with no history of CVD, 9% had a major abnormality and 15% a minor abnormality. Within this subgroup, 23% also had no hypertension, and their prevalence of a major abnormality was 4%, while 9% had a minor abnormality.

A multivariable analysis of potential risk factors among the entire study cohort showed that patients with hypertension had nearly triple the prevalence of a major ECG abnormality as those without hypertension, and men had double the prevalence of a major abnormality compared with women. Other markers that significantly linked with a higher rate of a major abnormality were older age, higher body mass index, higher A1c levels, and moderately depressed renal function.

"While the criteria the authors used for differentiating major and minor criteria are reasonable, in an asymptomatic patient even the presence of frequent premature atrial contractions on a baseline ECG has been associated with the development of AFib and a higher risk for stroke. The presence of left or right bundle branch block could spur additional evaluation with an echocardiogram," said Kusumoto, president-elect of the Heart Rhythm Society.

"Generally an ECG abnormality is supplemental to clinical data in deciding the choice and timing of next therapeutic steps or additional testing. Physicians should have a fairly low threshold for obtaining ECG in patients with diabetes since it is inexpensive and can provide supplemental and potentially actionable information," he said. "The presence of ECG abnormalities increases the possibility of underlying cardiovascular disease. When taking care of patients with diabetes at initial evaluation or without prior cardiac history or symptoms referable to the heart, two main issues are identifying the likelihood of coronary artery disease and atrial fibrillation."

Harms and coauthors, and Kusumoto, had no disclosures.

This article originally appeared on MDedge.com, part of the Medscape Professional Network.

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