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ECG alterations suggestive of hyperkalemia in normokalemic versus hyperkalemic patients
Csaba Varga1,2, Zsolt Kálmán1, Alíz Szakáll1
1Department of Emergency Medicine, Somogy County Kaposi Mór General Hospital, Tallián Gyula street 20-32, Kaposvár, 7400, Hungary.
Insights
Electrocardiogram (ECG) changes suggestive of hyperkalemia are not always present in patients with high potassium levels. Caution is advised when initiating hyperkalemia treatment in prehospital settings, as some ECG changes can occur in patients with normal potassium levels.
Area of Science:
- Cardiology
- Emergency Medicine
- Clinical Biochemistry
Background:
- Hyperkalemia is a common reversible cause of periarrest and resuscitation emergencies.
- Electrocardiogram (ECG) alterations can indicate hyperkalemia, necessitating prompt identification of reversible causes.
- Distinguishing ECG changes in hyperkalemic versus normokalemic patients is crucial for appropriate clinical management.
Purpose of the Study:
- To compare the prevalence of ECG alterations suggestive of hyperkalemia in patients with normal potassium levels versus those with moderate to severe hyperkalemia.
- To evaluate the diagnostic utility of specific ECG findings in identifying hyperkalemia in emergency department patients.
- To assess the frequency of both typical and atypical ECG changes associated with varying degrees of hyperkalemia.
Main Methods:
- Retrospective, cross-sectional study of 305 patients (170 normokalemic, 135 hyperkalemic).
- Analysis of ECGs obtained upon admission by two independent, blinded emergency physicians.
- Statistical comparison using SPSS22 software, employing chi-squared and Fischer exact tests.
Main Results:
- 46% of hyperkalemic patients and 24% of normokalemic patients exhibited ECG alterations suggestive of hyperkalemia.
- Significantly more frequent typical hyperkalemia ECG changes (wide QRS, peaked T-waves, AV-block, bradycardia) were observed in severely hyperkalemic patients compared to normokalemic patients.
- Prolonged QTc interval was significantly more prevalent in both moderate and severe hyperkalemia groups compared to the normokalemic group.
Conclusions:
- A significant proportion of hyperkalemic patients lack typical ECG changes, and some normokalemic patients may present with ECG findings suggestive of hyperkalemia.
- Treatment for hyperkalemia in prehospital settings should be approached with caution due to potential ECG misinterpretations.
- The presence of multiple ECG alterations warrants attention for potentially life-threatening conditions, even in the absence of clear hyperkalemia indicators.
Background:
In periarrest situations and during resuscitation it is essential to rule out reversible causes. Hyperkalemia is one of the most common, reversible causes of periarrest situations. Typical electrocardiogram (ECG) alterations may indicate hyperkalemia. The aim of our study was to compare the prevalence of ECG alterations suggestive of hyperkalemia in normokalemic and hyperkalemic patients.
Methods:
170 patients with normal potassium (K+) levels and 135 patients with moderate (serum K+ = 6.0-7.0 mmol/l) or severe (K+ > 7.0 mmol/l) hyperkalemia, admitted to the Department of Emergency Medicine at the Somogy County Kaposi Mór General Hospital, were selected for this retrospective, cross-sectional study. ECG obtained upon admission were analyzed by two emergency physicians, independently, blinded to the objectives of the study. Statistical analysis was performed using SPSS22 software. χ2 test and Fischer exact tests were applied.
Results:
24% of normokalemic patients and 46% of patients with elevated potassium levels had some kind of ECG alteration suggestive of hyperkalemia. Wide QRS (31.6%), peaked T-waves (18.4%), Ist degree AV-block (18.4%) and bradycardia (18.4%) were the most common and significantly more frequent ECG alterations suggestive of hyperkalemia in severely hyperkalemic patients compared with normokalemic patients (8.2, 4.7, 7.1 and 6.5%, respectively). There was no significant difference between the frequency of ECG alterations suggestive of hyperkalemia in normokalemic and moderately hyperkalemic patients. Upon examining ECG alterations not typically associated with hyperkalemia, we found that prolonged QTc was the only ECG alteration which was significantly more prevalent in both patients with moderate (17.5%) and severe hyperkalemia (21.1%) compared to patients with normokalemia (5.3%).
Conclusions:
A minority of patients with normal potassium levels may also exhibit ECG alterations considered to be suggestive of hyperkalemia, while more than half of the patients with hyperkalemia do not have ECG alterations suggesting hyperkalemia. These results imply that treatment of hyperkalemia in the prehospital setting should be initiated with caution. Multiple ECG alterations, however, should draw attention to potentially life threatening conditions.
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