Effects of plasma potassium on myocardial function: a POTCAST substudy

Area of Science:

• Cardiology
• Electrophysiology
• Cardiovascular Research

Background:

• Small studies suggest plasma potassium (p-K) levels influence cardiac function.
• Short-term POTCAST trial data indicated improved myocardial function with potassium-increasing treatment.
• Long-term effects of elevated p-K on cardiac function require further investigation.

Purpose of the Study:

• To assess long-term effects of potassium-increasing treatment on diastolic and systolic myocardial function.
• Utilized echocardiography in a Danish implantable cardioverter-defibrillator (ICD) cohort.
• Compared outcomes between high-normal potassium and control groups.

Main Methods:

• Substudy of the POTCAST trial involving 289 ICD patients.
• Randomization to usual therapy (control) or potassium supplements/mineralocorticoid receptor antagonists (high-normal potassium group).
• Echocardiography at baseline and >6 months follow-up to measure LVEF, GLS, GCW, and diastolic parameters (E, e', E/e').

Main Results:

• High-normal potassium group showed a mean p-K increase of 0.22 mmol/L compared to controls.
• Significant improvements observed: e'lat increased by 0.77 cm/sec (P=0.020) and E/e'lat decreased by -1.15 (P=0.013) in the high-normal potassium group.
• No significant differences in changes for LVEF, GLS, GCW, or other diastolic parameters between groups.

Conclusions:

• Long-term potassium-increasing treatment resulted in minor diastolic function improvements.
• No significant impact on systolic function was detected with long-term potassium-increasing treatment.
• Findings contrast with short-term observations, highlighting the need for further research on potassium's role in cardiac function.