The relationship of electrocardiographic left ventricular hypertrophy to decreased serum potassium.

Background: Low serum potassium (K) is associated with increased blood pressure, impaired cardiac function and renal dysfunction. Although lower serum K is associated with cardiac hypertrophy in animal models, the relationship of low serum K to the presence and severity of electrocardiographic left ventricular hypertrophy (LVH) is unclear.

Methods: Baseline and yearly Cornell product LVH levels were examined in relation to low serum K (serum K ≤ 3.90 mEq/l, the lowest quartile of baseline K levels) in 8586 patients with baseline K levels. Patients were randomized to losartan-vs atenolol-based treatment and additional hydrochlorothiazide (HCTZ) therapy as needed.

Results: After adjusting for age, sex, race, prior antihypertensive treatment, losartan vs atenolol therapy, HCTZ use, baseline diastolic and systolic pressure, body mass index, serum creatinine and urine albumin/creatinine ratio, baseline serum K ≤ 3.90 was associated with significantly higher mean baseline Cornell product LVH (2898 vs 2801 mm•ms, p = 0.001) and a 24% higher risk of Cornell product LVH > 2440 mm•ms at baseline (OR 1.24, 95% CI 1.11-1.38, p < 0.001). After also adjusting for baseline Cornell product and changes in diastolic and systolic pressure between baseline and each year of measurement, in-treatment serum K ≤ 3.90 determined yearly was associated with significantly higher mean Cornell product LVH at years 1-3 and with statistically significant 16-32% increased risks of LVH by Cornell product at years 1-4.

Conclusions: A low serum K is independently associated with a greater likelihood and severity of Cornell product LVH during antihypertensive therapy.