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.