Effect of isosorbide dinitrate on sinoatrial node pacemaker activity in patients with stable angina pectoris of III and IV functional classes associated with hypertension

Aim. To study the effect of isosorbide dinitrate on heart rate variability in patients with III and IV functional classes of stable angina and concomitant essential hypertension. Methods. The study involved 122 patients with III and IV functional classes of stable angina and concomitant essential hypertension, mean age 58.4±5.8 years. All patients underwent electrocardiography, Doppler echocardiography, 24-hour ECG monitoring. Rhythmocardiography was performed in the morning before the drug intake (acetylsalycilic acid, beta-blockers, statins, angiotensin-converting enzyme inhibitors) and 1.5 hours after 10 mg isosorbide dinitrate intake. Results. There was a statistically significant increase in overall heart rate variability at Valsalva’s maneuver and active postural test in patients with III and IV functional classes of stable angina and concomitant essential hypertension, which was most likely due to the amplitude of humoral-metabolic waves. The amplitude of the sympathetic pacing fluctuations increased in all samples, while the parasympathetic pacing fluctuation amplitude decreased at Valsalva’s maneuver, Ashner’s test and while lying flat. There was a vegetative spectrum shift towards the humoral-metabolic effect in sympathetic active postural test, sympathetic shift in all tests except for sympathetic active postural test, and significant decrease in parasympathetic effect at Ashner’s test, sympathetic active postural test and while lying flat. Conclusion. In patients with III and IV functional classes of stable angina and concomitant essential hypertension there was an increase in the overall heart rate variability mainly due to the humoral-metabolic and sympathetic waves amplitude increase and parasympathetic amplitude decrease. Isosorbide dinitrate intake resulted in vegetative spectrum redistribution towards humoral and sympathetic metabolic regulation patterns and decrease of parasympathetic regulation pattern, which normally prevails.

rhythmocardiography, heart rate variability, stable angina, isosorbide dinitrate