Chronotropic Incompetence As Pathophysiological Mechanism Reduction of Exercise Tolerance in Patients with Arterial Hypertension and Clinical Signs of Heart Failure with Preserved Left Ventricular Ejection Fraction

Abstract

The objective: to determine the contribution of chronotropic incompetence (CI) , as one of the mechanisms for reducing exercise tolerance (ET) in patients with heart failure and preserved ejection fraction (HFpEF) of the left ventricle (LV).

Materials and methods. AT prospective study we consistently enrolled 39 patients with hypertension in conjunction with clinical signs and symptoms of heart failure, left ventricular ejection fraction ≥ 50% and symptoms of DD according to Doppler ECG, and compared with 30 patients with heart failure and LVEF 40–49%. Patients were determined level of NTproBNP, except standard laboratory indicators. Pulsed wave velocity (carotid-femoral) was determined using aplanation tonometry Using ECG, standard indicators were determined, and a diastolic stress test was performed when determining the E/e’ index in the range of 9–13. According to the levels of NTproBNP and LVEF patients were divided into three groups. Group 1 with NTproBNP level less than 125 pg/ml included 11 to group 2 (NTproBNP ≥125 pg/ml) – 28 to a group of 3–30 patients.

Results. According to the test results of diastolic stress test, 72,7% of patients group 1 achieved submaximal heart rate compared to 39,2% in group 2 and 10% in group 3 (p<0,05 and p<0,01). Time of work and executed load in patients of group 1 were higher compared to groups 2 and 3 (p<0,05 and p<0,01). Assessing the heart rate at an intermediate stage (50 W), there was a statistical difference between patients in groups 1 and 2 (p<0,01). CI and double product at the peak of exercise in patients of group 1 higher than in patients of groups 2 and 3 (p<0,01), according to comparable values of 2 and 3 groups. According to the results of the correlation analysis, these indicators in patients of group 2 correlated directly with the load performed (r=0,665; p<0,01 and r=0,665; p<0,02) and the load time (r=0,587; p<0,01 and r=0,477; p<0,01) and DT – with the time of the work performed (r=0,435; p<0,01). E/e’ with exercise inversely correlated with the load performed (r=–0,419; p<0.01).

Conclusions. In patients with hypertension signs of HF and preserved LV EF with a NTproBNP level ≥125 pg/ml, the value of chronotropic reserve and double work at maximum exercise is less than those with NTproBNP level <125 pg/ml and comparable to those in patients with HF with intermediate (40–49%) LV EF. Patients with hypertension symptoms of heart failure with preserved ejection fraction with a level NTproBNP ≥125 pg/ml value of chronotropic reserve and double product at peak of exercise directly proportionally correlated to the applied load and operating time, and E/E’ at exercise inversely correlated with the performance of the load.