Rhythmocardiography used to study the impact of validol and nitroglycerin on heart rate variability among patients with stable stenocardia

Abstract

Introduction: One of the main reasons of frequent able-bodied citizens’ mortality is ischemic heart disease. Nitroglycerin is used for the reduction of stenocardia attacks, but in case of intolerance of the medication or if side effects appear, it may be substituted for validol. Nowadays peripheral vegetotropic effects of these medications are not completely studied, thus the research that is being carried out is of great topicality. Aims: The present research is aimed at studying the way nitroglycerin and validol affect heart rate variability among patients with stable stenocardia. In the research were included 32 patients with stable stenocardia of I (16%) %), II (56%) and III (28%) dynamic classes from the Cardiology department of outpatient clinic №8 (Chelyabinsk, Russia). The average age of the group is 54±6,2 years. Rhythmocardiography was realized on apparatus-program complex “Micor” (Russia) of high resolution in order to study heart rate variability. Rhythmocardiography was carried out 2 minutes before and 2 minutes after sublingual nitroglycerin intake and on the other day 10 minutes before and 10 minutes after sublingual validol intake. Heart rate variability was studied initially in lying position (ph) and also in 4 stimulating probes: Vm- Modified Valsalva Maneuver, pAAshner-Danjiny Test, AOP -Active Orthostatic Test, PWC120 -Loading Test Power Working Capacity simultaneously measured with EKG in real-time. Following findings were determined: RR - beat-to-beat interval; SDNN - Standard Deviation of Normal-to-Normal Intervals of sinus heart rate HR; ARA -Amplitude respiratory arrhythmia; separately were defined: quadratic dispersion of humoral-metabolic HR deflections (al), sympathetic HR deflections (am), parasympathetic fluctuations (as) and their spectral analogues for determination of control factors’ correlation in constitutional deflection spectrum BCP -VLF%, LF%, HF%. Statistics were elaborated with the help of StatPlus® program (2009). Results: It was proved from the realized research that with validol and nitroglycerin intake the total heart rate variability (SDNN) significantly increased in all probes. With nitroglycerin intake in comparison with the reference level the RR duration in the background probe fell (ph) (p<0,0001), humoral metabolic impact increased aloud: al b ph (p<0,05), Vm (p<0,001), pA (p<0,0001), VLF% b ph (p<0,01), pA (p<0,05); sympathetic manipulation: am b Vm (p<0,0001), pA (p<0,01), AOP (p<0,001), PWC (p<0,01), LF% b AOP (p<0,01); parasympathetic regulation fell: as b ph (p<0,01),HF% b ph (p<0,001), Vm (p<0,01), pA (p<0,0001); with nitroglycerin intake the response value to stimulus in AOP increased: d-a NN% (p<0,01), d-a NN, sec (p<0,05). In probe with validol significantly increased the RR range in all other probes: ph, AOP (p<0, 0001), Vm, pA (p<0,001), PWC (p<0, 01); humoral-metabolic and sympathetic impact increased in all probes, except PWC, the amount of parasympathetic deflections (as) increased in AOP (p<0, 01) and PWC (p<0, 05), meanwhile the percentage of parasympathetic impact (HF %) (p<0, 05) for certain reduced by ph. Thus, the prescription of these medications has both: positive aspects - SDNN increase after nitroglycerin and validol intake, with validol intake the RR increase in all probes may be observed, as in AOP and PWC and negative aspects-the increase of humoral-metabolic and sympathetic regulation under the impact of surveyed medications, as normally parasympathetic regulation should predominate. It brings about the necessity of specific control of the prescription and the individual selection of the medications even contrary to standard schemes.