Rr variability in patients with systolic and diastolic heart failure

ABSTRACT

This study aimed at determining the difference in heart rate variability [HRV] in patients with diastolic dysfunction as compared to patients with systolic dysfunction and normal subjects. This study is a case control analytic study that was conducted in the National Heart Institute in order to determine the heart rate variability in patients with diastolic heart failure in comparison to patients with systolic heart failure and normal healthy control. The study included the following 3 groups Group I 20 patients with diastolic heart failure with preserved lv systolic function [EF > 50%]. Group II 20 patients with systolic heart failure [EF < 50%] and Group III 10 healthy normal control subjects. Patients with hypertrophic obstructive cardiopmyopathy, atrial fibrillation, excessive ectopy and or cardiac pacing, significant valvular lesion and diabetes mellitus were excluded from the study. All patients included in the study were subjected to Full history taking with special emphasis on history of diabetes mellitus and cardiac history, full general and local examination of the heart, chest and abdomen, 12 leads resting HCG, 24 hours ambulatory ECG recording [Holter monitoring] using Burdick recorder [Spacelab Inc. USA] in order to measure the heart rate variability. The parameters measured for heart rate variability analysis and its definitions are summarized in the next table. Echocardiographic study was done using two dimensional echo with continuous and pulsed wave Doppler studies were performed using echocardiographic machine General Electric vivid 3 equipped with 2.5 and 3.5 Megahertz [MHz] probes. For assessment of LV systolic and diastolic function as well as assessment of any valvular lesion for exclusion. Patients with systolic heart failure had a lower NNS, NN mean, SDNN, SDNNIDX, rMSSD and PNN > 50 than the patients with diastolic heart failure [P < 0.05]. Patients with diastolic heart failure had a significantly lower time domain measurements than that of the normal control subjects [P < 0.05]. Patients with systolic heart failure had a lower RR MEAN, Total power, VLF power, LF power, HF power than the patients with diastolic heart failure [P < 0.05]. Patients with diastolic heart failure had a significantly lower frequency domain measurements than that of the normal control subjects [P < 0.05]. All the time domain and frequency domain parameters were significantly lower in the patients with systolic heart failure than those with diastolic heart failure [P < 0.0]. Patients with grade II and grade III diastolic dysfunction had a lower NNS, NN mean, SDNN, SDNNIDX, rMSSD and PNN >50 than the patients with grade I diastolic dysfunction [P < 0.05].Patients with grade II and grade III diastolic dysfunction had a lower RR MEAN, Total power, VLF power, LF power, HF power than the patients with grade I diastolic dysfunction [P < 0.05]. Patients with EF between 20-30% and patients with HF between 31-40% had a lower time domain par imeters than those with EF between 41 - <50% [P <0.05]. Patients with 3F between 2030% and patients with HF between 31- 40% had a lower frequency domain parameters than those with HF between 41 -< 50% [P < 0.05]. Patients with both systolic and diastolic heart failure or dysfunction had abnormal autonomic modulation of the heart rate as assessed by the different heart rate variability parameters as compared to normal subjects. Patients with systolic heart failure had a lower time domain and frequency domain parameters than patients with diastolic dysfunction that may reflect more autonomic neuropathy in systolic heart failure and contributes to the poor prognosis in systolic heart failure. Abnormalities in Heart rate variability parameters were correlated with the severity of both systolic and diastolic dysfunction