Heart rate variability and arrhythmic patterns of 24-hour Holter electrocardiography among Nigerians with cardiovascular diseases

Figures & data

Table 1 Clinical characteristics of the studied groups

Parameters	Number of patients	Sex Females: n (%)/males: n (%)	Age (years)	BMI (kg/m^2)
Palpitation	71	35 (49.3%)/36 (50.7%)	53.13±20.73	26.60±5.19
Syncope	49	35 (71.4%)/49 (28.6%)	59.20±9.75	25.87±3.37
HHF	45	23 (51.0%)/22 (49.0%)	65.73±13.92	25.02±4.31
HHD with LVH	42	27 (64.3%)/15 (35.7%)	57.14±11.72	28.55±10.37
Stroke	33	17 (51.5%)/16 (48.5%)	63.70±12.16	–
Known Arrhythmia	13	9 (69.2%)/4 (30.8%)	49.69±18.50	24.95±5.09
Unexplained DOE	10	4 (40.0%)/6 (60.0%)	59.20±9.75	25.87±3.37
Dizziness	10	3 (30.0%)/7 (70.0%)	39.10±20.04	27.08±4.32
DM with Autonomic neuropathy	10	7 (70.0%)/3 (30.0%)	54.50±9.21	28.86±4.32
DCM	7	4 (57.1%)/3 (42.9%)	61.29±14.19	22.40±3.50
Chest pain	6	2 (33.3%)/4 (66.7%)	49.33±19.77	30.32±5.32
VHD	4	3 (75.0%)/1 (25.0%)	47.25±19.60	19.52±5.47
Pacemaker rhythm	1	1 (100.0%)/0 (0.0%)	72.00±0.00	20.00±0.00
Not Indicated	9	7 (77.8%)/2 (22.2%)	52.67±13.74	25.02±4.53
Total	310	176 (56.8%)/134 (43.2%)	55.60±17.40	26.38±5.99 (excluding stroke)

Abbreviations: BMI, body mass index; HHF, hypertensive heart failure; HHD, hypertensive heart disease; LVH, left ventricular hypertrophy; DOE, dyspnea on exertion; DM, diabetes mellitus; DCM, dilated cardiomyopathy; VHD, valvular heart disease.

Figure 1 Bar chart showing the clinical indications for Holter ECG.

Abbreviations: ECG, electrocardiography; HHF, hypertensive heart failure; HHD, hypertensive heart disease; LVH, left ventricular hypertrophy; Une DOE, unexplained dyspnea on exertion; DM, diabetes mellitus; AUT Nero, autonomic neuropathy; DCM, dilated cardiomyopathy; VHD, valvular heart disease.

Table 2 Clinical indication

Clinical indication	Number of patients (N=310)	%
Palpitation	71	23.0
Syncope	49	15.8
HHF	45	14.5
HHD with LVH	42	13.6
Stroke	33	10.6
Known arrhythmia	13	4.2
Unexplained DOE	10	3.2
Dizziness	10	3.2
DM with AUT neuropathy	10	3.2
DCM	7	2.3
Chest pain	6	1.9
VHD	4	1.3
Pacemaker rhythm	1	0.3
Not indicated	9	2.9
Total	310	100

Abbreviations: HHF, hypertensive heart failure; HHD, hypertensive heart disease; LVH, left ventricular hypertrophy; DOE, dyspnea on exertion; DM, diabetes mellitus; AUT, autonomic; DCM, dilated cardiomyopathy; VHD, valvular heart disease.

Table 3 Distribution of clinical indications for Holter ECG by age group

Parameters	Age range in years
Clinical indications	15–30 N (%)	31–40 N (%)	41–50 N (%)	51–60 N (%)	61–70 N (%)	>70 N (%)	Total N
Palpitation	13 (18.3)	7 (9.9)	8 (11.3)	14 (19.7)	15 (21.1)	14 (19.7)	71
Syncope	7 (14.3)	11 (22.5)	5 (10.2)	14 (28.6)	6 (12.2)	6 (12.2)	49
HHF	0 (0)	3 (6.7)	3 (6.7)	8 (17.7)	13 (28.9)	18 (40.0)	45
HHD with LVH	1 (2.4)	3 (7.1)	6 (14.3)	15 (35.7)	12 (28.6)	5 (11.9)	42
Stroke	0 (0)	0 (0)	5 (15.1)	12 (36.4)	7 (21.2)	9 (27.3)	33
Known Arrhythmia	2 (15.4)	2 (15.4)	3 (23.1)	1 (7.6)	2 (15.4)	3 (23.1)	13
Unexplained DOE	0 (0)	1 (10.0)	0 (0)	4 (40.0)	4 (40.0)	1 (10.0)	10
Dizziness	5 (50)	0 (0)	1 (10.0)	3 (30.0)	0 (0)	1 (10.0)	10
DM with AUT neuropathy	0 (0)	2 (20.0)	0 (0)	5 (50.0)	3 (30.0)	0 (0)	10
DCM	0 (0)	0 (0)	1 (14.3)	3 (42.8)	2 (28.6)	1 (14.3)	7
Chest pain	1 (16.7)	2 (33.3)	0 (0)	1 (16.7)	1 (16.7)	1 (16.7)	6
VHD	1 (25.0)	0 (0)	1 (25.0)	1 (25.0)	1 (25.0)	0 (0)	4
Pacemaker rhythm	0 (0)	0 (0)	0 (0)	0 (0)	0 (0)	1 (100)	1
Not indicated	0 (0)	3 (33.3)	0 (0)	3 (33.3)	3 (33.3)	0 (0)	9
Total	30 (9.7)	34 (11.0)	33 (10.6)	84 (27.1)	69 (22.3)	60 (19.3)	310

Abbreviations: ECG, electrocardiography; HHF, hypertensive heart failure; HHD, hypertensive heart disease; LVH, left ventricular hypertrophy; DOE, dyspnea on exertion; DM, diabetes mellitus; AUT, autonomic; DCM, dilated cardiomyopathy; VHD, valvular heart disease.

Figure 2 Seventy year-old woman, known hypertensive with an episode of ventricular tachycardia during 24-hour Holter ECG.

Abbreviation: ECG, electrocardiography.

Table 4 24-hour Holter electrocardiogram rhythm distribution

Parameters	Clinical indication
Rhythm	Palp N (%)	Syncope N (%)	HHF N (%)	HHD N (%)	Stroke N (%)	Known arrhythmia N (%)	Unexplained DOE N (%)	Dizziness N (%)	DM (AUT neuropathy) N (%)	DCM N (%)	Chest pain N (%)	VHD N (%)	Pacemaker N (%)	Not indicated N (%)	Total N (%)
Normal	37 (52.1)	23 (46.9)	10 (22.2)	30 (71.4)	18 (54.6)	1 (7.7)	2 (20)	5 (50)	8 (80)	1 (14.3)	2 (33.3)	0 (0)	0 (0)	5 (55.6)	143 (45.8)
PVC	17 (23.9)	11 (22.5)	13 (28.9)	7 (16.6)	10 (30.3)	5 (38.4)	4 (40)	5 (50)	1 (10)	4 (57.1)	3 (50)	3 (75)	0 (0)	3 (33.3)	86 (27.7)
PAC	7 (9.9)	5 (10.2)	6 (13.3)	1 (2.4)	1 (3.0)	2 (15.4)	1 (10)	0 (0)	0 (0)	0 (0)	1 (16.7)	1 (25)	0 (0)	0 (0)	25 (8.1)
NSVT	5 (7.1)	5 (10.2)	4 (9.0)	2 (4.8)	1 (3.0)	1 (7.7)	1 (10)	0 (0)	0 (0)	1 (14.3)	0 (0)	0 (0)	0 (0)	1 (11.1)	21 (6.8)
Sustained VT	2 (2.8)	0 (0)	1 (2.2)	0 (0)	1 (3.0)	1 (7.7)	0 (0)	0 (0)	0 (0)	1 (14.3)	0 (0)	0 (0)	0 (0)	0 (0)	6 (1.9)
SVT	0	2 (4.1)	1 (2.2)	0 (0)	2 (6.1)	2 (15.4)	0 (0)	0 (0)	0 (0)	0 (0)	0 (0)	0 (0)	0 (0)	0 (0)	7 (2.2)
AF	1 (1.4)	1 (2.0)	5 (11.1)	1 (2.4)	0 (0)	1 (7.7)	2 (20)	0 (0)	0 (0)	0 (0)	0 (0)	0 (0)	0 (0)	0 (0)	11 (3.6)
Severe bradycardia	2 (2.8)	2 (4.1)	5 (11.1)	1 (2.4)	0 (0)	0 (0)	0 (0)	0 (0)	1 (10)	0 (0)	0 (0)	0 (0)	0 (0)	0 (0)	11 (3.6)
Pacemaker tachycardia	0 (0)	0 (0)	0 (0)	0 (0)	0 (0)	0 (0)	0 (0)	0 (0)	0 (0)	0 (0)	0 (0)	0 (0)	1 (100)	0 (0)	1 (0.3)
Total	71 (100)	49 (100)	45 (100)	42 (100)	33 (100)	13 (100)	10 (100)	10 (100)	10 (100)	7 (100)	6 (100)	4 (100)	1 (100)	9 (100)	310 (100)

Abbreviations: Palp, palpitation; HHF, hypertensive heart failure; HHD, hypertensive heart disease; DOE, dyspnea on exertion; DM, diabetes mellitus; AUT, autonomic; DCM, dilated cardiomyopathy; VHD, valvular heart disease; PVC, premature ventricular complex; PAC, premature atrial complex; NSVT, non-sustained ventricular tachycardia; VT, ventricular tachycardia; SVT, supraventricular tachycardia; AF, atrial fibrillation.