Vandeni C. Kunz

The relationship between cardiac autonomic function and clinical and angiographic characteristics in patients with coronary artery disease

BACKGROUND A reduction in heart rate variability (HRV) is considered an important indicator of autonomic dysfunction. OBJECTIVES The aims of this study were to evaluate the presence of autonomic dysfunction measured by HRV in patients with coronary artery disease (CAD) and to compare them with normal subjects. METHODS A sample of 52 men (mean age 54±5.39 years) was allocated into three groups: obstructive CAD ≥50% (CAD+ n=18), obstructive CAD <50%, (CAD- n=17) and apparently healthy controls (CG n=17). Heart rate (HR) was measured at rest using a Polar®S810i for 15 min. HRV was analyzed via Shannon entropy (SE) and symbolic analysis (0V and 2ULV), which relate to sympathetic and vagal predominance, respectively. Statistical analysis included the Kruskal-Wallis test and multivariate analysis (p<0.05). RESULTS The CAD+ group presented lower SE and 2ULV% values and higher 0V% compared to CAD- and control groups (p<0.05). In the multivariate analysis, the presence of the clinical characteristics such as myocardial infarction and revascularization in the CAD+ group lead to a lower SE and higher 0V compared to the CAD- group. The use of angiotensin converting enzymes led to a higher SE in the CAD- group compared to the CAD+ (p<0.05). CONCLUSION In uncomplicated CAD+ patients the patterns of HRV have a lower complexity, a greater sympathetic modulation and a lower parasympathetic modulation compared to CAD- and control groups in supine resting conditions. These results indicate that autonomic heart dysfunction is related to the degree of coronary occlusion and cardiac compromise.

Lack of Association of Estrogen Receptor Alpha Gene Polymorphisms with Cardiorespiratory and Metabolic Variables in Young Women

This study examined the association of estrogen receptor alpha gene (ESR1) polymorphisms with cardiorespiratory and metabolic parameters in young women. In total, 354 healthy women were selected for cardiopulmonary exercise testing and short-term heart rate (HR) variability (HRV) evaluation. The HRV analysis was determined by the temporal indices rMSSD (square root of the mean squared differences of successive R–R intervals (RRi) divided by the number of RRi minus one), SDNN (root mean square of differences from mean RRi, divided by the number of RRi) and power spectrum components by low frequency (LF), high frequency (HF) and LF/HF ratio. Blood samples were obtained for serum lipids, estradiol and DNA extraction. ESR1 rs2234693 and rs9340799 polymorphisms were analyzed by PCR and fragment restriction analysis. HR and oxygen uptake (VO2) values did not differ between the ESR1 polymorphisms with respect to autonomic modulation. We not find a relationship between ESR1 T–A, T–G, C–A and C–G haplotypes and cardiorespiratory and metabolic variables. Multiple linear regression analysis demonstrated that VO2, total cholesterol and triglycerides influence HRV (p < 0.05). The results suggest that ESR1 variants have no effect on cardiorespiratory and metabolic variables, while HRV indices are influenced by aerobic capacity and lipids in healthy women.

Interval training based on ventilatory anaerobic threshold increases cardiac vagal modulation and decreases high-sensitivity c-reative protein: randomized clinical trial in coronary artery disease

Background: Autonomic dysfunction and inflammatory activity are involved in the development and progression of coronary artery disease (CAD), and exercise training has been shown to confer a cardiovascular benefit. Objective: To evaluate the effects that interval training (IT) based on ventilatory anaerobic threshold (VAT) has on heart rate variability (HRV) and high-sensitivity C-reactive protein (hs-CRP) levels, as well as the relationship between both levels, in patients with CAD and/or cardiovascular risk factors (RF). Method: Forty-two men (aged 57.88±6.20 years) were divided into two training groups, CAD-T (n= 12) and RF-T (n= 10), and two control groups, CAD-C (n= 10) and RF-C (n=10). Heart rate and RR intervals in the supine position, cardiopulmonary exercise tests, and hs-CRP levels were measured before and after IT. HRV was analyzed by spectral and symbolic analysis. The CAD-T and RF-T underwent a 16-week IT program of three weekly sessions at training intensities based on the VAT. Results: In the RF-T, cardiac sympathetic modulation index and hs-CRP decreased (p<0.02), while cardiac parasympathetic modulation index increased (p<0.02). In the CAD-T, cardiac parasympathetic modulation index increased, while hs-CRP, systolic, and diastolic blood pressures decreased (p<0.02). Both control groups showed increase in hs-CRP parameters (p<0.02). There was a strong and significant association between parasympathetic and sympathetic modulations with hs-CRP. Conclusion: The IT program based on the VAT promoted a decrease in hs-CRP associated with improvement in cardiac autonomic modulation.

Association of estrogen receptor alpha gene polymorphisms with autonomic modulation of heart rate in users and nonusers of oral contraceptives

BACKGROUND This study examined the association between estrogen receptor α gene (ESR1) polymorphisms and blood pressure (BP), heart rate (HR) and autonomic modulation of HR in a sample population. STUDY DESIGN Two hundred thirty-two young healthy women were selected, and those using oral contraceptives (OC) were compared with nonusers (control group). Short-term HR variability (HRV) was evaluated in both the supine and sitting positions using temporal indices rMSSD [square root of the mean squared differences of successive R-R intervals (RRi) divided by the number of RRi minus one], SDNN (root mean square of differences from mean RRi, divided by the number of RRi) and frequency domain methods. Power spectral components were reported at low frequency (LF) and high frequency (HF) and as LF/HF ratio. ESR1 c.454-397T>C (rs2234693) and c.454-351A>G (rs9340799) polymorphisms were determined by polymerase chain reaction and fragment restriction analysis. RESULTS The ESR1 T>C and A>G polymorphisms had no effect on HR, rMSSD, SDNN, LF, HF or LF/HF ratio (supine or sitting), independently of OC use. The ESR1 T-A, T-G, C-A and C-G haplotypes were not associated with HR, BP or HRV. CONCLUSIONS ESR1 variants had no effect on the autonomic modulation of HR in young women users and nonusers of OC and may not be implicated in cardiovascular risk in young women.

Ratings of perceived exertion at anaerobic threshold in patients with coronary artery disease

O objetivo do estudo foi identificar e comparar a percepcao subjetiva do esforco (PSE) no limiar anaerobio ventilatorio (LAV) em individuos saudaveis e com doenca arterial coronariana (DAC). Foram estudados 30 homens, sendo 10 saudaveis que constituiram o grupo controle (GC) e 20 diagnosticados com DAC, dos quais 10 faziam uso de medicamento betabloqueador (G-DACb) e 10 nao faziam uso (G-DAC). Os voluntarios foram submetidos a um teste de exercicio cardiopulmonar (TECP) com protocolo continuo tipo rampa para determinacao do LAV, atraves da analise visual grafica (perda do paralelismo entre o consumo de oxigenio e a producao de dioxido de carbono). Durante a realizacao do TECP, foi solicitado aos voluntarios que relatassem ao final de cada minuto a percepcao subjetiva do esforco de membros inferiores (PSE-M) e a percepcao subjetiva do esforco respiratorio (PSE-R), atraves da escala CR-10 de Borg. O GC apresentou maiores valores de potencia, consumo de oxigenio, producao de dioxido de carbono, ventilacao e frequencia cardiaca no LAV comparado aos grupos G-DAC e G-DACb (p ;0,05). Valores entre cinco e seis na escala CR-10 de Borg correspondeu ao LAV na amostra estudada. Entretanto, outros parâmetros devem ser utilizados concomitantemente para a prescricao da intensidade de exercicio nos protocolos de treinamento fisico, em niveis proximos ao LAV para pacientes com DAC.

Percepção subjetiva do esforço no limiar anaeróbio em pacientes com doença arterial coronariana

O objetivo do estudo foi identificar e comparar a percepcao subjetiva do esforco (PSE) no limiar anaerobio ventilatorio (LAV) em individuos saudaveis e com doenca arterial coronariana (DAC). Foram estudados 30 homens, sendo 10 saudaveis que constituiram o grupo controle (GC) e 20 diagnosticados com DAC, dos quais 10 faziam uso de medicamento betabloqueador (G-DACb) e 10 nao faziam uso (G-DAC). Os voluntarios foram submetidos a um teste de exercicio cardiopulmonar (TECP) com protocolo continuo tipo rampa para determinacao do LAV, atraves da analise visual grafica (perda do paralelismo entre o consumo de oxigenio e a producao de dioxido de carbono). Durante a realizacao do TECP, foi solicitado aos voluntarios que relatassem ao final de cada minuto a percepcao subjetiva do esforco de membros inferiores (PSE-M) e a percepcao subjetiva do esforco respiratorio (PSE-R), atraves da escala CR-10 de Borg. O GC apresentou maiores valores de potencia, consumo de oxigenio, producao de dioxido de carbono, ventilacao e frequencia cardiaca no LAV comparado aos grupos G-DAC e G-DACb (p ;0,05). Valores entre cinco e seis na escala CR-10 de Borg correspondeu ao LAV na amostra estudada. Entretanto, outros parâmetros devem ser utilizados concomitantemente para a prescricao da intensidade de exercicio nos protocolos de treinamento fisico, em niveis proximos ao LAV para pacientes com DAC.

Cardiopulmonary exercise testing in the early-phase of myocardial infarction

OBJECTIVE To evaluate and to compare the cardiorespiratory and metabolic variables at the ventilatory anaerobic threshold level (AT) and at submaximal cardiopulmonary exercise testing (CPET) in both, healthy volunteers and in patients in the early phase after acute myocardial infarction (AMI). METHOD Twenty-six volunteers underwent a submaximal or symptom-limited cardiopulmonary exercise testing (CPET) on a cycle ergometer and were divided into AMI group (AMIG=12, 56.33±8.65 years) and healthy group (CG=14, 53.33±3.28 years). The primary outcome measures were the cardiorespiratory and metabolic variables obtained at the peak workload and at the AT of the CPET. Statistical test: independent Students t-test, α=5%. RESULTS The AMIG presented lower values at the AT and the peak workload of the CPET compered to the CG: power in watts (91.06±30.10 and 64.88±19.92; 154.93±34.65 and 120.40±29.60); VO2 mL.kg-1.min-1 (17.26±2.71 and 12.19±2.51; 25.39±5.73 and 19.41±5.63); VCO2 L/min-1 (1.43±0.31 and 0.93±0.23; 2.07±0.43 and 1.42±0.36), VO2 L/min-1 (1.33±0.32 and 1.00±0.23; 1.97±0.39 and 1.49±0.36); VE L/min-1 (42.13±8.32 and 27.51±5.86; 63.07±20.83 and 40.82±11.96); HR (bpm) (122.96±14.02 and 103.46±13.38; 149.67±13.77 and 127.60±10.04), double product (DP) (bpm.mmHg.min-1) (21835.86±3245.93 and 17333.25±2716.51; 27302.33±3053.08 and 21864.00±2051.48), respectively. The variable oxygen uptake efficiency slope (OUES L/min) was lower in the AMIG (1.79±0.51) than the CG (2.26±0.37). The AMIG presented neither ECG alterations nor symptoms that limited the CPET. CONCLUSION The results suggest that patients with AMI Killip class I presented lower functional capacity and DP compared to the CG without presenting ischemic alterations. Thus, the study suggests that submaximal CPET can be applied at an early stage to evaluate cardiorespiratory status since it is both safe and highly sensitive to detect changes.

Cardiac baroreflex sensitivity in coronary patients with and without type 2 diabetes

Background: Aging promotes increased levels of circulating proinflammatory markers and decrease in cardiac autonomic function that can be evaluated by high sensitivity C-reactive protein (hsCRP) and heart rate variability (HRV), respectively. Studies shown relation between the immune system and HRV, however, few studies are related to the baroreflex sensitivity (BRS). Aim: To evaluate the relationship between cardiovascular autonomic nervous system (BRS) and hsCRP in natural human aging in a wide range of age and gender. Methods: One hundred and ten apparently healthy individuals (without hsCRP values suggestive of acute inflammation, above 3.0 mg/L) were divided into 2 groups (men and women) and then, equally assigned into 5 groups (21-30; 31-40; 41-50; 51-60 and 61-70 years), 11 subjects in each group. The electrocardiographic, respiratory andnoninvasivefinger arterial pressure signalswere recorded for 15 minutes, in rest supine (REST) and in orthostatic position (STAND), and sampled at 400Hz. Stable sequences of 256 points in REST and STAND were chosen. Cross-spectral analysis was performed to compute coherence, phase and BRS in low (LF) frequency. Blood was collected after a 12-hour fasting. The turbidimetry method was used for hsCRP analysis. Results: Spearman correlation test showed a negative significant relationship (p b 0.05) between hsCRP and phase (r = -0.576) and between hsCRP and BRS (r = -0.356) in LF in STAND inwomen, however, no correlation was found in men. Conclusion: The relationship between proinflammatory marker and cardiovascular autonomic nervous system showed a gender dependency therefore gender should be taken into account in the analysis of the cardiovascular autonomic nervous system. Financial support: FAPESP: 2010/52070-4; CNPq: 311938/2013-2; CNPq: 140164/2015-4.

Percepción subjetiva del esfuerzo en el liminar anaeróbico en pacientes con enfermedad arterial coronaria

O objetivo do estudo foi identificar e comparar a percepcao subjetiva do esforco (PSE) no limiar anaerobio ventilatorio (LAV) em individuos saudaveis e com doenca arterial coronariana (DAC). Foram estudados 30 homens, sendo 10 saudaveis que constituiram o grupo controle (GC) e 20 diagnosticados com DAC, dos quais 10 faziam uso de medicamento betabloqueador (G-DACb) e 10 nao faziam uso (G-DAC). Os voluntarios foram submetidos a um teste de exercicio cardiopulmonar (TECP) com protocolo continuo tipo rampa para determinacao do LAV, atraves da analise visual grafica (perda do paralelismo entre o consumo de oxigenio e a producao de dioxido de carbono). Durante a realizacao do TECP, foi solicitado aos voluntarios que relatassem ao final de cada minuto a percepcao subjetiva do esforco de membros inferiores (PSE-M) e a percepcao subjetiva do esforco respiratorio (PSE-R), atraves da escala CR-10 de Borg. O GC apresentou maiores valores de potencia, consumo de oxigenio, producao de dioxido de carbono, ventilacao e frequencia cardiaca no LAV comparado aos grupos G-DAC e G-DACb (p ;0,05). Valores entre cinco e seis na escala CR-10 de Borg correspondeu ao LAV na amostra estudada. Entretanto, outros parâmetros devem ser utilizados concomitantemente para a prescricao da intensidade de exercicio nos protocolos de treinamento fisico, em niveis proximos ao LAV para pacientes com DAC.

Aerobic Physical Training On The Pulmonary Function Of Men With Coronary Arterial Disease: A Randomized Controlled Trial

Objective: to evaluate the pulmonary function of patients with coronary arterial disease (CAD) before and after exercise-based cardiac rehabilitation program with emphasis on aerobic physical training. Methods: 19 men with CAD, divided in trained group TG (n=10) and control group CG (n=9) were studied. Forced vital capacity (FVC) and forced expiratory volume in one second (FEV1) were carried out at 2 points for both groups: at the beginning and finale of the experimental protocol to evaluate and to compare the CG and TG. The CG participated in the evaluations only and is not subjected to any intervention, and the TG was submitted to 48 supervised aerobic physical training sessions to verify the effects of physical training on pulmonary function. Results: At the beginning of the study all the patients showed low values for FVC and FEV1 in relation to what was expected (CG: 72.2 ± 9.1% and 72.4 ± 16.3%, respectively; TG: 77.5 ± 12.1% and 75.2 ± 13.6%, respectively). After the training period, the CG values did not show any significant changes in comparison to the pre-training conditions for FVC (76.1 ± 11.5%) and FEV1 (75.4 ± 17.2%). In the TG there was a significant increase in both FVC (86.1 ± 12.1%) and FEV1 (86.0 ± 15.3%). Conclusion: There was a significant increase in FVC and FEV1 values in the TG patients after four months of participation in exercise-based cardiac rehabilitation program, and this fact suggests beneficial effects of aerobic exercise on the pulmonary function of patients with CAD.