An Assessment of Cardiovascular Functional Capacity of a Group of Chronic Heart Failure Patients Using the 6-Minute Walk Test in a Cameroonian Urban Setting

Background: Chronic heart failure is a public health problem worldwide. It has a high mortality rate and is accompanied by a decreased functional capacity and alteration of the quality of life. Objective: This study aimed to assess the cardiovascular functional capacity of a group of patients suffering from heart failure using the 6-minute walk test (6 MWT). Methods: This was a cross-sectional study carried out in the cardiology unit of Douala’s general hospital for 4 months. We included all eligible patients aged 18 years or more who had stable chronic heart failure and gave informed consent. Those who had an acute coronary syndrome (≤1 month), tachycardia (HR ≥ 120 bpm), high blood pressure (SBP ≥ 180 mmHg and/or DBP ≥ 100 mmHg) and reduced mobility due to orthopaedic reasons were excluded. A 6 MWT was done according to the American Thoracic Society guidelines. The 6 MWT result was considered poor for - 450 m and good for >450 m. Results: We recruited a total of 81 patients (61.7% women) with a mean age of 65.9 ± 10.6 years. The most frequent risk factor for heart failure was high blood pressure (77.8%), alcohol consumption(69.1%) and a sedentary lifestyle (53.1%). The left ventricular ejection fraction was mostly preserved (42.0%) or mildly altered (46.9). The 6 MWT results were poor in 55.6% of cases, average in 19.8% of cases and good in only 24.7% of cases. More than half (59.3%) of the participants perceived the effort as being difficult. The cardiovascular functional capacity was significantly associated with age, heart failure stage and physical activity (p Conclusion: Most patients suffering from chronic stable heart failure in the general hospital of Douala have poor cardiovascular functional capacity.

Effects of 6-minute walk test on the QT dispersion in patients with congestive heart failure

Objective: To investigate the clinical value of QT dispersion (QTd) and the effects of 6-minute walk test (6-MWT) mimicking the patients' daily activities on QTd in patients with congestive heart failure (CHF).Methods: Twenty-eight CHF patients and 22 normal subjects participated these study, who all completed 6-MWT without developing severe arrhythmias.Before and after 6-MWT, standardized 12-lead surface ECGs were obtained to measure QTd and corrected QTd (QTcd).Results: Both before and after 6-MWT, the QTd and QTcd in CHF patients were longer than those in the controls (P<0.001), and QTd and QTcd after 6-MWT were significantly shorter than those before 6-MWT in CHF patients (P=0.007, and 0.018).There was no significant difference in the measurement in the control group.Conclusion: QTd and QTcd are longer in CHF patients than in normal subjects.Moderate exercise may improve the inhomogeneity of ventricular repolarization dispersion in CHF patients.

Normative Values of Cardio-Respiratory Endurance in Adults in Benin

Cardiorespiratory endurance is a determining factor in the assessment of the state of health of a person. Objective: To determine the reference values for cardiorespiratory endurance in Beninese adults. Methods: Prospective transversal study, with a descriptive and analytical aim. It was carried out on healthy adult subjects (18 to 50 years old), of Cotonou and Abomey cities, from October 2017 to May 2018, without clinically identifiable orthopedic, cardiorespiratory, osteoarticular or neuromotor impairment. These subjects performed three different cardio-respiratory endurance tests: The six-minute walk test (WT6), cycloergometer test (CT) and the step test (ST). Data processing and analysis were done using SPSS version 22 software. A linear regression model was used to establish the prediction equation of maximal oxygen uptake (VO2 max) with the WT6 data. The significance level chosen was 5%. Results: Subjects average age was 30.0 ± 9.8 years. It was especially men (54.20%), students (42.13%), with a normal corpulence (69.91%). At WT6, they walked 365 m to 798 m (557.1 ± 93.6 m) with extreme heart rates (EHR) of 67 to 189 (136.7 ± 19.0) beats per minute. At ST, the extreme powers developed were 2.7 watts/kg and 11.8 watts/kg (6.4 ± 1.8 watts/kg), with EHR of 99 to 204 (168.4 ± 15.4) beats per minute. The predictor equation of VO2 max by WT6 was function of the subject’s weight, age and sex (R = 0.73). Conclusion- Discussion: These normative values of cardio-respiratory endurance of Beninese subjects seem to be specific to them. An extension of the present study to a larger sample nevertheless seems desirable.

冠状动脉介入治疗对急性心肌梗死患者心功能的影响

目的探究冠状动脉介入治疗对急性心肌梗死患者心功能的影响。方法选取2020年7月-2023年6月我院收治的86例急性心肌梗死患者,根据不同治疗方式分成对照组和观察组,每组各43例。对照组接受常规治疗,观察组接受冠状动脉介入,对比两组治疗前后心功能指标[左室舒张末期容积指数(LVEDVI)、左室收缩末期容积指数(LVESVI)、左心室射血分数(LVEF)]、6 min步行试验(6-minute walk test,6MWT)以及心脏不良事件发生率。结果治疗前,两组心功能标对比(P>0.05),治疗4周后,观察组LVEDVI、LVESVI下降较对照组明显,LVEF提升较对照组明显,具有显著差异(P<0.05);治疗1周后,两组6MWT对比无统计学意义(P>0.05),治疗2周、治疗4周后,两组6MWT逐渐提升,观察组较对照组提升明显,具有统计学意义(P<0.05);两组心脏不良事件发生率对比,观察组更低(P<0.05)。结论急性心肌梗死患者行冠状动脉介入治疗,能改善患者心功能,提高患者6MWT距,改善运动耐力,对于心脏不良事件发生率的降低有积极作用。

Relationship between 6-minute walk test and pulmonary function test in stable chronic obstructive pulmonary disease with different severities

Background The relationship between the 6-minute walk test （6MWT） and pulmonary function test in stable chronic obstructive pulmonary disease （COPD） remains unclear. We evaluate the correlation of 6MWT and spirometric parameters in stable COPD with different severities. 6MWT data assessed included three variables： the 6-minute walk distance （6MWD）, 6-minute walk work （6MWORK）, and pulse oxygen desaturation rate （SPO2%）. Methods 6MWT and pulmonary function test were assessed for 150 stable COPD patients with different severities. Means and standard deviations were calculated for the variables of interest. Analysis of variance was performed to compare means. Correlation coefficients were calculated for 6MWT data with the spirometric parameters and dyspnea Borg scale. Multiple stepwise regression analysis was used to screen pulmonary function-related predictors of 6MWT data. Results The three variables of 6MWT all varied as the severities of the disease. The 6MWD and 6MWORK both correlated with some spirometric parameters （positive or negative correlation; the absolute value of r ranging from 0.34 to 0.67; P 〈0.05） in severe and very severe patients, and the SPO2% correlated with the dyspnea Borg scale in four severities （t= -0.33, -0.34, -0.39, -0.53 respectively; P 〈0.05）. The 6MWD was correlated with the 6MWORK in four severities （r=0.56, 0.57, 0.72, 0.81 respectively, P 〈0.05）, and neither of them correlated with the SPO2%. The percent of predicted forced expiratory volume in 1 second （FEV1% predicted） and residual volume to total lung capacity ratio （RV/TLC） were predictors of the 6MWD, and the maximum voluntary ventilation （MW） was the predictor of the 6MWORK. Conclusions 6MWT correlated with the spirometric parameters in severe and very severe COPD patients. 6MWT may be used to monitor changes of pulmonary function in these patients.

Cardiac catheterization and comprehensive clinical evaluation after bidirectional Glenn shunt surgery in 60 patients with complex congenital heart disease

Background The bidirectional Glenn shunt surgery is a palliative procedure for patients with complex congenital heart disease（CHD） who are not suitable for biventricular repair in early life. There is limited evidence of successful strategies for long-term hemodynamic stabilization. Furthermore, there have been no data on optimal hemodynamics that could be used as a reference for patients＇ follow-on management. Methods Sixty CHD patients, 44 male and 16 female, with bidirectional Glenn shunt surgery and cardiac catheterization were enrolled at our hospital between January 2014 and December 2016. Pre-and post Glenn shunt percutaneous oxygen saturation（SpO_2）, 6-minute walk test（6 MWT）, superior vena cava pressure（SVCP）, pulmonary arterial pressure（PAP）, pulmonary capillary wedge pressure（PCWP）, pulmonary vascular resistance（PVR）, small pulmonary vascular resistance（s PVR） were measured. Pre-and post-total cavopulmonary connection（TCPC） SpO_2, and in-hospital complications were monitored. The optimal hemodynamic cutoff values for TCPC patient selection were estimated by receive operating characteristic（ROC） curve analysis. Results SpO_2 was significantly increased by bidirectional Glenn shunt surgery（75.42 ± 9.62% to 86.98 ± 7.63%, P 〈 0.001） from 82.70 ± 5.99% to 95.00 ±4.07% in the 47 patients with TCPC. Forty-two patients completed the 6 MWT with a mean distance of 362.7 ±75.0 m and a SpO_2 decrease from 81.80 ± 7.84% to 67.59 ± 1.82%（P 〈 0.001）. The △SpO_2 and 6-minute walk distance（6 MWD） in the 32 who underwent TCPC and ten of them did not reach statistical significance（17.22 ±13.82% vs. 13.87 ± 8.74%, P = 0.08 and 358.88 ± 78.97 m vs. 374.80 ± 62.55 m, P = 0.564]. After cardiac catheterization, 47 patients were selected for TCPC. The right pulmonary artery systolic pressure（s RPAP）, mean right pulmonary artery pressure（m RPAP）, mean left pulmonary artery pressure（m LPAP）, PVR, and s PVR were significantly lower in the TCPC group than in the non-TCPC group. The differences in superior vena cava systolic blood pressure（s SVCP）, mean superior vena cava pressure（m SVCP）, and left pulmonary artery systolic pressure（s LPAP） were not significant. The optimal cutoff values for TCPC were s SVCP ≤ 20 mm Hg（P = 0.025）,s RPAP ≤ 22 mm Hg（P = 0.0001, mRPAP ≤ 13 mm Hg（P =0.003）, s LPAP ≤ 27 mm Hg（P =0.03）, m LPAP ≤ 11 mm Hg（P = 0.01）, PVR ≤ 4.3 Wood U/m^2（P 〈0.0001） and were significantly associated with TCPC selection,except for m SVCP ≤ 19 mm Hg（P = 0.06） and s PVR ≤ 2.0 wood U/m^2（P = 0.0531）. One patient died because of low cardiac output after TCPC. In-hospital mortality was 2.1%. Conclusion The SpO_2 can be significantly improved after bidirectional Glenn shunt and TCPC surgery. The 6 MWT is an index of activity tolerance prior toTCPC. Hemodynamic values of s SVCP ≤ 20 mm Hg, s RPAP ≤ 22 mm Hg, m RPAP ≤ 13 mm Hg, s LPAP ≤ 27 mm Hg, m LPAP ≤ 11 mm Hg, and PVR ≤ 4.3 Wood U/m^2 can help identify post Glenn-shunt patients indicated for TCPC.