Effect of percutaneous transluminal coronary angioplasty on QT dispersion and heart rate variability parameters

Background

The aim of the study was to analyse parameters reflecting the sympathovagal control of ventricular depolarisation and repolarisation [heart rate variability (HRV) and QT interval dispersion (QTd)] in patients undergoing elective percutaneous transluminal coronary angioplasty (PTCA), and determine whether HRV correlates with QT dispersion parameters.

Methods

The study consisted of 26 consecutive patients (16 men, 10 women) with single-vessel coronary artery disease (CAD) who underwent elective coronary angioplasty. HRV analyses of all subjects were obtained with the time- and frequency-domain methods. For frequency-domain analysis, low-frequency HRV (LF), high-frequency HRV (HF) and the LF:HF ratio were measured. For time-domain analysis, standard deviations of the normal-to-normal QRS intervals (SDNN) and square roots of the mean squared differences of successive N–N intervals (rMSSD) were obtained. QT intervals were also corrected for heart rate using the Bazett’s formula, and the corrected QT interval dispersion (QTcd) was then calculated. All measurements (HRV parameters and QTcd) were made before and immediately after PTCA.

Results

QTcd was significantly decreased after PTCA (52.2 ± 3.5 vs 42 ± 3.9 ms). SDNN (94.1 ± 22 vs 123.9 ± 35.2 ms), rMSSD (43.7 ± 20.1 vs 73.4 ± 14.5 ms) and HF (51.1 ± 48.8 vs 64.2 ± 28.6 ms²) were significantly higher after PTCA, whereas LF (142 ± 41.5 vs 157.2 ± 25.9 ms²) and the ratio of LF:HF (3.3 ± 1.9 vs 2.1 ± 1.2) were significantly decreased after PTCA. We observed a significant negative correlation after PTCA between QTcd and LF (r = −0.87, p = 0.01) and between QTcd and the ratio of LF:HF (r = −056, p < 0.05).

Conclusion

Among the patients with CAD undergoing PTCA, QTcd significantly decreased after PTCA, and negatively correlated with LF, the parameter reflecting the sympathetic system.     

Medication adherence,self-care behaviour and knowledge on heart failure in urban South Africa: the Heart of Soweto study

Background

There is a paucity of data on treatment adherence in patients with chronic heart failure (CHF) in Africa.

Methods

We examined the pattern of treatment adherence, self-care behaviour and treatment knowledge in 200 consecutive patients with CHF attending the Chris Hani Baragwanath Hospital, Soweto, South Africa via a combination of questionnaire (100%, n = 200) and pill count (41%, n = 82).

Results

Mean age was 56 ± 14 years, 157 were black African (79%) and 109 (55%) were male. CHF-specific treatment included loop diuretics (93%), beta-blockers (84%), ACE inhibitors (74%), spironolactone (64%) and cardiac glycosides (24%); mean number of medications was 6 ± 2. Overall, 71% (58 of 82) adhered to their prescribed CHF regimen and individual medication adherence ranged from 64 to 79%. Behavioural adherence varied from 2.5 to 98%. Patient treatment knowledge was poor; 56% could not name medication effects or side effects. However, an average knowledge score of 69% was achieved on 10 questions concerning CHF management.

Conclusion

As in other regions of the world, non-adherence to complex CHF treatment is a substantial problem in Soweto. Our data confirm the need for a dedicated CHF management programme to optimise CHF-related outcomes in a low-resource environment.     

Increased QT dispersion and P wave dispersion in major depressive disorder

BACKGROUND:

QT and P wave dispersion parameters can indicate abnormalities in autonomic nervous system and cardiac functioning.

OBJECTIVES:

To determine QT and P wave dispersion in patients with major depressive disorder compared with healthy volunteers.

METHODS:

Fifty newly diagnosed patients with major depressive disorder and 50 age- and sex-matched healthy volunteers underwent 12-lead electrocardiography. QT interval, QT dispersion, heart rate-corrected QT dispersion and P wave dispersions were calculated manually by a blinded specialist.

RESULTS:

Groups were comparable in terms of age, sex, body mass index, smoking status, metabolic diseases and left ventricular ejection fraction. The major depressive disorder group had significantly higher QT dispersion (58.5±9.9 versus 41.7±3.8; P<0.001), heart rate-corrected QT dispersion (62.5±10.0 versus 45.2±4.3; P<0.001) and P wave dispersion (46.9±4.8 versus 41.5±5.1; P<0.001).

CONCLUSION:

Increased QT dispersion, heart-rate corrected QT dispersion and P wave dispersion in major depressive disorder patients may be indicative of autonomic imbalance and increased risk of cardiac morbidity and mortality.     

Pattern of heart failure in Abuja,Nigeria: an echocardiographic study

Aim

Despite heart failure having been identified in subjects in sub-Saharan Africa over the last 60 years, there is still a dearth of data, especially echocardiographic data on heart failure. We therefore set out to analyse the clinical and echocardiographic features of all consecutive subjects presenting with heart failure in a tertiary institution in Nigeria.

Methods

Three hundred and forty subjects with heart failure, according to the guidelines of the European Society of Cardiology, were studied. Each patient had two-dimensional guided transthoracic echocardiography.

Results

The mean age of the patients was 50.60 ± 15.29 years, and 50.9% of the study population were males while 49.1% were females. The commonest cause of heart failure identified was hypertension in 61.5% of the patients; 75.5% had systolic heart failure, whereas 23.5% had heart failure with preserved ejection fraction.

Conclusions

Untreated hypertension has been identified as the leading cause of heart failure in Abuja, Nigeria, which is similar to that in many other parts of sub-Saharan Africa. Coronary artery disease is a rare cause of heart failure in this population group.     

Cardiovascular complications in newly diagnosed rheumatic heart disease patients at Mulago Hospital,Uganda

Background

Complications of rheumatic heart disease are associated with severe morbidity and mortality in developing countries where the disease prevalence remains high. Due to lack of screening services, many patients present late, with severe valve disease. In Uganda, the disease and its complications are still not well studied.

Objective

To profile and describe cardiovascular complications in newly diagnosed rheumatic heart disease patients attending the Mulago National Referral Hospital in Uganda.

Methods

This was a cross-sectional study where consecutive, newly diagnosed rheumatic heart disease patients were assessed and followed up for complications, such as heart failure, pulmonary hypertension, atrial fibrillation, recurrence of acute rheumatic fever, and stroke.

Results

A total of 309 (115 males and 196 females) definite rheumatic heart disease patients aged 15–60 years were enrolled in the study and analysed. Complications occurred in 49% (152/309) of the newly diagnosed rheumatic heart disease cases, with heart failure (46.9%) the most common complication, followed by pulmonary arterial hypertension (32.7%), atrial fibrillation (13.9%), recurrence of acute rheumatic fever (11.4%), infective endocarditis (4.5%) and stroke (1.3%). Atrial fibrillation and acute rheumatic fever were the most common complications associated with heart failure.

Conclusion

In this study we found that about 50% of newly diagnosed rheumatic heart disease patients in Uganda presented with complications. Heart failure and pulmonary arterial hypertension were the most commonly observed complications.     

QT dispersion as a predictor for arrhythmias in patients with acute ST elevation myocardial infarction

Aims and Objectives

To study the effect of Heart Rate Variability (HRV) and QT dispersion (QTd) in patients presenting with Acute ST elevation myocardial infarction (STEMI).

Methods

This is a retrospective study conducted on patients admitted with the diagnosis of acute ST elevation myocardial infarction. In all 100 patients with acute myocardial infarction in one year were subjected to a complete evaluation in terms of history and examination. Besides routine investigations standard 12 lead ECG was evaluated in all cases on admission, after 4 hrs, 24 hrs, 48 hrs and on discharge.

Results

The most common presenting symptoms were chest pain (88%) and dyspnea (50%). Tachycardia was seen in 56% while congestive heart failure was present in 29% patients. Patients who died had a higher QTd in comparison to patients who survived.

Conclusions

Markers of autonomic regulation of heart like QTd provides valuable information about the future course of events in a patient following acute STEMI which can be utilized to plan the future course of management in patients especially predisposed to adverse and catastrophic outcomes.     

Patient activation,knowledge, and health literacy association with self-management behaviors in persons with heart failure

Background

More evidence is needed about factors that influence self-management behaviors in persons with heart failure.

Heart rate variability as an indicator of left ventricular systolic dysfunction

Objectives

The aim was to compare measures of heart rate variability (HRV) in patients who presented with non-cardiac vascular episodes with age- and gender-matched control patients.

Methods

One hundred and fifty patients, randomly selected from a cohort of 522 subjects, were enrolled in a screening study. Of these, 256 were identified to have had a stroke or transient ischaemic attack (TIA), or to have peripheral vascular disease (PVD) at the first presentation to Ninewells Hospital, Dundee, Scotland. Only 114 patients remained in the study (100 cases and 14 controls). Multiple regression analysis was used to assess the association between HRV parameters and measures of mean heart rate and ejection fraction.

Results

Heart rate and HRV indices were significantly inversely correlated with both normal left ventricular (LV) function [r = 0.2–0.5; p = 0.037–0.0001] and left ventricular systolic dysfunction (LVSD) [r = 0.3–0.5; p = 0.07–0.01] in the patients. HRV did not predict LVSD in this cohort of patients. Multiple regression analysis showed only ischaemic heart disease (IHD) and cigarette smoking had an independent relation to HRV parameters. Cigarette smoking (p = 0.008), IHD (p = 0.02) and diabetes (p = 0.03) were significant predictors of reduced HRV (standard deviation of the normal-to-normal interval: SDNN), independent of LVSD.

Discussion

There were no significant differences in HRV indices between non-cardiac vascular patients (TIA, stroke, PVD) and their age- and gender-matched controls. HRV had no diagnostic value as a pre-screening test to identify suspected LVSD in these patients.

Conclusion

HRV cannot be used as a screening test to identify hidden LVSD. Further studies will be needed to assess the possibilities that HRV is a convenient marker of endothelial dysfunction.     

Nurses' decision making in heart failure management based on heart failure certification status

Background

Research findings on the value of nurse certification were based on subjective perceptions or biased by correlations of certification status and global clinical factors. In heart failure, the value of certification is unknown.

Treatment with spironolactone for 24 weeks decreases the level of matrix metalloproteinases and improves cardiac function in patients with chronic heart failure of ischemic etiology

BACKGROUND:

The myocardial extracellular matrix is believed to be central to the remodelling that takes place following myocardial infarction. The contribution of markers of collagen metabolism to this process remains less well understood. The present study examined the contribution of some of the markers of collagen metabolism in cardiac remodelling, as well as the effect of spironolactone on the remodelling process.

OBJECTIVES:

To investigate the pathological contribution of markers of collagen metabolism, including matrix metalloproteinases (MMPs), tissue inhibitors of metalloproteinases (TIMPs), type I collagen carboxyterminal telopeptide (ICTP) and procollagen type I carboxyterminal propeptide (PICP), in cardiac remodelling following ischemic cardiomyopathy, and to examine the pharmacoregulatory effects of spironolactone on collagen metabolism.

METHOD:

Eighty-six consecutive patients (62 men and 24 women) with chronic heart failure of ischemic etiology (patient group) and 25 age-matched controls were enrolled in the study. The subjects in the patient group were randomly assigned into a spironolactone or nonspironolactone group. Plasma levels of MMP-9, TIMP-1, ICTP and PICP were measured using ELISA and radioimmunoassay techniques. Furthermore, left ventricular diastolic diameter and ejection fraction were assessed using two-dimensional and Doppler echocardiography.

RESULTS:

The plasma concentrations of MMP-9, TIMP-1 and the MMP-9 to TIMP-1 ratio, as well as ICTP, were significantly increased in the patient group. The PICP to ICTP ratio in the patient group was significantly lower than that in the age-matched control subjects. After a follow-up period of 24 weeks, the PICP to ICTP ratio increased, and MMP-9, TIMP-1 and the MMP-9 to TIMP-1 ratio decreased in the spironolactone subgroup.

CONCLUSIONS:

Biomarkers of collagen degradation were elevated and correlated with depressed heart function; spironolactone may partially reverse the dysregulation in collagen metabolism.     

The effect of sympathomimetic medication on cardiovascular functioning of children with attention-deficit/hyperactivity disorder

Objective

The aim of this study was to investigate the effects of sympathomimetic medication on the cardiovascular system of children with attention-deficit/hyperactivity disorder (ADHD).

Methods

Cardiovascular functioning of children with ADHD (n = 19) was tested while the children were stimulant free and during a period in which they were on stimulant medication. Electrocardiograms (ECGs) were obtained by means of a Schiller CardioLaptop AT-110 ECG recorder using the standard 12-lead cable positioning for a resting ECG. Blood pressure was measured by means of a stethoscope and mercury sphygmomanometer.

Results

The main findings of this study were that methylphenidate usage is associated with increases in heart rate (HR) and blood pressure (BP), and that it does not adversely affect HR-corrected QT and JT intervals or cardiac dispersion values.

Conclusion

Methylphenidate causes an increase in HR as well as increases in both systolic and diastolic BP, but no change in cardiac depolarisation and repolarisation duration or homogeneity.     

Electrocardiomatrix facilitates qualitative identification of diminished heart rate variability in critically ill patients shortly before cardiac arrest

Background

Although heart rate variability (HRV) has diagnostic and prognostic value for the assessment of cardiac risk, HRV analysis is not routinely performed in a hospital setting. Current HRV analysis methods are primarily quantitative; such methods are sensitive to signal contamination and require extensive post hoc processing.

Influence of Spironolactone on Matrix Metalloproteinase-2 in Acute Decompensated Heart Failure

Background

Matrix metalloproteinases (MMPs) are a family of enzymes important for the resorption of extracellular matrices, control of vascular remodeling and repair. Increased activity of MMP2 has been demonstrated in heart failure, and in acutely decompensated heart failure (ADHF) a decrease in circulating MMPs has been demonstrated along with successful treatment.

Objective

Our aim was to test the influence of spironolactone in MMP2 levels.

Methods

Secondary analysis of a prospective, interventional study including 100 patients with ADHF. Fifty patients were non-randomly assigned to spironolactone (100 mg/day) plus standard ADHF therapy (spironolactone group) or standard ADHF therapy alone (control group).

Results

Spironolactone group patients were younger and had lower creatinine and urea levels (all p < 0.05). Baseline MMP2, NT-pro BNP and weight did not differ between spironolactone and control groups. A trend towards a more pronounced decrease in MMP2 from baseline to day 3 was observed in the spironolactone group (-21 [-50 to 19] vs 1.5 [-26 to 38] ng/mL, p = 0.06). NT-pro BNP and weight also had a greater decrease in the spironolactone group. The proportion of patients with a decrease in MMP2 levels from baseline to day 3 was also likely to be greater in the spironolactone group (50% vs 66.7%), but without statistical significance. Correlations between MMP2, NT-pro BNP and weight variation were not statistically significant.

Conclusion

MMP2 levels are increased in ADHF. Patients treated with spironolactone may have a greater reduction in MMP2 levels.     

Correlation of corrected QT dispersion with the severity of coronary artery disease detected by SYNTAX score in non-diabetic patients with STEMI

Introduction

Determination of the QT interval dispersion by means of a standard ECG at rest has been widely used for cardiovascular risk assessment during the last 15 years as one of the recent explanations for the development of life threatening ventricular arrhythmias. However, little is known about the relation between QT dispersion and the severity of coronary artery atherosclerosis as defined by SYNTAX score.

Myocardial repolarization is affected in patients with ascending aortic aneurysm

Objective

Ascending aortic aneurysm (AAA) is one of the major causes of ventricular diastolic dysfunction. Diastolic dysfunction can induce ventricular repolarization dispersion. Nevertheless, myocardial repolarization dispersion is not yet to be fully evaluated in patients with AAA. We aimed to evaluate ventricular repolarization using QT and Tp-Te interval and corrected (c) Tp-Te/QT ratio in patients with AAA.

Reversible autonomic dysfunction during antiviral treatment in patients with chronic hepatitis C virus infection: Anti-HCV therapy and autonomic function

Background

The first clinical sign of chronic hepatitis C virus (HCV) infection can be one of the various extrahepatic manifestations. During antiviral treatment, symptoms of HCV-associated neuropathies usually improve, but can also worsen and lead to discontinuation of anti-HCV therapy. Recently, we have reported autonomic dysfunction in patients with HCV infection.

Objectives

In the present prospective study, we analyzed the changes of autonomic function during anti-HCV treatment.

Patients and Methods

Cardiovagal autonomic function was assessed in 22 HCV RNA-positive, treatment-naive patients by determining heart rate variability (HRV) and baroreflex sensitivity (BRS), at the beginning of treatment and 12, 24 and 48 weeks of antiviral therapy. interferon alfa-2 and ribavirin were given according to the guidelines.

Results

Both HRV and BRS time and frequency domain indices decreased after 12 weeks of therapy compared to the pre-treatment values; then the mean±SD values increased significantly by week 24 and continued to improve by week 48 of therapy-253.0±156.1 ms before therapy vs 111.6±81.9 at week 12, and 183.4±169.6 at week 24 vs 211.6±149.1 ms at week 48 for low-frequency HRV index; p<0.05 for all comparisons). These changes were independent from the presence of cryoglobulins and from virologic response.

Conclusions

The first rise followed by reversible autonomic dysfunction during antiviral therapy may be caused by the immunomodulatory actions of interferon alfa-2.     

Value of QT dispersion in evaluating spatial dispersion of ventricular repolarization during acute myocardial ischemia

OBJECTIVES:

To study the value of epicardial QT interval dispersion in predicting ischemia-induced heterogeneity of ventricular repolarization.

ANIMALS AND METHODS:

Ischemia was produced by total occlusion of the obtuse branch of the circumflex coronary artery in seven open-chest sheep. A 64-channel electrocardiogram (ECG) was acquired from the epicardium before and after coronary artery occlusion. Wavelet transformation was used to determine the characteristic points of the epicardial ECGs, and to measure the QT interval and activation-recovery interval (ARI) and their dispersions.

RESULTS:

The average QT interval and ARI from the epicardial ECG were not changed by acute myocardial ischemia (P=0.07 and P=0.13, respectively). QT dispersion remained unchanged during ischemia (P=0.17), whereas ARI dispersion was significantly increased by acute ischemia (59.9±24.0 ms versus 126.3±32.1 ms, P<0.001).

CONCLUSIONS:

These findings indicate that epicardial QT dispersion is less sensitive than ARI dispersion in estimating repolarization heterogeneity induced by acute myocardial ischemia.     

Impact of Psychotropic Drugs on QT Interval Dispersion in Adult Patients

Background

Drug-induced increase in QT dispersion has been associated with potentially fatal ventricular arrhythmias. Little is known about the use of psychotropic substances, alone or in combination with other drugs on QT dispersion.

Objectives

To evaluate the impact of psychotropic drugs on QT interval dispersion in adults.

Methods

An observational cohort study was designed involving 161 patients hospitalized from an emergency department at a tertiary hospital, divided into psychotropic users or non-users. Demographic, clinical, laboratory data and drugs used on a regular basis were collected on admission, in addition to 12-lead electrocardiogram with QT dispersion measurement.

Results

QT dispersion was significantly higher in the psychotropic user group compared to non-users (69.25 ± 25.5 ms vs. 57.08 ± 23.4 ms; p = 0.002). The QT interval corrected by Bazzett formula was also higher in the psychotropic drugs user group, with statistical significance. (439.79 ± 31.14 ms vs. 427.71 ± 28.42 ms; p = 0.011). A regression analysis model showed a positive association between the number of psychotropic drugs used and QT interval dispersion, with r = 0.341 and p < 0.001.

Conclusions

The use of psychotropic drugs was associated with increased QT dispersion and this increase was accentuated, as the number of psychotropic drugs used was higher.     

Pattern of congestive heart failure in a Kenyan paediatric population

Background

Heart failure in children is a common cause of morbidity and mortality, with high socio-economic burden. Its pattern varies between countries but reports from Africa are few. The data are important to inform management and prevention strategies.

Objective

To describe the pattern of congestive heart failure in a Kenyan paediatric population.

Methods

This was a retrospective study done at Kenyatta National Hospital, Nairobi Kenya. Records of patients aged 12 years and younger admitted with a diagnosis of heart failure between January 2006 and December 2010 were examined for mode of diagnosis, age, gender, cause, treatment and outcome. Data were analysed using the Statistical Programme for Social Scientists version 16.0 for windows, and presented in tables, bar and pie charts.

Results

One hundred and fifty-eight cases (91 male, 67 female) patients’ records were analysed. The mean age was 4.7 years, with a peak at 1–3 years. The male:female ratio was 1.4:1. All the cases were in New York Heart Association (NYHA) class II–IV. Evaluation of infants was based on the classification proposed by Ross et al. (1992). Diagnosis was made based on symptoms and signs combined with echocardiography (echo) and electrocardiography (ECG) (38%); echo alone (12.7%); ECG, echo and chest X-ray (CXR) (11.4%); and ECG alone (10.8%). The underlying cause was established on the basis of symptoms, signs, blood tests, CXR, echo and ECG results. Common causes were infection (22.8%), anaemia (17.1%), rheumatic heart disease (14.6%), congenital heart disease (13.3%), cardiomyopathy (7.6%), tuberculosis and human immunodeficiency virus (6.9% each); 77.9% of patients recovered, 13.9% after successful surgery, and 7.6% died.

Conclusion

Congestive heart failure is not uncommon in the Kenyan paediatric population. It occurs mainly before five years of age, and affects boys more than girls. The majority are due to infection, anaemia, and rheumatic and congenital heart diseases. This differs from those in developed countries, where congenital heart disease and cardiomyopathy predominate. The majority of children usually recover. Prudent control of infection and correction of anaemia are recommended.