Heart Care Info - Heart Disease Prevention & Treatment

Resting heart rate in patients with ischemic heart disease in Saudi Arabia and Egypt

AJ Kinsara, HK Najm, MA Anazi... - Journal of the Saudi Heart ..., 2011 - Elsevier Mean age of CAD patients was 56.7 10.4 and the mean RHR was 78.9 13.9 b/m. 1686 patients (83.1%) were on β-blockers for whom the RHR was 78.5 14.0 b/m (95.5% had RHR 60 b/m, which is higher than recommended by the guidelines). 1094 (73.5%) of patients on β- ...

Furthermore, a large body of evidence provided by epidemiological studies suggests that high HR is an important cardiovascular risk factor, and should be a therapeutic target for clinicians. The association between HR and cardiovascular disease has been found not only in patients with chronic ischemic heart disease, but also among patients with heart failure ( [Benetos et al., 1999], [EUROASPIRE, 1997] and [Tverdal et al., 2008]).

However, little is known about HR level in current medical practice in the outpatient population with cardiovascular diseases. To date no data is available about RHR in CAD patients in Saudi Arabia and Egypt. In spite of the evidence, resting HR is not yet a routine component of cardiovascular disease risk assessment, or in deciding whether modification of treatment is indicated. This gives a vast potential to further improve the management in patients with coronary disease or heart failure; because by not controlling HR there appears to be a therapeutic opportunity that is being missed.

More recently the BEAUTIFUL study has provided significant evidence that in patients with CAD and left-ventricular systolic dysfunction, elevated HR (70 bpm or greater) identifies those at increased risk of cardiovascular outcomes, with a differential effect on outcomes associated with HR and outcomes associated with coronary events (Fox et al., 2008).

The primary objective of this study was to assess the level of RHR in a population presenting with stable CAD. The secondary objective was to measure the association of RHR with current therapeutic management strategies for cardiovascular events. In addition the agreement between the two HR measurements were assessed using the physical palpation and the electronic device by calculating the correlation coefficient for the association between these two measurements.

An observational cross-sectional, multi-center survey was carried out in the major cities of Saudi Arabia and Egypt. A total of 2049 patients were selected based on a cluster sampling technique. Twenty centers were randomly selected by the authors among tertiary referral hospitals. A random sample of 100 cardiologists each recruited 20 patients based on a stratified consecutive (Quota) sampling technique. These patients were presented to the clinic. The stratified aspect of this sampling procedure was based on the CAD status of the patient. The consecutive (Quota) aspect of the sampling was applied to the first 20 patients presenting with stable CAD. Since the objectives of the study are descriptive in nature, statistical sample size was not calculated, whereas a convenient sample was selected for this study.

Eligible subjects were male and female outpatients aged ⩾ 18 with a history of stable CAD, i.e., with stable angina, history of revascularization, history of myocardial infarction or of hospitalization for unstable angina, or having angiographic evidence of at least 70% narrowing of one of the major coronary arteries.

Resting blood pressure and HR: The patients should be at rest in a sitting position for 5 min. Systolic blood pressure and diastolic blood pressure were measured by a sphygmomanometer. RHR was measured in three ways; by physical palpation and counting for 1 min, confirmation of the accuracy of measurements was done either by ECG reading or by an electronic device (optional). Since the results between the physical palpitation and ECG readings were not statistically different, the former was taken as reference.

Data were collected for patients, during a single visit, using structured questionnaires which included a study-specific identification number and was not related to the patients medical record number. Patient demographics collected included: (age and sex). Cardiovascular risk factors included smoking, weight, height, family history of CVD, dyslipidemia, hypertension, diabetes, and exercise. Moreover, information on history of cardiovascular events (target organ damage and history of hospitalization) was also collected and for patients included for stable angina, average number of angina attacks, short-acting nitrate consumption and grade of pain (according to the Canadian Cardiology Society Scale). Current cardiovascular treatments (name of the drug and the total dose/day in mg). β-blocker dose was defined as high dose once the patient took the optimal recommended dose as per the SPC and was defined as low for any dose less than indicated.

To take the stratified sampling procedure adopted in this study into consideration, all statistical analyses were carried out in those with stable CAD (without clinical HF symptoms). Descriptive analyses with means, standard deviations, and 95% confidence intervals around the mean, were calculated for the HR variable.

Bivariate statistical analyses were carried out to assess the association between the RHR and each of the different categories of collected information; demographic variables, cardiovascular risk factors, history of cardiovascular events, NYHA class (for HF patients), and current cardiovascular treatments. P-values for these associations were calculated using Student s t-test (for association with dichotomous variables, such as sex), ANOVA (for association with categorical variables with more than two categories, such as smoking status), and Pearson correlation (for association with continuous variables, such as age).

Data were entered into a Microsoft Access database structured specifically for this study. Data management and analyses were carried out using the Statistical Analysis Software (SAS, Release 8, SAS Institute Inc., Cary, NC, 1999, USA) (SAS 1999). The study was approved by the hospital research committee.

A total of 2049 patients from different centers in the two countries were included in the study (1035 from Saudi Arabia, and 1014 from Egypt). The general demographics of the patients in the study are demonstrated in Table 1. The mean age of the patients was 56.7 ( 10.4). Moreover 1403 (70.2%) of the patients were males.