Influence of different echocardiographic criteria for detection of left ventricular hypertrophy on cardiovascular risk stratification in recently diagnosed essential hypertensives

Echocardiographic partition values and prevalence of left ventricular hypertrophy in hypertensive Nigerians

BACKGROUND

Left ventricular hypertrophy (LVH) is a well known independent risk factor for cardiovascular events. It has been shown that combination of left ventricular mass (LVM) and relative wall thickness (RWT) can be used to identify different forms of left ventricular (LV) geometry. Prospective studies have shown that LV geometric patterns have prognostic implications, with the worst prognosis associated with concentric hypertrophy. The methods for the normalization or indexation of LVM have also recently been shown to confer some prognostic value especially in obese population. We sought to determine the prevalence of echocardiographic lLVH using eight different and published cut-off or threshold values in hypertensive subjects seen in a developing country's tertiary centre.

METHODS

Echocardiography was performed in four hundred and eighty consecutive hypertensive subjects attending the cardiology clinic of the University college Hospital Ibadan, Nigeria over a two-year period.

RESULTS

Complete data was obtained in 457 (95.2%) of the 480 subjects (48.6% women). The prevalence of LVH ranged between 30.9-56.0%. The highest prevalence was when LVM was indexed to the power of 2.7 with a partition value of 49.2 g/ht2.7 in men and 46.7 g/ht2.7 in women. The lowest prevalence was observed when LVM was indexed to body surface area (BSA) and a partition value of 125 g/m2 was used for both sexes. Abnormal LV geometry was present in 61.1%-74.0% of our subjects and commoner in women.

CONCLUSION

The prevalence of LVH hypertensive patients is strongly dependent on the cut-off value used to define it. Large-scale prospective study will be needed to determine the prognostic implications of the different LV geometry in native Africans.

Is Electrocardiography Still Useful in the Diagnosis of Cardiac Chamber Hypertrophy and Dilatation?

The echocardiogram undoubtedly is part of the cardiologist's armamentarium in the diagnosis and elucidation of cardiac abnormalities, but the ECG still continues to be the most frequently recorded noninvasive test in medicine. For many patients, particularly those who have newly diagnosed hypertension, a 12-lead ECG recording may be the only test that is required as a baseline measure. For those who have possible heart failure, an ECG and B-type natriuretic peptide measurement may be sufficient to obviate the need for an echocardiogram. Electrocardiography and echocardiography will continue to live side-by-side for the foreseeable future.

Change in cardiovascular risk profile by echocardiography in medium-risk elderly hypertensives

It has been clearly demonstrated that ageing and arterial hypertension are both associated with an increased prevalence of left ventricular hypertrophy (LVH), which is a powerful risk factor for cardiovascular (CV) events. The objective of this study was to assess the impact of echocardiographic LVH in profiling the absolute CV risk stratification according to the 1999 World Health Organization-International Society of Hypertension (WHO/ISH) guidelines in elderly hypertensive patients. A total of 223 never-treated elderly patients (> or =65 years) with essential hypertension (98 men, 125 women, mean age 72+/-5 years) referred to our outpatient hospital clinic were included in the study. They underwent the following procedures: (1) medical history, physical examination, and clinic blood pressure; (2) routine blood chemistry and urine analysis and (3) electrocardiogram. The risk was initially stratified according to the routine procedures suggested by WHO/ISH guidelines and subsequently reassessed by adding the results of echocardiography (LVH as left ventricular mass index >51 g/m(2.7) in men and >47g/m(2.7) in women). According to routine classification, 56% (n=125) were medium-risk patients, 29% (64) high-risk and 15% (34) very-high-risk patients. The overall prevalence of LVH was 56% (48% in medium-risk and 62% in high-risk or very-high-risk patients, P<0.01). A marked change in risk stratification was observed when echocardiographic LVH was taken into consideration: medium-risk patients decreased to 29% and high-risk patients rose to 56% (P<0.01). In conclusion, ultrasound assessment of cardiac target organ damage is extremely useful in obtaining a more valid assessment of global cardiovascular risk in elderly hypertensives, because stratification based on diagnostic routine procedures can underestimate the overall risk in a large fraction (48%) of medium-risk subjects.