Cardioversion of atrial arrhythmias: audit of anticoagulation management

Patients undergoing cardioversion for chronic atrial fibrillation should receive anticoagulation for three weeks before and four weeks after the procedure. Patients with atrial flutter and acute atrial fibrillation are also at risk of thromboembolic complications, so they too should be anticoagulated for cardioversion. Of the 36 acutely admitted patients who were cardioverted, 18 were in atrial fibrillation and 18 in atrial flutter. All except three of those in fibrillation were anticoagulated with heparin before cardioversion, but only seven received warfarin after cardioversion. Of those in flutter, 10 received heparin and eight received no anticoagulation before cardioversion. One patient underwent transoesophageal echocardiography before cardioversion to exclude atrial thrombi. Only two patients received warfarin for a month after cardioversion. Of the 20 elective cardioversions, 10 were in atrial fibrillation and 10 in atrial flutter. Five of those in fibrillation had received at least three weeks' treatment with warfarin before cardioversion and two underwent transoesophageal echocardiography; the other three received either up to two hours of heparin or no anticoagulation before cardioversion. Only five patients received warfarin for a month after cardioversion. Nine of those in flutter received a few hours of heparin before cardioversion and one was not anticoagulated; none underwent transoesophageal echocardiography or received warfarin after cardioversion. The results of this audit demonstrate that anticoagulation for atrial arrhythmias was inconsistent and often inadequate. A formal anticoagulation policy for cardioversion has now been adopted.

Left ventricular hypertrophy and QT dispersion in hypertension

The interlead variation in QT length on a standard electrocardiograph reflects regional repolarization differences in the heart. To investigate the association between this interlead variation (QT dispersion) and left ventricular hypertrophy, we subjected 100 untreated subjects to 12-lead electrocardiography and echocardiography. Additionally, 24 previously untreated subjects underwent a 6-month treatment study with ramipril and felodipine. In the cross-sectional part of the study, QT dispersion corrected for heart rate (QTc dispersion) was significantly correlated with left ventricular mass index (r = .30, P < .01), systolic pressure (r = .30, P < .01), the ratio of peak flow velocity of the early filling wave to peak flow velocity of the atrial wave (E/A ratio) (r = -.22, P = .02), isovolumic relaxation time (r = .31, P < .01), and age (r = .21, P < .04). In the treatment part of the study, lead-adjusted QTc dispersion decreased from 24 to 19 milliseconds after treatment, and after a subsequent 2 weeks of drug washout remained at 19 milliseconds (P < .01). The changes in left ventricular mass index at these stages were 144, 121, and 124 g/m2 (P < .01). Systolic pressure decreased from 175 to 144 mm Hg and increased again to 164 mm Hg after drug washout (P < .01). The E/A ratio (0.97, 1.02, and 1.02; P = 69) and isovolumic relaxation time (111, 112, and 112; P = .97) remained unchanged through the three assessment points. In conclusion, QT dispersion is increased in association with an increased left ventricular mass index in hypertensive individuals. Antihypertensive therapy with ramipril and felodipine reduced both parameters. If an increased QT dispersion is a predictor of sudden death in this group of individuals, then the importance of its reduction is evident.

The effects of antihypertensive therapy on carotid vascular structure in man

OBJECTIVE

An increased carotid intima-media thickness (IMT) has been found to be associated with a number of cardiovascular risk factors such as age, hypertension, cigarette smoking, hypercholesterolaemia and left ventricular hypertrophy. Our objective was to assess whether carotid intima-media thickness in hypertensive patients could be reduced by antihypertensive therapy.

METHODS

13 hypertensive patients, 10 previously untreated, were examined using carotid ultrasonography and echocardiography at baseline and then at 8 weeks and 39 weeks after commencement of antihypertensive therapy with ramipril and the second-line addition of felodipine.

RESULTS

By the end of the study significant regression of IMT (0.1(0.05-0.16) mm, F-value 10.2, P < 0.01) and left ventricular mass index had occurred (25(10.7-39.3) g/m2, F-value 9.7, P < 0.01). The reduction in IMT was significantly related to the reduction in mean arterial pressure, r = 0.55, P = 0.05).

CONCLUSION

Antihypertensive therapy with ramipril and felodipine causes regression of IMT in hypertensive patients, probably chiefly through blood pressure reduction. Large prospective studies are required to assess whether a reduction in IMT results in a reduction in morbidity and mortality.

Left ventricular diastolic function in hypertension: a 4 year follow-up study

In order to assess the long term effects of antihypertensive treatment on left ventricular diastolic function, 26 hypertensive patients were followed up for a mean of 4.25 years with two-dimensional and Doppler echocardiography. A significant reduction in left ventricular mass index was first apparent after 9 months of therapy (mean (S.D.) 124 (22) vs. 114 (18) g/m2, P < 0.01), and this was maintained over the 4.25 year period (124 (22) vs. 117 (17) g/m2, p < 0.05). At 9 months there was no change in either isovolumic relaxation time (108 (26) vs. 108 (17) ms, P = N.S.) or left ventricular filling as assessed by peak flow velocity E/A ratio (0.94 (0.22) vs. 0.95 (0.27), P = N.S.). However, after 4.25 years there was a significant improvement in IVRT (108 (26) vs. 83 (11) ms, P < 0.01) with a trend towards an improved peak flow velocity E/A ratio, although this did not reach statistical significance (0.95 (0.27) vs. 1.02 (0.26), P = N.S.). Of the 14 patients who had an abnormal isovolumic relaxation time at baseline, 12 normalised and 2 improved. These findings suggest that left ventricular diastolic dysfunction in hypertension may be reversed by prolonged antihypertensive treatment.

Left ventricular structure and function in previously untreated hypertensive patients: the importance of blood pressure, the nocturnal blood pressure dip and heart rate

BACKGROUND

Cardiac assessment is an important part of risk stratification in hypertensive patients. Left ventricular hypertrophy in particular is a powerful predictor of subsequent cardiovascular morbidity and mortality. Previous studies assessing haemodynamic factors that may be responsible for cardiac changes in hypertensive patients have been performed in those previously treated for hypertension. To investigate more fully these haemodynamic relationships, a large group of previously untreated patients were studied.

METHODS

Ninety-eight previously untreated hypertensive patients underwent electrocardiography, two-dimensional and Doppler echocardiography, 24 h ambulatory blood pressure monitoring and exercise stress testing.

RESULTS

The left ventricular mass index (LVMI) was more closely related to mean 24 h than to clinic blood pressures (24 h systolic r = 0.48, P < 0.01; 24 h diastolic r = 0.49, P < 0.01; clinic systolic r = 0.28, P < 0.01; clinic diastolic r = 0.31, P < 0.01). In addition, the systolic nocturnal blood pressure dip was found to be inversely related to LVMI in men (r = -0.32, P < 0.01). Of the indices of left ventricular diastolic function, age (r = -0.64, P < 0.01), heart rate (r = -0.25, P = 0.02) and LVMI (r = -0.22, P = 0.02) were independently related to the E-A ratio. Age (r = 0.40, P < 0.01), blood pressure (systolic r = 0.39, P < 0.01; diastolic r = 0.43, P < 0.01), the nocturnal blood pressure dip (systolic r = -0.38, P < 0.01, diastolic r = -0.31, P < 0.01) and LVMI (r = 0.37, P < 0.01) were independently related to the isovolumic relaxation time.

CONCLUSIONS

Blood pressure was the only independent determinant of LVMI; nocturnal blood pressure may be particularly important in men. Age and both haemodynamic and structural factors are independent determinants of parameters of left ventricular diastolic function in hypertensive patients.

Ventricular arrhythmias in hypertension: in which patients do they occur?

OBJECTIVE

It has been suggested that the increased incidence of sudden death in hypertensive patients, particularly those with left ventricular hypertrophy, may be casually related to the increased number and complexity of ventricular arrhythmias that have been demonstrated in these patients. The objective of the present study was to assess some of the factors which might be responsible for these arrhythmias.

SUBJECTS AND METHODS

One hundred and three untreated subjects were divided into four groups on the basis of blood pressure and echocardiographic measurements: hypertensive patients with left ventricular hypertrophy (n = 38), hypertensive patients without left ventricular hypertrophy (n = 16), patients with borderline or white-coat hypertension (n = 26) and normotensive subjects (n = 23). Each subject underwent two-dimensional and Doppler echocardiography, 12-lead electrocardiogram examination, 12-lead electrocardiogram exercise stress testing, 24-h ambulatory blood pressure monitoring and 24-h Holter monitoring. A further 17 hypertensive patients with left ventricular hypertrophy who were on long-term antihypertensive therapy were also investigated in the same manner and compared with untreated hypertensive patients with left ventricular hypertrophy who were matched for age, sex and race.

RESULTS

Untreated hypertensive patients, even with left ventricular hypertrophy, had a low prevalence of frequent or complex arrhythmias (seven out of 80 patients with Lown score 2+). In contrast, hypertensive patients with left ventricular hypertrophy on long-term antihypertensive therapy had a significantly greater prevalence of complex arrhythmias than untreated patients with left ventricular hypertrophy (eight out of 17 treated patients compared with two out of 17 untreated patients with Lown score 2+).

CONCLUSIONS

Hypertensive patients with left ventricular hypertrophy who had received long-term antihypertensive therapy were found to have a high prevalence of complex ventricular arrhythmias, which was in contrast to untreated hypertensive patients, even those with left ventricular hypertrophy. This may reflect the consequences on the left ventricle of long-term antihypertensive treatment. If complex ventricular arrhythmias are implicated in the excess of sudden deaths in hypertensive patients, this might be an important factor.

Structural changes in the cardiovascular system of untreated essential hypertensives

Arterial hypertension is associated with structural changes in the cardiovascular system. This study has examined the effect of hypertension on the carotid artery wall and examined the relation between changes in the structure of carotid artery wall and left ventricle in untreated hypertensives. The carotid artery wall was visualized using a high resolution ultrasound technique in 37 untreated hypertensive patients (25 males, 12 females) and 37 age and sex matched normotensive individuals and carotid intima-media thickness (IMT) and carotid artery diameter measured. IMT and intima-media cross sectional area was significantly greater in the hypertensive group compared with the normotensive group, though the carotid artery diameter did not differ significantly. There was a significant association between age and IMT in both groups. In the hypertensive group there was also a significant association between left ventricular mass index, ventricular septal or posterior wall thickness and IMT. This study indicates that there is an association between cardiac and carotid arterial structure in hypertension. Such a relationship may be important in understanding the associated risks of high blood pressure.

Racial differences in cardiac structure and function in essential hypertension

OBJECTIVE

To assess racial differences in cardiac structure and function in patients presenting with previously untreated hypertension.

DESIGN

Untreated black patients with hypertension were compared with untreated white patients matched for age and sex. Both groups had similar body mass indices, blood pressures, and reported duration of hypertension.

SETTING

Cardiovascular risk factor clinic for outpatients.

SUBJECTS

36 men and 22 women with untreated essential hypertension.

MAIN OUTCOME MEASURES

Variables of heart structure and function on cross sectional and Doppler echocardiography.

RESULTS

The black patients had a significantly greater interventricular septal thickness (mean 1.23 (95% confidence interval 1.14 to 1.33) v 1.09 (1.02 to 1.16) cm; P = 0.02) and posterior wall thickness (mean 1.14 (1.07 to 1.22) v 0.96 (0.88 to 1.03) cm; P = 0.001) than the white patients, although left ventricular internal diameter was not significantly different (mean 4.90 (4.68 to 5.12) v 4.82 (4.64 to 5.01) cm; P = 0.59). This resulted in a significantly greater left ventricular mass index (mean 151 (137 to 164) v 120 (107 to 133) g/m2; P = 0.001) and relative wall thickness (mean 0.47 (0.43 to 0.51) v 0.40 (0.37 to 0.42) cm; P = 0.004) in the black patients. Comparison of Doppler measures of left ventricular diastolic function showed a significantly longer isovolumic relaxation time in black patients (mean 107 (98 to 116) v 92 (83 to 101) ms; P = 0.02) compared with white patients, although peak early to atrial filling ratios were similar in both groups (mean 1.14 (0.95 to 1.32) v 1.04 (0.94 to 1.15); P = 0.37).

CONCLUSION

Among previously untreated hypertensive patients, black subjects compared with white subjects have significantly higher left ventricular mass index and relative wall thickness, as well as more impairment of left ventricular function during diastole.

Structural changes in the heart and carotid arteries associated with hypertension in humans

Hypertension is associated with structural changes in the vascular system and in the heart. This study has examined the relationships between carotid artery intima-media thickness and other risk factors in 52 untreated patients (20 hypertensive). Carotid intima-media thickness was measured bilaterally using a Duplex doppler ultrasonic scanner. In the hypertensive individuals the left ventricle was examined by echo-cardiography and the left ventricular mass index determined. There was a significant association between age and IMT, and both SBP and DBP and IMT. The IMT in the hypertensive group was significantly larger than in the normotensive group and in the hypertensive subjects there was a positive association between left ventricular mass index and IMT. There was no significant difference in calculated media stress between the normotensive and hypertensive groups, probably due to a small increase in carotid intima-media area combined with a small reduction in carotid lumen diameter. Hypertension is associated with a thickening of the intima-media of the carotid artery and an increase in left ventricular mass. Whether these changes in cardiac and arterial structure are in response to similar influences remains to be established.

Self-assessment of medical knowledge: do physicians overestimate or underestimate?

The relationship between doctors' medical knowledge and their inability to assess correctly what they know was investigated. Sixty out of 65 hospital physicians sat a MRCP Part 1 multiple-choice examination. In addition to the factual questions, they had to estimate how certain they were that their answers were correct. We confirmed that factual knowledge increased with clinical experience from the grade of house officer through to that of senior registrar. The self-assessment of likelihood of being correct revealed that, on average, doctors underestimated their knowledge by 8%. However, those who had passed their MRCP examination within the past three years over-estimated on average by 6%. We suggest that this inadequacy of self-assessment could have serious clinical implications, and should be assessed.