Prognostic value of ventricular arrhythmias in systemic hypertension

Certain beta blockers (e.g., bisoprolol) may be reevaluated in hypertension guidelines for patients with left ventricular hypertrophy to diminish the ventricular arrhythmic risk

Hypertensive left ventricular hypertrophy (HTN LVH) is associated with almost threefold increased risk of ventricular tachycardia (VT)/ventricular fibrillation (VF). Furthermore, HTN LVH increases the risk of sudden cardiac death (SCD). The reverse LV remodeling due to efficient antihypertensive therapy lowers the incidence rates of cardiovascular events and SCD and the vast majority of available arterial hypertension (HTN) guidelines recommend renin angiotensin system (RAS) blockers and calcium channel blockers (CCBs) for HTN LVH aiming for LVH regression. On the other hand, beta blockers (BBs) as a class are not recommended in HTN LVH due to their insufficient capacity to reverse LVH remodeling even though they are recommended as the first-line drugs for prevention/treatment of VT/VF (in general, unrelated to HTN LVH). Moreover, BBs are the best antiarrhythmic (against VT/VF) among antihypertensive drugs. Despite that, BBs are currently not recommended for LVH treatment in HTN Guidelines. It is important to prevent VT/VF in patients at high risk, such as those with HTN LVH. Therefore, certain BBs (such as Bisoprolol) may be reevaluated in guidelines for HTN (in the section of HTN LVH).

Hypertension and cardiac arrhythmias: a consensus document from the European Heart Rhythm Association (EHRA) and ESC Council on Hypertension, endorsed by the Heart Rhythm Society (HRS), Asia-Pacific Heart Rhythm Society (APHRS) and Sociedad Latinoamericana de Estimulación Cardíaca y Electrofisiología (SOLEACE)

Hypertension is a common cardiovascular risk factor leading to heart failure (HF), coronary artery disease, stroke, peripheral artery disease and chronic renal insufficiency. Hypertensive heart disease can manifest as many cardiac arrhythmias, most commonly being atrial fibrillation (AF). Both supraventricular and ventricular arrhythmias may occur in hypertensive patients, especially in those with left ventricular hypertrophy (LVH) or HF. Also, some of the antihypertensive drugs commonly used to reduce blood pressure, such as thiazide diuretics, may result in electrolyte abnormalities (e.g. hypokalaemia, hypomagnesemia), further contributing to arrhythmias, whereas effective control of blood pressure may prevent the development of the arrhythmias such as AF. In recognizing this close relationship between hypertension and arrhythmias, the European Heart Rhythm Association (EHRA) and the European Society of Cardiology (ESC) Council on Hypertension convened a Task Force, with representation from the Heart Rhythm Society (HRS), Asia-Pacific Heart Rhythm Society (APHRS), and Sociedad Latinoamericana de Estimulación Cardíaca y Electrofisiología (SOLEACE), with the remit to comprehensively review the available evidence to publish a joint consensus document on hypertension and cardiac arrhythmias, and to provide up-to-date consensus recommendations for use in clinical practice. The ultimate judgment regarding care of a particular patient must be made by the healthcare provider and the patient in light of all of the circumstances presented by that patient.

Nonsustained Ventricular Tachycardia in the Normal Heart: Risk Stratification and Management

Nonsustained ventricular tachycardia (NSVT) may trigger concern, particularly in patients with known congestive heart failure, structural heart disease, or prolonged QT interval. When NSVT occurs in patients with normal hearts, it usually has a benign prognosis. Therefore, establishing the presence or absence of structural or inherited heart disease is a critical step in each patient's evaluation. It is important to approach a wide-complex tachycardia in a systematic manner, to ensure correct diagnosis and treatment. When NSVT occurs in a patient with a normal heart, treatment is targeted toward symptoms and may consist of observation, medical therapy, or catheter ablation.

Intramural Reentrant Ventricular Tachycardia in a Patient with Severe Hypertensive Left Ventricular Hypertrophy

We describe the case of a patient with severe hypertensive left ventricular hypertrophy and sustained hemodynamically unstable ventricular tachycardia (VT). Entrainment was demonstrated in the electrophysiological study. Activation mapping and pacemapping identified the location of the intramural reentrant VT with the exit site close to the epicardium. However, VT persisted after ablation at the epicardial exit site. Successful ablation was performed endocardially at the corresponding position.

[The effect of esmolol on corrected-QT interval, corrected-QT interval dispersion changes seen during anesthesia induction in hypertensive patients taking an angiotensin-converting enzyme inhibitor]

BACKGROUND AND OBJECTIVES

The importance of minimizing the exaggerated sympatho-adrenergic responses and QT interval and QT interval dispersion changes that may develop due to laryngoscopy and tracheal intubation during anesthesia induction in the hypertensive patients is clear. Esmolol decreases the hemodynamic response to laryngoscopy and intubation. However, the effect of esmolol in decreasing the prolonged QT interval and QT interval dispersion as induced by laryngoscopy and intubation is controversial. We investigated the effect of esmolol on the hemodynamic, and corrected-QT interval and corrected-QT interval dispersion changes seen during anesthesia induction in hypertensive patients using angiotensin converting enzyme inhibitors.

METHODS

60 ASA I-II patients, with essential hypertension using angiotensin converting enzyme inhibitors were included in the study. The esmolol group received esmolol at a bolus dose of 500mcg/kg followed by a 100mcg/kg/min infusion which continued until the 4th min after intubation. The control group received 0.9% saline similar to the esmolol group. The mean blood pressure, heart rate values and the electrocardiogram records were obtained as baseline values before the anesthesia, 5min after esmolol and saline administration, 3min after the induction and 30s, 2min and 4min after intubation.

RESULTS

The corrected-QT interval was shorter in the esmolol group (p=0.012), the corrected-QT interval dispersion interval was longer in the control group (p=0.034) and the mean heart rate was higher in the control group (p=0.022) 30s after intubation. The risk of arrhythmia frequency was higher in the control group in the 4-min period following intubation (p=0.038).

CONCLUSION

Endotracheal intubation was found to prolong corrected-QT interval and corrected-QT interval dispersion, and increase the heart rate during anesthesia induction with propofol in hypertensive patients using angiotensin converting enzyme inhibitors. These effects were prevented with esmolol (500mcg/kg bolus, followed by 100mcg/kg/min infusion). During induction, the blood pressure tends to decrease with esmolol where care is needed.

Specific electrocardiographic features associated with Cushing's disease

OBJECTIVE

Hypercortisolaemia is associated with an increased risk of cardiovascular disease (CVD), either through a direct action on the myocardium or by increased traditional cardiovascular risk factors. The aim of this study was to investigate whether the alterations in the ECG in Cushing's disease (CD) are predictable from risk factor analysis alone.

DESIGN

In 79 patients with a diagnosis of CD, retrospectively recruited, ECG features [corrected for heart rate QT (QTc), QTc dispersion (QTcd), left ventricular hypertrophy (ECG-LVH), right ventricular hypertrophy (ECG-RVH)], systolic (SBP) and diastolic (DBP) blood pressure were assessed. Biochemical, hormonal (cortisol at 09·00 h or cortisol day curve, CDC) and carbohydrate abnormalities (CHA), history of hypertension and cardiovascular disease were recorded. For comparison reasons, a group of 42 healthy subjects matched for gender, age and body mass index previously subjected to ECG assessment were selected.

RESULTS

In patients with CD, we noted the following prevalence: metabolic syndrome 39%, hypertension 81%, CVD 21·5%, hypercholesterolaemia 37%, hypertriglyceridaemia 29%, CHA 41%, but a history of cardiac dysrhythmia was only noted in a single patient. No difference in QTc or QTcd was shown between patients with normal or low potassium levels. QTcd >50 ms was associated with both increased ECG-LVH and ECG-RVH. When compared to the control group, patients had longer QTcd (P < 0·001), more prevalent LVH (P < 0·001) and RVH (P = 0·001), and higher SBP and DBP (P < 0·001), but similar QTc. Both CD and ECG evidence of LVH predicted prolonged QTcd, but the association of CD with a prolonged QTcd was independent of other risk factors, including hypertension.

CONCLUSIONS

Prolonged QTcd in association with ECG evidence of LVH appears to be the specific feature of CD. This may be relevant in the choice of medical therapy for CD and for consideration of treatment of the comorbidities that are associated with hypercortisolaemia.

Losartan decreased premature ventricular contractions in patients with hypertension

Losartan, enalapril and amlodipine reduced the number of premature ventricular contractions (PVCs) in patients with essential hypertension as well as blood pressure. The effect of losartan was the most prominent among the three drugs.

Correlation between 24-hour profile of blood pressure and ventricular arrhythmias and their prognostic significance in patients with arterial hypertension

Background/Aim. Left ventricular hypertrophy (LVH), apart from arterial hypertension, is a risk factor for electrophysiologic heart condition disorder and sudden cardiac death. The aim of this study was to examine a relationship between complex ventricular arrhythmias and parameters of 24-hour ambulatory blood pressure monitoring in the patients with arterial hypertension and left ventricular hypertrophy (LVH), as well as their prognostic significance during a five-year follow-up. Methods. Ninety patients with arterial hypertension and LVH were included in this study (mean age 55.2?8.3 years). There were 35 healthy people in the control group (mean age 54.5?7.1 years). Left ventricular mass index was 171.9?32.4 g/m2 in the LVH group and 102.4?13.3 g/m2 in the control group. Clinical examination, echocardiogram, 24-hour ambulatory blood pressure monitoring and 24-hour holter monitoring were done in all of the examined persons. Ventricular arrhythmias were classified by the Lown classification. Results. In the LVH group there were 54 (60.0%) of the patients with ? III Lown class. The best predictor of a Lown class were left ventricular mass index by using multivariate stepwise regression analyses (? = 0.212; p < 0.05) and small decrease of diastolic blood pressure during the night (? = -0.293; p < 0.01). The main predictor of bad prognosis was left ventricular mass index during a five year follow-up (? = 0.302; p < 0.01, for stepwise regression model: F = 8.828; p < 0.01, adjusted R2 = 0.091). Conclusion. Left ventricular arrhythmias are frequent in patients with lower decrease of blood pressure during the night. There was no correlation between the degree of ventricular arrhythmias and parameters from 24-hour blood pressure monitoring and a five-year prognosis in the patients with arterial hypertension and LVH. A bad five-year follow-up outcome of hypertensive disease depends on left ventricular mass index.

Lack of Correlation Between QTc Dispersion and Morning Blood Pressure Surge in Recently Diagnosed Essential Hypertensive Patients

BACKGROUND

Cardiovascular events are known to occur more frequently in patients with a high morning surge in blood pressure (BP), but the correlation between a morning BP surge and corrected QT dispersion (QTc) has not been confirmed to date.

METHODS AND RESULTS

The correlation between the morning BP surge and QTc was studied in 82 patients recently diagnosed with high BP (47 males, 35 females). Twenty-four-hours BP monitoring was conducted to classify patients into dipper (n=45) or nondipper (n=37) groups according to the degree of nocturnal BP reduction. QTc was found to be significantly longer in the nondippers compared with the dippers (36.1+/-17.2 vs 47.6+/-20.7, p<0.001). In addition, there was a significant increase in the end-diastolic interventricular septum thickness (IVSd), left ventricular posterior wall thickness in diastole (PWT) and left ventricular mass index (LVMI) in the nondippers vs the dippers (respectively, 0.93+/-0.09 vs 1.03+/-0.05, p<0.001, 0.94+/-0.09 vs 1.01+/-0.04, p<0.01, 109.7+/-12.8 vs 129.1+/-20.9, p<0.001). QTc had a significant positive correlation with nighttime BP, IVSd, PWT, and LVMI, but negatively correlated with the nocturnal BP reduction rate. These results were maintained even after adjusting for age and gender. However, a significant correlation between the morning BP surge and QTc was not confirmed.

CONCLUSION

In the present nondipper hypertensive patients, QTc, nighttime BP, LVMI, and wall thickness were significantly greater than in the dipper patients. However, there was no significant correlation between the morning BP surge and QTc.

Usefulness of QT-interval parameters for cardiovascular risk stratification in type 2 diabetic patients with arterial hypertension

QT-interval parameters are potential indicators of increased cardiovascular risk. We evaluated prospectively their prognostic value, in relation to other risk markers, for cardiovascular fatal and nonfatal events in a cohort of 271 hypertensive type 2 diabetic outpatients. QT intervals were measured from 12-lead standard ECGs obtained on admission and maximum rate-corrected QT-interval duration and QT-interval dispersion (QTd) calculated. Clinical and laboratory data and 2-D echocardiograms (available in 126 patients) were recorded. Survival analyses included Kaplan-Meier survival curves, uni and multivariate Cox proportional-hazards models. After a median follow-up of 55 months (range 2-84), 68 total fatal or nonfatal cardiovascular events and 34 cardiovascular deaths (24 of them from cardiac causes) were observed. In multivariate Cox analysis, QTd was an independent predictor for total cardiovascular events (HR: 1.16, 95% CI: 1.01-1.34, for each 10 ms increments) and for cardiac deaths (HR: 1.28, 95% CI: 1.01-1.60). Other independent risk indicators for cardiovascular morbidity and mortality were echocardiographic left ventricular hypertrophy (Echo-LVH), serum triglycerides, presence of pre-existing cardiac and peripheral arterial disease, age, diabetes duration, heart rate and the presence of frequent ventricular premature contractions on ECG. The combination of QTd and Echo-LVH improved cardiovascular risk stratification compared with either alone, the presence of both prolonged QTd (>65 ms) and Echo-LVH was associated with a 3.2-fold (95% CI: 1.7-6.1) increased risk of a first cardiovascular event and a 5.9-fold (95% CI: 2.1-16.4) increased risk of cardiovascular death. Thus, QT provided additive prognostic information for cardiovascular morbidity and mortality beyond that obtained from conventional risk markers, including Echo-LVH, in type 2 diabetic patients with arterial hypertension.

Relation of QT interval and QT dispersion to regression of echocardiographic and electrocardiographic left ventricular hypertrophy in hypertensive patients: the Losartan Intervention For Endpoint Reduction (LIFE) study

BACKGROUND

In hypertensive patients, both echocardiographic and electrocardiographic left ventricular hypertrophy (LVH) increase the risk of sudden death, possibly in part because of LVH-induced proarrhythmic repolarization changes. Experimentally, regression of LVH normalizes ventricular electrophysiology.

METHODS

To assess the relation of regression of LVH to changes in electrocardiographic measures of ventricular repolarization, we studied 317 hypertensive (61.2% men, mean age 65 +/- 7 years) participants in the Losartan Intervention For Endpoint Reduction (LIFE) study with electrocardiographic evidence of LVH, at study baseline, and after 1 year of blood pressure-lowering treatment with losartan or atenolol and hydrochlorothiatzide as the first adjunct therapy if needed to reach target blood pressure of 140/90 mm Hg. As indexes of LVH, we used echocardiographically determined LV mass as well as the Sokolow-Lyon and Cornell voltages from the electrocardiogram. QT interval duration and QT dispersion from the 12-lead electrocardiogram were used as ventricular repolarization measures.

RESULTS

By using tertiles of LV mass change and adjusting for the difference in treatment (losartan or atenolol), shortening of the rate-adjusted QT intervals as well as reduction in QT(apex) dispersion were observed in the tertile showing the greatest decrease in LV mass but not in the tertile without substantial changes in LV mass despite a significant reduction in blood pressure. Similar results were obtained with the use of Sokolow-Lyon and Cornell voltage change tertiles.

CONCLUSIONS

In hypertensive patients with electrocardiographic evidence of LVH, regression of echocardiographically determined LV mass and electrocardiographic indexes of LVH may partially reverse the LVH-induced proarrhythmic repolarization changes. This may have a beneficial impact on the increased incidence of sudden death in these patients.

[Holter EKG for the hypertensive heart disease]

During chronic mechanical overload induced by hypertension, left ventricular hypertrophy predisposes to atrial and ventricular arrhythmias. Atrial arrhythmias, mainly atrial fibrillation, decrease cardiac output and increase the risk of embolism whereas ventricular arrhythmias remain the major cause of sudden death. In hypertensive patients, Holter EKG recordings frequently detect atrial or ventricular premature beats and more rarely atrial or ventricular tachycardia. In these patients, the presence of non-sustained ventricular tachycardia is considered as an independent predictor of mortality. Moreover, this non invasive method through the assessment of heart rate variability allows the study of the autonomic control of the heart, known to modulate occurrence of arrhythmias.

Hypertension, left ventricular hypertrophy, and sudden death

Left ventricular hypertrophy (LVH), a form of end-organ damage in hypertension, is associated with increased incidence of sudden cardiac death (SCD). This review explores the possible mechanisms behind this phenomenon. SCD in LVH could be thrombotic/ischemic or arrhythmic (eg, myocardial ischemia, even in the absence of significant coronary artery disease, may be one important factor). Abnormalities of flow-mediated dilatation, endothelial function, and a hypercoagulable state are well-observed abnormalities in association with hypertension and LVH, although their precise contributory role is as yet undefined in the pathogenesis of sudden death. Electrophysiologic abnormalities are also well documented in LVH, and such patients are more predisposed to arrhythmias. In the past decade, many studies have investigated the regression of LVH, and recent studies are addressing whether the latter translates into a prognostic benefit.

Predictors of sudden cardiac death in never previously treated patients with essential hypertension: long-term follow-up

Increased QT dispersion has been associated with ventricular arrhythmia and sudden death in a variety of cardiac disorders. Left ventricular hypertrophy (LVH) has also been associated with increased incidence of sudden cardiac death in patients with essential hypertension. Furthermore, patients with essential hypertension, particularly those with LVH, are more likely to develop ventricular arrhythmias than are the normal population. The relationship between LVH, QT dispersion, complex ventricular arrhythmia and sudden cardiac death in previously untreated patients over long-term follow-up in hypertension has not been reported before and is the purpose of this study. Fifty-nine adult subjects with essential hypertension, who had never been previously on antihypertensive treatment were followed up for a total of 119.2 +/- 26.2 months. QTc (corrected QT), blood pressure, electrocardiograms, and 24-h Holter ECG recordings were performed in all patients at the time of entry to the study. Ventricular arrhythmias were classified using a modified Lown's scoring system. During the follow-up period death occurred in 12 cases (20%) of which only six (10%) deaths were sudden. The findings of this study indicate that LVH and complex ventricular arrhythmias (Lown's score > or =3) are the only significant predictors of sudden death. Although patients who died suddenly had higher systolic and diastolic blood pressures and greater QTc dispersion compared to surviving patients, this difference was statistically not significant. Similarly, when those who died suddenly were compared to those non-cardiac deaths, LVH and complex ventricular arrhythmias were the only significant predictors of sudden death. In spite of increased QTc dispersion in hypertensive patients, this finding was not associated with increased risk of sudden death and only LVH and high grade ventricular arrhythmias identified hypertensive patients at risk of sudden cardiac death over a 10-year follow-up period.

Relation of QT interval and QT dispersion to echocardiographic left ventricular hypertrophy and geometric pattern in hypertensive patients. The LIFE study. The Losartan Intervention For Endpoint Reduction

OBJECTIVE

In hypertensive patients, left ventricular hypertrophy (LVH) predicts increased mortality, in part due to an increased incidence of sudden death. Repolarization-related arrhythmogenesis may be an important mechanism of sudden death in hypertensive patients with LVH. Increased QT interval and QT dispersion are electrocardiographic (ECG) measures of ventricular repolarization, and also risk markers for ventricular tachyarrhythmias. We assessed the relation of QT intervals and QT dispersion to echocardiographically determined left ventricular (LV) mass and geometry in a large population of hypertensive patients with ECG evidence of LVH.

METHODS

QT intervals and QT dispersion were determined from baseline 12-lead ECGs in 577 (57% male; mean age 65 +/- 7 years) participants in the LIFE study. LV mass index (LVMI) and geometric pattern were determined by echocardiography and QT interval duration and QT dispersion were assessed in relation to gender-specific LVMI quartiles.

RESULTS

In both genders, increasing LVMI was associated with longer rate-adjusted QT intervals. QT dispersion measures showed a weaker association with LVMI quartiles. Both concentric and eccentric LVH were associated with increased QT interval duration and QT dispersion. These relations remained significant after controlling for relevant clinical variables.

CONCLUSIONS

In hypertensive patients with ECG evidence of LVH, increased LVMI and LVH are associated with a prolonged QT interval and increased QT dispersion. These findings suggest that an increased vulnerability to repolarization-related ventricular arrhythmias might in part explain the increased risk of sudden death in hypertensive patients with increased LV mass.

Adverse cardiac effects of salt with fludrocortisone in hypertension

The effect of salt on blood pressure (BP) is controversial. A more important question is whether salt can produce cardiac target-organ damage, irrespective of its effect on BP. We assessed the effect of salt with fludrocortisone on QT dispersion and echocardiographic left ventricular diastolic function in a prospective interventional study involving 29 hypertensive subjects with a raised aldosterone/renin ratio who were hospitalized for investigation of possible primary aldosteronism. Each subject over 4 days was given a total of 28.8 g (480 mmol) of sodium chloride and 1.5 mg of fludrocortisone with potassium supplementation. Baseline and posttreatment 12-lead ECGs and echocardiograms were obtained. There were no significant changes in body weight, pulse rate, or BP after treatment with salt and fludrocortisone. Plasma sodium was significantly increased from 141.4 (SD 2.1) to 142.6 (SD 2.4) mmol/L (P:=0.001). QT and QTc dispersion both significantly increased: +19.6 (SD 16.5) ms (95% CI, 13.4 to 25.9) (P:<0.001) and +19.8 (SD 20.9) ms (95% CI, 11.8 to 27.7) (P:<0.001), respectively. There were no significant changes in (n=15) left ventricular dimensions or systolic function, but all diastolic filling indexes, including the preload-independent index, flow propagation velocity (55.49 [SD 10.91] to 48.96 [SD 11.40] cm/s, P:=0.018) worsened, suggesting significant deterioration of left ventricular diastolic function with salt and fludrocortisone. In conclusion, a combination of salt with fludrocortisone increased QT dispersion and impaired left ventricular diastolic relaxation in hypertensive patients with high aldosterone/renin ratios. This raises the possibility that salt may have BP-independent adverse cardiac effects in susceptible hypertensive subjects.

Arterial hypertension and cardiac arrhythmias

PURPOSE AND DATA IDENTIFICATION: One of the main clinical problems of patients with arterial hypertension is the presence of arrhythmias, especially if left ventricular hypertrophy exists. Recent results from our group and all data available via Med-Line-search have been analysed. The analysis was focused on atrial and ventricular arrhythmias and arrhythmic risk prediction, using non-invasive markers. RESULTS OF ANALYSIS AND CONCLUSION: Arterial hypertension is a major cause of non-rheumatic atrial fibrillation and other supraventricular arrhythmias. The prevalence of ventricular arrhythmias is increased in hypertensive patients without left ventricular hypertrophy, compared to normotensives. If left ventricular hypertrophy is present, the risk for ventricular tachycardias is quadrupled. The presence of left ventricular hypertrophy is associated with an increase in all-cause mortality by a factor of seven in men and nine in women. In particular, patients with hypertrophy, increased rate of ventricular extrasystoles up to non-sustained ventricular tachycardia and ST-depression in long-term ECG are threatened by sudden cardiac death. At present, it is not possible to safely identify patients with increased risk. Regression of hypertrophy exists along with a decreased rate of ventricular extrasystoles. We hypothesize that by the regression of hypertrophy, the prevalence of sustained ventricular tachycardia decreases and therefore the prognosis of those patients can be improved, although controlled studies are not yet available.

Cardiac arrhythmias and left ventricular hypertrophy in dipper and nondipper patients with essential hypertension

To evaluate the behavior of cardiac arrhythmias in dipper and nondipper hypertensive patients, 48-h ambulatory blood pressure monitoring, 24-h Holter electrocardiogram recording and echocardiographic studies were performed in 56 untreated outpatients with essential hypertension. These patients were divided into 2 groups according to the presence (dipper, n=33) or absence (nondipper, n=23) of reduction of both systolic and diastolic blood pressure during nighttime by an average of more than 10% of daytime blood pressure. Mean 48-h systolic and diastolic blood pressures did not differ between the 2 groups. Nondipper patients had a significantly larger left atrial dimension (31.9+/-3.8 vs 35.6+/-3.7 mm; p<0.01), left ventricular mass index (114+/-26 vs 136+/-36 g/m2; p<0.05), as well as a larger number of total supraventricular (16+/-19 vs 89+/-197 beats; p<0.05) and ventricular ectopic beats (7+/-14 vs 47+/-96 beats; p<0.05) during daytime as compared with dippers. In conclusion, nondipper hypertensive patients are likely to experience supraventricular and ventricular arrhythmias more frequently than dippers. A blunted nocturnal blood pressure fall may be involved in the appearance of cardiac arrhythmias in patients with essential hypertension.

Markers of electrical instability in hypertensive patients with and without ventricular arrhythmias. Are they useful in identifying patients with different risk profiles?

BACKGROUND

Markers of electrical instability of the ventricular myocardium, namely abnormal repolarization and late potentials, are frequently observed in patients with hypertension when both ventricular arrhythmias and left ventricular hypertrophy are present. This information cannot be extrapolated to the population of hypertensive patients with ventricular arrhythmias but without left ventricular hypertrophy.

OBJECTIVE

To evaluate QT duration, QT dispersion and the incidence of ventricular late potentials in patients with essential hypertension, already on anti-hypertensive therapy, both with and without non-sustained ventricular arrhythmia.

DESIGN

The study population consisted of 49 patients with essential hypertension who were compared to 89 control normotensive subjects both with and without frequent (> 30 per h) ventricular ectopic beats (VPBs). Patients were divided into four groups: (1) hypertensive patients without VPBs (H, n = 19), (2) hypertensive patients with VPBs (HA, n = 30), (3) normotensive subjects without VPBs (C, n = 28), and (4) normotensive subjects with VPBs (CA, n=61).

METHODS

Echocardiographic parameters, QT interval, QT dispersion and signal-averaged ECG were evaluated without withdrawing anti-hypertensive drugs.

RESULTS

In no case was left ventricular hypertrophy documented. The number of VPBs during 24 h Holter recording (median 11 343 versus 7617) and the incidence of repetitive VPBs (37 versus 46% of patients) were similar in the two groups of patients (HA versus CA). Signal-averaged ECG parameters were normal and not different between the four groups. QT interval was longer in hypertensive patients compared to controls irrespective of the presence of VPBs. QT dispersion was slightly greater in subjects with VPBs, both hypertensive and normotensive, compared to subjects without arrhythmias.

CONCLUSIONS

In patients with hypertension well-controlled by drug therapy and without left ventricular hypertrophy, frequent VPBs are not associated with markers indicating an electrophysiological substrate for re-entrant arrhythmias. However, QT prolongation suggests the persistence of a higher risk of cardiovascular mortality that is independent of the presence of VPBs.

QT dispersion and hypertensive heart disease in the elderly

AIM

To determine the predictors and risk of increased QT dispersion in the elderly hypertensive patients.

METHODS

A 12-lead electrocardiogram (ECG), M-mode echocardiography and ambulatory blood pressure as well as Holter monitoring were performed for 67 patients over 60 years of age with essential hypertension (I and II(o) WHO). The presence of ischaemic changes on ECG was evaluated based on the Minnesota Code. QT intervals were corrected with Bazett's formulae and QT dispersion was determined as the difference between maximal and minimal QTc intervals. Interventricular septal thickness (IVSTd), left ventricular internal diameter (LVDd) and posterior wall thickness (PWTd) were measured and left ventricular mass index (LVMI) was calculated. Subjects were divided according to the median of QTc dispersion (0.10 s). The differences between groups were assessed using chi-squared and Student's t-test.

RESULTS

Subjects with increased QTc dispersion did not differ from those with low QTc dispersion when age, gender and body mass index were analysed. Similarly, the average systolic blood pressure, diastolic blood pressure and blood pressure variability were comparable in both groups. The mean QTc interval was similar in both groups. In patients with increased QT dispersion, left ventricular hypertrophy (LVH) and ischaemic changes on ECG were more frequently recognized (respectively 41.2 versus 18.2%, P < 0.001; 47.1 versus 21.2%, P < 0.05). Moreover, these subjects presented a significantly greater number of premature ventricular beats (317.1 +/- 665.6 versus 64.88 +/- 188.6, P < 0.05) and higher classes of Lown's arrhythmia scale (classes III-IV, 23.35% versus 9.1%). LVMI was insignificantly higher in the group with greater QTc dispersion (165.82 +/- 54.5 versus 145.07 +/- 36.47 g/ m2). Other echocardiographic indices of LVH were similar in both groups. On the other hand, the analysis of regression indicated positive correlation between the dispersion of QTc interval and thickness of left ventricle walls (for IVSd - r = 0.37; for PWd - r = 0.31), relative wall thickness (r = 0.28) and LVMI (r = 0.28).

CONCLUSIONS

QTc dispersion is increased in the elderly hypertensive individuals, with the presence of LVH and myocardial ischaemia on ECG. These patients are more likely to demonstrate severe ventricular dysrhythmias.

Irbesartan reduces QT dispersion in hypertensive individuals

Angiotensin type 1 receptor antagonists have direct effects on the autonomic nervous system and myocardium. Because of this, we hypothesized that irbesartan would reduce QT dispersion to a greater degree than amlodipine, a highly selective vasodilator. To test this, we gathered electrocardiographic (ECG) data from a multinational, multicenter, randomized, double-blind parallel group study that compared the antihypertensive efficacy of irbesartan and amlodipine in elderly subjects with mild to moderate hypertension. Subjects were treated for 6 months with either drug. Hydrochlorothiazide and atenolol were added after 12 weeks if blood pressure (BP) remained uncontrolled. ECGs were obtained before randomization and at 6 months. A total of 188 subjects (118 with baseline ECGs) were randomized. We analyzed 104 subjects who had complete ECGs at baseline and after 6 months of treatment. Baseline characteristics between treatments were similar, apart from a slight imbalance in diastolic BP (irbesartan [n=53] versus amlodipine [n=51], 99.2 [SD 3. 6] versus 100.8 [3.8] mm Hg; P=0.03). There were no significant differences in BP normalization (diastolic BP <90 mm Hg) between treatments at 6 months (irbesartan versus amlodipine, 80% versus 88%; P=0.378). We found a significant reduction in QT indexes in the irbesartan group (QTc dispersion mean, -11.4 [34.5] milliseconds, P=0.02; QTc max, -12.8 [35.5] milliseconds, P=0.01), and QTc dispersion did not correlate with the change in BP. The reduction in QT indexes with amlodipine (QTc dispersion, -9.7 [35.4] milliseconds, P=0.06; QTc max, -8.6 [33.2] milliseconds, P=0.07) did not quite reach statistical significance, but there was a correlation between the change in QT indexes and changes in systolic BP. In conclusion, irbesartan improved QT dispersion, and this effect may be important in preventing sudden cardiac death in at-risk hypertensive subjects.