Comparison of actions of irbesartan versus atenolol on cardiac repolarization in hypertensive left ventricular hypertrophy: results from the Swedish Irbesartan Left Ventricular Hypertrophy Investigation Versus Atenolol (SILVHIA)

Sex-Specific Associations of Anxiety With Left Ventricular Hypertrophy and Transmural Dispersion of Repolarization in Hypertensive Patients

Background

The previous studies have shown that individuals with hypertension and anxiety have a higher mean left ventricular mass index (LVMI) and QTc dispersion. We explored the associations between anxiety and left ventricular hypertrophy (LVH) and between anxiety and transmural dispersion of repolarization (TDR) (as detected by T peak-T end interval/QT interval, Tp–Te/QT ratio) in patients with hypertension.

Methods

A total of 353 patients with uncomplicated hypertension from the Shaanxi Provincial People’s Hospital were enrolled between 2017 and 2021. Anxiety was defined as a Hamilton Anxiety Scale (HAM-A) score ≥ 14. Logistic regression models were used to estimate the association between HAM-A and LVH. The association between HAM-A score and Tp–Te/QT was estimated using linear regression.

Results

Participants were divided into two groups based on the presence of anxiety. LVMI was significantly higher in patients with hypertension and anxiety than in those with hypertension without anxiety (no anxiety: 84.36 ± 23.82, anxiety: 105.75 ± 25.45 g/m², p < 0.001). HAM-A score was positively correlated with LVMI (r = 0.578, p < 0.001) and with Tp–Te/QT (r = 0.252, p < 0.001). Logistic regression models showed that patients with hypertension and anxiety were at higher risk of LVH than were patients with hypertension without anxiety (adjusted OR, 2.44, 95% CI, 1.35–4.43, p = 0.003). The linear regression analysis showed that the HAM-A score was associated with Tp–Te/QT ratio (adjusted β, 0.001, 95% CI, 0.001–0.002, p = 0.013). There was an interaction between sex and anxiety for LVH risk (p for interaction = 0.035) and for increased Tp–Te/QT (p for interaction = 0.014). After stratification by sex, anxiety was associated with increased risk for LVH in men with hypertension (adjusted OR, 5.56, 95% CI, 2.07–14.98, p = 0.001), but not in women (adjusted: OR, 1.44, 95% CI, 0.64–3.26, p = 0.377) with hypertension. The HAM-A score was also positively associated with Tp–Te/QT ratio in male (adjusted β, 0.002, 95% CI, 0.001–0.003, p < 0.001), but not in women (adjusted β, 0.001, 95% CI, –0.0002–0.002, p = 0.165).

Conclusion

Our results indicated that anxiety was associated with LVH and with increased TDR in men with hypertension, but not in women with hypertension.

First-line drugs inhibiting the renin angiotensin system versus other first-line antihypertensive drug classes for hypertension

BACKGROUND

This is the first update of a Cochrane Review first published in 2015. Renin angiotensin system (RAS) inhibitors include angiotensin converting enzyme (ACE) inhibitors, angiotensin receptor blockers (ARBs) and renin inhibitors. They are widely prescribed for treatment of hypertension, especially for people with diabetes because of postulated advantages for reducing diabetic nephropathy and cardiovascular morbidity and mortality. Despite widespread use for hypertension, the efficacy and safety of RAS inhibitors compared to other antihypertensive drug classes remains unclear.

OBJECTIVES

To evaluate the benefits and harms of first-line RAS inhibitors compared to other first-line antihypertensive drugs in people with hypertension.

SEARCH METHODS

The Cochrane Hypertension Group Information Specialist searched the following databases for randomized controlled trials up to November 2017: the Cochrane Hypertension Specialised Register, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE (from 1946), Embase (from 1974), the World Health Organization International Clinical Trials Registry Platform, and ClinicalTrials.gov. We also contacted authors of relevant papers regarding further published and unpublished work. The searches had no language restrictions.

SELECTION CRITERIA

We included randomized, active-controlled, double-blinded studies (RCTs) with at least six months follow-up in people with elevated blood pressure (≥ 130/85 mmHg), which compared first-line RAS inhibitors with other first-line antihypertensive drug classes and reported morbidity and mortality or blood pressure outcomes. We excluded people with proven secondary hypertension.

DATA COLLECTION AND ANALYSIS

Two authors independently selected the included trials, evaluated the risks of bias and entered the data for analysis.

MAIN RESULTS

This update includes three new RCTs, totaling 45 in all, involving 66,625 participants, with a mean age of 66 years. Much of the evidence for our key outcomes is dominated by a small number of large RCTs at low risk for most sources of bias. Imbalances in the added second-line antihypertensive drugs in some of the studies were important enough for us to downgrade the quality of the evidence.Primary outcomes were all-cause death, fatal and non-fatal stroke, fatal and non-fatal myocardial infarction (MI), fatal and non-fatal congestive heart failure (CHF) requiring hospitalizations, total cardiovascular (CV) events (fatal and non-fatal stroke, fatal and non-fatal MI and fatal and non-fatal CHF requiring hospitalization), and end-stage renal failure (ESRF). Secondary outcomes were systolic blood pressure (SBP), diastolic blood pressure (DBP) and heart rate (HR).Compared with first-line calcium channel blockers (CCBs), we found moderate-certainty evidence that first-line RAS inhibitors decreased heart failure (HF) (35,143 participants in 5 RCTs, risk ratio (RR) 0.83, 95% confidence interval (CI) 0.77 to 0.90, absolute risk reduction (ARR) 1.2%), and that they increased stroke (34,673 participants in 4 RCTs, RR 1.19, 95% CI 1.08 to 1.32, absolute risk increase (ARI) 0.7%). Moderate-certainty evidence showed that first-line RAS inhibitors and first-line CCBs did not differ for all-cause death (35,226 participants in 5 RCTs, RR 1.03, 95% CI 0.98 to 1.09); total CV events (35,223 participants in 6 RCTs, RR 0.98, 95% CI 0.93 to 1.02); and total MI (35,043 participants in 5 RCTs, RR 1.01, 95% CI 0.93 to 1.09). Low-certainty evidence suggests they did not differ for ESRF (19,551 participants in 4 RCTs, RR 0.88, 95% CI 0.74 to 1.05).Compared with first-line thiazides, we found moderate-certainty evidence that first-line RAS inhibitors increased HF (24,309 participants in 1 RCT, RR 1.19, 95% CI 1.07 to 1.31, ARI 1.0%), and increased stroke (24,309 participants in 1 RCT, RR 1.14, 95% CI 1.02 to 1.28, ARI 0.6%). Moderate-certainty evidence showed that first-line RAS inhibitors and first-line thiazides did not differ for all-cause death (24,309 participants in 1 RCT, RR 1.00, 95% CI 0.94 to 1.07); total CV events (24,379 participants in 2 RCTs, RR 1.05, 95% CI 1.00 to 1.11); and total MI (24,379 participants in 2 RCTs, RR 0.93, 95% CI 0.86 to 1.01). Low-certainty evidence suggests they did not differ for ESRF (24,309 participants in 1 RCT, RR 1.10, 95% CI 0.88 to 1.37).Compared with first-line beta-blockers, low-certainty evidence suggests that first-line RAS inhibitors decreased total CV events (9239 participants in 2 RCTs, RR 0.88, 95% CI 0.80 to 0.98, ARR 1.7%), and decreased stroke (9193 participants in 1 RCT, RR 0.75, 95% CI 0.63 to 0.88, ARR 1.7% ). Low-certainty evidence suggests that first-line RAS inhibitors and first-line beta-blockers did not differ for all-cause death (9193 participants in 1 RCT, RR 0.89, 95% CI 0.78 to 1.01); HF (9193 participants in 1 RCT, RR 0.95, 95% CI 0.76 to 1.18); and total MI (9239 participants in 2 RCTs, RR 1.05, 95% CI 0.86 to 1.27).Blood pressure comparisons between first-line RAS inhibitors and other first-line classes showed either no differences or small differences that did not necessarily correlate with the differences in the morbidity outcomes.There is no information about non-fatal serious adverse events, as none of the trials reported this outcome.

AUTHORS' CONCLUSIONS

All-cause death is similar for first-line RAS inhibitors and first-line CCBs, thiazides and beta-blockers. There are, however, differences for some morbidity outcomes. First-line thiazides caused less HF and stroke than first-line RAS inhibitors. First-line CCBs increased HF but decreased stroke compared to first-line RAS inhibitors. The magnitude of the increase in HF exceeded the decrease in stroke. Low-quality evidence suggests that first-line RAS inhibitors reduced stroke and total CV events compared to first-line beta-blockers. The small differences in effect on blood pressure between the different classes of drugs did not correlate with the differences in the morbidity outcomes.

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.

First-line drugs inhibiting the renin angiotensin system versus other first-line antihypertensive drug classes for hypertension

BACKGROUND

Renin-angiotensin system (RAS) inhibitors are widely prescribed for treatment of hypertension, especially for diabetic patients on the basis of postulated advantages for the reduction of diabetic nephropathy and cardiovascular morbidity and mortality. Despite widespread use of angiotensin converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARBs) for hypertension in both diabetic and non-diabetic patients, the efficacy and safety of RAS inhibitors compared to other antihypertensive drug classes remains unclear.

OBJECTIVES

To evaluate the benefits and harms of first-line RAS inhibitors compared to other first-line antihypertensive drugs in patients with hypertension.

SEARCH METHODS

We searched the Cochrane Hypertension Group's Specialised Register, MEDLINE, MEDLINE In-Process, EMBASE and ClinicalTrials.gov for randomized controlled trials up to November 19, 2014 and the Cochrane Central Register of Controlled Trials (CENTRAL) up to October 19, 2014. The WHO International Clinical Trials Registry Platform (ICTRP) is searched for inclusion in the Cochrane Hypertension Group's Specialised Register.

SELECTION CRITERIA

We included randomized, active-controlled, double-blinded studies with at least six months follow-up in people with primary elevated blood pressure (≥130/85 mmHg), which compared first-line RAS inhibitors with other first-line antihypertensive drug classes and reported morbidity and mortality or blood pressure outcomes. Patients with proven secondary hypertension were excluded.

DATA COLLECTION AND ANALYSIS

Two authors independently selected the included trials, evaluated the risk of bias and entered the data for analysis.

MAIN RESULTS

We included 42 studies, involving 65,733 participants, with a mean age of 66 years. Much of the evidence for our key outcomes is dominated by a small number of large studies at a low risk of bias for most sources of bias. Imbalances in the added second-line antihypertensive drugs in some of the studies were important enough for us to downgrade the quality of the evidence.Primary outcomes were all-cause death, fatal and non-fatal stroke, fatal and non-fatal myocardial infarction (MI), fatal and non-fatal congestive heart failure (CHF) requiring hospitalization, total cardiovascular (CV) events (consisted of fatal and non-fatal stroke, fatal and non-fatal MI and fatal and non-fatal CHF requiring hospitalizations), and ESRF. Secondary outcomes were systolic blood pressure (SBP), diastolic blood pressure (DBP) and heart rate (HR).Compared with first-line calcium channel blockers (CCBs), we found moderate quality evidence that first-line RAS inhibitors decreased heart failure (HF) (35,143 participants in 5 RCTs, RR 0.83, 95% CI 0.77 to 0.90, ARR 1.2%), and moderate quality evidence that they increased stroke (34,673 participants in 4 RCTs, RR 1.19, 95% CI 1.08 to 1.32, ARI 0.7%). They had similar effects on all-cause death (35,226 participants in 5 RCTs, RR 1.03, 95% CI 0.98 to 1.09; moderate quality evidence), total CV events (35,223 participants in 6 RCTs, RR 0.98, 95% CI 0.93 to 1.02; moderate quality evidence), total MI (35,043 participants in 5 RCTs, RR 1.01, 95% CI 0.93 to 1.09; moderate quality evidence). The results for ESRF do not exclude potentially important differences (19,551 participants in 4 RCTs, RR 0.88, 95% CI 0.74 to 1.05; low quality evidence).Compared with first-line thiazides, we found moderate quality evidence that first-line RAS inhibitors increased HF (24,309 participants in 1 RCT, RR 1.19, 95% CI 1.07 to 1.31, ARI 1.0%), and increased stroke (24,309 participants in 1 RCT, RR 1.14, 95% CI 1.02 to 1.28, ARI 0.6%). They had similar effects on all-cause death (24,309 participants in 1 RCT, RR 1.00, 95% CI 0.94 to 1.07; moderate quality evidence), total CV events (24,379 participants in 2 RCTs, RR 1.05, 95% CI 1.00 to 1.11; moderate quality evidence), and total MI (24,379 participants in 2 RCTs, RR 0.93, 95% CI 0.86 to 1.01; moderate quality evidence). Results for ESRF do not exclude potentially important differences (24,309 participants in 1 RCT, RR 1.10, 95% CI 0.88 to 1.37; low quality evidence).Compared with first-line beta-blockers, we found low quality evidence that first-line RAS inhibitors decreased total CV events (9239 participants in 2 RCTs, RR 0.88, 95% CI 0.80 to 0.98, ARR 1.7%), and low quality evidence that they decreased stroke (9193 participants in 1 RCT, RR 0.75, 95% CI 0.63 to 0.88, ARR 1.7% ). Our analyses do not exclude potentially important differences between first-line RAS inhibitors and beta-blockers on all-cause death (9193 participants in 1 RCT, RR 0.89, 95% CI 0.78 to 1.01; low quality evidence), HF (9193 participants in 1 RCT, RR 0.95, 95% CI 0.76 to 1.18; low quality evidence), and total MI (9239 participants in 2 RCTs, RR 1.05, 95% CI 0.86 to 1.27; low quality evidence).Blood pressure comparisons between RAS inhibitors and other classes showed either no differences or small differences that did not necessarily correlate with the differences in the morbidity outcomes.In the protocol, we identified non-fatal serious adverse events (SAE) as a primary outcome. However, when we extracted the data from included studies, none of them reported total SAE in a manner that could be used in the review. Therefore, there is no information about SAE in the review.

AUTHORS' CONCLUSIONS

We found predominantly moderate quality evidence that all-cause mortality is similar when first-line RAS inhibitors are compared to other first-line antihypertensive agents. First-line thiazides caused less HF and stroke than first-line RAS inhibitors. The quality of the evidence comparing first-line beta-blockers and first-line RAS inhibitors was low and the lower risk of total CV events and stroke seen with RAS inhibitors may change with the publication of additional trials. Compared with first-line CCBs, first-line RAS inhibitors reduced HF but increased stroke. The magnitude of the reduction in HF exceeded the increase in stroke. The small differences in effect on blood pressure between the different classes of drugs did not correlate with the differences in the primary outcomes.

Comprehensive overview: efficacy, tolerability, and cost-effectiveness of irbesartan

Background

Hypertension represents a major health problem, affecting more than one billion adults worldwide. Irbesartan, an angiotensin II receptor blocker, is considered to be a highly effective treatment in the management of hypertension. The purpose of this review is to evaluate the efficacy, safety and tolerability profile , and cost-effectiveness of treatment with irbesartan in hypertension.

Methods

A review of the literature was conducted using the electronic PubMed and Cochrane Library databases and the Health Economic Evaluations Database of search terms relating to irbesartan efficacy, tolerability, and cost-effectiveness, and the results were utilized.

Results

Findings from the present analysis show that irbesartan either as monotherapy or in combination with other antihypertensive agents can achieve significant reductions in blood pressure, both systolic and diastolic, compared with alternative treatment options. Irbesartan was also found to have a renoprotective effect independent of its blood pressure-lowering in patients with type 2 diabetes and nephropathy. Furthermore, irbesartan demonstrated an excellent safety and tolerability profile , with either lower or equal adverse events compared with placebo and other alternative treatments. In terms of economic analyses, compared with other antihypertensive therapy alternatives, irbesartan was found to be a preferred option, that is less costly and more effective.

Conclusion

The evidence indicates that treating patients with hypertension alone or with type 2 diabetes and nephropathy using irbesartan can control hypertension, prolong life, and reduce costs in relation to existing alternatives.

Effects of aliskiren on QT duration and dispersion in hypertensive patients with type 2 diabetes mellitus

AIM

To evaluate the effect of aliskiren compared to amlodipine on QT duration and dispersion in hypertensive patients with type 2 diabetes.

METHODS

A total of 170 outpatients aged 50-75 years with mild to moderate hypertension (SBP >130 and <180 mmHg and DBP >80 and <100 mmHg) and type 2 diabetes were randomly treated with aliskiren 300 mg or amlodipine 10 mg, both given once daily for 24 weeks, according to a prospective, open label, blinded-end point, parallel group design. At the end of the placebo run-in, and after 12, and 24 weeks of treatment blood pressure (BP) measurements (by mercury sphygmomanometer, Korotkoff I and V), plasma biochemistry and a standard 12-lead surface ECG were evaluated.

RESULTS

Both aliskiren and amlodipine significantly reduced systolic blood pressure (SBP)/diastolic blood pressure (DBP) values (-27.2/-14.3 mmHg, p < 0.001 vs. placebo and -27.8/-14.2 mmHg, p < 0.001 vs. placebo, respectively), with no statistical difference between the two drugs. Aliskiren, but not amlodipine, significantly reduced maximum QT interval (QTmax) (-14 ms at 12 weeks and -17 ms at 24 weeks, both p < 0.05 vs. placebo) and corrected QT max (QTc max) (-26 ms and -31 ms, p < 0.01) as well as the dispersion of both QT (-11 ms and -13 ms, p < 0.01) and QTc (-18 ms and -19 ms, p < 0.01).

CONCLUSIONS

Despite similar BP lowering effect, aliskiren, but not amlodipine, reduced QT duration and dispersion, which might be related to the ability of aliskiren to interfere with mechanisms underlying myocardial electrical instability in the heart of diabetic hypertensive patients.

Long-term use and tolerability of irbesartan for control of hypertension

In this review, we discuss the pharmacological and clinical properties of irbesartan, a noncompetitive angiotensin II receptor type 1 antagonist, successfully used for more than a decade in the treatment of essential hypertension. Irbesartan exerts its antihypertensive effect through an inhibitory effect on the pressure response to angiotensin II. Irbesartan 150-300 mg once daily confers a lasting effect over 24 hours, and its antihypertensive efficacy is further enhanced by the coadministration of hydrochlorothiazide. Additionally and partially beyond its blood pressure-lowering effect, irbesartan reduces left ventricular hypertrophy, favors right atrial remodeling in atrial fibrillation, and increases the likelihood of maintenance of sinus rhythm after cardioversion in atrial fibrillation. In addition, the renoprotective effects of irbesartan are well documented in the early and later stages of renal disease in type 2 diabetics. Furthermore, both the therapeutic effectiveness and the placebo-like side effect profile contribute to a high adherence rate to the drug. Currently, irbesartan in monotherapy or combination therapy with hydrochlorothiazide represent a rationale pharmacologic approach for arterial hypertension and early-stage and late-stage diabetic nephropathy in hypertensive type II diabetics.

Increased left ventricular arrhythmogenicity in metabolic syndrome and relationship with myocardial performance, risk factors for atherosclerosis, and low-grade inflammation

Metabolic syndrome (MetS) is a clustering of cardiovascular risk factors recently associated with left ventricular dysfunction. Limited data exist on the association between MetS and ventricular arrhythmogenicity. This study examined differences in ventricular arrhythmogenicity assessed by classic (QT interval) and newer (spatial QRS-T angle [spQRS-Ta]) electrocardiographic markers in subjects with and without MetS. A total of 306 subjects, 153 with and 153 without MetS, matched for sex and age were examined. The spQRS-Ta, which vectorcardiographically quantifies the deviation between the directions of ventricular depolarization and repolarization, was measured using a computer-based electrocardiograph. Left ventricular mass index and myocardial performance were evaluated echocardiographically. The spQRS-Ta was significantly higher in subjects with in comparison with those without MetS. Left ventricular mass index, QT interval, and its dispersion were not different between the 2 groups. Left ventricular myocardial performance was worse in subjects with MetS and was associated with higher values of the spQRS-Ta. Multivariate linear regression analysis demonstrated MetS status as the strongest predictor of ventricular arrhythmogenicity. Addition of the high-sensitivity C-reactive protein in the model increased the explained variance of the spQRS-Ta by 11%. In conclusion, ventricular arrhythmogenicity is present in MetS and is associated with myocardial dysfunction, risk factors for atherosclerosis, and low-grade inflammation. The independent association between the spQRS-Ta and MetS implies that the clustering of the metabolic disturbances has additional prognostic information than its individual components in terms of ventricular arrhythmogenicity and may explain in part the excess cardiovascular risk in subjects with MetS.

Are there effects of renin-angiotensin system antagonists beyond blood pressure control?

Angiotensin-converting enzyme (ACE) inhibitors or angiotensin receptor blockers (ARBs) are recognized to reduce cardiovascular and renal morbidity and mortality, which is primarily attributed to their antihypertensive effects. Activation of the renin-angiotensin system (RAS) may also play an important role in the pathogenesis of cardiovascular and renal disease through blood pressure-independent mechanisms mediated by angiotensin II. Thus, inhibiting the RAS with either an ARB or an ACE inhibitor may confer additional benefit in people with advanced nephropathy that cannot be explained totally by reductions in blood pressure. Preclinical evidence suggests that blood pressure lowering is not solely responsible for the organ and tissue protective effects of ACE inhibitors or ARBs. Furthermore, clinical studies evaluating effects on end organs and surrogate markers have shown that these agents have blood pressure-independent effects. There is also intriguing evidence that agents in the same class may differ in their effects on renal function despite similar blood pressure control. Support for blood pressure-independent effects comes from outcome studies. Agents evaluated in such studies and that appear to have effects independent of blood pressure lowering include irbesartan, losartan, ramipril, and telmisartan. Taken together, this body of evidence indicates that the clinical benefits of ARBs and ACE inhibitors in patients with advanced nephropathy extend beyond blood pressure reduction. Therefore, although antihypertensive efficacy is of primary importance in choosing a treatment to provide cardiovascular and renal protection, consideration should be given to the effects of an agent that extend beyond blood pressure.

Effect of telmisartan on QT interval variability and autonomic control in hypertensive patients with left ventricular hypertrophy

OBJECTIVES

The aim of the study was to examine the effect of the antihypertensive AT1 receptors antagonist telmisartan on cardiovascular autonomic function and QT dispersion in hypertensive patients with LVH.

METHODS

Twenty-five patients (18 males and seven women, mean age 49.8±5.2 years) with mild essential arterial hypertension and LVH were compared with 25 age-matched healthy controls. All the participants underwent a complete clinical examination, including electrocardiogram for QT interval measurements and 24h ambulatory ECG monitoring for measurement of heart rate variability. The ECG, 24h ambulatory ECG, and echocardiogram were repeated after eight weeks of treatment.

RESULTS

At baseline, hypertensive patients showed QT dispersion (p<0.001) and QTc dispersion (p<0.001) significantly higher than control subjects. An eight-week telmisartan treatment significantly reduced blood pressure (p<0.0001), without significant change in left ventricular mass. Telmisartan-based treatment induced an increased vagal activity without significant change of sympathetic activity and a reduction of QT dispersion (p<0.001) and QTc dispersion (p<0.001).

CONCLUSIONS

These data suggest that therapy with telmisartan significantly improves the sympathovagal balance increasing parasympathetic activity, and cardiac electrical stability reducing the heterogeneity of ventricular repolarization in hypertensive subjects. These effects could contribute to reduce arrhythmias as well as sudden cardiac death in at-risk hypertensive patients.

Understanding heart failure with preserved ejection fraction: clinical importance and future outlook

Heart failure (HF) with preserved ejection fraction (HF-PEF) accounts for approximately one half of all HF patients admitted with acute decompensated HF and carries a significant morbidity and mortality burden. This condition, however, has been largely understudied because it is difficult to diagnose, and management guidelines are still being discussed. This article provides an overview of HF-PEF and its pathophysiology, diagnosis, and treatment, with a focus on clinical trials using renin-angiotensin-aldosterone system (RAAS) blockers. Inhibitors of the RAAS have been studied in HF-PEF to determine whether their benefits extend beyond blood pressure control. However, the 3 trials conducted to date (CHARM-Preserved, PEP-CHF, and I-PRESERVE) with candesartan, perindopril, and irbesartan, have failed to demonstrate significant morbidity and mortality benefits. Although no agent has proven statistically significant benefits in morbidity and mortality in HF-PEF, recent studies have added to the breadth of clinical data and understanding of the demographics of these patients.

Short-term electrophysiological effects of losartan, bisoprolol, amlodipine, and hydrochlorothiazide in hypertensive men

BACKGROUND AND AIM

Hypertension-induced left ventricular structural remodelling associates with repolarization abnormalities. We investigated if antihypertensive drugs can modulate ventricular repolarization.

METHODS

A total of 183 hypertensive men received for 4 weeks drugs (losartan 50 mg, bisoprolol 5 mg, amlodipine 5 mg, hydrochlorothiazide (HCTZ) 25 mg) in a randomized order, separated by 4-week placebo periods. Electrocardiograms (ECG) were recorded at the end of placebo and drug periods. Measurements of repolarization duration (QT intervals), repolarization heterogeneity (T-wave peak to T-wave end (TPE) intervals), and T-wave morphology (T-wave principal component analysis (PCA) ratio, T-wave morphology dispersion (TMD), and total cosine R-to-T (TCRT)) during each drug were compared to placebo measurements.

RESULTS

Losartan and bisoprolol shortened maximum and mean rate-adjusted QT intervals as well as mean TPE interval, decreased TMD, and increased TCRT. Losartan also shortened precordial maximum TPE interval and decreased PCA ratio. Amlodipine had no repolarization effects, whereas HCTZ prolonged precordial maximum TPE interval and mean TPE interval.

CONCLUSION

Losartan and bisoprolol have beneficial short-term ECG repolarization effects. Amlodipine seems to have no repolarization effects. HCTZ seems to prolong the ECG TPE interval, potentially reflecting increased repolarization heterogeneity. These findings show that antihypertensive drugs may relatively rapidly and treatment-specifically modulate ECG markers of ventricular repolarization.

Cardiac repolarization and its relation to ventricular geometry and rate in reverse remodelling during antihypertensive therapy with irbesartan or atenolol: results from the SILVHIA study

Hypertensive left ventricular (LV) hypertrophy is associated with a substantial risk for malignant arrhythmias and sudden death. According to recent results, antihypertensive therapy with the angiotensin II type 1 receptor blocker irbesartan reverses both structural and electrical remodelling. However, the relation between the LV geometric pattern (concentric vs eccentric) and electrical reverse remodelling has not been characterized, neither has the relation between repolarization and rate (QT/RR and JT/RR relation), which presumably reflects the propensity for bradycardia-dependent ventricular arrhythmia. In this study, repeat echocardiographic and electrocardiographic measurements were performed in hypertensive patients with LV hypertrophy, randomized to double-blind therapy with irbesartan (n = 44) or the beta(1)-adrenoceptor blocker atenolol (n = 48) for 48 weeks; 53 patients had concentric and 39 eccentric LV hypertrophy. In addition, 37 matched hypertensive subjects without LV hypertrophy and no current therapy served as controls. Irbesartan induced structural and electrophysiological reverse remodelling, independent of LV geometry. In contrast, atenolol had similar beneficial effect only in patients with concentric LV hypertrophy, while the response in those with eccentric hypertrophy was unfavourable with both prolonged repolarization time and an increased QT/RR slope (suggesting reverse-use dependence). In conclusion, there is a significant geometry-related difference in the reverse remodelling processes induced by irbesartan and atenolol. Echocardiographic characterization of the geometry in hypertension-induced LV hypertrophy might become an important step in the selection of optimal antihypertensive therapy.

Reduction of QTc Dispersion by the Angiotensin II Receptor Blocker Valsartan May Be Related to Its Anti-Oxidative Stress Effect in Patients with Essential Hypertension

QT dispersion has been reported to increase in patients with essential hypertension, and abnormal QT dispersion is associated with arrythmias and sudden cardiac death. However, whether change in QT dispersion is related to oxidative stress is unclear. We examined the effect of the angiotensin II receptor blocker valsartan on QT dispersion and the relationship between oxidative stress and QT dispersion in patients with essential hypertension. Hypertensive patients whose systolic blood pressure (SBP) was more than 140 mmHg and/or diastolic blood pressure (DBP) was more than 90 mmHg were treated with valsartan. Blood pressure was measured once a month for 6 months. The difference between the maximal and minimal QT intervals within a 12-lead surface ECG was measured and QT dispersion and QTc dispersion corrected by heart rate were obtained before and 6 months after treatment. Left ventricular mass (LVM) assessed by echocardiography was obtained at baseline and 6 months after treatment. Venous blood samples were obtained at baseline and 6 months after treatment to measure serum levels of lipoperoxidation (LPO) and type I and III procollagen. Treatment with valsartan significantly decreased SBP and DBP. QTc dispersion decreased significantly 6 months after treatment with valsartan as compared to the baseline values. Valsartan treatment did not affect the LVM. Valsartan significantly decreased the abnormally high LPO levels. The changes in QTc dispersion were positively correlated with changes in the serum levels of LPO and with changes in DBP. The correlation between changes in LPO and QTc dispersion was more close than that between changes in DBP and QTc dispersion. In conclusion, antihypertensive therapy with valsartan reduces QTc dispersion and this may be related to the ability of valsartan to reduce oxidative stress in patients with essential hypertension.

Blockade of renin-angiotensin system reduces QT dispersion and improves intracellular Ca/Mg status in hemodialysis patients

BACKGROUND

Electrolyte impairments are common in hemodialysis (HD) patients. Consequently, QT dispersion (QTd) is prolonged, correlating with high intracellular magnesium. In patients with cardiac disorders, renin-angiotensin system (RAS) inhibition reduces QTd.

AIM

To compare the effects of ACE inhibition or AT-1 blockade on QTd duration and intracellular magnesium (Mg)/calcium (Ca) in peripheral blood mononuclear cells (PBMC) from chronic HD patients.

METHODS

24 HD patients received cilazapril for 8 weeks and, following a 2-week withdrawal, were switched to valsartan for additional 8 weeks. QTd measurements and PBMC isolation were performed at the beginning and the end of each period. Total intracellular Ca and Mg were assessed by atomic spectrometer, and cytosolic free Ca2+ by fluorocytometer.

RESULTS

Both treatments significantly decreased QTd, demonstrating similar reduction magnitudes. In both groups, PBMC exhibited basally low cytosolic Ca2+ and undisturbed high transmembrane Ca2+ influx following phytohemagglutinin stimulation. Total intracellular Ca was increased, while Mg was reduced, following either treatment. The total intracellular Ca/Mg ratio inversely correlated with QTd duration.

CONCLUSIONS

(1) RAS inhibition reduces prolonged QTd in HD patients. (2) In PBMC from ordinarily Ca-depleted HD patients, RAS suppression brings about elevation of total intracellular Ca. (3) RAS blockade decreases high intracellular Mg in PBMC from HD patients. Consequently, the Ca/Mg ratio increases, inversely correlating with QTd reduction.

Pacing-induced electrophysiological remodeling in hypertrophic obstructive cardiomyopathy--observations on cardiac memory

BACKGROUND

Hypertrophic cardiomyopathy carries an increased risk for sudden cardiac death. While pacing therapy reduces the left ventricular outflow tract gradient and improves symptoms in a subgroup of hypertrophic obstructive cardiomyopathy (HOCM) patients, its electrophysiological consequences are unknown and were therefore assessed in this prospective study.

METHODS AND RESULTS

Fifteen consecutive HOCM patients were studied and compared with 14 patients without HOCM paced because of sinus bradycardia. ECG intervals were measured before pacemaker implantation and after > or =3 months of DDD pacing in HOCM patients and > or =5 weeks in controls. Both groups showed similar ECG signs of cardiac memory development. In HOCM patients, with baseline QTc 447 +/- 33 ms, cardiac memory development was not associated with any significant changes in ECG intervals. In contrast, baseline repolarization in control patients was significantly prolonged by 6% (QTc 429 +/- 33 vs 454 +/- 46 ms; P < 0.05). Furthermore, in HOCM patients repolarization was 7% shorter during DDD pacing compared to sinus rhythm (JTc 329 +/- 25 vs 353 +/- 21 ms; P < 0.05), despite a significantly prolonged ventricular activation time (QRS duration 155 +/- 16 vs 91 +/- 9 ms; P < 0.01).

CONCLUSIONS

Importantly, the development of cardiac memory-induced different repolarization responses depending on baseline structure and electrophysiology. In HOCM patients repolarization was shorter during right ventricular apical pacing than during normal activation despite prolonged activation time.

Angiotensin II, angiotensin II antagonists and spironolactone and their modulation of cardiac repolarization

Angiotensin II and aldosterone produce pro-arrhythmic effects by several mechanisms, including the modulation of voltage-dependent K(+) channels involved in human cardiac repolarization. Drugs that inhibit the renin-angiotensin-aldosterone system exert anti-arrhythmic actions that are related to the blockade of the pro-arrhythmic actions of angiotensin II and aldosterone. These anti-arrhythmic actions include inhibition of electrical and structural cardiac remodeling, inhibition of neurohumoral activation, reduction of blood pressure and stabilization of electrolyte disturbances. In this article, several angiotensin II AT(1) receptor antagonists (candesartan, E3174, eprosartan, irbesartan and losartan) and aldosterone receptor antagonists (canrenoic acid and spironolactone) that directly modulate the activity of the voltage-dependent K(+) channels are reviewed; the effects of these antagonists might be useful in the prevention and treatment of cardiac arrhythmias.

Effect of nebivolol on QT dispersion in hypertensive patients with left ventricular hypertrophy

Hypertensive patients with left ventricular hypertrophy (LVH) have increased QT dispersion, which is considered an early indicator of end-organ damage and a non-invasive marker of risk for clinically important ventricular arrhythmias and cardiac mortality. The purpose of this study was to examine the effect of nebivolol antihypertensive therapy on QT dispersion in hypertensive subjects. Twenty-five subjects (15 men and 10 women, mean age 53.6 +/- 4.5 years) with essential arterial hypertension and mild-to-moderate LVH (blood pressure: 147.2 +/- 6.2/90.6 +/- 3.8 mmHg; left ventricular mass indexed: 149.1 +/- 10.7 g/m(2)) were compared with 25 age-matched healthy control subjects. All the participants underwent a complete clinical examination, including electrocardiogram for QT interval measurements. The QT dispersion was defined as the difference between the longest and the shortest QT interval occurring in the 12-lead electrocardiogram. The QT dispersion was corrected (QTc) with Bazett's formula. Hypertensive subjects were treated with 5 mg daily of nebivolol. The ECG and echocardiogram were repeated after four weeks of treatment. At baseline, hypertensive patients showed QT dispersion (56.9 +/- 6.4 vs. 31.7 +/- 8.4 ms, P < 0.001) and QTc dispersion (58.3 +/- 6.2 vs. 33.2 +/- 7.8 ms, P < 0.001) significantly higher than control subjects. Four-week nebivolol treatment reduced blood pressure from 147.2 +/- 6.2/90.6 +/- 3.6 mmHg to 136.3 +/- 3.1/83.3 +/- 2.5 mmHg (P < 0.0001), and resting heart rate from 75.3 +/- 4.7 to 64.2 +/- 3.0 bpm (P < 0.001), without significant change in left ventricular mass (LVMi: 149.1 +/- 10.7 vs. 151.4 +/- 9.8 g/m(2), ns). Nebivolol-based treatment improved QT dispersion (56.9 +/- 6.4 vs. 40.5 +/- 5.8 ms, P < 0.001) and QTc dispersion (58.3 +/- 6.2 vs. 42.2 +/- 5.6 ms, P < 0.001), which remained higher than in control subjects (P < 0.001 in both cases). The reduction of QT dispersion did not correlate with arterial BP reduction. In conclusion, nebivolol reduced increased QT dispersion in hypertensive subjects after four weeks. This effect, occurred without any change in LVM, did not seem to be related to the blood pressure lowering and could contribute to reduce arrhythmias as well as sudden cardiac death in at-risk hypertensive patients.

Enhanced external counterpulsation therapy: significant clinical improvement without electrophysiologic remodeling

BACKGROUND

Enhanced external counterpulsation therapy (EECP), in addition to improving coronary flow and increasing the time to ischemia, noninvasively alters hemodynamics in patients with severe coronary artery disease (CAD). Other treatments that alter hemodynamics, for example, balloon valvuloplasty, left ventricular assist devices, and pharmacologic antagonism of the rennin-angiotensin system, promote electrophysiologic remodeling, as evidenced by alterations in the QT interval.

METHODS

We studied 28 patients who completed a 7-week, 35-hour session of EECP to assess whether such therapy would also result in electrophysiologic remodeling.

RESULTS

All patients had class II-III angina, imaging-proven ischemia, and severe, near-inoperable CAD. Of 28 patients, with a mean age 62 +/- 13 years (mean +/- SD), 78% were male, 46% diabetic, 82% hypertensive, 60% had undergone angioplasty, and 67% had undergone bypass surgery. The mean ejection fraction was 44% (range 25-60%). Following EECP, most patients (82%) had at least a one full class improvement in their anginal pattern. In most patients, there was substantial baseline conduction system disease present: a mean QRS of 105 +/- 19 ms. It is to be noted that there was no significant change in heart rate (HR), PR, QRS, or QT(c) intervals before and after EECP in either clinical responders or nonresponders. When analyzed by response to EECP, ejection fraction, or history of revascularization, there were still no detectable changes in ECG parameters (all P = NS).

CONCLUSIONS

While EECP remains an effective treatment for severe CAD, it does not prompt early electrical remodeling of the heart.

Irbesartan: a review of its use in hypertension and in the management of diabetic nephropathy

Irbesartan (Avapro, Aprovel) is a potent and selective angiotensin II subtype 1 receptor antagonist indicated for use in patients with hypertension, including those with type 2 diabetes mellitus and nephropathy. Once-daily administration of irbesartan provided 24-hour control of blood pressure (BP). In patients with mild-to-moderate hypertension irbesartan was as effective as enalapril, atenolol and amlodipine, and more effective than valsartan in terms of absolute reduction in BP and response rates. Irbesartan produced a greater reduction in diastolic BP at trough than once-daily losartan, but had a smaller effect than olmesartan; the reduction in systolic BP achieved with irbesartan was similar or greater than that with losartan and similar to that seen with olmesartan. The combination of irbesartan with hydrochlorothiazide produced additive effects on BP reduction. Irbesartan also induced regression of left ventricular mass in patients with hypertension and left ventricular hypertrophy. In two large studies (IRbesartan MicroAlbuminuria type 2 diabetes mellitus in hypertensive patients [IRMA 2] and the Irbesartan Diabetic Nephropathy Trial [IDNT]) irbesartan exerted a renoprotective effect in hypertensive patients with type 2 diabetes at both the early and later stages of diabetic nephropathy. The renoprotective effect was at least partly independent of the BP-lowering effect. In the IRMA 2 trial, the proportion of patients progressing to overt nephropathy was significantly lower for recipients of irbesartan 300mg once daily than placebo. In patients with overt nephropathy in the IDNT, irbesartan 300mg once daily provided significantly greater renoprotection than amlodipine 10mg once daily or placebo. The relative risk of doubling of serum creatinine was significantly lower with irbesartan than amlodipine or placebo. Irbesartan is well tolerated in hypertensive patients, including those with type 2 diabetes and incipient or overt nephropathy. The overall incidence of adverse events with irbesartan was similar to that with placebo. Irbesartan was associated with a lower incidence of cough than enalapril and was not associated with ankle oedema or with any clinically significant drug interactions. In conclusion, irbesartan is a well tolerated and effective antihypertensive agent. It also slows the progression of renal disease in hypertensive patients with type 2 diabetes at both the early and later stages of diabetic nephropathy. Thus, irbesartan is a valuable agent in the management of patients with these indications.