Beta blockers and left ventricular hypertrophy in hypertension

Regression from pathological hypertrophy in mice is sexually dimorphic and stimulus-specific

Pathological cardiac hypertrophy is associated with increased morbidity and mortality. Understanding the mechanisms whereby pathological cardiac growth can be reversed could have therapeutic value. Here, we show that pathways leading to regression of pathological cardiac hypertrophy are strongly dependent on the hypertrophic trigger and are significantly modified by sex. Two pathological stimuli causing hypertrophy via distinct pathways were administered to male and female mice: Angiotensin II [Ang II] or Isoproterenol [Iso]. Stimuli were removed after 7 days of treatment, and left ventricles (LV) were studied at 1, 4, and 7 days. Ang II-treated Females did not show regression after stimulus removal. Iso-treated males showed rapid LV hypertrophy regression. Somewhat surprisingly, RNAseq analysis at day 1 after removal of triggers revealed only 45 differentially regulated genes in common among all groups, demonstrating distinct responses. Ingenuity Pathway Analysis predicted strong downregulation of the TGFβ1 pathway in all groups except for Ang II-treated females. Consistently, we found significant downregulation of Smad signaling after stimulus removal including in Ang II-treated females. Additionally, the ERK1/2 pathway was significantly reduced in the groups showing regression. Finally, protein degradation pathways were significantly activated only in Iso-treated males 1 day after stimulus removal. Our data indicate that TGFβ1 downregulation may play a role in the regression of pathological cardiac hypertrophy via downregulation of the ERK1/2 pathway and activation of autophagy and proteasome activity in Iso-treated males. This work highlights that the reversal of pathological hypertrophy does not utilize universal signaling pathways and that sex potently modifies this process.

Is hepatic steatosis associated with left ventricular mass index increase in the general population?

AIM

To investigate the association between hepatic steatosis and change in left ventricular mass index (LVMI) over five years, and examine whether systolic and diastolic blood pressures are mediators of the association between hepatic steatosis and LVMI using a general population sample.

METHODS

We analyzed data from the Study of Health in Pomerania. The study population comprised 1298 individuals aged 45 to 81 years. Hepatic steatosis was defined as the presence of a hyperechogenic pattern of the liver together with elevated serum alanine transferase levels. Left ventricular mass was determined echocardiographically and indexed to height^2.7. Path analyses were conducted to differentiate direct and indirect paths from hepatic steatosis to LVMI encompassing systolic and diastolic blood pressure as potential mediating variables.

RESULTS

Hepatic steatosis was a significant predictor for all measured echocardiographic characteristics at baseline. Path analyses revealed that the association of hepatic steatosis with LVMI change after five years was negligibly small (β = -0.12, s.e. = 0.21, P = 0.55). Systolic blood pressure at baseline was inversely associated with LVMI change (β = -0.09, s.e. = 0.03, P < 0.01), while no association between diastolic blood pressure at baseline and LVMI change was evident (β = 0.03, s.e. = 0.05, P = 0.56). The effect of the indirect path from hepatic steatosis to LVMI via systolic baseline blood pressure was small (β = -0.20, s.e. = 0.10, P = 0.07). No indirect effect was observed for the path via diastolic baseline blood pressure (β = 0.03, s.e. = 0.06, P = 0.60). Similar associations were observed in the subgroup of individuals not receiving beta-blockers, calcium channel blockers, or drugs acting on the renin-angiotensin system.

CONCLUSION

Baseline associations between hepatic steatosis and LVMI do not extend to associations with LVMI change after five years. More studies are needed to study the longitudinal effects of hepatic steatosis on LVMI.

Left Ventricular Hypertrophy in Pediatric Hypertension: A Mini Review

Adults with arterial hypertension (HTN) have stroke, myocardial infarction, end-stage renal disease (ESRD), or die at higher rates than those without. In children, HTN leads to target organ damage, which includes kidney, brain, eye, blood vessels, and heart, which precedes "hard outcomes" observed in adults. Left ventricular hypertrophy (LVH) or an anatomic and pathologic increase in left ventricular mass (LVM) in response to the HTN is a pediatric surrogate marker for HTN-induced morbidity and mortality in adults. This mini review discusses current definitions, clinically relevant methods of LVM measurements and normalization methods, its epidemiology, management, and issue of reversibility in children with HTN. Pediatric definition of LVH and abnormal LVM is not uniformed. With multiple definitions, prevalence of pediatric HTN-induced LVH is difficult to ascertain. In addition while in adults cardiac magnetic resonance imaging is considered "the gold standard" for LVM and LVH determination, pediatric data are limited to "special populations": ESRD, transplant, and obese children. We summarize available data on pediatric LVH treatment and reversibility and offer future directions in addressing LVH in children with HTN.

Risk and management of hypertension-related left ventricular hypertrophy

Knowledge gained from epidemiological studies and clinical trials on hypertension has led to impressive reductions in morbidity and mortality, particularly from stroke and coronary heart disease (CHD) as complications of end-organ damage from untreated, prolonged systemic hypertension. Data on reductions in stroke when hypertension is treated have been clear and convincing from individual clinical trials. Most of these trials, however, have consistently shown only trends towards a reduction in CHD, and few have individually reported statistically significant reductions. A recent meta-analysis, however, suggests that a significant beneficial reduction in CHD exists when the overall data are examined, although at a lower magnitude of benefit and lesser degree of certainty than for stroke. The presence of left ventricular hypertrophy (LVH) increases the risk of subsequent cardiovascular disease events, cardiovascular mortality and all-cause mortality in hypertensive patients. Although echocardiography appears more sensitive than electrocardiography in diagnosing LVH, much of the information demonstrating risks from LVH is from electrocardiography data, and it is not clear how echocardiography will change the risk prediction. Some data from large clinical trials and populations studies suggest that LVH regresses, particularly if the hypertension is adequately treated. A meta-analysis of a large number of small clinical studies in hypertensive patients suggests that the 4 commonly used antihypertensive drug classes, beta-blockers, diuretics, calcium channel antagonists and ACE inhibitors, are all associated with significant reductions in left ventricular mass. While the primary indication for treatment is clearly the hypertension and not the LVH, the presence of the latter necessitates careful treatment and follow-up of these hypertensive individuals.

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.

Effects of bisoprolol on left ventricular hypertrophy in essential hypertension

Previous studies have shown that beta-adrenergic blocking drugs can reverse ventricular hypertrophy in patients with systemic hypertension. Thirty patients with essential hypertension and left ventricular hypertrophy were studied at baseline after withdrawing all previous treatments and after 6 months of treatment with 5-20 mg of bisoprolol, a new beta-selective agent, to assess its possible action on left ventricular mass. Three patients did not finish the study. Blood pressure was reduced to below 160/90 mmHg in 22 of the remaining 27 patients. At the end of follow-up, the left ventricular mass (echocardiography) was reduced from 308.1 +/- 89 g to 262.3 +/- 51 g (p < 0.001) and left ventricular mass index from 165 +/- 47.4 g/m2 to 141.03 +/- 26.7 g/m2 (p < 0.001). The ratio of E wave/A wave velocity of transmitral blood flow measured by Doppler increased from 0.86 +/- 0.44 to 1.07 +/- 0.45 (p = 0.005). Peak filling rate, derived from nuclear ventriculography, changed from 2.05 +/- 0.4 EDV/sec before the treatment to 2.23 +/- 0.47 EDV/sec after it (p = 0.0046). Serum lipids as well as other biochemical tests were unchanged. Left ventricular volumes and ejection fraction did not change, and treadmill exercise time increased from 343 +/- 125 seconds to 420 +/- 135 seconds (p = 0.002). Maximal systolic blood pressure during exercise decreased from 197.2 +/- 19.7 mmHg to 182.9 +/- 25.8 mmHg (p = 0.011). There were few side effects. We conclude that bisoprolol reduces left ventricular mass, preserves systolic function, and improves diastolic function of the left ventricle in hypertensive subjects with left ventricular hypertrophy.

Left ventricular function after reversal of myocardial hypertrophy in systemic hypertension, and response to acute increase of afterload by cold pressor test

Using digitized M-mode echocardiography, the left ventricular (LV) response to acute increase in blood pressure after regression of myocardial hypertrophy due to an effective antihypertensive treatment was evaluated. Fifteen hypertensive patients with basal LV hypertrophy (LV mass greater than 230 g, and normal LV diastolic diameter) and normal LV mass after 3 to 4 months of treatment with angiotensin-converting enzyme inhibitors were selected for study. Subjects performed a cold pressor test before and after therapy. LV systolic function was normal in all subjects. LV diastolic function (impaired at basal evaluation in 13 subjects) improved after therapy in all subjects, with normalization in 10. Before treatment, the cold pressor test induced significant increases in blood pressure and heart rate without changes in LV parameters. After regression of hypertrophy, the cold pressor test induced increases in hemodynamic parameters comparable to those of the basal test, and LV parameters remained unchanged. Our results indicate that regression of myocardial hypertrophy induced by angiotensin-converting enzyme inhibitors does not impair the ability of the left ventricle to face acute increases in afterload. The improvement in LV diastolic function (found at rest after reversal of hypertrophy) persists during the cold pressor test, which confirms that it is primarily due to LV mass reduction and is not simply a consequence of decrease in afterload induced by treatment.

Is the decrease in arterial pressure the sole factor for reduction of left ventricular hypertrophy?

The increasing evidence that identifies left ventricular hypertrophy (LVH) as a powerful prognostic factor leads to the question whether or not reduction of LVH is a desirable goal of antihypertensive therapy and, moreover, whether a decrease in arterial pressure per se is the only or the main determinant for reduction of LVH. An analysis of the underlying pathogenic mechanisms suggests the presence of multiple interacting pathogenic factors in the development of LVH. Conversely, disparate rates of reduction of LVH with various antihypertensive drugs as well as conflicting results in different hypertensive patients point to the existence of blood pressure-independent factors influencing reduction of LVH.

Regression of left ventricular hypertrophy and systolic function in hypertensive patients during long-term treatment with ketanserin

It is now generally accepted that antihypertensive therapy can induce regression of left ventricular hypertrophy (LVH) in hypertensive subjects. However, the influence of LVH reversal on both the systolic and diastolic functions, and particularly the ability of the heart to meet sudden overloads caused by exercise and/or recurrence of hypertension, remain unanswered questions. The long-term effects of ketanserin, a selective serotonin S2-receptor antagonist with additional alpha 1-adrenergic blocking properties, on LVH and systolic function were studied in 13 untreated subjects (age range 35-55 years) with mild-to-moderate essential hypertension, echocardiographic evidence of LVH, and normal ejection fraction. Blood pressure values and echocardiographic measurements of dimensions, wall thicknesses, and indices of LV mass were determined before and after 3, 6, and 12 months treatment; ejection fractions at rest and during exercise were evaluated by equilibrium multigated radionuclide angiocardiography at baseline and after 12 months of therapy. Mean arterial pressure was significantly reduced from the first month of treatment (p less than 0.001) and remained well controlled up to the end of the trial. Both posterior and septum wall thicknesses decreased after 3 months of therapy and remained stable throughout the whole study period. LV mass index decreased from a mean +/- SD of 187.7 +/- 47.6 g/m2 to a mean of 157.81 +/- 31.63 g/m2 (p less than 0.01) at the third month, reaching greater decreases after 6 months (156.05 +/- 31.00 g/m2) and after 12 months (153.21 +/- 28.80 g/m2) of treatment. A significant correlation was found between LV mass and posterior wall thickness at the different observation times in the study. Finally, the regression of LVH at the end of therapy was not associated with impairment of systolic function, as assessed by measurements of ejection fraction at rest and during exercise.

Improvement of diastolic function after reversal of left ventricular hypertrophy induced by long-term antihypertensive treatment with tertatolol

In 15 previously untreated hypertensive subjects with left ventricular (LV) hypertrophy who responded favorably (supine blood pressure less than or equal to 140/90 mm Hg) to antihypertensive treatment with a nonselective beta-blocking agent, tertatolol, the effects of reversal of LV hypertrophy on systolic and diastolic function were assessed. Patients underwent echocardiographic and radionuclide studies in control conditions (phase 1), after 1 month of blood pressure normalization (phase 2), after reversal of LV hypertrophy or at least a 20% reduction of LV mass compared to basal value (phase 3) and finally, after a 1-month washout (phase 4). In phase 2, blood pressure (130 +/- 2/85 +/- 1 vs 148 +/- 4/104 +/- 1 mm Hg) and heart rate (59 +/- 1 vs 76 +/- 2 beats/min) decreased (both p less than 0.01); LV mass remained unchanged. There were improvements in peak filling rate (end-diastolic volume/s) (2.4 +/- 0.1 vs 2.0 +/- 0.1), ejection fraction (65 +/- 1 vs 61 +/- 1%) and their ratio (stroke counts/s) (3.7 +/- 0.2 vs 3.2 +/- 0.1) (all p less than 0.05). In phase 3, blood pressure and heart rate were unchanged and reversal of LV hypertrophy was accompanied by a further increase in peak filling rate (2.9 +/- 0.1), ejection fraction (69 +/- 1%) and their ratio (4.1 +/- 0.1) compared to phase 2 (all p less than 0.01). Finally, in phase 4 blood pressure and heart rate returned to the basal value, but peak filling rate (2.7 +/- 0.1) and ejection fraction (65 +/- 1%), although reduced compared to phase 3, were still higher than phase 1.(ABSTRACT TRUNCATED AT 250 WORDS)

Hemodynamic effects of dilevalol in patients with systemic hypertension and left ventricular dysfunction

Hemodynamic and left ventricular function parameters were measured in patients with mild to moderate hypertension and compromised left ventricular function who were given dilevalol, an antihypertensive agent with selective beta 2-agonism and nonselective beta-antagonist activity. After a 2- to 3-week placebo washout period, 9 patients were given dilevalol titrated upward from 100 to 600 mg twice daily over a 7-week period to achieve a supine diastolic blood pressure of less than 90 mm Hg with a decrease of greater than or equal to 10 mm Hg from baseline. Multigated radionuclide ventriculography and systolic and diastolic time intervals were performed after the pretreatment placebo washout, at the end of 2 weeks' maintenance dosing, and after a 7- to 10-day post-treatment discontinuation and placebo washout period. At an average daily dose of dilevalol, 444 mg, heart rate at rest decreased significantly (p less than 0.01) during treatment and increased during post-treatment placebo. Systolic and diastolic blood pressures at rest decreased significantly (p less than 0.01) during treatment and increased during post-treatment placebo. At maximal exercise, changes in blood pressure and heart rate were significantly blunted (p less than 0.05) during treatment. Ejection fraction at rest increased significantly (p less than 0.01) during treatment, with no significant change occurring during exercise, and decreased during post-treatment placebo. Preejection period decreased significantly during treatment (p less than 0.005) and increased during post-treatment placebo.(ABSTRACT TRUNCATED AT 250 WORDS)

Regression of left ventricular mass is accompanied by improvement in rapid left ventricular filling following antihypertensive therapy with metoprolol

Left ventricular hypertrophy is associated with abnormal left ventricular diastolic filling in patients with hypertension. To assess the effects of antihypertensive therapy on the heart in nine previously untreated patients with echocardiographically-detected left ventricular hypertrophy, left ventricular mass and rapid left ventricular filling rate were compared before and after 6 months of treatment with metoprolol monotherapy. Metoprolol was given in doses of 100 to 400 mg/day (average dose, 167 mg/day in two divided doses) and significantly reduced both casual, office blood pressure (150/101 to 130/86 mm Hg, p less than 0.01) and 24-hour ambulatory blood pressure (139/91 to 126/79 mm Hg, p less than 0.05 for systolic, p less than 0.01 for diastolic). Following treatment with metoprolol, left ventricular mass index decreased from 135 +/- 20 to 120 +/- 13 gm/m2 (p less than 0.05), while rapid left ventricular filling rate increased from 1.89 +/- 0.24 to 2.09 +/- 0.27 end-diastolic volumes/sec (p less than 0.01). The reduction in left ventricular mass index was secondary to decreased posterior and septal wall thicknesses (13% and 11%, respectively, p less than 0.05 for both), as there were no changes in the left ventricular internal dimensions. Neither resting nor exercise left ventricular ejection fraction changed on metoprolol therapy compared to the baseline values. These data demonstrate that regression of left ventricular hypertrophy in never-previously-treated hypertensive patients is accompanied by improved diastolic performance following beta-adrenergic blocker monotherapy.