Elevated Myocardial Repolarization Lability and Arterial Baroreflex Dysfunction in Healthy Individuals With Nondipping Blood Pressure Pattern

Myredal, Anna; Friberg, Peter; Johansson, Mats

doi:10.1038/ajh.2009.252

Cited by 26 publications

(18 citation statements)

References 27 publications

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“…These increased BP levels parallel the reported increase in HR of BACHD mice also measured during the day [16], suggesting a global dysregulation of the cardiovascular system causing it to be hyperactive during the rest period. The blunted depression in BP levels during rest would be similar to a nondipping pressure profile observed in humans, which in many cases is an indication of dysautonomia [22] [23]. Nondippers have a higher risk for future cardiovascular events, as well as damage to other organs [23] [24].…”

Section: Discussionmentioning

confidence: 62%

Baroreceptor reflex dysfunction in the BACHD mouse model of Huntington’s disease.

et al. 2011

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Huntington’s disease is a progressive, neurodegenerative disorder that presents with a triad of clinical symptoms, which include movement abnormalities, emotional disturbance and cognitive impairment. Recent studies reported dysfunction of the autonomic nervous system in Huntington’s disease patients, which may contribute to the increased incidence of cardiovascular events in this patient population that often leads to death. We measured the baroreceptor reflex, a process dependent on proper autonomic function, in the BACHD mouse model of Huntington’s disease. We found a blunted response of the baroreceptor reflex as well as significantly higher daytime blood pressure in BACHD mice compared to WT controls, which are both indications of autonomic dysfunction. BACHD mice had increased heart weight to tibia length ratios at 7 and 12 mo of age suggesting hypertrophic changes of the heart, which we speculate is a response to the increased blood pressure and aberrant baroreceptor reflex. Despite these structural changes, the hearts of BACHD mice continue to function normally as assessed by echocardiographic analysis. Studies of autonomic and cardiovascular function in BACHD mice may help elucidate the pathophysiology of Huntington’s disease and aid in the development of clinical strategies to offset the incidence of fatal cardiovascular events in the Huntington’s disease patient population.

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Section: Discussionmentioning

confidence: 62%

Baroreceptor reflex dysfunction in the BACHD mouse model of Huntington’s disease.

et al. 2011

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“…Speculations include nocturnal autonomic imbalance favoring sympathetic overactivity, 26 altered baroreceptor sensitivity, 26,27 increased liability of myocardial repolarization, 27 increased salt sensitivity or renal dysfunction, with nocturnal volume overload needing higher nighttime BPs to sustain natriuresis, 21,28 the presence of sleep-disordered breathing conditions or poor sleep quality, 8,29 hyperaldosteronism status, 30 increased arterial stiffness, 31 chronic low-grade inflammation and endothelial dysfunction, 32,33 and daytime orthostatic hypotension. 25,34 On the other hand, the physiopathological mechanisms underlying the possible differential prognostic effect of extreme dipping pattern according to antihypertensive status are completely unexplored, but we may speculate that it might involve orthostatic hypertension, exaggerated morning BP surge, increased BP variability, or increased arterial stiffness in extreme dippers, 24,35,36 which may partially be attenuated by antihypertensive treatment.…”

Section: Discussionmentioning

confidence: 99%

Prognostic Effect of the Nocturnal Blood Pressure Fall in Hypertensive Patients

et al. 2016

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A mbulatory blood pressure (BP) monitoring (ABPM) has been increasingly used in clinical management of hypertension. 1,2 It has been consistently demonstrated that ambulatory 24-hour BPs are better cardiovascular risk predictors than office BPs 2,3 and that average nighttime sleep BPs are generally better predictors of adverse cardiovascular outcomes than average daytime awake BP levels on ABPM.2,4,5 There is a normal circadian BP variability, with higher levels during daytime and a 10% to 20% BP fall during sleep.2 In 1988, O'Brien et al 6 reported for the first time that hypertensives with a blunted nocturnal BP fall had a greater prevalence of strokes and named these patients nondippers, in contrast to the normal dippers. Since then, several prospective studies reported on the prognostic value of the nocturnal BP fall both in hypertensives 7-18 and in population-based samples. [19][20][21] However, these results were not consistent possibly because of differences in methodology, study populations, sample sizes, and end points. In particular, many previous studies either did not adjust the Abstract-The prognostic importance of the nocturnal systolic blood pressure (SBP) fall, adjusted for average 24-hour SBP levels, is unclear. The Ambulatory Blood Pressure Collaboration in Patients With Hypertension (ABC-H) examined this issue in a meta-analysis of 17 312 hypertensives from 3 continents. Risks were computed for the systolic night-today ratio and for different dipping patterns (extreme, reduced, and reverse dippers) relative to normal dippers. ABC-H investigators provided multivariate adjusted hazard ratios (HRs), with and without adjustment for 24-hour SBP, for total cardiovascular events (CVEs), coronary events, strokes, cardiovascular mortality, and total mortality. Average 24-hour SBP varied from 131 to 140 mm Hg and systolic night-to-day ratio from 0.88 to 0.93. There were 1769 total CVEs, 916 coronary events, 698 strokes, 450 cardiovascular deaths, and 903 total deaths. After adjustment for 24-hour SBP, the systolic night-to-day ratio predicted all outcomes: from a 1-SD increase, summary HRs were 1.12 to 1.23.Reverse dipping also predicted all end points: HRs were 1.57 to 1.89. Reduced dippers, relative to normal dippers, had a significant 27% higher risk for total CVEs. Risks for extreme dippers were significantly influenced by antihypertensive treatment (P<0.001): untreated patients had increased risk of total CVEs (HR, 1.92), whereas treated patients had borderline lower risk (HR, 0.72) than normal dippers. For CVEs, heterogeneity was low for systolic night-to-day ratio and reverse/reduced dipping and moderate for extreme dippers. Quality of included studies was moderate to high, and publication bias was undetectable. In conclusion, in this largest meta-analysis of hypertensive patients, the nocturnal BP fall provided substantial prognostic information, independent of 24-hour SBP levels.

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“…[10][11][12][13][14] Hoshide et al studied 74 community-dwelling Japanese normotensives and showed that atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP) and LVMI were increased in non-dippers compared with dippers. 10 An increase in these parameters is established evidence of cardiac remodeling and left ventricular hypertrophy, which sig- Data are mean ± SD or n(%).…”

Section: Discussionmentioning

confidence: 99%

“…[4][5][6][7][8][9] In patients with normal blood pressure, NDP can also lead to end organ damage as seen on echocardiography, bio-inflammatory markers and microalbuminuria. [10][11][12][13] In a prospective study of individuals with normal 24-hr blood pressure, a 5% decrease in the nocturnal decline in diastolic blood pressure was significantly associated with a 20% increase in cardiovascular mortality risk. 14 Several studies have demonstrated that NDP is more common in Black hypertensives compared with other races.…”

Section: Introductionmentioning

confidence: 99%

Nocturnal Non-dipping Blood Pressure Profile in Black Normotensives Is Associated with Cardiac Target Organ Damage

Mezue

Isiguzo²,

Madu

et al. 2016

Ethn Dis

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Purpose: A non-dipping pattern of nocturnal blood pressure in hypertensive patients is an established predictor of cardiovascular risk, especially in Blacks. However, data on non-dipping normotensives and cardiovascular risk in this population is sparse. In this study, we aim to determine if a non-dipping profile in a cohort of Black normotensives is associated with cardiac target organ damage. Methods: We studied ambulatory blood pressure patterns in 43 normotensive Black patients of Caribbean origin and classified their profiles as dippers (DP) and nondippers (NDP) based on their nocturnal blood pressure profiles. Cardiac target organ damage was estimated from 2-D echocardiogram. Results: The mean age of the cohort was 52 years. Both groups were similar with respect to baseline age, sex, weight, height, body mass index and daytime ambulatory BP. There was a statistically significant difference in nocturnal blood pressure between DP and NDP groups (112 ± 7/64 ± 2 mm Hg vs 117 ± 3/69 ± 2 mm Hg, P=.004). The NDP cohort showed evidence of cardiovascular target damage on echocardiography with a significantly increased relative wall thickness (.35 ± .07cm vs .42 ± .05 cm, P=.001), left ventricular mass index (95 ± 14 vs 105 ± 14 g/m2, P=.018) and left atrial volume index (26 ± 3.5 vs. 30 ± 3.4, P=.001). Left ventricular geometry in the non-dippers also showed increased concentric remodeling, concentric and eccentric hypertrophy. Conclusions: Our study demonstrates that nocturnal non-dipping of blood pressure in normotensive Blacks of Caribbean origin may be associated with cardiovascular end organ damage thereby providing new surveillance and therapeutic targets. Ethn Dis.2016;26(3):279-284; doi:10.18865/ed.26.3.279

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Elevated Myocardial Repolarization Lability and Arterial Baroreflex Dysfunction in Healthy Individuals With Nondipping Blood Pressure Pattern

Abstract: A nondipping BP pattern in healthy subjects is associated with elevated myocardial repolarization lability and impaired baroreflex function, suggesting dysfunction of the autonomic nervous system.

Cited by 26 publications

References 27 publications

Baroreceptor reflex dysfunction in the BACHD mouse model of Huntington’s disease.

Baroreceptor reflex dysfunction in the BACHD mouse model of Huntington’s disease.

Prognostic Effect of the Nocturnal Blood Pressure Fall in Hypertensive Patients

Nocturnal Non-dipping Blood Pressure Profile in Black Normotensives Is Associated with Cardiac Target Organ Damage

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