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Acknowledgement

With thanks to Dr Niemi for his comments.

Shorter sleep is bad for blood pressure

Shorter sleep durations may be linked to an increased risk for developing hypertension, according to new data.

Kristen Knutson (University of Chicago, IL, USA) and colleagues studied 578 residents of Chicago participating in the Coronary Artery Risk Development in Young Adults (CARDIA) Study, a large, ongoing cohort study. None of the study subjects were taking antihypertensive medication at baseline.

Participants’ blood pressure levels were measured in 2000 and 2001, and then again in 2005 and 2006, and their sleep parameters were measured twice using wrist actigraphy for 3 consecutive days in 2003 and 2005.

On average, subjects slept 6 h each night, and were awake approximately 11% of the time after falling asleep. Almost half (43%) slept less than 6 h, and only 1% averaged 8 h or more sleep.After adjusting for age, gender and race, shorter sleep duration and lower sleep maintenance were independently associated with higher systolic and diastolic blood pressures (p < 0.05).

Participants who slept fewer hours had increased risk for developing hypertension; a 37% increased odds ratio for hypertension with each 1-h reduction in sleep duration was observed.

Interestingly, further analysis showed that African–American men slept much less than white women, leading the authors to speculate that: “The well-documented higher blood pressure in African–Americans and men might be partly related to sleep duration.”

Together, the data suggest that sleep duration may be an important modifiable risk factor for hypertension, a hypothesis that the authors feel is important to test: “Intervention studies are needed to determine whether optimizing sleep duration and quality can reduce the risk of increased blood pressure.”

Source: Knutson KL, Van Cauter E, Rathouz PJ et al. Association between sleep and blood pressure in midlife: the CARDIA sleep study. Arch. Intern. Med. 169(11), 1055–1061 (2009).

Early B-type natriuretic peptide response predicts outcome in acute heart failure

Reduced levels of B-type natriuretic peptide (BNP) following treatment for acutely decompensated heart failure may indicate a better prognosis, according to new research carried out by Alain Cohen-Solal and colleagues (Université Denis Diderot, Paris, France). The new data suggest that lower levels of BNP over the first 5 days following treatment are associated with better survival at 1 and 6 months.

The researchers retrospectively analyzed data from 1038 patients enrolled in the Survival of Patients with Acute Heart Failure in Need of Intravenous Inoptropic Support (SURVIVE) trial, which aimed to examine the effect of levosimendan and dobutamine on 1- and 6-month mortality in severe acutely decompensated heart failure patients. Criteria for enrollment in the trial included a left ventricular ejection fraction of 30% or less and being in need of inotropic support, as indicated by an insufficient response to intravenous diuretics and/or vasodilators, with at least one out of: oliguria, dyspnea at rest or on mechanical ventilation, and pulmonary-capillary wedge pressure of greater than 18 mmHg or cardiac index of less than 2.2 l/min.

Patients classified as responders (follow-up BNP level at least 30% lower than baseline) at days 1, 3 and 5 had lower all-cause mortality than nonresponders (p < 0.001), whereas patients with an increase in BNP between baseline and day 5 had three or more times higher 1-month mortality than responders. Responders at day 5 had a 67% reduction in 1-month and a 47% reduction in 6-month all-cause mortality compared with nonresponders (both p < 0.001).

Mihai Georghiade and Peter Pang (Northwestern University Feinberg School of Medicine, Il, USA), who wrote an editorial to accompany Cohen-Solal’s research article, commented that the study “raises an important hypothesis that remains to be tested: in patients hospitalized with severe heart failure, a significant decrease in BNP over a few days irrespective of any specific therapy is a better predictor of prognosis than the baseline BNP measurement.”

Source: Cohen-Solal A, Logeart D, Huang B, Cai D, Nieminen MS, Mebazaa A. Lowered B-type natriuretic peptide in response to levosimendan or dobutamine treatment is associated with improved survival in patients with severe acutely decompensated heart failure. J. Am. Coll. Cardiol. 53(25), 2343–2348 (2009).

Laying the foundation for cardiovascular music therapy

According to new research carried out by Luciano Bernardi and colleagues (University of Pavia, Italy), the cardiovascular and respiratory systems can synchronize with musical patterns, with crescendos capable of arousing the autonomic system. Researchers hope that this may lay the foundation for music as a therapeutic tool.

Bernardi et al. studied 24 subjects, comprising 12 trained choristers and 12 musically untrained people. To assess whether music with variable emphases produces parallel cardiovascular and respiratory responses, participants were either played music by Bach, Beethoven, Puccini and Verdi in random order as 10-s rhythmic phrases or silence, while monitoring heart rate, respiration, blood pressure, middle cerebral artery flow velocity and skin vasomotion.

Participants had significant increases in midcerebral artery flow velocity compared with baseline in response to Va pensiero and Libiam nei lieti calici by Verdi and a Bach cantata at 70.4, 70.2 and 70.9 cm/s, respectively, versus 67.6 cm/s at baseline.

Changes in heart-rate interval, systolic and diastolic blood pressure, midcerebral artery flow velocity and skin vasomotion all correlated significantly with the musical envelope. Musicians and controls showed similar responses to Beethoven and Bach except for heart rate interval and middle cerebral artery flow velocity.

Most crescendos or emphases in the music induced progressive skin vasoconstriction, along with increased blood pressure and heart rate, in proportion to the degree of change in music profile. The changes were reversed during silence, with progressive skin vasodilation and reductions in heart rate and blood pressure. The researchers noted a particularly large response to the two Verdi arias, observing significant coherence between musical changes and cardiovascular responses, particularly for vasoconstriction, increases in systolic and diastolic blood pressure, and mid-cerebral artery flow velocity, with equivalent delays in responses of 0.3 and 0.6 s during the two pieces.

The team said: “This may better explain the efficacy of music in pathologic conditions such as stroke, and it opens new areas for music therapy in rehabilitative medicine.”

Source: Bernardi L, Porta C, Casucci G et al. Dynamic interactions between musical, cardiovascular, and cerebral rhythms in humans. Circulation 119(25), 3171–3180 (2009).