Effect of four classes of antihypertensive drugs on cardiac repolarization heterogeneity: A double-blind rotational study

Background

T-wave area dispersion (TW-Ad) is a novel electrocardiographic (ECG) repolarization marker associated with sudden cardiac death. However, limited data is available on the clinical correlates of TW-Ad. In addition, there are no previous studies on cardiovascular drug effects on TW-Ad. In this study, we examined the relation between TW-Ad and left ventricular mass. We also studied the effects of four commonly used antihypertensive drugs on TW-Ad.

Methods

A total of 242 moderately hypertensive males (age, 51±6 years; office systolic/diastolic blood pressure during placebo, 153±14/100±8 mmHg), participating in the GENRES study, were included. Left ventricular mass index was determined by transthoracic echocardiography. Antihypertensive four-week monotherapies (a diuretic, a beta-blocker, a calcium channel blocker, and an angiotensin receptor antagonist) were administered in a randomized rotational fashion. Four-week placebo periods preceded all monotherapies. The average value of measurements (over 1700 ECGs in total) from all available placebo periods served as a reference to which measurements during each drug period were compared.

Results

Lower, i.e. risk-associated TW-Ad values correlated with a higher left ventricular mass index (r = −0.14, p = 0.03). Bisoprolol, a beta-blocker, elicited a positive change in TW-Ad (p = 1.9×10⁻⁵), but the three other drugs had no significant effect on TW-Ad.

Conclusions

Our results show that TW-Ad is correlated with left ventricular mass and can be modified favorably by the use of bisoprolol, although demonstration of any effects on clinical endpoints requires long-term prospective studies. Altogether, our results suggest that TW-Ad is an ECG repolarization measure of left ventricular arrhythmogenic substrate.

The association of endothelial injury and systemic inflammation with perioperative myocardial infarction

Background

Major surgery predisposes to endothelial glycocalyx injury. Endothelial glycocalyx injury associates with cardiac morbidity, including spontaneous myocardial infarction. However, the relation between endothelial glycocalyx injury and the development of perioperative myocardial infarction remains unknown.

Methods

Fifteen perioperative myocardial infarction patients and 60 propensity-matched controls were investigated in this prospective study. The diagnosis of perioperative myocardial infarction was based on repeated cardiac troponin T measurements, electrocardiographs and recordings of ischaemic signs and symptoms. We measured endothelial glycocalyx markers – soluble thrombomodulin, syndecan-1 and vascular adhesion protein 1 – and an inflammatory marker, namely interleukin-6, preoperatively and 6 h and 24 h postoperatively. We calculated the areas under the receiver operating characteristics curves (AUCs) to compare the performances of the different markers in predicting perioperative myocardial infarction. The highest value of each marker was used in the analysis.

Results

The interleukin-6 concentrations of perioperative myocardial infarction patients were significantly higher preoperatively and 6 and 24 h postoperatively ( P =  0.002, P =  0.002 and P =  0.001, respectively). The AUCs (95% confidence intervals) for the detection of perioperative myocardial infarction were 0.51 (0.34–0.69) for soluble thrombomodulin, 0.63 (0.47–0.79) for syndecan-1, 0.54 (0.37–0.70) for vascular adhesion protein 1 and 0.69 (0.54–0.85) for interleukin-6.

Conclusions

Systemic inflammation, reflected by interleukin-6, associates with cardiac troponin T release and perioperative myocardial infarction. Circulating interleukin-6 demonstrated some potential to predict perioperative myocardial infarction, whereas endothelial glycocalyx markers did not.

Genome-wide association study of nocturnal blood pressure dipping in hypertensive patients

Background

Reduced nocturnal fall (non-dipping) of blood pressure (BP) is a predictor of cardiovascular target organ damage. No genome-wide association studies (GWAS) on BP dipping have been previously reported.

Methods

To study genetic variation affecting BP dipping, we conducted a GWAS in Genetics of Drug Responsiveness in Essential Hypertension (GENRES) cohort (n = 204) using the mean night-to-day BP ratio from up to four ambulatory BP recordings conducted on placebo. Associations with P < 1 × 10^− 5 were further tested in two independent cohorts: Haemodynamics in Primary and Secondary Hypertension (DYNAMIC) (n = 183) and Dietary, Lifestyle and Genetic determinants of Obesity and Metabolic Syndrome (DILGOM) (n = 180). We also tested the genome-wide significant single nucleotide polymorphism (SNP) for association with left ventricular hypertrophy in GENRES.

Results

In GENRES GWAS, rs4905794 near BCL11B achieved genome-wide significance (β = − 4.8%, P = 9.6 × 10^− 9 for systolic and β = − 4.3%, P = 2.2 × 10^− 6 for diastolic night-to-day BP ratio). Seven additional SNPs in five loci had P values < 1 × 10^− 5. The association of rs4905794 did not significantly replicate, even though in DYNAMIC the effect was in the same direction (β = − 0.8%, P = 0.4 for systolic and β = − 1.6%, P = 0.13 for diastolic night-to-day BP ratio). In GENRES, the associations remained significant even during administration of four different antihypertensive drugs. In separate analysis in GENRES, rs4905794 was associated with echocardiographic left ventricular mass (β = − 7.6 g/m², P = 0.02).

Conclusions

rs4905794 near BCL11B showed evidence for association with nocturnal BP dipping. It also associated with left ventricular mass in GENRES. Combined with earlier data, our results provide support to the idea that BCL11B could play a role in cardiovascular pathophysiology.

Electronic supplementary material

The online version of this article (10.1186/s12881-018-0624-7) contains supplementary material, which is available to authorized users.

Postpericardiotomy syndrome

Postpericardiotomy syndrome (PPS) is a common complication following cardiac surgery. In most cases it develops 2 to 3 weeks after the operation. An inflammatory reaction develops in the pericardium or pleural space with fever, chest pain and dyspnea as typical symptoms. The disease process is usually self-limiting. At present, the etiology is unknown, but an immunological mechanism is suspected as the cause of the disease. The incidence of PPS is essentially dependent on diagnostic criteria, patient group and type of operation. Treatment is carried out with anti-inflammatory analgesics, combined with colchicine in more severe cases.

Postoperative Cardiac Ischemia Detection by Continuous 12-Lead Electrocardiographic Monitoring in Vascular Surgery Patients: A Prospective, Observational Study

OBJECTIVES

Elderly patients undergoing vascular surgery are at major risk for perioperative cardiac complications. The authors investigated continuous electrocardiographic Holter monitoring in a postoperative setting to determine the degree of postoperative ischemic load and its possible associations with perioperative myocardial infarction.

DESIGN

A prospective, observational study.

SETTING

One university hospital.

PARTICIPANTS

The study comprised 51 patients aged 65 years or older undergoing peripheral arterial surgery.

INTERVENTIONS

Continuous electrocardiographic monitoring with a Holter device was started postoperatively and continued for 72 hours or until discharge. Postural changes were recorded using a 3-axis accelerometer. Standard 12-lead electrocardiography, high-sensitive troponin T measurements, and an inquiry of ischemic symptoms were performed 4 times perioperatively.

MEASUREMENTS AND MAIN RESULTS

The primary outcomes were ischemic load (area under the function of ischemic ST-segment deviation and ischemic time) and perioperative myocardial infarction. During 3,262.7 patient-hours of monitoring, 17 patients (33.3%) experienced 608 transient ischemic events, all denoted by ST-segment depression. Of these 17 patients, 5 experienced perioperative myocardial infarction. The mean ischemic load in all patients was 913.2±2,797.3 µV×minute. Ischemic load predicted perioperative myocardial infarction, with an area under receiver operating characteristics curve (95% confidence interval) of 0.87 (0.75-0.99). Ischemic changes occurred most frequently during hours 24 to 60 of monitoring. Ischemia was asymptomatic in 14 of 17 patients (82.4%).

CONCLUSION

Postoperative myocardial ischemia was common in peripheral vascular surgery patients and may progress to perioperative myocardial infarction. Ischemic load was a good predictor of perioperative myocardial infarction. Ambulatory electrocardiographic monitoring solutions for continuous postoperative ischemia detection are warranted in the surgical ward.

Perioperative Myocardial Infarction in Non-Cardiac Surgery Patients: A Prospective Observational Study

Background and Aims:

Perioperative myocardial infarction is an underdiagnosed complication causing morbidity, mortality, and considerable costs. However, evidence of preventive and therapeutic options is scarce. We investigated the incidence and outcome of perioperative myocardial infarction in non-cardiac surgery patients in order to define a target population for future interventional trials.

Material and Methods:

We conducted a prospective single-center study on non-cardiac surgery patients aged 50 years or older. High-sensitivity troponin T and electrocardiograph were obtained five times perioperatively. Perioperative myocardial infarction diagnosis required a significant troponin T release and an ischemic sign or symptom. Perioperative risk calculator was used for risk assessment.

Results:

Of 385 patients with systematic ischemia screening, 27 patients (7.0%) had perioperative myocardial infarction. The incidence was highest in vascular surgery—19 of 172 patients (11.0%). The 90-day mortality was 29.6% in patients with perioperative myocardial infarction and 5.6% in non–perioperative myocardial infarction patients ( p <  0.001). Perioperative risk calculator predicted perioperative myocardial infarction with an area under curve of 0.73 (95% confidence interval: 0.64–0.81).

Conclusion:

Perioperative myocardial infarction is a common complication associated with a 90-day mortality of 30%. The ability of the perioperative risk calculator to predict perioperative myocardial infarction was fair supporting its routine use.

[Perioperative cardiac infarction - an underdiagnosed problem]

Perioperative cardiac infarction (PMI) associated with surgery and the postoperative period significantly restricts the outcome of operative treatment. PMI is encountered in 0.5 to 1% of surgical patients, but among high-risk patients the incidence exceeds 10%. The disorder is associated with a mortality of 10 to 25%, corresponding to at least 1 000 patient deaths annually, as adjusted to the numbers of operative treatment in Finland, and its care requires at least 20000 extra days of hospitalization.

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.

Relationship of electrocardiographic repolarization measures to echocardiographic left ventricular mass in men with hypertension

OBJECTIVE

Arterial hypertension often leads to an increase in left ventricular mass (LVM). Marked left ventricular hypertrophy (LVH) is associated with potentially arrhythmogenic ventricular repolarization abnormalities, which may contribute to the increased risk of sudden cardiac death in this disorder. We studied whether electrocardiographic repolarization changes are already detectable in mild LVM increase associated with hypertension.

METHODS

In 220 men (mean age 51+/-6 years) attending the GENRES hypertension study, we measured QT intervals (QTend and QTpeak), T-wave peak to T-wave end (TPE) intervals, and novel T-wave morphology parameters (principal component analysis ratio, T-wave morphology dispersion, total cosine R-to-T, and T-wave residuum) from a digital standard 12-lead electrocardiogram, and related them to echocardiographically determined LVM.

RESULTS

In this group of moderately hypertensive men, the mean LVM index (LVMI; LVM divided by body surface area) was 99+/-19 g/m2, with only 18% of the subjects showing evidence of echocardiographic LVH (LVMI>116 g/m2). LVMI correlated significantly with QT intervals (r=0.16-0.21, P=0.018-0.002), TPE intervals (r=0.23-0.27, P<0.001), and T-wave morphology parameters (r=0.22-0.39, P<0.001). Except for the QTpeak interval, the relationship between LVMI and electrocardiographic repolarization parameters was independent in multivariate analyses.

CONCLUSION

Altered electrocardiographic ventricular repolarization, indicating reduced repolarization reserve and possibly increased repolarization heterogeneity, is already present in hypertensive men with only mild LVM increase. At a population level, this may carry important risk implications for the large group of hypertensive patients.

Predictors of antihypertensive drug responses: initial data from a placebo-controlled, randomized, cross-over study with four antihypertensive drugs (The GENRES Study)

BACKGROUND

Only a minority of hypertensive individuals is adequately controlled for their hypertension, partially because reliable predictors for efficient antihypertensive drug therapy are lacking.

METHODS

In a prospective, randomized, double-blind, cross-over, placebo-controlled study (The GENRES Study), 208 moderately hypertensive Finnish men (aged 35 to 60 years) were treated for 4 weeks with antihypertensive drugs from four different classes: amlodipine (5 mg), bisoprolol (5 mg), hydrochlorothiazide (25 mg), or losartan (50 mg) daily. Each individual received each of the four monotherapies in a randomized order. Four-week placebo periods were included before and between drug treatment periods. Antihypertensive responses were assessed with 24-h ambulatory and office measurements and analyzed according to age, body mass index, triceps skin fold thickness, waist-to-hip ratio, duration of hypertension, number of previous antihypertensive drugs, number of affected parents, and blood pressure (BP) levels, and profiles during placebo periods.

RESULTS

The median BP responses in 24-h ambulatory recordings (systolic/diastolic) were 11/8 mm Hg for bisoprolol, 9/6 mm Hg for losartan, 7/5 mm Hg for amlodipine, and 5/2 mm Hg for hydrochlorothiazide. The highest pairwise within-subject correlations in BP responses were seen for the combinations of bisoprolol-losartan and amlodipine-hydrochlorothiazide. The BP responses to bisoprolol and losartan did not vary according to the variables. Amlodipine and hydrochlorothiazide responses were positively correlated with age, placebo BP level, and lower night-time dipping on placebo.

CONCLUSIONS

Baseline clinical and BP parameters may be used to predict the efficacy of antihypertensive therapies. The GENRES Study material should provide an excellent platform for future pharmacogenetic analyses of antihypertensive drug responsiveness.

Lameness and fertility of sows and gilts in randomly selected loose-housed herds in Finland

The prevalence of lameness among 646 sows and gilts in 21 selected herds was determined; 8.8 per cent of the animals were lame and the most common clinical diagnoses were osteochondrosis, infected skin lesions and claw lesions. The lame animals had higher serum concentrations of haptoglobin and C-reactive protein than the sound animals. Animals housed on slatted floors had twice the odds of being lame and 3.7 times the odds of being severely lame than animals housed on solid floors. Yorkshire pigs had 2.7 times the odds of being lame than Landrace or crossbred animals. Higher parity and the use of roughage decreased the odds of the sows not becoming pregnant; however, lameness was not a risk factor for non-pregnancy.

Baroreflex sensitivity and variants of the renin angiotensin system genes

OBJECTIVES

Because the renin-angiotensin-aldosterone system (RAS) modifies cardiovascular autonomic regulation, we studied the possible associations between baroreflex sensitivity (BRS) and polymorphism in the RAS genes.

BACKGROUND

Wide intersubject variability in BRS is not well explained by cardiovascular risk factors or life style, suggesting a genetic component responsible for the variation of BRS.

METHODS

Baroreflex sensitivity as measured from the overshoot phase of the Valsalva maneuver and genetic polymorphisms were examined in a random sample of 161 women and 154 men aged 41 to 61 years and then in an independent random cohort of 29 men and 37 women aged 36 to 37 years. An insertion/deletion (I/D) polymorphism of angiotensin-converting enzyme (ACE), M235T variants of angiotensinogen (AGT) and two diallelic polymorphisms in the gene encoding aldosterone synthase (CYP11B2), one in the promoter (-344C/T) and the other in the second intron, were identified by polymerase chain reaction.

RESULTS

In the older population, BRS differed significantly across CYP11B2 genotype groups in women (10.1 +/- 4.5, 8.7 +/- 3.8 and 7.1 +/- 3.2 ms x mm Hg(-1) in genotypes -344TT, CT and CC, respectively, p = 0.003 and 11.1 +/- 4.4, 8.9 +/- 4.1 and 7.5 +/- 3.4 ms x mm Hg(-1) in intron 2 genotypes 1/1, 1/2 and 2/2, respectively, p = 0.002), but not in men. No comparable associations were found for BRS with the I/D polymorphism of ACE or the M235T variant of AGT. In the younger population, BRS was even more strongly related to the CYP11B2 promoter genotype (p = 0.0003). The association was statistically significant both in men (p = 0.015) and in women (p = 0.03).

CONCLUSIONS

Common genetic polymorphisms in the aldosterone synthase (CYP11B2) gene is associated with interindividual variation in BRS.

Associations between human aldosterone synthase (CYP11B2) gene polymorphisms and left ventricular size, mass, and function

BACKGROUND

Aldosterone has direct and indirect effects on the heart, and genetic variations in aldosterone synthesis could therefore influence cardiac structure and function. Such variations might be associated with polymorphisms in the gene encoding aldosterone synthase (CYP11B2), the enzyme catalyzing the last steps of aldosterone biosynthesis.

METHODS AND RESULTS

A Finnish population sample of 84 persons (44 women) aged 36 to 37 years was studied by M-mode and Doppler echocardiography to assess left ventricular size, mass, and function. Subjects were genotyped through the use of the polymerase chain reaction for two diallelic polymorphisms in CYP11B2: one in the transcriptional regulatory region (promoter) and the other in the second intron. In multiple regression analyses, the CYP11B2 promoter genotype predicted statistically significant variations in left ventricular end-diastolic diameter (beta=.40, P<.0001), end-systolic diameter (beta=.33, P=.0009), and mass (beta=.17, P=.023). These effects were independent of potentially confounding factors, including sex, body size, blood pressure, physical activity, smoking, and ethanol consumption. Genotype groups also differed in a measure of left ventricular diastolic function, the heart rate-adjusted atrial filling fraction (P=.018). Increased dietary salt, which is known to predict increased left ventricular mass, had this effect only in association with certain CYP11B2 genotypes (P<.001).

CONCLUSIONS

Genetic variations in or near the aldosterone synthase (CYP11B2) gene strongly affect left ventricular size and mass in young adults free of clinical heart disease. These polymorphisms may also influence the response of the left ventricle to increases in dietary salt.

Evolution of heart rate variability in cardiac transplant recipients: a clinical study

OBJECTIVES

To investigate in cardiac transplant patients whether post-transplantation time, graft arteriosclerosis, allograft rejection, or earlier cytomegalovirus infection affect the neural regulatory mechanisms of the donor heart.

DESIGN

A consecutive series of heart transplant patients during a 12-month period.

SETTING

A university hospital in Finland.

SUBJECTS

Consecutive cardiac transplant recipients (n = 38) attending the hospital for their annual clinical examination were studied. Their mean (SD) age was 45.4 (11.5) years, 37 were male, and the median (range) time since transplantation was 36 (12-72) months.

INTERVENTIONS

Power spectral analysis of R-R intervals (during 5 min of controlled breathing, the Valsalva manoeuvre, and deep breathing), routine coronary arteriography, cytomegalovirus serology.

RESULTS

R-R interval (r = 0.67; P < 0.001), the root mean square difference of successive R-R intervals (r = 0.38; P < 0.05), the total R-R interval power (r = 0.45; P < 0.01), the power of the very low frequency (0.0-0.07 Hz) component (r = 0.53; P < 0.01), and the power of the nonrespiratory (0.0-0.15 Hz) component (r = 0.49; P < 0.01) were related to the length of time since the operation. Patients having had a transplantation 3 years ago or more had significantly greater median (range) total R-R interval power than those having had the operation less than 3 years ago (59 [10-265] vs. 20 [3-113] ms2; P = 0.02). There was also a difference between the two groups in the very low frequency component (18 [1-226] vs. 5 [0-45] ms2; P = 0.01), in the nonrespiratory component (30[1-227] vs. 9 [0-53]ms2; P = 0.02), and in the Valsalva ratio (0.995 [0.955-1.065] vs. 1.020 [0.975-1.155]; P = 0.03). Patients with and without graft arteriosclerosis, episodes of rejection, or earlier cytomegalovirus infection showed no difference in the power spectral measures.

CONCLUSIONS

The donor heart rate variability increases with post-transplantation time. Heart rate variability in transplant recipients is not related to the extent of graft arteriosclerosis, episodes of allograft rejection, or earlier cytomegalovirus infection.

Influence of negative intrathoracic pressure on right atrial and systemic venous dynamics

To investigate the effect of a sustained fall in intrathoracic pressure (Mueller manoeuvre) on blood flow through the right heart and on systemic venous dynamics, 16 patients were studied using thermodilution, cinevenograms and simultaneous pressure recordings with two micromanometric transducers. The reductions in airway pressure (median [range]) during two graded Mueller manoeuvres were 25 (20-30) and 42 (22-52) mmHg. Right atrial mean pressure decreased by 17 (2-25) mmHg during the former and 38 (0-49) mmHg during the latter, and simultaneously, pressure gradients of 23 (1-32) and 45 (1-82) mmHg developed between the inferior vena cava and right atrium (P < 0.003 for all). Internal jugular venous pressure decreased by 16 (4-25) and 24 (4-43) mmHg (P < 0.03 for both), respectively, and no pressure gradient developed between internal jugular and superior caval veins. The minimum diameter of the proximal inferior vena cava decreased by 69 (-49-84)% (P = 0.002) during the greater manoeuvre. Cardiac index tended to increase by 26 (-17-40)% (P < 0.066) during the lesser manoeuvre but did not change statistically significantly during the greater. In conclusion, during negative intrathoracic pressure caused acutely by the Mueller manoeuvre, right atrial pressure decreases and the inferior vena cava collapses partially at or below the diaphragm. Despite a significant venous obstruction between the lower body and right atrium, blood flow through the right heart increases or remains constant.

Heart rate and blood pressure variability and baroreflex sensitivity in hypercholesterolaemia

To evaluate cardiovascular autonomic function in hypercholesterolaemia, we studied 16 age-matched pairs of healthy males with elevated serum cholesterol and normocholesterolaemic control subjects (altogether 37 men, aged 27-56 years). We used power spectral analysis to measure short-term heart rate and blood pressure variability, and the phenylephrine method to determine baroreceptor reflex sensitivity. The mean (SD) serum cholesterol concentration was 6.43 (1.22) among the hypercholesterolaemic subjects and 4.30 (0.44) mmol/l among the control men (P < 0.001). The respective low density lipoprotein (LDL) cholesterol concentrations were 4.44 (1.22) and 2.46 (0.38) mmol/l (P < 0.001). The total power (0.0-0.5 Hz) of heart rate and blood pressure variability did not differ between the groups, and neither did the high-frequency (0.15-0.5 Hz) and medium-frequency components (0.07-0.15 Hz). Mean (SD) baroreceptor reflex sensitivity was 18.1 (7.9) in hypercholesterolaemic and 19.4 (6.3) ms mmHg-1 in normocholesterolaemic subjects (P = 0.352). when all the subjects were analysed together, we observed a slight inverse trend between serum LDL cholesterol and baroreceptor reflex sensitivity (r = -0.235, P = 0.161). In conclusion, hypercholesterolaemia does not alter autonomic neural regulation of the cardiovascular system as assessed heart rate and blood pressure variability and baroreflex sensitivity.

Effect of negative intrathoracic pressure on left ventricular pressure dynamics and relaxation

To investigate the effect of a fall of intrathoracic pressure on left ventricular (LV) hemodynamics and relaxation, simultaneous micromanometric recordings of LV and aortic pressures were performed at rest and during two graded Mueller maneuvers in 16 patients undergoing cardiac catheterization for aortic valve stenosis (n = 8) or chest pain (n = 8). The reductions (means +/- SE) of airway pressure during the lesser and greater maneuvers were 26 +/- 1 and 42 +/- 1 mmHg, respectively. Simultaneously, LV isovolumic-developed pressure increased by 9 +/- 3 and 21 +/- 4 mmHg, respectively (P < 0.03 for both). During the greater maneuver, the individual changes of the time constant of LV isovolumic relaxation (tau) correlated with the changes of LV isovolumic-developed pressure (r = 0.73; P = 0.002). In patients with a > 20-mmHg rise in isovolumic-developed pressure, tau increased by 10.3 +/- 4.6 ms. By multiple-regression analysis, the change of tau was related directly to the change of isovolumic-developed pressure (standardized coefficient beta = 0.80; P = 0.001) and inversely related to the resting systolic LV-aortic pressure gradient (beta = -0.37; P = 0.050). The other hemodynamic changes were independent of aortic valve stenosis. In conclusion, during the Mueller maneuver, the LV isovolumic contraction load increases and tau lengthens, particularly with higher elevations of LV systolic load.

Atrial septal defect blunts the impairment of left ventricular function during the Mueller maneuver

To investigate whether atrial septal defect (ASD) modifies the left ventricular (LV) hemodynamic response to a fall of intrathoracic pressure (Mueller maneuver), we studied 15 patients with an uncomplicated ASD and 16 healthy control subjects. LV function was measured by M-mode and Doppler echocardiography at rest and during the maneuver. Indicator-dilution technique was used to quantify the pulmonary-to-systemic flow ratio. During comparable changes (means +/- SE) of intrathoracic pressure (-33 +/- 2 mmHg in persons with ASD vs. -34 +/- 2 mmHg in those without), LV systolic function and filling diminished in both groups but patients with ASD showed smaller reductions in LV stroke dimension (-0.9 +/- 0.5 vs. -2.5 +/- 0.4 mm; P = 0.016), peak diameter shortening rate (-4 +/- 2 vs. -12 +/- 2 mm/s; P = 0.007), transmitral velocity-time integral (-1.0 +/- 0.3 vs. -2.2 +/- 0.4 cm; P = 0.022), and cardiac output (-6 +/- 3 vs. -18 +/- 3%; P = 0.029). The pulmonary-to-systemic flow ratio increased from 2.1 +/- 0.1 to 2.6 +/- 0.2 in the ASD group (P = 0.014). In conclusion, LV function diminishes significantly in healthy persons during the Mueller maneuver. In patients with ASD, the changes are directionally similar but quantitatively smaller. An interatrial communication mitigates the impairment of LV function after an acute and sustained drop of intrathoracic pressure.

Left ventricular size, mass, and function in relation to angiotensin-converting enzyme gene polymorphism in humans

Angiotensin-converting enzyme (ACE) exhibits genetic variation related to insertion/deletion (I/D) polymorphism in intron 16 of the ACE gene. The DD genotype results in high ACE activity and is overrepresented in diseases characterized by left ventricular (LV) hypertrophy and dysfunction. We studied whether the ACE gene polymorphism predicts LV mass or function in the absence of heart disease. Polymerase chain reaction of leukocyte DNA was used to determine the I/D genotype, and M-mode and Doppler echocardiography were used to quantify LV mass and function in 86 human subjects, 36-37 yr of age. All were free of clinical heart disease. The LV mass-to-body height ratio averaged 99 +/- 19 (SD) g/m in subjects with the II genotype (n = 25), 99 +/- 30 g/m in those with the ID genotype (n = 35), and 94 +/- 24 g/m in those with the DD genotype (n = 26; P = 0.790). The indexes of LV systolic and diastolic function were also unrelated to the ACE genotype. We conclude that in the absence of heart disease the ACE gene variation has no major influence on LV mass or function that is detectable at echocardiography.

Acute alcohol intake decreases short-term heart rate variability in healthy subjects

1. The acute effects of a moderate dose of ethanol (1g/kg body weight) on heart rate and blood pressure variability and baroreflex sensitivity were studied in 12 healthy male subjects in a juice-controlled experiment. Electrocardiographic and finger blood pressure data were recorded and stored in a minicomputer during 5 min of controlled breathing (15 cycles/min) and during deep breathing (5 s inspiration, 5 s expiration, four cycles) before drinking and hourly thereafter for 3 h. 2. Mean breath alcohol concentration rose to 18.9 mg/100 ml. In the time domain analysis, the root mean square difference of successive R-R interval decreased significantly with ethanol as compared with the juice experiment. The difference remained statistically significant even after adjustment for the shorter R-R interval after alcohol. In the frequency domain analysis the high-frequency (0.15-0.5 Hz) spectral power showed a significant decrease after alcohol intake. Also, the index of sensitivity of the baroreceptor reflex (square root of R-R interval power/systolic blood pressure power) decreased significantly in the high-frequency component. Ethanol did not change finger systolic blood pressure, and power spectral analysis did not show significant variability in blood pressure. 3. These data indicate that acute intake of moderate amounts of alcohol causes a significant decrease in heart rate variability owing to diminished vagal modulation of the heart rate.

Correlates of left ventricular mass in a population sample aged 36 to 37 years. Focus on lifestyle and salt intake

BACKGROUND

Echocardiographically determined left ventricular (LV) mass predicts adverse cardiovascular events in the general population. We have assessed the correlates of LV mass in a population-based study focusing on lifestyle and salt intake.

METHODS AND RESULTS

A random sample of 120 persons born in 1954 was invited; 93 (42 men) entered the study. The subjects' physical activity and alcohol, tobacco, and coffee consumption were quantified by 2-month dairy follow-up, and sodium intake was quantified by 7-day food records. Blood pressure was averaged for casual cuff measurements made 2 months apart. LV mass was determined by M-mode echocardiography, and stroke volume was determined by Doppler. Hematocrit and serum insulin were measured. In multiple linear regression analysis, LV mass was related positively and independently (P < .05) to body weight, systolic blood pressure, stroke volume, sodium intake, hematocrit, and energy expenditure in leisure-time physical activity. Additional analyses showed that the relation of LV mass to daily sodium intake depended on blood pressure (P < .001 for the interaction); the multiple regression coefficient (+/- SE) was 0.41 +/- 0.11 g.mEq-1 x d-1 (P = .001) in subjects with systolic blood pressure above the population median but statistically nonsignificant (-0.15 +/- 0.10 g.mEq-1 x d-1) in those with lower blood pressure. LV mass was clearly elevated only in persons with both blood pressure and sodium intake above the population medians.

CONCLUSIONS

Body weight, blood pressure, stroke volume, sodium intake, physical activity, and hematocrit are independent predictors of LV mass among unselected persons aged 36 to 37 years. The synergistic interaction of dietary salt with blood pressure suggests that high sodium intake may sensitize the heart to the hypertrophic stimulus of pressure load. Prospective studies are needed to confirm these cross-sectional associations.

Prevalence and predictors of audible physiological third heart sound in a population sample aged 36 to 37 years

BACKGROUND

A physiological third heart sound (S3) is common in youth but allegedly very rare after the age of 40 years. The mechanism of its disappearance is not known. The aim of this work was to study the prevalence and predictors of physiological S3 in a population-based sample of persons approaching 40 years of age.

METHODS AND RESULTS

A random sample of 120 persons born in 1954 was invited; 93 (42 men) entered the study. Their physical activity, alcohol and tobacco consumption, and salt intake were quantified by diary follow-up. The presence of an S3 was determined by auscultation and confirmed by phonocardiography. Left ventricular (LV) size, mass, and systolic function were assessed by M-mode echocardiography and LV filling by Doppler velocimetry of transmitral flow. An audible S3 was detected in 22 subjects, 1 of whom had heart disease. The prevalence of physiological S3 was 23.1%. Subjects with physiological S3 had a lower body mass index (22.3 +/- 2.8 versus 24.6 +/- 4.1 kg/m2 [mean +/- SD], P = .005), lower heart rate (63 +/- 7 versus 68 +/- 10 beats per minute, P = .015), higher peak early diastolic transmitral velocity (67 +/- 10 versus 58 +/- 8 cm/s, P = .002), and higher acceleration of early diastolic velocity (717 +/- 148 versus 622 +/- 122 cm/s2, P = .012) than those without S3. No differences were noted in the lifestyle characteristics, blood pressure, or LV mass and systolic function. Body mass index and peak early diastolic transmitral velocity were independent predictors of physiological S3 in logistic regression analysis.

CONCLUSIONS

Nearly one fourth of persons approaching their forties still have an audible physiological S3. The presence of S3 is predicted by leanness and a high early diastolic LV inflow velocity; the disappearance of S3 is unlikely to be secondary to increasing blood pressure and relative LV hypertrophy, as is widely presented, but reflects a more primary age-related alteration of LV early diastolic function.

Short-term heart rate variability and factors modifying the risk of coronary artery disease in a population sample

Heart rate (HR) variability is impaired in chronic coronary artery disease (CAD), but the mechanism is not fully resolved. This study was aimed at assessing whether HR variability is influenced by the risk factors of CAD. Of a random sample of 120 subjects born in 1954, 88 (41 men and 47 women) could be included in the analyses. No subject had clinical heart disease. The subjects' physical activity, alcohol consumption and smoking were quantified by 2-month diary follow-up. Serum lipids and insulin were measured. The tests of HR variability included power spectral analysis and calculation of the root-mean-square difference of RR intervals at rest under controlled respiration. HR variability indexes were asymmetrically distributed and strongly HR-dependent, and therefore, all statistical tests were performed on log-transformed data adjusted to the population mean HR. Multiple regression analyses showed independent inverse relations between the root-mean-square RR difference and low-density lipoprotein (LDL) cholesterol (beta = -0.22; p = 0.008), and between the total RR-interval power and LDL cholesterol (beta = -0.25; p = 0.007), as well as smoking (beta = -0.19; p = 0.035). In women, alcohol use influenced the RR-interval root-mean-square difference (beta = 0.31; p = 0.015), total power (beta = 0.33; p = 0.017) and high-frequency power (beta = 0.26; p = 0.056). It is concluded that short-term HR variability is related inversely to LDL cholesterol and smoking in the population, and directly to alcohol use in women.(ABSTRACT TRUNCATED AT 250 WORDS)

Use of non-invasive finger blood pressure monitoring in the estimation of aortic pressure at rest and during the Mueller manoeuvre

The aim of this investigation was to evaluate whether reliable estimates of aortic pressure can be derived using non-invasive finger blood pressure monitoring. Finger blood pressure (Ohmeda 2300 Finapres device; Finapres, Englewood, CO) was compared with simultaneous ascending aortic pressure measured with a catheter-transducer system both at rest and during acute negative intrathoracic pressure (the Mueller manoeuvre). Thirty-eight patients aged 17-73 years were studied. All were undergoing routine diagnostic or therapeutic cardiac catheterization. Beat-to-beat values of systolic, diastolic and mean non-invasive finger and invasive aortic blood pressure were measured at rest and factors which might have an influence on the difference between methods were examined. The mean finger-aortic difference was +5 +/- 14 mmHg for systolic, -2 +/- 7 mmHg for diastolic, -5 +/- 8 mmHg for mean and +6 +/- 13 mmHg for pulse pressure. In multivariate linear regression analysis, the difference in systolic pressure was related to aortic systolic pressure (standardized coefficient beta = -0.33, P = 0.01), heart rate (beta = 0.49, P < 0.000), age (beta = -0.29, P < 0.025) and height (beta = 0.40, P < 0.005). The linear regression equations to derive resting aortic pressures from the non-invasive finger pressure readings had correlation coefficients between 0.83 and 0.87 and standard errors of estimate between 6 and 14 mmHg. During the Mueller manoeuvre, Finapres reproduced average pressure changes reliably compared with intra-aortic pressure. Due to moderate inter-individual variation in the finger-aortic differences the correlation coefficients ranged from 0.83 to 0.93 and the standard errors of estimate from 3 to 6 mmHg. Non-invasive finger blood pressure monitoring could be used to estimate central aortic mean and diastolic blood pressure fairly reliably at rest, but with respect to systolic pressure the variance in finger-aortic difference was marked. The average intra-aortic pressure changes caused by the Mueller manoeuvre were reliably reproduced by the Finapres device.