Patients with a Hypertensive Response to Exercise Have Impaired Left Ventricular Diastolic Function

Blood pressure behavior during exercise in patients with diastolic dysfunction and a hypertensive response to exercise

A hypertensive response to exercise is a precursor leading to hypertension, which is a major risk factor for the development of heart failure and diastolic dysfunction. Herein, we aimed to assess blood pressure (BP) in patients with a hypertensive response to exercise and different degrees of diastolic dysfunction. Between January 2009 and December 2014, 373 patients with a hypertensive response to exercise (HRE) and echocardiographic data assessing diastolic function were enrolled at the University Hospital of Zurich. ANCOVA was used to assess the changes in BP response during exercise testing in individuals with different degrees of diastolic dysfunction. Normalization of systolic BP was blunted in patients with grade II and III diastolic dysfunction after 3 min of recovery in univariable [β (95%) - 9.2 (-13.8 to - 4.8) p < .001, -16.0 (-23.0 to 9.0) p < .001, respectively] and adjusted models. In fully adjusted models, when taking maximal effort into account, there were no differences with regard to systolic BP during exercise. Patients without diastolic dysfunction achieved higher heart rates (HRs) [both in absolute terms (p < .001) and as a percentage of the calculated maximum (p = .003)] and greater wattage (p < .001) at maximum exertion. The findings of this cross-sectional study suggest that exercise capacity is compromised in patients with diastolic dysfunction. A hypertensive response to exercise and the finding of a blunted BP recovery may help identify patients at risk of developing heart failure.

Usability of myocardial work parameters to demonstrate subclinical myocardial involvement in normotensive individuals with exaggerated hypertensive response in treadmill exercise testing

Early determination of changes in myocardial functions is essential for the protection of cardiovascular diseases. This study aimed to evaluate myocardial work parameters in healthy individuals who developed an exaggerated hypertensive response during the treadmill exercise test procedure. The study included a total of 64 patients for whom an exercise electrocardiography test was planned for functional capacity evaluation. The study population was divided according to the presence of exaggerated hypertensive response to exercise (EBPRE) (SBP/DBP ≥210/105 mmHg in males ≥190/105 mmHg in females) and normal blood pressure response to exercise (NBPRE). Patients' echocardiographic evaluations were made at rest, and myocardial work parameters were calculated. There was no statistical difference between the groups (NBPRE vs. EBPRE, respectively) in terms of left ventricular 2,3 and 4 chamber strains and global longitudinal strain (GLS) values (-20.6 ± -2.3, -19.7 ± -1.9, p:.13; -21.3 ± -2.7, -21 ± -2.4, p:.68; -21.2 ± -2.2, -21.2 ± -2.3, p:.93; and -20.8 ± -1.5, -20.4 ± -1.5, p:.23, respectively). Global constrictive work (GCW), global waste work (GWW), and global work efficiency (GWE) were not statistically different between the two groups (2374 ± 210, 2465 ± 204, p:.10; 142 ± 64, 127 ± 42, p:.31; 94.3 ± 2.5, 95.1 ± 1.5, p:.18, respectively). In contrast, global work index (GWI) parameters were different between the two groups (2036 ± 149, 2147 ± 150, p < .001). The GWI was independently associated with EBPRE (odds ratio with 95% 3.32 (1.02-11.24), p = .03). The partial effect plots were used for GWI to predict EBPRE, according to the results, an increase in GWI predicts probability of exaggerated hypertensive response. In conclusion, Myocardial work analyses might be used to identify early signs of myocardial involvement in normotensive patients with EBPRE.

Effect of twice daily inhaled albuterol on cardiopulmonary exercise outcomes, dynamic hyperinflation, and symptoms in secondhand tobacco-exposed persons with preserved spirometry and air trapping: a randomized controlled trial

BACKGROUND

In tobacco-exposed persons with preserved spirometry (active smoking or secondhand smoke [SHS] exposure), air trapping can identify a subset with worse symptoms and exercise capacity. The physiologic nature of air trapping in the absence of spirometric airflow obstruction remains unclear. The aim of this study was to examine the underlying pathophysiology of air trapping in the context of preserved spirometry and to determine the utility of bronchodilators in SHS tobacco-exposed persons with preserved spirometry and air trapping.

METHODS

We performed a double-blinded placebo-controlled crossover randomized clinical trial in nonsmoking individuals at risk for COPD due to exposure to occupational SHS who had preserved spirometry and air trapping defined as either a residual volume-to-total lung capacity ratio (RV/TLC) > 0.35 or presence of expiratory flow limitation (EFL, overlap of tidal breathing on maximum expiratory flow-volume loop) on spirometry at rest or during cardiopulmonary exercise testing (CPET). Those with asthma or obesity were excluded. Participants underwent CPET at baseline and after 4-week trials of twice daily inhalation of 180 mcg of albuterol or placebo separated by a 2-week washout period. The primary outcome was peak oxygen consumption (VO2) on CPET. Data was analyzed by both intention-to-treat and per-protocol based on adherence to treatment prescribed.

RESULTS

Overall, 42 participants completed the entire study (66 ± 8 years old, 91% female; forced expiratory volume in 1 s [FEV1] = 103 ± 16% predicted; FEV1 to forced vital capacity [FVC] ratio = 0.75 ± 0.05; RV/TLC = 0.39 ± 0.07; 85.7% with EFL). Adherence was high with 87% and 93% of prescribed doses taken in the treatment and placebo arms of the study, respectively (P = 0.349 for comparison between the two arms). There was no significant improvement in the primary or secondary outcomes by intention-to-treat or per-protocol analysis. In per-protocol subgroup analysis of those with RV/TLC > 0.35 and ≥ 90% adherence (n = 27), albuterol caused an improvement in peak VO2 (parameter estimate [95% confidence interval] = 0.108 [0.014, 0.202]; P = 0.037), tidal volume, minute ventilation, dynamic hyperinflation, and oxygen-pulse (all P < 0.05), but no change in symptoms or physical activity.

CONCLUSIONS

Albuterol may improve exercise capacity in the subgroup of SHS tobacco-exposed persons with preserved spirometry and substantial air trapping. These findings suggest that air trapping in pre-COPD may be related to small airway disease that is not considered significant by spirometric indices of airflow obstruction.

Hypertensive response to exercise, hypertension and heart failure with preserved ejection fraction (HFpEF)-a continuum of disease?

INTRODUCTION

Heart failure with preserved ejection fraction (HFpEF) has been shown to be a long-term consequence of uncontrolled arterial hypertension (aHT). Other than that, hypertensive response to exercise (HRE) precedes aHT. We aim to evaluate the available evidence for a continuum of HRE, aHT and HFpEF.

METHODS

A literature search on PubMed was conducted to assembly the most recent data on the topic. After collecting the data, a qualitative analysis was instrumented.

RESULTS

10 studies including 16,165 subjects were analyzed with respect to the association between HRE and the future risk of developing aHT. With the exception of one study, all reported on a positive association between HRE and the future development of aHT despite methodological issues related to different definitions for HRE. Furthermore, HRE was associated with an increased risk of coronary artery disease. Moreover, we analysed 6 studies including overall 1366 subjects investigating the association between HRE and HFpEF. In these studies, increased left atrial volume index (LAVI), elevated E/e' (as surrogate parameters of increased LV end-diastolic filling pressure and of diastolic dysfunction) and higher LV mass index have been proposed as independent predictor of HRE in patients with no known HFpEF diagnosis.

DISCUSSION AND CONCLUSION

The literature search revealed suggestive data on a connection of HRE, aHT and HFpEF. HRE seems to be an independent risk factor for aHT and aHT in turn is one of the main risk factors for HFpEF. However, further research is needed to improve our knowledge of a possible continuum of disease.

Hypertensive Response to Exercise in Athletes: Unremarkable Finding or Relevant Marker for Future Cardiovascular Complications?

Background. In the general population, hypertensive response to exercise (HRE) predicts new-onset resting hypertension or other cardiovascular diseases. Methods. PubMed was searched for English articles published between January 1st 2000 and April 30th 2020. Additional studies were identified via reference lists of included studies. 92 papers were selected for full text analysis, finally 30 studies were included. Results. The results from 5 follow-up studies suggested an association between HRE and the risk of developing hypertension, while 10 studies reported a link with adverse cardiovascular events in the general population. Another study showed an association between HRE and future hypertension in athletes after a follow-up of 7 years. HRE in athletes was associated with left ventricular hypertrophy in three studies. Two other studies showed a link between HRE and focal myocardial fibrosis in triathletes and myocardial injury, respectively. One study found lower Apoliprotein-1 serum levels in athletes with HRE leading to a higher risk for cardiovascular disease. Only in one study no association with cardiovascular dysfunction in athletes with HRE was found. Conclusions. Based on current evidence, HRE is not a normal finding in athletes. If detected, it should be interpreted as a risk factor for future cardiovascular complications. Future research should address the adequate follow-up and management of athletes with HRE.

Remote exposure to secondhand tobacco smoke is associated with lower exercise capacity through effects on oxygen pulse, a proxy of cardiac stroke volume

BACKGROUND

Past exposure to secondhand tobacco smoke (SHS) is associated with exercise limitation. Pulmonary factors including air trapping contribute to this limitation but the contribution of cardiovascular factors is unclear.

OBJECTIVE

To determine the contribution of cardiovascular mechanisms to SHS-associated exercise limitation.

METHODS

We examined the cardiovascular responses to maximum-effort exercise in 245 never-smokers with remote, prolonged occupational exposure to SHS and no known history of cardiovascular disease. We estimated the contribution of oxygen-pulse (proxy for cardiac stroke volume) and changes in systolic blood pressures (SBP), diastolic blood pressures and heart rate (HR) towards exercise capacity, and examined whether the association of SHS with exercise capacity was mediated through these variables.

RESULTS

At peak exercise (highest workload completed (WattsPeak)=156±46 watts (135±33 %predicted)), oxygen consumption and oxygen-pulse (O2-PulsePeak) were 1557±476 mL/min (100±24 %predicted) and 11.0±3.0 mL/beat (116±25 %predicted), respectively, with 29% and 3% participants not achieving their predicted normal range. Oxygen saturation at peak exercise was 98%±1% and remained >93% in all participants. Sixty-six per cent showed hypertensive response to exercise. In models adjusted for covariates, WattsPeak was associated directly with O2-PulsePeak, HRPeak and SBPPeak and inversely with SHS, air trapping (residual volume/total lung capacity) and rise of SBP over workload (all p<0.01). Moreover, SHS exposure association with WattsPeak was substantially (41%) mediated through its effect on O2-PulsePeak (p=0.038). Although not statistically significant, a considerable proportion (36%) of air trapping effect on WattsPeak seemed to be mediated through O2-PulsePeak (p=0.078). The likelihood of having baseline respiratory symptoms (modified Medical Research Council score ≥1) was associated with steeper rise in SBP over workload (p<0.01).

CONCLUSION

In a never-smoker population with remote exposure to SHS, abnormal escalation of blood pressure and an SHS-associated reduction in cardiac output contributed to lower exercise capacity.

Blood pressure response during treadmill exercise testing and the risk for future cardiovascular events and new-onset hypertension

OBJECTIVE

The physiologic response to exercise may provide valuable prognostic information. We investigated the association of blood pressure (BP) measurements during exercise stress testing (EST) with long-term risk of myocardial infarction, stroke or death (major adverse cardiovascular event, MACE), as well as the development of new-onset hypertension.

METHODS

A retrospective analysis of treadmill ESTs (years 2005-2019) performed by the Bruce protocol in patients aged 35-75 years without a history of cardiovascular disease (n = 14 792; 48% women). BP was documented at rest, submaximal exercise (Bruce stage-2), peak exercise and recovery (2 min). Association of SBP measures with study outcomes during median follow-up of 6.5 years was investigated.

RESULTS

Highest vs. lowest SBP quartile at rest (≥140 vs. <120 mmHg), submaximal-exercise (≥170 vs. <130 mmHg), peak-exercise (≥180 vs. ≤145 mmHg) and recovery (≥160 vs. <130 mmHg) was associated with an increase in the adjusted hazard ratio and 95% confidence interval (CI) for MACE: 1.53 (1.23-1.88), 1.33 (1.01-1.76), 1.30 (1.05-1.61), 1.35 (1.09-1.68), respectively. The association between SBP at submaximal exercise and recovery with MACE displayed a J-shaped pattern. Among nonhypertensive patients (n = 8529), excessive SBP response to peak exercise (≥190 mmHg in women and ≥210 mmHg in men) was an independent predictor of hypertension [hazard ratio (95% CI)]: 1.87 (1.41-2.48), as were SBPs during submaximal exercise [>160 vs. ≤130 mmHg: 2.44 (1.97-3.03)] and recovery [≥140 vs. ≤120 mmHg: 1.65 (1.37-1.98)].

CONCLUSION

BP measurement during rest, exercise and recovery phases of EST provides incremental prognostic information regarding long-term risk for cardiovascular events and the probability for developing hypertension.

Patients with hypertensive responses to exercise or dobutamine stress testing differ in resting hypertensive phenotype

Little is known of the importance of echocardiographic measures of resting systemic vascular resistance (SVR), cardiac output, and diastolic function in the development of a hypertensive response during dobutamine stress echocardiography. We performed a retrospective review of 325 subjects who underwent stress echocardiography and a resting echocardiogram on the same day. Logistical regressions were performed to determine associations between hypertensive response to each type of stress test and clinical and hemodynamic measurements obtained by transthoracic echocardiography. Patients with a hypertensive response to dobutamine or exercise stress modalities had Stage 1 hypertension. Those with a hypertensive response to dobutamine had a significantly elevated SVR and a lower cardiac output compared to those with a hypertensive response to exercise or a nonhypertensive response to dobutamine. An SVR ≥2000 dynes × sec/cm⁵ showed excellent discrimination between patients who did and did not have a hypertensive response to dobutamine (c = 0.80). A hypertensive response to both stress modalities showed an association with measures of diastolic dysfunction. The hemodynamic and echocardiographic phenotypes of individuals with a hypertensive response to exercise differ from those with a hypertensive response to dobutamine. Further work is necessary to understand and guide antihypertensive therapy when a hypertensive response to stress testing is discovered and to inform choice of stress modality when resting hypertension is present.

Arterial stiffness, sex, and age difference on hypertensive response to supine bicycle exercise

Contributors to a hypertensive response to exercise (HTR) according to sex and age have not been fully evaluated. The authors analyzed a database of supine bicycle exercise stress echocardiography findings. HTR was defined as peak systolic blood pressure ≥210 mmHg for men and ≥190 mmHg for women during exercise. A total of 797 patients (306 [38%] women) were analyzed, with a mean age of 64 ± 10 years. Female sex, hypertension; higher left ventricular ejection fraction, effective arterial elastance, and pulse wave velocity; and lower total arterial compliance were significantly related to HTR. Patients with HTR had higher relative wall thickness, ratio of early diastolic mitral inflow and annular velocity, and diastolic elastance (all P ≤ .05). In multivariable analysis, indices of arterial stiffness such as pulse wave velocity, arterial elastance, total arterial compliance, and systemic vascular resistance were more strongly related in women, while in men, index of sympathetic activation was additionally related to HTR (all P ≤ .05). Female sex and lower total arterial compliance in older patients (≥65 years) and higher systemic vascular resistance and left ventricular relative wall thickness in younger patients were more strongly related to HTR. In conclusion, HTR was related to arterial stiffness, sympathetic activation, and diastolic dysfunction; however, the associations were different according to sex and age, which might guide individualized therapy.

Hypertensive response to exercise: mechanisms and clinical implication

A hypertensive response to exercise (HRE) is frequently observed in individuals without hypertension or other cardiovascular disease. However, mechanisms and clinical implication of HRE is not fully elucidated. Endothelial dysfunction and increased stiffness of large artery contribute to development of HRE. From neurohormonal aspects, excess stimulation of sympathetic nervous system and augmented rise of angiotensin II seems to be important mechanism in HRE. Increasing evidences indicates that a HRE is associated with functional and structural abnormalities of left ventricle, especially when accompanied by increased central blood pressure. A HRE harbors prognostic significance in future development of hypertension and increased cardiovascular events, particularly if a HRE is documented in moderate intensity of exercise. As supported by previous studies, a HRE is not a benign phenomenon, however, currently, whether to treat a HRE is controversial with uncertain treatment strategy. Considering underlying mechanisms, angiotensin receptor blockers and beta blockers can be suggested in individuals with HRE, however, evidences for efficacy and outcomes of treatment of HRE in individuals without hypertension is scarce and therefore warrants further studies.

What global diastolic function is, what it is not, and how to measure it

Despite Leonardo da Vinci's observation (circa 1511) that “the atria or filling chambers contract together while the pumping chambers or ventricles are relaxing and vice versa,” the dynamics of four-chamber heart function, and of diastolic function (DF) in particular, are not generally appreciated. We view DF from a global perspective, while characterizing it in terms of causality and clinical relevance. Our models derive from the insight that global DF is ultimately a result of forces generated by elastic recoil, modulated by cross-bridge relaxation, and load. The interaction between recoil and relaxation results in physical wall motion that generates pressure gradients that drive fluid flow, while epicardial wall motion is constrained by the pericardial sac. Traditional DF indexes (τ, E/E′, etc.) are not derived from causal mechanisms and are interpreted as approximating either stiffness or relaxation, but not both, thereby limiting the accuracy of DF quantification. Our derived kinematic models of isovolumic relaxation and suction-initiated filling are extensively validated, quantify the balance between stiffness and relaxation, and provide novel mechanistic physiological insight. For example, causality-based modeling provides load-independent indexes of DF and reveals that both stiffness and relaxation modify traditional DF indexes. The method has revealed that the in vivo left ventricular equilibrium volume occurs at diastasis, predicted novel relationships between filling and wall motion, and quantified causal relationships between ventricular and atrial function. In summary, by using governing physiological principles as a guide, we define what global DF is, what it is not, and how to measure it.

Relation between exercise central haemodynamic response and resting cardiac structure and function in young healthy men

BACKGROUND

Left ventricular (LV) structure and function are predictors of cardiovascular (CV) morbidity and mortality and are related to resting peripheral haemodynamic load in older adults. The central haemodynamic response to exercise may reveal associations with LV structure and function not detected by traditional peripheral (brachial) measures in a younger population.

PURPOSE

To examine correlations between acute exercise-induced changes in central artery stiffness and wave reflections and measures of resting LV structure and function.

METHODS

Sixteen healthy men (age 26 ± 6 year; BMI 25·3 ± 2·7 kg m^-2 ) had measures of central haemodynamic load measured before/after a 30-s Wingate anaerobic test (WAT). Common carotid artery stiffness and reflected wave intensity were assessed via wave intensity analysis as a regional pulse wave velocity (PWV) and negative area (NA), respectively. Resting LV structure (LV mass) and function [midwall fractional shortening (mFS)] were assessed using M-mode echocardiography in the parasternal short-axis view.

RESULTS

There was a significant association between mFS and WAT-mediated change in carotid systolic BP (r = -0·57, P = 0·011), logNA (r = -0·58, P = 0·009) and PWV (r = -0·44, P = 0·045). There were no significant associations between resting mFS and changes in brachial systolic BP (r = -0·26, P>0·05). There were no associations between resting LV mass and changes in any haemodynamic variable (P>0·05).

CONCLUSION

Exercise-induced increases in central haemodynamic load reveal associations with lower resting LV function in young healthy men undetected by traditional peripheral haemodynamics.

Cardiopulmonary Exercise Test in Patients with Hypertension: Focused on Hypertensive Response to Exercise

The cardiopulmonary exercise test (CPET) provides integrative exercise responses including the cardiovascular, pulmonary and skeletal muscle systems. It can be used for the identification of myocardial ischemia, evaluation of exercise capacity and tolerance, and the assessment of chronotropic competence or arrhythmias with the addition of ventilatory and gas exchange measurement information. Among them, hypertensive response to exercise (HRE) is known to be related with higher risk of future heart failure and cardiovascular events in patients with hypertension. Proposed underlying mechanisms of HRE can be found in ventricular-vascular uncoupling including decreased aortic distensibility, increased left ventricular mass, endothelial dysfunction, and diastolic dysfunction. The CPET might be useful in the identification of masked hypertension and the assessment of antihypertensive treatment efficacy in patients with hypertension.

Influence of hyperhomocysteinemia on left ventricular diastolic function in Chinese patients with hypertension

OBJECTIVE

The aim of this study was to assess the effect of plasma homocysteine (Hcy) on left ventricular (LV) diastolic function in Chinese patients with essential hypertension.

PATIENTS AND METHODS

A total of 74 patients with hypertension were enrolled in the present study and were divided into two groups according to the plasma levels of Hcy: high levels of Hcy (Hhcy) group (n = 37) and control group (n = 37) with normal levels of homocysteine. The study participants consisted of 37 hypertensive patients with Hhcy and 37 hypertensive patients without Hhcy. Transthoracic Doppler echocardiography was performed to assess the LV diastolic function of the patients.

RESULTS

The plasma level of Hcy was directly related to LV diastolic echocardiographic parameters in patients with hypertension whereby the ratio E/e' was higher (12.7 ± 2.64 vs. 8.98 ± 1.55, p < 0.01), e'/a' was lower (0.59 ± 0.13 vs. 0.83 ± 0.20, p < 0.01), and the left atrial (LA) diameter was longer (43.4 ± 3.6 mm vs. 37.6 ± 5.0 mm, p < 0.01) in the Hhcy group than in the control group.

CONCLUSION

The LV diastolic function was significantly deteriorated in Chinese hypertensive patients with Hhcy and there were significant correlations between LV diastolic function indices and Hcy levels.

Attenuated muscle metaboreflex-induced increases in cardiac function in hypertension

Sympathoactivation may be excessive during exercise in subjects with hypertension, leading to increased susceptibility to adverse cardiovascular events, including arrhythmias, infarction, stroke, and sudden cardiac death. The muscle metaboreflex is a powerful cardiovascular reflex capable of eliciting marked increases in sympathetic activity during exercise. We used conscious, chronically instrumented dogs trained to run on a motor-driven treadmill to investigate the effects of hypertension on the mechanisms of the muscle metaboreflex. Experiments were performed before and 30.9 ± 4.2 days after induction of hypertension, which was induced via partial, unilateral renal artery occlusion. After induction of hypertension, resting mean arterial pressure was significantly elevated from 98.2 ± 2.6 to 141.9 ± 7.4 mmHg. The hypertension was caused by elevated total peripheral resistance. Although cardiac output was not significantly different at rest or during exercise after induction of hypertension, the rise in cardiac output with muscle metaboreflex activation was significantly reduced in hypertension. Metaboreflex-induced increases in left ventricular function were also depressed. These attenuated cardiac responses caused a smaller metaboreflex-induced rise in mean arterial pressure. We conclude that the ability of the muscle metaboreflex to elicit increases in cardiac function is impaired in hypertension, which may contribute to exercise intolerance.

Left ventricular torsion abnormalities in patients with obstructive sleep apnea syndrome: an early sign of subclinical dysfunction

BACKGROUND

Previous echocardiographic studies using tissue Doppler imaging (TDI) and speckle tracking imaging (STI) have demonstrated that obstructive sleep apnea syndrome (OSAS) patients may develop subclinical left ventricular (LV) systolic and diastolic dysfunction. Our purpose was to evaluate the impact of OSAS on LV torsion dynamics and aortic stiffness by using TDI and STI echocardiography.

METHODS

Forty-two patients with OSAS and no comorbidities were studied. They were classified into mild and severe OSAS according to the apnea-hypopnea index (AHI). Thirty-five healthy subjects were selected as controls. Fifteen patients with severe OSAS underwent chronic nocturnal nasal continuous positive airway pressure (CPAP) therapy. Standard echocardiographic parameters were assessed. Global LV longitudinal strain (LS), radial and circumferential strain were determined by STI. Averaged LV rotation and rotational velocities from the base and apex were obtained and used for calculation of LV torsion (LVtor). Mitral annular velocities and aortic wall velocities and strain (AoS) were also obtained by TDI.

RESULTS

Severe OSAS had decreased LS compared with control subjects. LVtor increased significantly in severe OSAS compared to normals (p<.001) as a result of a predominant increase in apical rotation and was independently related to AHI and AoS in a multiple stepwise linear regression model. The group treated with CPAP had a significant decrease in LVtor and aortic stiffness index and significant increase in LS and AoS.

CONCLUSIONS

LVtor, LS and AoS were identified as parameters demonstrating an association between LV dysfunction, aortic stiffness and severity of OSAS independently of other possible factors or comorbidities.

Stress induced hypertensive response: should it be evaluated more carefully?

Various diagnostic methods have been used to evaluate hypertensive patients under physical and pharmacological stress. Several studies have shown that exercise hypertension has an independent, adverse impact on outcome; however, other prognostic studies have shown that exercise hypertension is a favorable prognostic indicator and associated with good outcome. Exercise hypertension may be encountered as a warning signal of hypertension at rest and future hypertensive left ventricular hypertrophy. The results of diagnostic stress tests support that hypertensive response to exercise is frequently associated with high rate-pressure product in hypertensives. In addition to the observations on high rate-pressure product and enhanced ventricular contractility in patients with hypertension, evaluation of myocardial contractility by Doppler tissue imaging has shown hyperdynamic myocardial function under pharmacological stress. These recent quantitative data in hypertensives suggest that hyperdynamic myocardial function and high rate-pressure product response to stress may be related to exaggerated hypertension, which may have more importance than that it has been already given in clinical practice.

Hypertension impairs myocardial blood perfusion reserve in subjects without regional myocardial ischemia

Quantitative analysis of myocardial perfusion MRI can provide noninvasive assessments of myocardial perfusion reserve (MPR), which is associated with endothelial function. Endothelial function is influenced by various factors, including hypertension, diabetes, dyslipidemia, renal dysfunction and anemia. The purpose of this study was to evaluate which risk factor is the strongest effector of MPR in subjects without regional myocardial ischemia. We studied 110 patients (66 years ±10, male 68%, hypertension 76%, diabetes mellitus (DM) 40% and dyslipidemia 65%) without regional myocardial ischemia. Adenosine triphosphate (ATP) stress and rest first-pass perfusion magnetic resonance (MR) images were acquired with a 1.5-T MR system, and MPR was calculated as the ratio of stress to rest myocardial blood flow (MBF). Average rest MBF in 110 patients was 1.07±0.62 ml min⁻¹ g⁻¹, whereas stress MBF was 3.15±1.93 ml min⁻¹ g⁻¹ and the MPR was 3.33±1.82. Rest MBF correlated significantly with hematocrit, whereas stress MBF showed a strong correlation with estimated glomerular filtration rate (e-GFR). MPR was associated with hypertension, age, e-GFR, hematocrit and left ventricular mass index (LVMI). In multiple regression analysis, hypertension (P=0.003, β=-0.274) showed the strongest correlation with MPR among other risk factors, such as diabetes (P=ns), dyslipidemia (P=ns), e-GFR (P=ns), LVMI (P=0.007, β=-0.248) and hematocrit (P=ns) after adjusting age and gender. Hypertension is the most important effector of MPR in subjects without myocardial ischemia.

Role of smoking in the recurrence of atrial arrhythmias after cardioversion

We aimed to determine whether smoking status affects the recurrence of atrial fibrillation or atrial flutter in patients after cardioversion. The clinical data of patients undergoing cardioversion for atrial flutter from January 1, 2000 to December 31, 2005 were prospectively collected. Arrhythmia recurrences were detected by retrospective review of comprehensive medical records and were determined using electrocardiography. The smoking history was prospectively collected through a standardized clinical form and subsequently categorized as lifetime nonsmoker, exsmoker, or current smoker. Univariate and multivariate associations with end points for clinical and lifestyle variables were assessed with Cox proportional hazards models. Women who were current smokers at cardioversion had a greater risk of atrial arrhythmia recurrence than did nonsmokers (hazard ratio 1.71, 95% confidence interval 1.10 to 2.67, p = 0.02). The increased risk of arrhythmia recurrence in female smokers was not seen in male smokers. Compared to lifetime nonsmokers, the mortality hazard ratio among men was 1.18 (95% confidence interval 0.88 to 1.58; p = 0.28) in exsmokers and 1.93 (95% confidence interval 1.20 to 3.11; p = 0.007) in current smokers. The risk of death after cardioversion was not increased in women. In conclusion, smoking is an independent predictor of atrial arrhythmia recurrence after cardioversion in women; however, an increased mortality risk, but not arrhythmia recurrence risk, was seen in men.

Effect of rosuvastatin on cardiac remodeling, function, and progression to heart failure in hypertensive heart with established left ventricular hypertrophy

Hypertensive patients with left ventricular hypertrophy (LVH) are the most common high-risk group to develop heart failure with preserved ejection fraction. Recent reports have noted the favorable effect of statins on LVH. We evaluated the effect of rosuvastatin on cardiac remodeling, function, and progression to heart failure in a hypertensive rat model with established LVH. Dahl salt-sensitive rats were fed a high-salt diet until 13 weeks of age. After LVH was confirmed by echocardiography, rats were randomly assigned to control and statin treatment (n=18 each group). The statin-treated group was treated with rosuvastatin until 21 weeks of ages. Serial echocardiography, blood pressure monitoring, and miniaturized conductance catheter hemodynamic monitoring were performed at 21 weeks. Echocardiographic parameters were not significantly different between the groups. On hemodynamic monitoring, systolic performance parameters were similar between the groups, whereas end diastolic pressure-volume relationships were lower in the statin-treated group (0.014+/-0.008 versus 0.008+/-0.004 mm Hg/muL, P<0.05), suggesting improvement in myocardial stiffness. Pathological analysis showed attenuation of perivascular and interstitial fibrosis in the statin-treated group (P<0.02). Rosuvastatin therapy did not alleviate LVH in hypertensive rats with established LVH, but it attenuated myocardial fibrosis and LV stiffness. It seems that rosuvastatin has limited therapeutic value when used to prevent progression from LVH to heart failure in hypertensive hearts.