The influence of night-time hypertension on left ventricular mechanics

Phenotyping the hypertensive heart

Arterial hypertension remains the most frequent cardiovascular (CV) risk factor, and is responsible for a huge global burden of disease. Echocardiography is the first-line imaging method for the evaluation of cardiac damage in hypertensive patients and novel techniques, such as 2D and D speckle tracking and myocardial work, provide insight in subclinical left ventricular (LV) impairment that would not be possible to detect with conventional echocardiography. The structural, functional, and mechanical cardiac remodelling that are detected with imaging are intermediate stages in the genesis of CV events, and initiation or intensification of antihypertensive therapy in response to these findings may prevent or delay progressive remodelling and CV events. However, LV remodelling—especially LV hypertrophy—is not specific to hypertensive heart disease (HHD) and there are circumstances when other causes of hypertrophy such as athlete heart, aortic stenosis, or different cardiomyopathies need exclusion. Tissue characterization obtained by LV strain, cardiac magnetic resonance, or computed tomography might significantly help in the distinction of different LV phenotypes, as well as being sensitive to subclinical disease. Selective use of multimodality imaging may therefore improve the detection of HHD and guide treatment to avoid disease progression. The current review summarizes the advanced imaging tests that provide morphological and functional data about the hypertensive cardiac injury.

Blood pressure and left ventricular function changes in different ambulatory blood pressure patterns at high altitude

Acute high‐altitude (HA) exposure induces physiological responses of the heart and blood pressure (BP). However, few studies have investigated the responses associated with dipper and non‐dipper BP patterns. In this prospective study, 72 patients underwent echocardiography and 24‐h ambulatory BP testing at sea level and HA. Patients were divided into dipper and non‐dipper groups according to BP at sea level. Acute HA exposure elevated 24‐h systolic and diastolic BP and increased BP variability, particularly in the morning. Moreover, acute exposure increased left ventricular torsion, end‐systolic elastance, effective arterial elastance, and untwisting rate, but reduced peak early diastolic velocity/late diastolic velocity and peak early diastolic velocity/early diastolic velocity, implying enhanced left ventricular systolic function but impaired filling. Dippers showed pronounced increases in night‐time BP, while non‐dippers showed significant elevation in day‐time BP, which blunted differences in nocturnal BP fall, and lowest night‐time and evening BP. Dippers had higher global longitudinal strain, torsion, and untwisting rates after acute HA exposure. Variations in night‐time systolic BP correlated with variations in torsion and global longitudinal strain. Our study firstly demonstrates BP and cardiac function variations during acute HA exposure in different BP patterns and BP increases in dippers at night, while non‐dippers showed day‐time increases. Furthermore, enhanced left ventricular torsion and global longitudinal strain are associated with BP changes. Non‐dippers showed poor cardiac compensatory and maladaptive to acute HA exposure. However, the exact mechanisms involved need further illumination.

Isolated Nocturnal Hypertension: What Do We Know and What Can We Do?

Nocturnal hypertension has been recognized as a significant risk factor for cardio- and cerebrovascular diseases. Blood pressure (BP) monitoring significantly increased our awareness of nocturnal hypertension and studies revealed its influence on target organ damage. Nocturnal hypertension is associated with nonphysiological 24-h BP patterns, which consider inadequate drop or even increment of nighttime BP in comparison with daytime BP (nondipping and reverse dipping). Nevertheless, investigations showed that nocturnal hypertension was a predictor of adverse outcome independently of circadian BP pattern. There are still many uncertainties regarding diagnosis, mechanisms and treatment of nocturnal hypertension. There is a small difference between American and European guidelines in cutoff values defining nocturnal hypertension. Pathophysiology is also not clear because many conditions such as diabetes, metabolic syndrome, obesity, sleep apnea syndrome, and renal diseases are related to nocturnal hypertension and nonphysiological circadian BP pattern, but mechanisms of nocturnal hypertension still remain speculative. Therapeutic approach is another important issue and chronotherapy provided the best results so far. There are studies which showed that some groups of antihypertensive medications are more effective in regulation of nocturnal BP, but it seems that the timing of drug administration has a crucial role in the reduction of nighttime BP and conversion of circadian patterns from nonphysiologic to physiologic. Follow-up studies are necessary to define clinical benefits of nocturnal BP reduction and restoring unfavorable 24-h BP variations to physiological variant.