Short-term secondhand smoke exposure decreases heart rate variability and increases arrhythmia susceptibility in mice

Exposure to secondhand smoke (SHS), a major indoor air pollutant, is linked to increased cardiovascular morbidity and mortality, including cardiac arrhythmias. However, the mechanisms underlying the epidemiological findings are not well understood. Impaired cardiac autonomic function, indexed by reduced heart rate variability (HRV), may represent an underlying cause. The present study takes advantage of well-defined short-term SHS exposure (3 days, 6 h/day) on HRV and the susceptibility to arrhythmia in mice. With the use of electrocardiograph telemetry recordings in conscious mice, HRV parameters in the time domain were measured during the night after each day of exposure and 24 h after 3 days of exposure to either SHS or filtered air. The susceptibility to arrhythmia was determined after 3 days of exposure. Exposure to a low concentration of SHS [total suspended particle (TSP), 2.4 ± 3.2; and nicotine, 0.3 ± 0.1 mg/m3] had no significant effect on HRV parameters. In contrast, the exposure to a higher but still environmentally relevant concentration of SHS (TSP, 30 ± 1; and nicotine, 5 ± 1 mg/m3) significantly reduced HRV starting after the first day of exposure and continuing 24 h after the last day of exposure. Moreover, the exposed mice showed a significant increase in ventricular arrhythmia susceptibility and atrioventricular block. The data suggest that SHS exposure decreased HRV beyond the exposure period and was associated with an increase in arrhythmia susceptibility. The data provide insights into possible mechanisms underlying documented increases in cardiovascular morbidity and mortality in humans exposed to SHS.

Download Full-text

Cardiovascular Benefits of Extended-Time Nocturnal Hemodialysis

Current Vascular Pharmacology ◽

10.2174/1570161118666200401112106 ◽

2020 ◽

Vol 19 (1) ◽

pp. 21-33

Author(s):

Athanasios Roumeliotis ◽

Stefanos Roumeliotis ◽

Christopher Chan ◽

Andreas Pierratos

Keyword(s):

Heart Rate ◽

Heart Rate Variability ◽

Sleep Apnea ◽

Left Ventricular ◽

Cardiovascular Morbidity ◽

Morbidity And Mortality ◽

Lv Function ◽

Plasma Norepinephrine ◽

Nocturnal Hemodialysis ◽

Cardiovascular Morbidity And Mortality

Hemodialysis (HD) remains the most utilized treatment for End-Stage Kidney Disease (ESKD) globally, mainly as conventional HD administered in 4 h sessions thrice weekly. Despite advances in HD delivery, patients with ESKD carry a heavy cardiovascular morbidity and mortality burden. This is associated with cardiac remodeling, left ventricular hypertrophy (LVH), myocardial stunning, hypertension, decreased heart rate variability, sleep apnea, coronary calcification and endothelial dysfunction. Therefore, intensive HD regimens closer to renal physiology were developed. They include longer, more frequent dialysis or both. Among them, Nocturnal Hemodialysis (NHD), carried out at night while asleep, provides efficient dialysis without excessive interference with daily activities. This regimen is closer to the physiology of the native kidneys. By providing increased clearance of small and middle molecular weight molecules, NHD can ameliorate uremic symptoms, control hyperphosphatemia and improve quality of life by allowing a liberal diet and free time during the day. Lastly, it improves reproductive biology leading to successful pregnancies. Conversion from conventional to NHD is followed by improved blood pressure control with fewer medications, regression of LVH, improved LV function, improved sleep apnea, and stabilization of coronary calcifications. These beneficial effects have been associated, among others, with better extracellular fluid volume control, improved endothelial- dependent vasodilation, decreased total peripheral resistance, decreased plasma norepinephrine levels and restoration of heart rate variability. Some of these effects represent improvements in outcomes used as surrogates of hard outcomes related to cardiovascular morbidity and mortality. In this review, we consider the cardiovascular effects of NHD.

Download Full-text

Reappraisal of the importance of heart rate as a risk factor for cardiovascular morbidity and mortality

Clinical Therapeutics ◽

10.1016/s0149-2918(97)80036-7 ◽

1997 ◽

Vol 19 ◽

pp. 39-52 ◽

Cited By ~ 18

Author(s):

Gabriel Habib

Keyword(s):

Heart Rate ◽

Risk Factor ◽

Cardiovascular Morbidity ◽

Morbidity And Mortality ◽

Cardiovascular Morbidity And Mortality

Download Full-text

Fixed combination of bisoprolol and a low-dose hydrochlorothiazide in arterial hypertension

Srpski arhiv za celokupno lekarstvo ◽

10.2298/sarh160822016i ◽

2018 ◽

Vol 146 (5-6) ◽

pp. 330-337

Author(s):

Branislava Ivanovic ◽

Milan Pavlovic ◽

Arsen Ristic ◽

Dragan Kovacevic

Keyword(s):

Blood Pressure ◽

Heart Rate ◽

Arterial Hypertension ◽

Thiazide Diuretic ◽

Beta Blockers ◽

Cardiovascular Morbidity ◽

Morbidity And Mortality ◽

Thiazide Diuretics ◽

Cardiovascular Morbidity And Mortality ◽

Dose Dependent

Beta-blockers showed better results in lowering elevated blood pressure in the younger age group of patients with higher renin plasma levels. Actual recommendations from the European Society of Cardiology for treatment of arterial hypertension from 2013 insist that heart rate should always be measured along with blood pressure. These recommendations point out the significance of resting heart rate as an independent predictor of cardiovascular morbidity and mortality in patients with arterial hypertension. Beta-blockers have a compelling indication for treatment of arterial hypertension in patients with coexistence of coronary artery disease, especially post myocardial infarction, as well as in patients with systolic heart failure. Bisoprolol, a highly selective beta-blocker with a long half-life and a prolonged antihypertensive effect, has shown consistent blood pressure control over a period of 24 hours. It has been demonstrated in placebo-controlled studies that administration of thiazide diuretics, in addition to lowering blood pressure levels, had also been associated with a reduction of cardiovascular morbidity and mortality rates. It is evident that effectiveness of thiazide diuretics is dose-dependent; however, undesirable effects of drugs are also dose-dependent. Depending on the dose, they aggravate glucose intolerance, increase lipid levels, cause hypokalemia, hyponatremia, and hypomagnesemia, and increase levels of uric acid. Administration of very low doses of a thiazide diuretic is acceptable in combination with other antihypertensive drugs, because it potentiates the action of other drugs without causing undesirable metabolic effects. The effectiveness and safety of the combination of bisoprolol (in various doses) and a thiazide diuretic in a small dose has been proven in clinical trials.

Download Full-text