Impact of seasonal blood pressure variability in patients with heart failure

Background and objective: Blood pressure (BP) varies seasonally in inverse relation to temperature, although its impact on heart failure is poorly understood. The main objective was to compare BP readings between summer and winter using different measurement methods and to assess the clinical impact of these variations. Materials and methods: This was an observational, prospective, cross-sectional study of 50 patients with reduced or improved heart failure and optimised treatment, conducted at a single centre in southern Spain. Each patient was evaluated in summer (June--August) and winter (December--February) using BP measurements in the clinic, 3 days of home self-measurement (HBPM), and 24-h ambulatory monitoring (ABPM), completing 1 year of follow-up. Results: The mean age was 64 ± 12 years, 76% were men, with a mean ejection fraction of 43%. HBPM showed decreases in summer compared to winter in SBP (–7.6 mmHg; P < 0.001), DBP (–3.2 mmHg; P < 0.001) and mean BP (–4.6 mmHg; P < 0.001). ABPM detected slight daytime reductions in systolic (Δ –1.5 mmHg; P = 0.004), diastolic (Δ –2.2 mmHg; P = 0.001) and heart rate (Δ –3 bpm; P < 0.001), with no nocturnal changes. Nonsignificant concordant differences were observed in the clinic. Thirty-five per cent required therapeutic reduction in summer compared to 16% in winter ( P = 0.006), with a greater tendency to dizziness. Fourteen per cent experienced events: two renal deteriorations and one syncope in summer-autumn, compared to three decompensations and one noncardiovascular death in winter-spring. Conclusion: In patients with heart failure, summer is associated with a significant decrease in BP, best detected by HBPM, which requires therapeutic adjustments and clinical monitoring to prevent adverse events.