Introduction Acute heart failure (AHF) is an unstable and heterogeneous condition and a primary or contributory reason for 3.5 million NHS bed-days annually in the UK. It is generally believed that majority of patients admitted with AHF have severe shortness of breath at rest but some baseline data from large registries and surveys suggests that many patients were comfortable at rest with some signs of cardio-respiratory distress. However, these registries and surveys data are collected across a number of centres and by variety of staff that may select patients and interpret questions about symptoms differently which might lead to anomalous results.

Methods We conducted a retrospective case-note review in patients with a primary death or discharge diagnosis of heart failure to determine what proportions were Short Of Breath At Rest (SOBAR) or Comfortable At Rest but Breathless On Slight Exertion (CARBOSE). We collected blood pressure (BP) and heart (HR) and respiratory rate (RR) at initial presentation and frequently thereafter for the first 24 h and tracked mortality for 180 days, providing a cohort of approximately 701 patients (311 from Hull and 390 from London).

Results Of 701 patients, the median age was 76 (IQR 65–73) years, 38% were women, 46% were in atrial fibrillation and median NT-proBNP was 4082 (IQR: 1895–10279 ng/L); 45% had SOBAR and 55% had CARBOSE. Compared to patients with CARBOSE, patients with SOBAR were of similar age (76 v 76 years;) but had higher HR (100 v 84 bpm;), systolic BP (142 v 125 mmHg;) and RR (26 v 19 rpm). Vital readings changed little amongst patients with CARBOSE in the first 4–6 h but declined steeply in those with SOBAR (142 to 127 mmHg, 100 to 90 bpm, and 26 to 21 rpm at presentation and 4–6 h respectively). At presentation, systolic BP was >125 mmHg in 71% patients with SOBAR and 50% with CARBOSE, dropping to 52% and 43% respectively by 4–6 h. By 180 days after presentation 15% of SOBAR and 35% of CARBOSE patients had died (OR 1.92, p-value-0.001, CI 1.30–2.84). This difference in mortality remained significant in multi variable analysis.

Conclusion Contrary to general belief, most patients admitted with a primary diagnosis of heart failure don’t have dyspnoea at rest but are breathlessness on slight exertion. Patients presenting with SOBAR had higher heart rates, respiratory rates and systolic blood pressures and often respond very quickly to conventional treatments with rapid improvement in clinical signs. Although, patients with SOBAR have more alarming initial symptoms and signs, patients with CARBOSE have a worse prognosis, perhaps reflecting more severe cardiac dysfunction.