Angina at XXXX And Risk of imminent @entity583 (the ALARM study): a prospective, observational proof-of-concept study.

@entity1 @entity1187 @entity301 @entity1459 @entity951 @entity299 @entity583 @entity258
BACKGROUND: @entity583 ( @entity583 ) is often preceded by @entity1459 . Helping @entity1 identify the onset of @entity1459 rather than @entity583 may result in earlier treatment and improve outcomes. @entity1459 is @entity951 occurring at a lower-than-usual workload. Since heart rate (HR) is correlated with degree of exertion, we hypothesised that @entity951 occurring at low HR is a warning signal for @entity1459 and @entity583 . METHODS: In this prospective study, 111 @entity1 with @entity1187 ( @entity1187 ) or prognostically significant @entity301 were recruited. Each @entity1 's HR was measured using a portable electrocardiogram (ECG) recorder after regular class III exercise on the Canadian Cardiovascular Society Angina Grading Scale and the cumulative moving average and three-sigma (standard deviation) range were calculated for each new measurement. The HR was subsequently measured at the @entity951 ; a HR lower than the preceding three-sigma ranges for @entity299 was regarded as a 'warning signal'. The proportion of warning signals associated with @entity1187 occurring in the following 2  weeks was compared with that for non-warning signals. RESULTS: Nine cases of @entity1187 occurred in eight @entity1 . Two cases were preceded by warning signals; a signal marked the onset of @entity1187 in a third @entity1 , and four @entity1 failed to make anginal ECG recordings. There were 591 documented episodes of @entity951 during the study and ECGs were available for 383 (64.8  %) of these of which 55 were warning signals. Of these warning signals, 4 occurred in the 2  weeks preceding @entity1187 , compared with 4 of 328 non-warning signals (odds ratio, 6.4; 95  % confidence interval, 1.5-26.2; p   =   0.01; positive predictive value, 7.3  %; negative predictive value, 98.8  %). CONCLUSIONS: Low HR @entity951 may identify @entity1459 and serve as an early warning for @entity583 . In addition, @entity951 that does not occur at a @entity258 indicates that @entity1187 is very unlikely.
