THE INVESTIGATION OF SYNCOPE IN OLDER PATIENTS

Abstract

To the Editor: Regarding the recent article on the investigation of syncope in older patients,1 I note that only six of 28 (21%) centers agreed to participate in the study because of concerns over the protocol, including it being too complicated. I wonder whether the information gained from this study could help to devise a simplified pathway. It appears that in 197 of the 242 patients (80%), the correct diagnosis was made after the initial evaluation alone (although half of these patients went on to have a confirmatory test). This implies that a thorough clinical evaluation is the cornerstone of assessing these patients and that further investigations play mainly a supportive role. The performance of carotid Doppler, computerized tomography scanning, and electroencephalogram recordings led to no additional diagnostic information. Similarly, psychiatric evaluation failed to help, and so its place in the standard protocol could be questioned. Ambulatory blood pressure monitoring can detect general trends in blood pressure control but is far too insensitive to detect postural changes, and so it will have little place in identifying causes of syncope. The authors do not list the attributable cardiac causes, and so it is hard to understand which investigations were the most useful in this group. Coronary angiography is not without the potential to cause harm. It may show vessel narrowing but could not prove this to be the cause of the syncope (e.g., by an ischemia-induced arrhythmia). A 24-hour electrocardiogram (ECG) could only be reliably expected to demonstrate causation in patients who have daily symptoms. Most patients will require longer periods of ECG recording. Even if all of the cardiac investigations (other than an ECG) were omitted, only 15 of 242 (6%) patients would have missed out on a diagnosis. Putting the above points together, perhaps a simpler protocol could be written, as shown in Figure 1. Such an abbreviation may make it more likely for centers to adopt the protocol without significantly affecting patient care. A simplified protocol for the investigation of syncope in older people. *To be defined from the most useful tests within the study by Ungar et al. (or other case series). ECG=electrocardiogram. In addition, the authors used standing blood pressures at 1, 3, 5, and 10 minutes, although orthostatic syncope was defined as occurring within 5 minutes of standing up. So, is the 10-minute recording of any value? It should also be pointed out that the combination of prolonged standing at 60° and sublingual nitroglycerin can induce syncope in normal individuals. It is hard to know whether false positives were included in the data. This should have been made clear in the limitations of the study. An additional minor comment, Figure 2 in the paper shows the cardiac causes to number 32, yet the numbers add up to 22. Presumably the number of unexplained cases should number 11 (to match the other data). Finally, the total numbers of drug-induced and multifactorial cases in Figure 2 are five and 14, respectively, but the equivalent numbers in Table 4 are given as 11 and eight. Financial Disclosure: None. Author Contributions: Henry Woodford was the sole contributor to this letter. Sponsor's Role: None.