In our study only 8% of centenarians have a completely normal ECG. However, the abnormalities most frequently found have little clinical relevance, they are not related to their functional capacity, and only AF is associated with increased mortality.
The ECG abnormalities that appear with age have been widely studied. The most common findings are left ventricular hypertrophy, repolarisation abnormalities and Q/QS patterns, even in asymptomatic patients [4
]. The frequency of these findings increases with age [4
], and in some studies are associated with increased mortality [20
]. In general, men have more abnormalities related to ischemic heart disease [4
], although this difference fades with age [5
]. Among the rhythm disturbances, the most common are extra systolic beats, followed by AF [4
] and their prevalence also increases with age. Other minor abnormalities are commonly found, so that less than 40% of those over 65 have a completely normal ECG.
By contrast, ECG studies in centenarians are rare and their results have a wide variability [6
]. For example, the frequency of AF varies from 0 to 30%, or the ST segment changes from 9% to 40%. This is probably because of the difficulty of obtaining a wide sample [23
], which introduces many biases: small numbers of patients [7
], studies without established inclusion criteria, selected population collected [8
] or retrospective studies in a hospital setting [14
]. In addition, some of them do not perform a systematic analysis according to established criteria, such as the Minnesota code [9
]. In most studies the analysis is purely descriptive and differences by sex, cardiovascular disease or functional capacity are not considered. Similarly, they do not discuss whether these findings are associated with a higher mortality in centenarians, as in a younger population [24
Our study was designed to avoid these biases. We included the 95.2% of centenarians in our area, a systematic approach to baseline health status was performed at the patient's home, and they were followed up to their death. The main limitation that arises is the relatively low number of patients finally included, 80. Nonetheless, we consider that the sample is large enough compared to previous studies on centenarians.
Only 8% of centenarians had a normal ECG; thus, the frequency of ECG alterations was very high. This finding has been previously reported in an older population [5
] and also in centenarians [13
]. The fact that the frequency of ECG abnormalities increases with age, together with the absence of differences according to sex in our series, suggest that these abnormalities are related to aging itself more than to cardiovascular risk factors, which are more prevalent in men. Our data revealed that these changes were not related to greater disability or to cognitive impairment (Table ), probably because they are associated with a wide range of factors, of which heart disease is one of several.
Arrhythmias are common in these patients (55%) with extrasystole the most frequent. Interestingly, the frequency of AF in our series was high (26%), whereas such a prevalence has only been reported in a hospital-based retrospective study [14
]. Nevertheless, these data are consistent with those obtained in the general population over 85 [5
]. The lower prevalence of AF observed in previous studies on centenarians [8
] is probably related to the aforementioned sample bias.
The presence of left axis in 33.8% of cases, and left ventricular hypertrophy in 8.8% are both within the range reported in previous studies [7
]. The frequency of AV or intraventricular conduction defects was also high, similar to that reported in the centenarian population, and clearly superior to that reported in non-centenarian elderly [4
]. This is probably because of the aging process, also affecting the conduction tissue. Changes suggestive of ischaemia (disorder of repolarisation 31.3%, Q/QS pattern 16.3%), were also more frequent than those observed in a younger population, but not in the same proportion. This fact might suggest a bias of survival in the elderly who have no ischaemic heart disease.
In our series, AF has proven to be an independent predictor of mortality, a fact already reported in younger patients [21
]. This situation probably reflects a more serious underlying heart disease [22
]. This suggests that centenarians with AF could benefit from strict clinical control and optimal pharmacological treatment. In the same way, preventive strategies such as anticoagulation, which have shown a proven benefit in the younger population, might be considered in functionally independent centenarians without cognitive impairment.