Discussion
The currents study found that the incidence rate of any ventricular arrhythmia during the COVID-19 outbreak acute period was 9.9%. A total of 86 VA was observed, a small number of patients experienced arrhythmia requiring therapy from the ICD: 9 patients (1.7%) ATP and 8 (1.3%) shock. Importantly, there was no evidence of a significant increase of arrhythmic burden during the COVID-19 epidemic outbreak, if compared to a reference period, the same timeframe in 2019. The same result was found for sub-types of VA and for VA requiring ICD therapy. The main predictor of arrhythmic event during the study period was previous history of any device therapy, especially in the previous 12 months.
Little is known about COVID-19 and arrhythmias, especially among patients with an ICD implanted, for whom the risk is generally considered very high. Previous reports of high risk for cardiac damage and arrhythmia refer primarily to very sick populations admitted to hospital for severe acute respiratory syndrome caused by SARS-CoV2 (4,5,13) and, thus, cannot be generalized to larger spectrum of conditions, during the outbreak of an epidemic. In the series of fatal cases of COVID-19 from Wuhan, China, a high rate of arrhythmia was reported, leading to hypothesize that COVID-19 may exacerbate underlying cardiovascular diseases (13). However, only a small minority of patients had malignant and fatal cases of such complication.
No data are available on the cardiac effect of COVID-19 spread among general population and especially in patients with heart disease. We hypothesized that subjects with and ICD could be the subgroup at higher risk of arrhythmic manifestation of such an epidemic.
It is important to underscore that the Italian area considered in the study, is one with the highest rate of infection and death for COVID-19 (14, 15), thus a population-based approach could be considered highly informative.
Considering that hospital reports of cardiac abnormalities among patients with COVID-19 are limited to subjects admitted to intensive care unit (ICU), it is unclear how important is the impact of cardiovascular complication among non-hospitalized patients. The presence of myocardial damage, e.g. elevated cardiac troponin, in patients with COVID-19 is reported as independent factors associated with mortality (17), but there is a substantial possibility that overestimation of cardiac involvement in such a condition maybe attributed to studies focusing on very sick patients admitted to ICU with COVID-19. So that, cardiac involvement maybe less severe among asymptomatic and mildly symptomatic cases, that are missing from most reports.
A growing body of recently published evidence found that seasonal influenza epidemics could trigger acute coronary syndromes and arrhythmias (10, 11, 16). Therefore, it has also been proposed that the increment of underlying cardiovascular diseases may not be specific to COVID-19, but a more general feature of seasonal viral infections.
The International community is giving high priority to support cardiological practice in a setting of disruption of previously defined protocols, and, thus, knowledge of epidemiological data is of seminal relevance (12,18,19). The present study showed that, among unselected consecutive population of patients with an ICD, in a setting of high incidence of disease caused by SARS-CoV2 (20), the rate of ventricular arrhythmias was not significantly higher.
A number of limitations should be considered. First, the study approach does not allow us to verify the actual incidence of clinically relevant COVID-19 in the cohort. Nevertheless, our approach allowed us to verify the phenomenon in a large sample and to account for the effect of asymptomatic infections in one of the areas most affected by the COVID-19 pandemic. Furthermore, our approach allowed us to assess the impact of the epidemic from a holistic standpoint, which goes beyond the sole effect of viral activity. Second, we considered only patients with an ICD implanted, generally because considered at higher risk of ventricular arrhythmia due to underlying cardiac disease; this group may be one of the more carefully followed-up by cardiologists and device specialists, as suggested by the high proportion of anti-arrhythmic drugs taken by patients in the study. Fourth, we were unable to assess whether all patients suffering from COVID-19 were treated with the same pharmacological and non-pharmacological therapy. Nevertheless, treatment variability in the area was reduced by adherence to regional protocols.