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.