Hurricane Isaac brought extensive rainfall and storm surges along the Gulf Coast, resulting in widespread flooding and power outages in Louisiana, Mississippi and Alabama. However, due to newly released evidence linking the aftermath of Japan’s 2011 earthquake with an increase in the occurrence of cardiovascular events, new GlobalData analysis has questioned what role this latest disaster might play in the incidence of CV events in areas affected by the storm and how far the harm caused by Hurricane Isaac extends beyond the expected.
The great Japanese earthquake and consequent tsunami of March 11, 2011, which hit the northeast coast of Japan with a magnitude of 9.0 on the Richter scale, was one of the largest ocean-trench earthquakes ever recorded in Japan. In addition to claiming the lives of almost 16,000 and destroying nearly 400, 000 homes, the disaster resulted in a sharp increase in the number of CV events. This trend has been reported before, following similar incidences in Japan, China and the U.S. According to cardiologist Dr. Hiroaki Shimokawa, however, related studies only reported the short-term occurrence of individual CV events and not the mid-term effects of large-scale earthquakes.
Dr. Shimokawa and colleagues from the Tohoku University Graduate School of Medicine at Sendai, Japan, reviewed all 124,152 ambulance transport records in the Miyagi prefecture dating from February 11 to June 30 for each year from 2008 to 2011. Incidence records from before, during and after the disaster were compared, and earthquake aftershocks logged according to a seismic intensity of 1 or greater.
Results showed that the weekly occurrence of five conditions – heart failure (HF), acute coronary syndrome (ACS), stroke, cardiopulmonary arrest (CPA) and pneumonia – were considerably higher in the wake of the disaster than in the previous three years. The occurrence of HF and pneumonia showed a sustained increase for longer than six weeks following the tsunami, whereas those of ACS and CPA showed a rapid increase followed by a sharp decline. It was also found that the incidence of stroke and CPA increased when an aftershock of magnitude 7.0 hit on April 7, 2011.
According to Dr. Shimokawa, neither age, sex nor area of residence had a significant impact on the occurrence of CV events during or following the tsunami. The disruption to transport following the tsunami delayed the delivery of medications such as antihypertensive or antithrombotic drugs, which may have contributed to the significant climb in CV events. There was also a jump in the occurrence of ventricular tachyarrhythmias in patients with implantable cardiac defibrillators. At the European Society of Cardiology Congress in Munich, Dr. Shimokawa reported that in 2008 the incidence of confirmed cardiovascular disease (CVD) diagnoses in the Miyagi prefecture was 17,000. This increased to 20,000 diagnoses in 2011. Taken all together, Dr. Shimokawa believes that the discontinuation of drugs combined with patients’ rising blood pressure and the increased occurrence of tachyarrhythmia and infections contributed to the increased incidence of CV events.
When it comes to natural disasters such as earthquakes, hurricanes and tornadoes, the resulting disruptions are shown to have a negative impact on the health of the affected population. It is widely accepted through medical research that post-traumatic stress, which is induced by such events, may increase the risk of CV events. As a result, patients who have previously gone undiagnosed with CVD may come to light in the aftermath of such disasters. Accordingly, it is possible that the aftermath of Hurricane Isaac may trigger a surge in the number of CV events and the amount of patients diagnosed with CVD, but when compared to Japan’s 2011 earthquake, the scale is likely to be less substantial.