When an acute exacerbation has to be managed, a serious problem is that the COPD patient is rarely only “COPD patient”. Comorbidities are frequent in COPD and 12 of them negatively influence survival.For example, COPD and CHD share a common major risk factor, which is smoking. The coexistence has been reported as high as 30% or even higher in COPD patients.In some studies of COPD patients’ medical records, the undiagnosed cases of CHD have reached 70%.Also, AF and COPD are two common morbidities and often coexist.The presence and severity of COPD are associated with increased risk for AF/atrial flutter and nonsustained ventricular tachycardia. The prevalence of AF and nonsustained ventricular tachycardia among COPD patients has been reported to be as high as 23.3% and 13.0%, respectively.