| Background: Cardiotoxicity caused by cancer therapy and cardiovascular events is a growing concern among cancer Survivors.Recently we had reported cancer is the independent risk factor to all-cause mortality in ALQTS.This study aims to determine characteristics in ALQTS patients with malignant cancer showing a markedly prolonged QT interval(QTc?500ms).Methods: Electronic medical records were reviewed to identify severe ALQTS(QTc?500ms)in Hospitalized patients in a single study center from 9-2013 to4-2016.The primary exclusion criterion was Congenital long QT syndrome family history,unexplained syncope,cardiac arrest and sudden death,QRS duration >120 ms,such as the presence of complete left/right bundle branch blocks,ECGs showing atrial fibrillation/flutter,2nd and complete AV blocks,sinus,atrial and ventricular tachyarrhythmia,and acute coronary syndrome with dynamic ST-T and QT changes were excluded from QT measurement.Clinical follow-up was performed in both ALQTS group(QTc ? 500 ms,n=150)and control group(290ms? QTc ? 440 ms,n=293).Subjects between ALQTS group and control group were comparable(age62±13 years vs.62±13 years,gender 58% F vs.58%F,p=NS).Clinical characteristics,ECG parameters,chemotherapy drugs or QT-prolonging medications,laboratory test results or other risk factors to cardiac mortality were also elucidated.The death of all causes occurred during hospital stay and after discharge was investigated in all study subjects.Cox regression and Kaplan-Meier survival analyses were performed to determine the effects of markedly prolonged QTc on all-cause mortality.Results:1)Follow up for 402±336 days,the ALQTS subjects with a markedly prolonged QTc(520±28 ms vs.422±15 ms,p<0.0001)had a much higher all-cause mortality than the control group(63.3% vs.33.4%,Log Rank p<0.001).2)More patients in the ALQTS group had a baseline condition of hypertension(29.3% vs.16.4%,p<0.05),infection(21.3% vs.5.1%,p< 0.001),Anemia(12.0%vs.1.4%,p<0.001),Gastrointestinal diseases(18.7% vs.11.6%,p<0.05)?Respiratory diseases(17.3%vs.6.8%,p<0.05),Neurologic diseases(10.7%vs.3.4%,p<0.05),Type 2 mellitus(16.0%vs.9.6%,p<0.05),Heart Rate(88±17bpm vs.72±12bpm,p<0.001),QRSD(86ms vs.82 ms,p<0.05),hypokalemia(31.7% vs.5.2%,p<0.001),hypocalcemia(22.7%vs.4.9%,p<0.001),QT-prolonging drugs(31.3%vs.6.8%,p<0.001),Antimicrotubule agents(36%vs.28%,p<0.05).3)Logistic regression analysis revealed hypertension(OR 2.420,95%CI 1.307-4.481,p < 0.05),infectious disease(OR 3.623,95%CI 1.542-8.513,p<0.05),anemia(OR4.814,95%CI1.309-17.714,p<0.05),Antimicrotubule agents(OR 2.794,95%CI1.622-4.813,p<0.05),hypokalemia(OR 6.273,95%CI 3.001-13.113,p<0.05),QT-prolonging drugs(OR 4.873,95%CI 2.435-9.752,p<0.05)may affect malignant cancer patients myocardial reporlarization.4)Age(HR 1.023,95%CI 1.002-1.044,p<0.05),Gastrointestinal diseases(HR 2.987,95%CI 1.714-5.205,p<0.05),Renal failure(HR7.492,95%CI 2.382-23.56,p<0.05),Hypokalemia(HR2.361,95%CI 1.465-3.806,p<0.05),Antimetabolites agents(HR 1.775,95%CI 1.019-3.093,p<0.05)are the major contributors to all-cause mortality in ALQTS.Conclusion: The all-cause mortality is high in cancer patients with ALQTS compared with cancer patients without ALQTS.Age,renal dysfunction,gastrointestinal disease,hypokalemia,Antimetabolites agents are the independent risk factors to all-cause mortality in cancer patients with ALQTS.Closely monitoring acquired factors associated with QT prolongation could reduce risk of arrhythmia events or sudden cardiac death. |
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