Electrocardiography and cardio-oncology

Key points

• Baseline ECG in any cardiac or extracardiac tumors is mandatory since therapeutic side effects of chemotherapy on heart are proven.

• Comprehensive understanding of the cardiac effect of anticancer agents is mandatory to predict side effects and prevent irreversible damage.

Introduction

While life expectancy and quality of life have improved dramatically in this era of new oncology treatments, longer lifespan comes with its own set of issues and complications associated with new chemotherapy agents.

Although there are several techniques and modalities for detecting cardiac damage, such as echocardiography, nuclear medicine, and also measuring various biomarkers, the ECG is a simple, inexpensive, and rapid tool that can be used to diagnose clinical or subclinical cardiac damage prior to the progression of advanced cardiovascular disease. The electrocardiogram (ECG) can provide valuable information regarding the heart chambers, ischemia, and arrhythmia, among many other aspects. These alterations can be noticed prior to the onset of serious side effects from advanced treatment. For instance, anomalies in the left atrium caused by increased left ventricular end diastolic pressure (LVEDP) can be a prelude to atrial fibrillation ( Fig. 4.1 ), while a prolonged QT interval can signal Torsade de points and other dangerous cardiac arrhythmias .

Atrial fibrillation after developing multiepisodes of frequent PACs and atrial tachycardia in a patient who receives anthracycline.

There are many clues to modify chemotherapy according to ECG. These ECG changes such as frequent premature atrial contraction (PAC) or premature ventricular contraction (PVC) may be signals of further atrial fibrillation or malignant ventricular arrhythmia, respectively, which will be relieved by reducing chemotherapy drug doses. Also agents such as 5 fluorouracil and interleukin can make coronary spasm with its own changes on ECG ( Fig. 4.2 ).