Acute arrhythmogenicity of first-dose chemotherapeutic agents in children

ECG Markers of Cardiovascular Toxicity in Adult and Pediatric Cancer Treatment

When a cardiologist is asked to evaluate the cardiac toxic effects of chemotherapy, he/she can use several tools: ECG, echocardiography, coronary angiography, ventriculography, and cardiac MRI. Of all these, the fastest and easiest to use is the ECG, which can provide information on the occurrence of cardiac toxic effects and can show early signs of subclinical cardiac damage. These warning signs are the most desired to be recognized by the cardiologist, because the dose of chemotherapeutics can be adjusted so that the clinical side effects do not occur, or the therapy can be stopped in time, before irreversible side effects. This review addresses the problem of early detection of cardiotoxicity in adult and pediatric cancer treatment, by using simple ECG recordings.

Long-term cardiac and pulmonary complications of cancer therapy

Cardiac complications resulting from chemotherapy and radiation pose a significant risk for morbidity and mortality to the cancer survivor. Cardiac side effects may progress over time and are a concern for patients treated during childhood. Long-term pulmonary complications are relatively infrequent, and acute respiratory effects of drugs (mostly bleomycin) or radiation normally resolve early after therapy. Although most cardiovascular risk statistics and clinical experience are derived from patients treated before 1985, the modern radiation approach that limits the exposure of the heart and reduces the total dose seems to attenuate the previously observed cardiovascular risk. Potential preventive measures for high-risk patients are of increasing interest but remain experimental.

Cardiac involvement in an adolescent with acute lymphoblastic leukemia

Cardiac complications of the pediatric patients with acute leukemia are common. Most of the cardiac complications may be due to chemotherapeutics such as antracyclins, besides anemia, infections, or direct leukemic infiltrations of the heart. It is reported that leukemic infiltration is frequent in the postmortem examination of the myocardium and pericardium. However, at the antemortem examination, pericardial involvement is rare and there is no myocardial involvement reported at the time of diagnosis in patients with acute leukemia in the English literature. Here, the authors report an adolescent with acute lymphoblastic leukemia who had myocardial infiltration at the time of diagnosis.

Electrocardiographic findings after 5-HT3 receptor antagonists and chemotherapy in children with cancer

BACKGROUND

The antiemetic efficacy of serotonin-type 3 (5-HT3) receptor antagonists has been found to be superior to older antiemetic drugs in cancer patients. Following the administration of these agents, changes in ECG parameters and increased or decreased heart rates have been demonstrated, but there is no sufficient data in children with cancer who are treated with cytotoxic agents. The objective of this study is to evaluate the ECG changes after administration of 5-HT3 receptor antagonists and chemotherapeutic agents in children with cancer.

PROCEDURE

Thirty-eight patients with an age range between 2 and 19 years receiving chemotherapy for solid tumors were included in the study. The patients received 5-HT3 receptor antagonists 30 min before antineoplastic agents in 83 chemotherapy days. Antiemetic therapy consisted of ondansetron in 43 and granisetron in 40 chemotherapy days. Twelve-leads ECGs were obtained four times at the first day of each chemotherapy: just before 30, 90 min, and 24 hr after 5-HT3 receptor antagonists were given. Rate, rhythm, PR interval, QRS duration, ST segment, the shortest (QTca) and the longest (QTcb) QTc intervals with QTc dispersion (QTcd) were all evaluated.

RESULTS

We found a significant shortening of the PR interval and QRS complex durations in the granisetron group at 90th min and at 24th hr, respectively. Also, granisetron infusion caused a significant prolongation of the QTca interval at 90 min.

CONCLUSION

Although we observed minor ECG changes after 5-HT3 receptor antagonists and chemotherapy, neither dangerous rhythm disturbances nor serious ECG changes were seen.

Study of Cardiac Rate and Rhythm Patterns in Ambulatory and Hospitalized Children

Our aim was to underline possible differences in heart rate and rhythm patterns between ambulatory and hospitalized children. Holter monitoring was performed on 264 healthy ambulatory children and on 112 children who were hospitalized for noncardiotoxic conditions. Maximal, mean and minimal heart rates decreased with age. Maximal heart rate was significantly higher in ambulatory schoolchildren and adolescents than in hospitalized ones. Sinus arrhythmia was noted on every recording. Some children had episodes of first- or second-degree atrioventricular block while sleeping. Supraventricular and uniform ventricular extrasystoles were common. The incidence of all types of arrhythmia and conduction disturbances was similar in ambulatory and hospitalized children. These data can be taken as a basis for the analysis of 24-hour electrocardiogram monitoring in ambulatory but also in hospitalized children.

Late cardiac evaluation of children with solid tumors after anthracycline chemotherapy

BACKGROUND

The therapeutic potential of anthracycline antibiotics is limited by their cardiotoxicity. Electrocardiography, exercise testing, and two-dimensional echocardiography are non-invasive techniques used in the follow-up of children for cardiotoxicity. Plasma B-type natriuretic peptide (BNP) levels are thought to be useful markers in the early detection of AC induced cardiomyopathy.

PROCEDURE

We evaluated cardiac status of 34 patients with solid tumors treated with anthracycline antibiotics. All of the patients were asymptomatic and had no evidence of residual malignancy. They were evaluated by electrocardiography, exercise testing, echocardiography, and plasma BNP levels measured before and after the exercise testing.

RESULTS

Electrocardiography revealed only minor abnormalities of little clinical significance. All of the patients completed the exercise testing without complication, and the duration of the exercise for each patient was between normal limits. Cardiac output (CO) and wall stress (WS) were significantly increased in patients, than in controls in echocardiographic evaluation of systolic functions (P < 0.001). Diastolic filling patterns showed various abnormalities; M-E, M-A, T-E, T-A, AT, and IVRT were significantly higher than those of controls. Mean plasma BNP levels of the patients (10.56 +/- 10.22 pg/ml) were significantly higher than BNP levels of the healthy controls (4.09 +/- 2.26 pg/ml) (P < 0.016), before exercise testing. The mean plasma BNP levels of the patients (15.70 +/- 14.06 pg/ml) were higher than resting state after exercise testing, but it was not statistically significant (P > 0.05).

CONCLUSION

Our findings demonstrated that echocardiographic and biochemical abnormalities could be found even at low cumulative doses of AC antibiotics. The use of serial echocardiographic studies and plasma BNP determinations to identify high-risk patients for cardiotoxicity needs to be verified by additional studies.