Cardiac toxicity of chemotherapy for breast cancer: do angiotensin-converting enzyme inhibitors and beta blockers protect?

Cardiotoxicity is a relatively frequent and potentially serious side effect of anticancer treatments, particularly anthracyclines and trastuzumab, widely used in the treatment of breast cancer. The increase in cancer survivors has generated a growing interest in the prevention of cardiotoxicity. Although early studies suggested an overall benefit on cardiac function with the use of ACE inhibitors (ACEIs) and beta blockers (BBs), more recent randomized trials have demonstrated little or no effect of pharmacological interventions.

Prevention of chemotherapy-induced left ventricular dysfunction.

Prevention of left ventricular dysfunction predominantly induced by anthracyclines and/or trastuzumab still represents a challenge for cardio-oncology today. Indeed, this complication threatens to limit the significant gain in cancer survival achieved to date. Oncology strategies with cumulative dose limitation, continuous infusion, dexrazoxane, and liposomal formulations have been shown to decrease the risk of anthracycline cardiotoxicity.

Ventricular dyssynchrony: 12-month evaluation in ischemic versus nonischemic CRT patients.

Objective: Few data exist about the potential differences in the dyssynchrony status of cardiac resynchronization therapy (CRT) candidates stratified by etiology of heart failure, and about the evolution of dyssynchrony at long-term follow-up. We provided a description of intra-ventricular dyssynchrony at baseline, 6 months and 12 months in ischemic and nonischemic CRT patients.

Methods: Tissue Doppler Imaging was performed in 35 CRT candidates (18 ischemic, 17 nonischemic) at baseline, and at 6-month and 12-month follow-up.

Effects of pink grapefruit juice on QT variability in patients with dilated or hypertensive cardiomyopathy and in healthy subjects.

Recent evidence shows that pink grapefruit juice, which is a recommended dietary addition that contains high amounts of the antioxidant flavonoid naringenin, prolongs the corrected QT (QT(c)), a noninvasive electrophysiological marker of spatial myocardial repolarization, and does so by inhibiting the rapid component of the delayed rectifier K+ current (I(Kr)). Prompted by the observation that all class III antiarrhythmic drugs inhibit this current, thereby sometimes provoking torsades de pointes, we compared the effects of a liter of freshly squeezed pink grapefruit juice with those of 2 commonly used class III antiarrhythmics amiodarone and sotalol on the major noninvasive markers of temporal variability in myocardial repolarization used to stratify the risk of sudden death from malignant ventricular arrhythmias. In 32 subjects, 10 with postischemic dilated cardiomyopathy, 12 with hypertensive cardiomyopathy, and 10 healthy, we assessed QT(c) and QT variability index (QTVI) after administration of fresh pink grapefruit juice, placebo, amiodarone, or sotalol.

Increased QT variability in young asymptomatic patients with beta-thalassemia major.

Background: Despite recent progress in iron chelation therapy, sudden cardiac death due to malignant ventricular arrhythmias remains a vexing, clinical problem in patients with beta-thalassemia major (TM). In this study we assessed whether the major indices of QT variability, emerging tools for risk stratification of sudden cardiac death, differ in young asymptomatic patients with TM and healthy persons.

Methods: Thirty patients with TM and 30 healthy control subjects underwent a 5-min electrocardiography recording to calculate the following variables: QT variance (QT(v)), QT(v) normalized for mean QT (QTVN) and QT variability index (QTVI).

QT variability strongly predicts sudden cardiac death in asymptomatic subjects with mild or moderate left ventricular systolic dysfunction: a prospective study.

Aims: The most widely accepted marker for stratifying the risk of sudden cardiac death (SCD) in post myocardial infarction patients is a depressed left ventricular function. Left ventricular ejection fractions (EF) of 35% or less increase the risk of sudden death but values between 35 and 40% raise concern. The underlying pathophysiological mechanism is sustained ventricular tachycardia or fibrillation, both associated with increased cardiac repolarization variability.

Age and QT variability index during free breathing, controlled breathing and tilt in patients with chronic heart failure and healthy control subjects.

Unlabelled: The QT variability index (QTVI) indicates temporal dispersion in myocardial repolarization, and a high QTVI is associated with a propensity for sudden death from malignant ventricular arrhythmias in subjects at high risk. In this study, the authors assessed the effects of free breathing, controlled breathing, and sympathetic stress (tilt) on the QTVI in patients with chronic heart failure (CHF) and healthy control subjects. The authors also examined the influence of age on the same variables.

Influence of cardiac-resynchronization therapy on heart rate and blood pressure variability: 1-year follow-up.

Background: Several studies have shown that cardiac-resynchronization therapy (CRT) improves haemodynamic function, cardiac symptoms, and heart rate variability (HRV) and reduces the risk of mortality and sudden death in subjects with chronic heart failure (CHF). In subjects with CHF, power spectral values for the low-frequency (LF) component of RR variability < or =13 ms2, are associated with an increased risk of sudden death.

Aims And Methods: To assess whether spectral indexes obtained by power spectral analysis of HRV and systolic blood pressure (SBP) variability could predict malignant ventricular arrhythmias in patients with severe CHF treated with an implantable cardioverter-defibrillator (ICD) alone or with ICD+CRT.

Power spectral analysis of heart rate variability as a predictive test in choosing the most effective length for tilt-training.

Background: In patients with refractory neurally mediated syncope, tilt training--standing motionless against a wall for increased periods of time per day over one month--can often eliminate recurrent episodes and reduce presyncopal symptoms. We designed dual retrospective and prospective studies to assess cardiovascular autonomic function in subjects with recurrent syncope and identify the most effective length of tilt training between one and three months.

Methods And Results: In the retrospective study, before tilt training, and in the prospective study, before and after training, all subjects underwent a recording for short-term spectral analysis of heart rate and systolic blood pressure variability.

Autonomic cardiovascular control and diastolic dysfunction in hypertensive subjects.

Background: Early hypertension is associated with left ventricular diastolic dysfunction due to increased end-diastolic pressure. This increase, through the cardiopulmonary reflexes, can influence autonomic cardiovascular control.

Methods: We assessed autonomic nervous system modulation of cardiovascular signals by power spectral analysis of RR interval and systolic arterial pressure variabilities in subjects with recently diagnosed hypertension with or without diastolic dysfunction and in normotensive control subjects.

Factors influencing heart rate variability power spectral analysis during controlled breathing in patients with chronic heart failure or hypertension and in healthy normotensive subjects.

A decreased LFP (low-frequency power) spectral component of HRV [HR (heart rate) variability] is a risk factor for sudden death in patients with CHF (chronic heart failure). In the present study, we evaluated factors (age, arterial pressures and HR) influencing LFP and HFP (high-frequency power) components in short-term recordings during controlled breathing in patients with CHF or hypertension, and healthy normotensive subjects. In patients with CHF, we also compared LFP values with known markers of sudden death [NYHA (New York Heart Association) class, HR and ejection fraction].