Potential of non-antiarrhythmic drugs to provide an innovative upstream approach to the pharmacological prevention of sudden cardiac death

Public Knowledge and Attitudes towards Bystander Cardiopulmonary Resuscitation in China

The rate of bystander CPR is much lower in China than in developed countries. This survey was implemented to assess the current status of layperson CPR training, to analyze the willingness of bystanders to perform CPR, and to identify barriers to improving bystander CPR rates. The questionnaire included individual information, current status of bystander CPR training, and individual's willingness and attitude towards performing CPR. There were 25.6% laypersons who took CPR training. The majority (98.6%) of laypersons would perform CPR on their family members, but fewer laypersons (76.3%) were willing to perform CPR on strangers. Most respondents (53.2%) were worried about legal issues. If laws were implemented to protect bystanders who give aid, the number of laypersons who were not willing to perform CPR on strangers dropped from 23.7% to 2.4%. An increasing number of people in China know CPR compared with the situation in the past. CPR training in China is much less common than in many developed countries. The barriers are that laypersons are not well-trained and they fear being prosecuted for unsuccessful CPR. More accredited CPR training courses are needed in China. The laws should be passed to protect bystanders who provide assistance.

Sudden death due to the atrioventricular node contusion: Three cases report

INTRODUCTION

Atrioventricular node (AVN) contusion usually results in cardiogenic shock and arrhythmia and is a rare but fatal condition. The condition is difficult to diagnose and easily overlooked because it develops rapidly and is asymptomatic. We here report 3 cases that demonstrate blunt chest impact and hemorrhages of the posterior atrioventricular junction, eventually result in death.

CLINICAL FINDINGS

Autopsy and histological examination were performed on all cases. External inspection revealed bruises in the hearts and fractures in the sternum and ribs. However, histological examinations were conclusive and showed cardiac contusion on the surface of the posterior atrioventricular junction of the individuals, and the death was due to the AVN contusion. The position of the AVN on the heart surface is determined by detailed examinations via an autopsy and microscopic, both of which are critical in the certification of cause of death.

CONCLUSION

The report is intended to raise our understanding and make forensic pathologists aware of the surface of the posterior atrioventricular junction.

Clinical management and prevention of sudden cardiac death

Despite the revolutionary advancements in the past 3 decades in the treatment of ventricular tachyarrhythmias with device-based therapy, sudden cardiac death (SCD) remains an enormous public health burden. Survivors of SCD are generally at high risk for recurrent events. The clinical management of such patients requires a multidisciplinary approach from postresuscitative care to a thorough cardiovascular investigation in an attempt to identify the underlying substrate, with potential to eliminate or modify the triggers through catheter ablation and ultimately an implantable cardioverter-defibrillator (ICD) for prompt treatment of recurrences in those at risk. Early recognition of low left ventricular ejection fraction as a strong predictor of death and association of ventricular arrhythmias with sudden death led to significant investigation with antiarrhythmic drugs. The lack of efficacy and the proarrhythmic effects of drugs catalyzed the development and investigation of the ICD through several major clinical trials that proved the efficacy of ICD as a bedrock tool to detect and promptly treat life-threatening arrhythmias. The ICD therapy is routinely used for primary prevention of SCD in patients with cardiomyopathy and high risk inherited arrhythmic conditions and secondary prevention in survivors of sudden cardiac arrest. This compendium will review the clinical management of those surviving SCD and discuss landmark studies of antiarrhythmic drugs, ICD, and cardiac resynchronization therapy in the primary and secondary prevention of SCD.

Repolarization effects of multiple-cycle chemotherapy and predictors of QTc prolongation: a prospective female cohort study on >2000 ECGs

PURPOSE

Oncological patients are at increasing risk of QT prolongation, a risk factor for ventricular arrhythmia. We assessed impact and risk factors for corrected QT (QTc) prolongation during multiple-cycle chemotherapy.

METHODS

We enrolled 100 outpatients initiating chemotherapy in a university center specializing in female cancer. Clinical, drug, laboratory, and 12-lead ECG data collection at baseline and at each chemotherapy cycle was performed.

RESULTS

Enrolled patients were followed for 992 chemotherapy cycles (median 7; interquartile range 6-13); 2438 ECGs were recorded (20; 18-31) 36.8% pre-therapy, 36.8% following chemotherapy, and 22.5% 7-10 days after chemotherapy. Maximum QTc (Max-QTc) was recorded after 4 chemotherapy administrations in >50% of the entire cohort and also within every subset of patients with prolonged QTc (57% 471-480 ms; 54% 481-500 ms; 66% >500 ms). No cumulative effect on QTc was shown. QTc prolongation was comparable among the various protocols. Prophylactic/supportive drugs were not associated with additional QTc prolongation. Variables independently associated with QTc prolongation >470 ms were age (OR 1.056 95% CI 1.006-1.108, p = 0.028) and the baseline-first chemotherapy averaged QTc (BC-QTc) (OR 1.092 95% CI 1.051-1.136), a novel parameter devised for this study. Only BC-QTc maintained significance for QTc >480 ms. BC-QTc >435 ms identified 100 % of patients with Max-QTc >500 ms, 96% with Max-QTc 481-500 ms, and 66% with Max-QTc 471-480 ms. Only 29% of patients with Max-QTc ≤470 ms presented a BC-QTc >435 ms.

CONCLUSIONS

Our results confirm the high prevalence of QTc prolongation after chemotherapy. Most of the patients reached Max-QTc after several cycles. BC-QTc may help in stratifying arrhythmic risk in real-world clinical practice.

Cardiac arrest: a public health perspective

This article reviews out-of-hospital cardiac arrest from a public health perspective. Case definitions are discussed. Incidence, outcome, and fixed and modifiable risk factors for cardiac arrest are described. There is a large variation in survival between communities that is not explained by patient or community factors. Study of variation in outcome in other related conditions suggest that this is due to differences in organizational culture rather than processes of care. A public health approach to improving outcomes is recommended that includes ongoing monitoring and improvement of processes and outcome of care.

Effects of early losartan therapy on ventricular late potentials in acute myocardial infarction

BACKGROUND

Ventricular late potentials (LPs) obtained by the signal-averaged electrocardiogram (SAECG) have prognostic significance as independent predictors of arrhythmic events after an acute myocardial infarction (AMI). Angiotensin receptor blockers reduce the overall mortality and risk of sudden cardiac death in postinfarction patients. The aim of this study was to investigate the effect of early losartan therapy on ventricular LPs, a noninvasive method for the evaluation of arrhythmogenic substrates in AMI patients.

METHODS

The study included 97 patients with their first AMI. Forty-eight patients (39 men and 9 women, aged 58.8 +/- 13.19 years), received early losartan therapy. The control group consisted of 49 patients (38 men and 11 women, aged 59.55 +/- 11.0 years), did not received early losartan therapy. The SAECG was performed at admission and day 14.

RESULTS

The baseline clinical, angiographic characteristics, and reperfusion methods were similar in both groups. The baseline SAECG findings were also similar in the two groups. There was a significant decrease in the rate of LP, between the first and last SAECG recordings, after reperfusion therapy in the losartan group. All of the parameters of LPs were significantly improved in the losartan group on the last SAECG recordings.

CONCLUSION

The results of this study showed that losartan treatment, early after an AMI, reduced the incidence of LP and may thus favorably affect arrhythmia substrates.

Prevention of atrial fibrillation following cardiac surgery: basis for a novel therapeutic strategy based on non-hypoxic myocardial preconditioning

Atrial fibrillation is the most common complication of cardiac surgical procedures performed with cardiopulmonary bypass. It contributes to increased hospital length of stay and treatment costs. At present, preventive strategies offer only suboptimal benefits, despite improvements in anesthesia, surgical technique, and medical therapy. The pathogenesis of postoperative atrial fibrillation is considered to be multifactorial. However oxidative stress is a major contributory factor representing the unavoidable consequences of ischemia/reperfusion cycle occurring in this setting. Considerable evidence suggests the involvement of reactive oxygen species (ROS) in the pathogenic mechanism of this arrhythmia. Interestingly, the deleterious consequences of high ROS exposure, such as inflammation, cell death (apoptosis/necrosis) or fibrosis, may be abrogated by a myocardial preconditioning process caused by previous exposure to moderate ROS concentration known to trigger survival response mechanisms. The latter condition may be created by n-3 PUFA supplementation that could give rise to an adaptive response characterized by increased expression of myocardial antioxidant enzymes and/or anti-apoptotic pathways. In addition, a further reinforcement of myocardial antioxidant defenses could be obtained through vitamins C and E supplementation, an intervention also known to diminish enzymatic ROS production. Based on this paradigm, this review presents clinical and experimental evidence supporting the pathophysiological and molecular basis for a novel therapeutic approach aimed to diminish the incidence of postoperative atrial fibrillation through a non-hypoxic preconditioning plus a reinforcement of the antioxidant defense system in the myocardial tissue.