Blunt Cardiac Trauma Review.

Patients suffering blunt cardiac trauma vary widely in the severity of their condition on presentation. Although some may present with mild sternal bruising, others may present with acute valvular rupture or malignant arrhythmia. Disposition for these patients ranges from discharge home to admission for urgent cardiac surgery. This article discusses some of the common types of blunt cardiac trauma and reviews the current literature and guidelines for their triage and initial management.

Cardiac sarcoidosis: electrophysiological outcomes on long-term follow-up and the role of the implantable cardioverter-defibrillator.

OBJECTIVES: The objectives of this study were to identify the predictors of life-threatening ventricular arrhythmias in patients with cardiac sarcoidosis (CS) and to evaluate the role of the implantable cardioverter-defibrillator (ICD) in this patient population. BACKGROUND: ICD implantation is a class IIA recommendation for patients with CS. However, some indications for ICD implantation in CS patients are still unclear and not enough data are available to establish predictors of malignant ventricular tachyarrhythmias in this group of patients. METHODS: We retrospectively identified all consecutive patients who were diagnosed with CS, during the period from March 2002 to April 2010. Cardiac rhythm devices were regularly interrogated and clinical data recorded during follow-up visits. RESULTS: Thirty-three patients (17 male) with CS were identified. The mean age was 53 ± 11. The mean left ventricular ejection fraction (LVEF) was 41 ± 18%. Thirty patients received an ICD. Twelve patients (36.3%) had sustained ventricular arrhythmias. Eleven patients received appropriate therapies and 9 patients received inappropriate shocks, representing 36.7% and 30.0% of the ICD population, respectively. Patients who received appropriate ICD therapies were younger with mean age 47.4 ± 7.8, and had a lower mean LVEF 33.0 ± 12.0 compared to those who did not receive ICD therapies (P = 0.0301 and 0.0341, respectively). There were no other demographic, clinical, electrocardiographic, electrophysiological, or imaging markers that predicted the future occurrence of appropriate ICD therapies in our cohort of patients. CONCLUSIONS: CS is strongly associated with malignant ventricular arrhythmias. No specific predictors of such tachyarrhythmias emerged, other than young age and low LVEF.

Idiopathic ventricular fibrillation in a 10-year-old boy: technical aspects of radiofrequency ablation and utility of antiarrhythmic therapy.

Idiopathic ventricular fibrillation (VF) is defined as spontaneous VF in the absence of structural heart disease. No prior reports exist addressing the technical aspects of idiopathic VF ablation in a child. We present the case of a 10-year-old boy with idiopathic VF, who presented a unique management challenge, particularly as regards the technical aspects of the ablation procedure. Ablation of idiopathic VF is feasible in a 10-year-old boy and oral quinidine seems more effective than other antiarrhythmic drugs in this condition.

Defibrillation threshold testing in patients with hypertrophic cardiomyopathy.

INTRODUCTION: Implantable cardioverter-defibrillators (ICDs) decrease sudden cardiac death in patients with hypertrophic cardiomyopathy (HCM). One of the vital aspects of ICD implantation is the demonstration that the myocardium can be reliably defibrillated, which is defined by the defibrillation threshold (DFT). We hypothesized that patients with HCM have higher DFTs than patients implanted for other standard indications. METHODS: We retrospectively reviewed the medical records of patients implanted with an ICD at the University of Maryland from 1996 to 2008. All patients with HCM who had DFTs determined were included. Data were compared to selected patients implanted for other standard indications over the same time period. All patients had a dual-coil lead with an active pectoral can system and had full DFT testing using either a step-down or binary search protocol. RESULTS: The study group consisted of 23 HCM patients. The comparison group consisted of 294 patients. As expected, the HCM patients were younger (49 ± 18 years vs 63 ± 12 years; P < 0.00001) and had higher left ventricular ejection fractions (66% vs 32%; P < 0.000001). The average DFT in the HCM group was 13.9 ± 7.0 Joules (J) versus 9.8 ± 5.1 J in the comparison group (P = 0.0004). In the HCM group, five of the 23 patients (22%) had a DFT ≥ 20 J compared to 19 of 294 comparison patients (6%). There was a significant correlation between DFT and left ventricle wall thickness in the HCM group as measured by echocardiography (r = 0.44; P = 0.03); however, there was no correlation between DFT and QRS width in the HCM group (r = 0.1; P = NS). CONCLUSIONS: Our results suggest that patients with HCM have higher DFTs than patients implanted with ICDs for other indications. More importantly, a higher percentage of HCM patients have DFTs ≥ 20 J and the DFT increases with increasing left ventricle wall thickness. These data suggest that DFT testing should always be considered after implanting ICDs in HCM patients.

The influence of fat thickness on the human epicardial bipolar electrogram characteristics: measurements on patients undergoing open-heart surgery.

AIMS: Reference values exist for endocardial but not for epicardial (EPI) substrate mapping in cases of cardiomyopathy-associated ventricular tachycardia. We sought to establish such values for EPI electrogram voltage, including areas with overlying fat. METHODS AND RESULTS: Ten patients (six males) undergoing cardiac surgery were studied. After opening the pericardium, the distal bipole of an electrophysiology catheter was placed tangential to the EPI surface to obtain an electrogram recording. The bipole was tangentially rotated 90 degrees and the higher of the two amplitudes (mV) was taken as the local amplitude. Recordings were taken from normal left and right ventricular myocardium (n = 26 data points each), over thick (> or = 0.5 cm) fat at both ventricular bases (n = 16) and thin (<0.5 cm) fat at the mid-ventricular level (n = 32). A total of 100 recordings (mean 10/patient) were analysed. Four patients underwent valvular surgery, three bypass surgery, and three combined procedures. Mean age was 61.7 +/- 10.4 years and mean left ventricular ejection fraction was 46 +/- 12%. Electrogram amplitude was inversely related to EPI fat thickness. Over thick fat, 31% of recordings were <0.5 mV. CONCLUSION: Human EPI electrogram amplitude varies by ventricular chamber and significantly by EPI fat thickness. A cut-off of 0.5 mV to define 'scar' will include normal areas with thick overlying fat. EPI substrate maps should include data on EPI fat thickness for higher specificity.