American College of Cardiology/American Heart Association Clinical Competence Statement on invasive electrophysiology studies, catheter ablation, and cardioversion: A report of the American College of Cardiology/American Heart Association/American College of Physicians-American Society of Internal Medicine Task Force on Clinical Competence

The role of aortic compliance in determination of coarctation severity: Lumped parameter modeling, in vitro study and clinical evaluation

Early detection and accurate estimation of the extent of coarctation of the aorta (COA) is critical to long-term outcome. Peak-to-peak trans-coarctation pressure gradient (PKdP) higher than 20mmHg is an indication for interventional/surgical repair. Patients with COA have reduced proximal and distal aortic compliances. A comprehensive study investigating the effects of variations of proximal COA and systemic compliances on PKdP, and consequently on the COA severity evaluation has never been done. This study evaluates the effect of aortic compliance on diagnostic accuracy of PKdP. Lumped parameter modeling and in vitro experiments were performed for COA severities of 50%, 75% and 90% by area. Modeling and in vitro results were validated against retrospective clinical data of PKdP, measured in 54 patients with COA. Modeling and in vitro. PKdP increases with reduced proximal COA compliance (+36%, +38% and +53% for COA severities of 50%, 75% and 90%, respectively; p<0.05), but decreases with reduced systemic compliance (-62%, -41% and -36% for COA severities of 50%, 75% and 90%, respectively; p<0.01). Clinical study. PKdP has a modest correlation with COA severity (R=0.29). The main determinants of PKdP are COA severity, stroke volume index and systemic compliance. Systemic compliance was found to be as influential as COA severity in PKdP determination (R=0.30 vs. R =0.34). In conclusion, PKdP is highly influenced by both stroke volume index and arterial compliance. Low values of PKdP cannot be used to exclude the severe COA presence since COA severity may be masked by reduced systemic compliance and/or low flow conditions.

Reliability of a 25-item low-stakes multiple-choice assessment of bronchoscopic knowledge

BACKGROUND

A need for improved patient safety, quality of care, and accountability has prompted the development of competency-based educational processes. Assessment tools related to bronchoscopy training, however, have not yet been developed or validated.

PURPOSES

To determine whether 25 multiple-choice questions (MCQs) extracted from the free, Web-based Essential Bronchoscopist (EB) learning guide qualify in their original form as a preliminary pool of questions for a low-stakes assessment of bronchoscopic knowledge.

MATERIALS AND METHODS

Twenty-five randomly selected MCQs from among the top 70 question-answer sets of the EB were administered to 40 self-declared novice bronchoscopists (n = 13), experienced bronchoscopists (n = 21), and expert bronchoscopists (n = 6). A difficulty index and a discrimination index (DI) were calculated for each item. Internal consistency reliability was calculated using item-total correlation and Cronbach alpha. Content validity was determined by five independent experts. Ideal test items based on a difficulty index and item-total correlation were administered to a different group of 24 bronchoscopists to prospectively reassess internal consistency reliability.

RESULTS

The mean (+/- SD) score for the 40 participants was 16.47 +/- 3.72 (median score, 17; score range, 7 to 22). The mean difficulty index was 0.65 +/- 0.22, and the mean DI was 0.52 +/- 0.28. Item total-correlations ranged from - 0.01 to + 0.71. Test content was unanimously validated. The Cronbach alpha was 0.69. There was no significant correlation between scores and the number of bronchoscopies performed or self-declared expertise. Eleven ideal test MCQs were identified. The internal consistency of these items remained satisfactory (Cronbach alpha = 0.75) when assessed prospectively in a different cohort.

CONCLUSION

Reliable and valid MCQs were identified to initiate a preliminary pool of questions for a low-stakes assessment of bronchoscopic knowledge.

Atrial flutter: a focus on treatment options for a common supraventricular tachyarrhythmia

Atrial flutter (AFl), a re-entrant atrial tachycardia, is a cardiac rhythm disturbance that arises in the upper chambers of the heart. This usually non-life-threatening condition can be treated by a number of medical intervention strategies, which include electrical cardioversion, pharmacological therapy, and catheter ablation. These options have been available in clinical practice for a number of years. However, catheter ablation, in the form of radiofrequency catheter ablation and cryo catheter ablation, is increasingly utilised as a first-line treatment option for AFl in certain patients. The purpose of this review article is two-fold: first, to briefly present an overview of AFl and the more familiar treatment options for this arrhythmia, and second to provide more in-depth coverage of catheter ablation technologies as a treatment option for patients with AFl. As part of the latter objective, recent clinical studies documenting the use of radiofrequency catheter ablation and cryo catheter ablation for AFl are presented and their results briefly discussed.

Ineffectiveness of Precordial Thump for Cardioversion of Malignant Ventricular Tachyarrhythmias

BACKGROUND

The Precordial Thump (PT) is commonly used for cardiopulmonary resuscitations both in and out of hospitals. However, the support for its efficiency relies mainly on sporadic cases. In this current prospective large study, we tested the effectiveness and safety of PT in a wide range of malignant ventricular tachyarrhythmias.

METHODS

The study included 80 patients who underwent electrophysiological study and/or implantation of a cardiodefibrillator device. During these procedures, once a malignant ventricular tachyarrhythmia was induced, PT was used as the first treatment option. If the PT failed, other means were used to discontinue the arrhythmia.

RESULTS

Polymorphic ventricular tachycardia occurred in 32 (40%) patients, ventricular fibrillation in 28 (35%) patients, and 20 (25%) patients had sustained monomorphic ventricular tachycardia. Except in one patient with monomorphic ventricular tachycardia, the PT was unsuccessful in terminating any of the other malignant tachyarrhythmias, and internal or external defibrillation was eventually required in all other 79 (99%) patients. The PT was not associated with any damage either to the sternal bone, ribs, or to the cardiodefibrillator device.

CONCLUSIONS

PT is not effective in terminating malignant ventricular tachyarrhythmia and should be reserved to a situation in which a defibrillator is not available.

Using Transthoracic Two-Dimensional Echocardiography to Guide the Placement of Coronary Sinus Catheters: A Randomized Study

OBJECTIVE

To assess the value of transthoracic echocardiography (TTE) as an image guide in placing a coronary sinus catheter into the coronary sinus.

METHODS

Sixty consecutive patients undergoing electrophysiologic study were randomized to TTE (30 patients, "TTE group") or x-ray fluoroscopy (30 patients, "x-ray group") as an image guide to assist in the placement of a coronary sinus catheter.

RESULTS

The success rate of placing the coronary sinus catheter was 96.7% in TTE group and 100% in x-ray group (P > 0.05). The procedure duration was 5.8 +/- 5.7 minutes in TTE group and 5.9 +/- 3.3 minutes in x-ray group (P > 0.05), The x-ray exposure time was 0.15 +/- 0 minute in TTE group and 4.2 +/- 2.8 minutes in x-ray group (P < 0.0001).

CONCLUSION

Using TTE as an image guide, coronary sinus cannulation is feasible and as rapid as standard x-ray fluoroscopy, without the radiation risk.

Percutaneous Ablation for Atrial Fibrillation: The Role of Cross-sectional Imaging

Percutaneous ablation is a well-established technique for treating cardiac arrhythmia by removing or isolating tissue at the site of the abnormal impulse formation. Various forms of energy for ablation procedures may be delivered via a catheter with fluoroscopic guidance. The procedures most commonly performed are radiofrequency ablation and cryotherapy. Atrial fibrillation, the most frequently occurring supraventricular tachyarrhythmia, may be initiated by ectopic beats that originate in the ostia of the pulmonary veins. The clinical efficacy of isolation (or focal ablation) of the pulmonary veins for treatment of atrial fibrillation has been well demonstrated. Pre- and postprocedural examinations with computed tomography (CT) or magnetic resonance (MR) imaging are frequently performed to depict the anatomy and to obtain baseline measurements of the pulmonary veins to enable early detection of complications from ablation. Venous stenosis or thrombosis and pulmonary hypertension may occur after radio-frequency ablation. Familiarity with the appearance of normal anatomic variants at CT and MR imaging and with the normal range of pulmonary vein diameters is essential for preoperative management and early detection of procedure-related complications.