Comparison of radionuclide angiographic synchrony analysis to echocardiography and magnetic resonance imaging for the diagnosis of arrhythmogenic right ventricular cardiomyopathy.

BACKGROUND: Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a heritable arrhythmia syndrome entailing a high risk of sudden cardiac death. Discernment from benign arrhythmia disorders, particularly right ventricular outflow tract ventricular tachycardia (RVOT VT), may be challenging, providing an impetus to explore alternative modalities that may facilitate evaluation of patients with suspected ARVC. OBJECTIVE: We evaluated the role of equilibrium radionuclide angiography (ERNA) as a diagnostic tool for ARVC. METHODS: ERNA measures of ventricular synchrony-synchrony (S) and entropy (E)-were examined in patients with ARVC (n = 16), those with RVOT VT (n = 13), and healthy controls (n = 49). The sensitivity and specificity of ERNA parameters for ARVC diagnosis were compared with those of echocardiography (ECHO) and cardiovascular magnetic resonance (CMR). RESULTS: ERNA right ventricular synchrony parameters in patients with ARVC (S = 0.91 ± 0.07; E = 0.61 ± 0.1) differed significantly from those in patients with RVOT VT (S = 0.99 ± 0.01 [P = .0015]; E = 0.46 ± 0.05 [P < .001]) and healthy controls (S = 0.97 ± 0.02 [P = .003]; E = 0.48 ± 0.07 [P = .001]). The sensitivity of ERNA synchrony parameters for ARVC diagnosis (81%) was higher than that for ECHO (38%; P = .033) and similar to that for CMR (69%; P = .162), while specificity was lower for ERNA (89%) than that for ECHO and CMR (both 100%; P = .008). CONCLUSION: ERNA right ventricular synchrony parameters can distinguish patients with ARVC from controls with structurally normal hearts, and its performance is comparable to that of ECHO and CMR for ARVC diagnosis. These findings suggest that ERNA may serve as a valuable imaging tool in the diagnostic evaluation of patients with suspected ARVC.

Reduced ventricular volumes and improved systolic function with cardiac resynchronization therapy: a randomized trial comparing simultaneous biventricular pacing, sequential biventricular pacing, and left ventricular pacing.

BACKGROUND: Cardiac resynchronization therapy has emerged as an important therapy for advanced systolic heart failure. Among available cardiac resynchronization therapy pacing modes that restore ventricular synchrony, it is uncertain whether simultaneous biventricular (BiV), sequential BiV, or left ventricular (LV) pacing is superior. The Device Evaluation of CONTAK RENEWAL 2 and EASYTRAK 2: Assessment of Safety and Effectiveness in Heart Failure (DECREASE-HF) trial is the first randomized trial comparing these 3 cardiac resynchronization therapy modalities. METHODS AND RESULTS: The DECREASE-HF Trial is a multicenter trial in which 306 patients with New York Heart Association class III or IV heart failure, an LV ejection fraction < or = 35%, and a QRS duration > or = 150 ms were randomized to simultaneous BiV, sequential BiV, or LV pacing. LV volumes and systolic and diastolic function were assessed with echocardiography at baseline, 3 months, and 6 months. All groups had a significant reduction in LV end-systolic and end-diastolic dimensions (P<0.001). The simultaneous BiV pacing group had the greatest reduction in LV end-systolic dimension (P=0.007). Stroke volume (P<0.001) and LV ejection fraction (P<0.001) improved in all groups with no difference across groups. CONCLUSIONS: Compared with LV pacing, simultaneous BiV pacing was associated with a trend toward greater improvement in LV size. There is little difference between simultaneous BiV pacing and sequential BiV pacing as programmed in this trial.

The 12-lead electrocardiogram in supraventricular tachycardia.

The 12-lead electrocardiogram (ECG) is an invaluable tool for the diagnosis of supraventricular tachycardia (SVT). Most forms of SVT can be distinguished with a high degree of certainty based on specific ECG characteristics by using a systematic, stepwise approach. This article provides a general framework with which to approach an ECG during SVT by describing the salient characteristics, ECG findings, and underlying electroanatomical relationships of each specific type of SVT encountered in adults. It concludes by providing a systematic algorithm for diagnosing SVT based on the findings of the 12-lead ECG.

Heberden's Angina-Pathophysiology and Treatment.

This seminar provides an overview of chronic angina pectoris. First, the differential diagnosis of chronic angina pectoris is described. The basic pathophysiology of effort angina, including coronary flow physiology as well as the factors that contribute to supply-demand mismatch are discussed. The authors review the published trials that provide the evidence on which angina therapies are based, identifying those treatments that prevent myocardial infarction and death and those that reduce symptoms and ischemia. Newer and investigational agents which can potentially benefit patients with refractory angina are presented. Finally, non-pharmacologic interventions for chronic angina are reviewed.