Cardiac resynchronization therapy during

Sogaard P, Egeblad H, Kim WY, et al. Tissue Doppler imaging predicts improved systolic performance and reversed left ventricular remodeling during long-term cardiac resynchronization therapy. J. Am. Coll. Cardiol. 2002 40 723-30. 

Tse HE, Sin CW, Lee KL, Fan K, Chan HW, Tang MO, Tsang V, Lee SW, Lau CP. The incremental benefit of rate-adaptive pacing on exercise performanee during cardiac resynchronization therapy. J Am CoU Cardiol 2005 46 2292-7. 

Disordered electrical and mechanical ventricular activation can compromise cardiac function. Pacing technology has been nsed to att pt to correct the inter- and intraventricular conduction in an effort to optimize cardiac performance. The earliest attempts were performed during surgery when epicardial leads were placed over the lateral left ventricle free wall. Later, the coronary sinus was utilized to activate the left ventricle. Cardiac-resynchronization therapy (CRT) for treatment of patients with congestive heart failure and ventricular dyssynchrony can have a remarkable beneficial effect. Use of this technology continues to evolve. 

Fig. 18.36 Posteroanterior chest radiograph obtained after the prior device was upgraded to a cardiac resynchronization therapy defibrillator system. During the course of the upgrade, the central venous circulation was perforated, and when dye was injected to determine the position of the sheath, the contrast material was seen in the mediastinum.

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