Transthoracic pacing

Transthoracic pacing is performed in two very different circumstances during resuscitation from asystolic cardiac arrest and after open-heart surgery via... 

The most common sensor is the activity sensor, which uses any of a variety of technologies (e.g., piezoelectric crystals and accelerometers) to detect body movement. Systems using a transthoracic-impedance sensor to estimate pulmonary minute ventilation or cardiac contractility are also commercially available. Numerous other sensors (e.g., stroke volume, blood temperature or pH, oxygen saturation, and right ventricular pressure) have been researched or market-released at various times. Some systems are dual-sensor, combining the best features of each sensor in a single pacing system. 

Fig. 4.68 Atrial lead placement through atriotomy and purseslring suture. Atrium and ventricular electrodes are positioned and the atriotomy is secured. (Westerman GR, Van Devanter SH. Transthoracic transatrial endocardial lead placement for permanent pacing. Ann Thorac Surg 1987 43(4) 445-446, with permission.)...

Westerman GR, Van Devanter SH. Transthoracic transatrial endocardial lead placement for permanent pacing. Ann Thorac Surg 1987 43 445. 

Transthoracic Very rapidly initiated Pacing wires are frequently not placed correctly Variable effectiveness for pacing (often because the patient is in extremis) High complication rate... 

Lee CY, Pellikka PA, McCully RB, et al. Nonexercise stress transthoracic echocardiography transesophageal atrial pacing vs. dobutamine stress. J Am Coll Cardiol 1999 33 506-511. 

Edhag O, et al. Cardiac pacing through transthoracic electrode in acute myocardial infarction. Acta Med Scand 1972 192 145. 

Altamura G, Bianconi L, Lo Bianco E, et al. Transthoracic DC shock may represent a serious hazard in pacemaker dependent patients. Pacing Clin Electrophysiol 1995 18 194-198. 

Transthoracic cardioversion uses relatively high voltages (up to 3.5kV) delivered by cutaneous patches. Modem pacemakers and ICDs employ specialized protective circuitry that minimizes the harmful effects of high energy. Despite this protective circuitry, several specific problans may be observed after transthoracic cardioversion or defibrUlation reversion of the pacemaker to the backup mode (under unusual conditions such as potential component failure or exposure to extreme temperatures some pacemakers will revert to a backup pacing mode at a specified rate) transient increases in capture thresholds aud actual destraction of the pacemaker circuitry (23-31). 

Das G, Eaton J. Pacemaker malfunction following transthoracic countershock. Pacing Clin Electrophysiol 1981 4 487 90. 

As early as the late 1700s, Physicians speculated that electrical current could be used to stimulate the heart. In 1882, von Ziemssen used electrical current to directly stimulate the heart of a woman whose anterior chest wall had been removed after resection of a chest tumor. In 1952, ZoU used transthoracic current to pace the heart, and in 1958 the first implantable pacanaker was placed by Ake Senning and Rune Elmquist. At the same time, Furman and Robinson demonstrated the feasibility of transvenous cardiac pacing. In the late 1960s, Mirowski and colleagues pioneered the concept of an implantable device that could be used to defibrillate the heart. Over the last 50 years, implantable cardiac devices have become the primary treatment for bradyarrhythmias and ventricular tachyarrhythmias and have emerged as an important adjunctive therapy for patients with heart failure. It is currently estimated that almost 400,000 pacemakers and defibrillators are implanted annually in the United States. 

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