Thoracic Key

Bradycardias Clinical Syndrome Sinus node dysfunction is characterized by disorders of impulse formation in and conduction out of the sinus node (see Table 11-1). Electrocardiographically these abnormalities in sinus node…

Antiarrhythmic Drugs Antiarrhythmic drugs are widely used in clinical electrophysiology to both prevent and terminate arrhythmias. The drugs can also be used to slow arrhythmias to make them hemodynamically tolerated…

Noninvasive Diagnostic Testing The Electrocardiogram The 12-lead electrocardiogram (ECG) provides an enormous amount of useful information for the prediction of arrhythmia risk. QRS Interval Prolongation in the QRS interval with…

Permanent Pacemakers Clinical Indications The clinical indications for permanent pacemaker (PPM) implantation are covered in detail in Chapter 11. A brief recapitulation is provided in the subsequent text. Sinus Node…

Clinical Management of Patients with Implantable Cardioverter Defibrillators In the wake of numerous scientific studies demonstrating the clinical benefit of implantable cardioverter defibrillators (ICDs), millions of these devices have been…

Sudden Death Syndromes The most common etiology of sudden cardiac death (SCD) is acute ischemia or ventricular tachycardia (VT) resulting from prior myocardial infarction. Dilated cardiomyopathy from a nonischemic cause…

Ventricular Tachycardia Ventricular tachycardias (VTs) include a spectrum of arrhythmias that range from nonsustained asymptomatic VT to a sustained arrhythmia that results in a cardiac arrest. VTs are defined by…

Syncope Syncope will occur in up to 50% of the population and is defined by the abrupt loss of consciousness due to cerebral hypoperfusion. Syncope must be distinguished from seizures,…

Supraventricular Tachycardia Introduction and Mechanisms Supraventricular tachycardia (SVT) refers to regular, narrow QRS complex rhythms typically in excess of 100 beats per minute (bpm). Atrial flutter and atrial fibrillation will…