Preceding chapters have described the major arrhythmias and atrioventricular (AV) conduction disturbances. These abnormalities can be classified in multiple ways. This review/overview chapter categorizes arrhythmias into two major clinical groups: bradycardias and tachycardias. The tachycardia group is further subdivided into…
The previous chapter focused primarily on disorders associated with delays in atrioventricular (AV) conduction, termed AV heart blocks. This chapter describes an entirely different class of AV conduction disorders, namely those related to abnormally early ventricular excitation ( preexcitation ).…
Normally, the only means of electrical communication (signaling) between the atria and ventricles is via the specialized conduction system of the heart. This relay network comprises the atrioventricular (AV) node, the bundle of His, and the bundle branch system (…
The three preceding chapters have focused primarily on supra ventricular arrhythmias, especially those related to rapidly occurring electrical disturbances arising in the area of the sinus node, the atria, or the atrioventricular (AV) node (junction). Assuming normal ventricular conduction, these…
This chapter discusses two of the most common and clinically important tachycardias: atrial flutter and atrial fibrillation (AF), schematized in Fig. 15.1 . Up to this point, we have focused primarily on those supraventricular tachycardias (SVTs) characterized by (1) organized atrial…
General Principles This chapter and the next two focus on rhythm disturbances with a rapid rate, namely supraventricular ( Fig. 14.1 ) and ventricular tachyarrhythmias. Key Concepts For any rapid, abnormal heart rhythm to occur, two major factors have to be…
Part II of this book deals with physiologic and abnormal cardiac rhythms. Systematically analyzing the cardiac rhythm from the electrocardiogram (ECG) allows you to address two key and interrelated sets of questions: 1. What pacemaker is controlling the heartbeat? There…
A wide variety of major disease processes may alter the electrocardiogram (ECG). Particularly important are conditions affecting the pericardium (acute pericarditis, pericardial effusion, and constrictive pericarditis), the myocardium itself (not including ischemia and infarction, which are discussed separately in 9,…
A number of common factors, including drug effects, electrolyte abnormalities, and a variety of metabolic conditions affect the electrocardiogram (ECG). Indeed, this almost universally available and inexpensive bedside test may be the major, initial indicator of a life-threatening abnormality, such…
Myocardial infarction (MI) may be associated with the appearance of classic ST segment elevation MI (STEMI), usually followed by T wave inversions, as described in Chapter 9 . Q waves may appear in one or more of these leads. However, in…