Symptoms of arrhythmias

• symptoms are typically caused by atrial-ventricular dissociation or decreased cardiac output

  • palpitations

  • lightheadedness

  • fatigue

  • dyspnea

  • syncope

  • sudden death

• cardiac output (CO) is the product of stroke volume (SV) and heart rate (HR)

• bradycardias decrease CO by decreasing heart rate

• tachycardias decrease CO by decreasing SV (suboptimal filling; increased HR cannot compensate)

bradyarrhythmias

• in normal hearts, specialized conduction tissues possess the ability to depolarize spontaneously

• intrinsic rates: fast upper, slow lower

  • SA node 60-100 bpm

  • AV node 40-60 bpm, which is almost able to sustain life

  • His-Purkinje system, ventricles <>

• AV node and His-Purkinje are less reliable than the SA node and backup rate might be too slow to maintain normal CO

Category: Cardiology Notes