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🌱 來自: Huppert’s Notes
Regular Atrial Rhythms🚧 施工中
Regular Atrial Rhythms
Sinus tachycardia (ST)
• Etiologies: Infection, hypovolemia/hemorrhage, hypoxia, anemia, anxiety, PE, alcohol withdrawal, hyperthyroidism. In the outpatient setting in a patient with chronic sinus tachycardia without an underlying cause consider: 1) Chronic inappropriate sinus tachycardia or 2) Postural orthostatic tachycardia syndrome (POTS)
• Treatment: Treat underlying etiology
SA node reentrant tachycardia (SANRT)
• Description: Reentrant loop in the SA node; hard to discern from sinus tachycardia except rapid on/off. Relatively rare rhythm.
AV nodal reentrant tachycardia (AVNRT)
• Description: Reentrant circuit using fast and slow circuits within the AV node.
• ECG: Regular, narrow QRS with rate usually 120–220 bpm, no P waves (buried, occasionally can see pseudo-R’ in V1, pseudo-S in inferior leads; only recognizable when comparing to the patient’s normal QRS), short RP interval.
• Treatment: Acute: 1) Vagal maneuvers and 2) IV adenosine (breaks) (Table 1.8). Chronic: Ablation vs. nodal blocking agents.
AV reentrant tachycardia (AVRT)
• Description: Reentrant circuit using the AV node and accessory pathway; frequently occurs in patients with Wolf-Parkinson White (WPW) syndrome (Table 1.9)
TABLE 1.9 • Wolff-Parkinson-White (WPW) and WPW Syndrome
• Subtypes:
- Orthodromic (85%): Impulse travels down through the AV node and up through an accessory pathway. Narrow QRS, regular, rate often >200 bpm (Figure 1.14).
- Antidromic (15%): Impulse travels down through an accessory pathway and up through the AV node. Wide QRS, regular (can look like VT), rate often >200 bpm.
• Treatment: 1) Vagal maneuvers, 2) IV adenosine (breaks), 3) Nodal agents
Atrial tachycardia (AT)
• Description: Impulse generated at a focus of enhanced automaticity in the atria other than the SA node. Associated with CAD, COPD, alcohol use, digoxin use; can occur in the absence of heart disease.
• ECG: P wave often looks different than a sinus P wave; atrial rate usually 110–250 bpm, ventricular rate can be regular or irregular (if variable block); narrow QRS, long RP interval; frequently occurs in recurrent self-terminating bouts.
• Treatment: Short-term use of BB or CCB. Long-term: BB, CCB, ablation.
Atrial flutter (Aflutter)
• Description: Irritable focus in the atria with reentrant circuit around the tricuspid annulus. Associated with mitral valve/tricuspid valve stenosis or regurgitation, or due to aging. Can occur in the absence of heart disease.
• ECG: Saw-toothed flutter waves best seen in leads II, III, aVF, or V1; atrial rate typically ~300 bpm; ventricular rate slower and can be regular (most common) or irregular (if variable AV nodal block); atrial to ventricular conduction usually in even ratio (e.g., 2:1 = 150 bpm, 4:1 = 75 bpm) (Figure 1.14).
- Counterclockwise flutter (most common) = inverted flutter waves in the inferior leads
- Clockwise flutter = upright flutter waves in the inferior leads
• Treatment: Similar to treatment of Afib.
- Acutely: Rate control with metoprolol, diltiazem, but note that flutter is usually more difficult to rate control than Afib. If unable to rate control, consider TEE/cardioversion.
- Chronically: Consider anticoagulation (by same criteria as Afib), ablation (success rate >90% in ablating flutter).