Key Points
- Stabilize ABCs; begin targeted evaluation without delaying life-saving therapy.
- Use system-specific risk tools to guide testing and disposition.
- Order high-yield tests first; escalate imaging when indicated.
- Start evidence-based initial therapy and reassess frequently.
Algorithm
- Primary survey and vitals; IV access and monitors.
- Focused history/physical; identify red flags and likely etiologies.
- Order system-appropriate labs and imaging (see Investigations).
- Initiate guideline-based empiric therapy (see Pharmacology).
- Reassess response; arrange consultation and definitive management.
Clinical Synopsis & Reasoning
For Supraventricular Tachycardia Acute, frame the differential by acuity and pathophysiology, then align diagnostics to the leading hypotheses. Prioritize stabilization while obtaining high‑yield studies such as EKG (Rhythm/ischemia), Troponin (Myocardial injury), CXR (Pulmonary edema/size), BMP/Mg2+ (Electrolytes/renal). Incorporate bedside imaging and targeted labs to define severity and identify complications; synthesize results with clinical trajectory to refine the working diagnosis and disposition needs.
Treatment Strategy & Disposition
Initiate disease‑directed therapy alongside supportive care, titrating to objective response. Pharmacologic options commonly include Aspirin, P2Y12 inhibitor, Heparin/LMWH, Beta-blocker. Use validated frameworks (e.g., Common Doses) to guide escalation and site of care. Address precipitating factors, de‑escalate empiric therapies with data, and arrange follow‑up for monitoring and risk‑factor modification; admit patients with instability, high risk of deterioration, or needs for close monitoring.
Epidemiology / Risk Factors
- Atherosclerotic risk (HTN, DM, HLD, smoking)
- Age/family history of premature CAD
Investigations
| Test | Role / Rationale | Typical Findings | Notes |
|---|---|---|---|
| EKG | Rhythm/ischemia | ST-T changes/arrhythmia | Serial |
| Troponin | Myocardial injury | Dynamic rise/fall | Trend |
| CXR | Pulmonary edema/size | Cardiomegaly/edema | |
| BMP/Mg2+ | Electrolytes/renal | Derangements | |
| CBC/Coags | Bleeding risk | Abnormal/INR |
Common Doses
| Drug | Dose (adult) |
|---|---|
| Adenosine | 6 mg rapid IV push → 12 mg if needed |
| Diltiazem | 0.25 mg/kg IV bolus then 0.35 mg/kg |
| Metoprolol | 5 mg IV q5 min up to 15 mg |
Pharmacology
| Medication | Mechanism | Onset | Role in Therapy | Limitations |
|---|---|---|---|---|
| Adenosine (IV push) | AV nodal blockade | Seconds | Acute termination of AVNRT/AVRT | Flushing, bronchospasm; ICU context |
| Diltiazem/Metoprolol | AV nodal blockade | Minutes | Rate control if adenosine contraindicated | Hypotension/bradycardia; ICU context |
Prognosis / Complications
- Prognosis by ischemic burden/LV function
- Arrhythmias and HF are complications
Patient Education / Counseling
- Explain red flags and when to seek emergent care.
- Reinforce medication adherence and follow-up plan.
Notes
Document rhythm before and after adenosine when possible. Treat triggers (stimulants, illness).