Medicina_Decoded
Internal medicine, decoded step by step.
Clinical algorithms, exam traps and practice questions for NEET PG and INI-CET aspirants and medicine residents. Built by Dr. Viraj Dhamat, MD Medicine.
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Approach to VPCs in the OPD
Red flags, reversible causes, burden, structural heart disease and when to ablate.
NewOpen algorithm →VPCs and ventricular bigeminy
Compensatory pause, RVOT morphology, digoxin, CAST and the pulse deficit.
FreeStart quiz →VPC recap sheet
The whole topic on one printable screen for last-minute revision.
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Algorithms
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Approach to VPCs and ventricular bigeminy
Two questions drive everything: is the heart structurally normal, and is the burden high or the patient symptomatic?
- Premature, wide QRS (≥120 ms) with bizarre morphology and no preceding premature P wave.
- ST–T discordant to the QRS. This is expected, not ischaemia.
- Usually a full compensatory pause: the RR around the VPC equals twice the sinus RR.
- Rule out a PAC with aberrancy: look for a premature P hidden in the preceding T wave.
- Syncope or presyncope, exertional symptoms, chest pain.
- Family history of sudden cardiac death at a young age.
- NSVT, multifocal VPCs, R-on-T (short coupling) or prolonged QTc on the ECG.
- Known LV dysfunction or prior MI.
IF YES
Continuous monitoring, troponin, electrolytes and echo. Treat as a possible malignant arrhythmia until proven otherwise.
- Electrolytes: hypokalaemia, hypomagnesaemia (correct Mg²⁺ or K⁺ will not hold).
- Drugs: digoxin toxicity (classically bigeminy), β-agonists, theophylline, QT-prolonging drugs, tricyclics.
- Stimulants: caffeine, energy drinks, alcohol, nicotine, cocaine.
- Systemic: thyrotoxicosis, hypoxia, anaemia, fever, acute ischaemia.
- ECG read: morphology, QTc, Q waves, Brugada pattern, epsilon waves.
- Burden: percentage of all beats that are VPCs. Above about 10% raises the risk of VPC-induced cardiomyopathy.
- Exercise test: VPCs that disappear with exercise are reassuring; those that increase with exercise or recovery need more workup.
- Cardiac MRI: if you suspect ARVC, sarcoidosis or myocarditis despite a normal echo.
- Morphology: LBBB pattern with an inferior axis suggests RVOT origin (usually benign). RBBB pattern means LV origin.
The substrate, not the VPC count, decides prognosis in a diseased heart.
IF YES
Guideline therapy for the underlying disease. Avoid class IC drugs (flecainide, encainide) after MI: in the CAST trial they increased mortality.
High burden can depress LV function even when the patient feels well, so burden alone can justify treatment.
IF NO
Explain that the beats are benign. Repeat Holter and echo at intervals if the burden is borderline, so cardiomyopathy is caught early.
Metoprolol or bisoprolol, or verapamil or diltiazem. Flecainide is an option only in a structurally normal heart.
VPC-induced cardiomyopathy often reverses after successful ablation of the focus.
Ventricular bigeminy: three bedside points
Pulse deficit
The VPC often produces no palpable pulse, so the radial pulse or SpO₂ monitor reads about half the true rate. Count from the ECG.
Think digoxin
Digoxin toxicity, especially with hypokalaemia, is the classic cause. Bidirectional VT signals severe toxicity.
Rule of bigeminy
The long pause after each VPC makes the next VPC more likely, so the pattern keeps itself going.
Suppressing asymptomatic VPCs after MI with class IC drugs increases mortality (CAST). After an MI, you treat the substrate: β-blocker, revascularisation and an ICD guided by EF.
Quizzes
Short sets with full explanations. Your best score is saved on this device.
VPCs and ventricular bigeminy
PDF notes
One-page recaps you can screenshot or print. All notes are written and drawn by Medicina Decoded.
VPCs on one screen
| Point | What to remember |
|---|---|
| ECG | Wide (≥120 ms), early, no premature P, discordant ST–T, full compensatory pause |
| vs PAC with aberrancy | Aberrancy: premature P before it, usually RBBB pattern, non-compensatory pause |
| Bigeminy | Every second beat is a VPC. Classic cause: digoxin toxicity. Pulse deficit |
| NSVT | ≥3 beats at >100/min lasting <30 seconds |
| RVOT origin | LBBB pattern + inferior axis. Commonest idiopathic, usually benign |
| Burden | >10% on Holter: watch for VPC-induced cardiomyopathy |
| Reassuring | Normal echo, low burden, VPCs vanish on exercise |
| Treatment | β-blocker or non-DHP CCB, then ablation if refractory or LVEF falls |
| Trap | CAST: class IC after MI increased mortality |
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Videos
Whiteboard explainers and ECG Decoded episodes, played straight from the Medicina Decoded YouTube channel.
ECG Decoded
One ECG, one puzzle, one takeaway per episode.
Links to YouTubeDiabetes drugs
Mechanism to exam trap for each drug class, based on Harrison.
Links to YouTube60-second concepts
Quick "why" questions answered in under a minute.
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Exam guidance
How to use this site for NEET PG and INI-CET medicine preparation.
1. Learn the approach, not the list
Medicine questions increasingly test the next step. Read each algorithm top to bottom once, then cover the boxes and rebuild it from memory.
2. Test the same day
Do the matching quiz right after the algorithm. Read every explanation, including for the questions you got right.
3. Revise from the recap
Use one-page recaps for spaced revision: after 1 day, 1 week and 1 month. Keep the screenshots in one folder.
4. Collect the traps
Every page ends with an examiner's trap. Keep a running list; these are the points that separate close ranks.
Exam pattern, dates and marking scheme change each year. Always confirm them in the official NBEMS and AIIMS bulletins.
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