Hi friend,
Welcome to Health Care Magic

THE FIRST STEP IS TO SEE A CARDIOLOGIST
What you are describing is ECTOPIC beat. A beat comes earlier than normal – this itself is not usually felt. The next beat is a bit delayed - longer time to recover form early extra beat – so heart fills more and the beat appears forcible – thud / lubb - - dubb - - lubb - - dubb - lub - - - DUBB. Irregular heart beats need to be DOCUMENTED by ElectroCardioGram (ECG / EKG). Skipped (Ectopic) beats can be from ventricle (lower chamber - Ventricular Ectopic; VPC) or Atrium (upper chamber - Atrial Ectopic; APC). APC are generally harmless. Even VPCs are often harmless – ‘benign’. If they are frequent (More than 5 per hour, 2 or more coming in succession –they need investigations further.
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Stress is definitely contributing in your case but may not be the only factor
Anxiety / Alcohol / Tobacco (smoking, chewing) / Caffeine (too much coffee, cola) are common causes.
Medicines may be responsible – like phenylephrine, used for ‘cold’ / Salbutamol, used for asthma / Illicit ‘drugs’ like amphetamine are notorious to cause abnormal beats
Occasionally, there are abnormal nerve paths (bypass tracts) in the heart.
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It is advisable to have it investigated.

A thorough history and physical examination is the first step -

Routine 12-lead Electrocardiogram (ECG) is part of clinical examination. If a routine ECG does not show, 24 to 48 hour ambulatory monitoring (Holter) is done to analyse and plan for further management

ECHOcardiogram is necessary to see the heart valves (Mitral Valve Prolapse) / heart muscle (Cardiomyopathy) and heart function (Ejection fraction, wall motion abnormality).

Treadmill exercise ECG (TMT) is done to exclude Ischemia (reduced blood flow).

Laboratory work-up is routine - like blood counts, sugar, urea, electrolytes (potassium in particular), thyroid (over-active) and so on. Your Internist shall suggest based on the situation.

If there are no clues and if you are still bothered by it to the extent of interfering with life style, they are advanced techniques of investigations of increasing complexity (and invasive) – like Electro Physiological Studies (EPS) > the test is the gold standard, it is invasive and has a minimal risk and is not generally done unless there are compelling indications. This super-speciality expert is called ELECTRO-PHYSIOLOGIST.
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A specific treatment is no always necessary. The first line medicine is generally beta blockers, like Metoprolol – slow release and small dose. It will benefit blood pressure, anxiety and missed beats. Your doctor will give proper prescription and follow up
     If they are not effective and if the problem is severe, several other classes of drugs are available – acting by different mechanisms - the specialist will decide tailored to your needs / they may have side effects and need follow up.
There are other advanced treatment modalities - like RF ablation, which could be done during EPS.
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You are tolerating the rate well - means that you may not have any basic disease of the valve, muscle and so on.
Be in touch with your doctor - it is a question of time and you will be well.
Medicine is well advanced nowadays – management is possible for almost all situations...

Take care
Wishing speedy recovery
God bless
Good luck

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