Dr. Usman's Cardiology Notes

Katz-Wachtel phenomenon (sometimes written as Katz-Wachtel waves). On ECG: It refers to the presence of giant, biphasic QRS complexes in the mid-precordial leads (V2–V5). The QRS complexes are very tall, often more than 50 mm, with both positive and negative deflections in the same complex. It reflects biventricular hypertrophy (both RVH and LVH present), because forces of both ventricles are so strong and opposing that they produce large biphasic complexes. Classically described in congenital heart diseases with large left-to-right shunts such as ventricular septal defect (VSD), endocardial cushion defect, or PDA with pulmonary hypertension. 👉 So in one line: Katz-Wachtel phenomenon = giant biphasic QRS complexes in mid-precordial leads, indicating biventricular hypertrophy, typically seen in large VSD or similar shunt lesions.

 👉 In practice, ablation is often considered when VT is drug-refractory, recurrent, or causing ICD shocks, provided the patient can safely undergo the procedure. How isoprenaline (isoproterenol) controls VT ? The way isoprenaline (isoproterenol) controls VT depends on the mechanism of arrhythmia. 1. Idiopathic VF / Brugada / Early repolarization syndrome These arrhythmias are triggered by phase-2 reentry or Purkinje PVCs. At slow heart rates, abnormal repolarization (J-wave accentuation, action potential heterogeneity) favors PVCs and VF. Isoprenaline (β-agonist) increases sympathetic tone → raises heart rate → shortens action potential duration and suppresses early afterdepolarizations. This reduces dispersion of repolarization and stabilizes the ventricular myocardium. Net effect: PVC suppression → VF/VT storm breaks. 2. General mechanism β-1 stimulation → increases HR and conduction → overrides pause-dependent triggers. β-2 stimulation → increases calcium influx → suppresses ph...

  Welcome to cardiology toacs mock exam , there will be 40 stations, time for each station is usually 3 mins in the exam but in this video it will be, 1 min. you can pause the video if you need more time.  Answer key is also shown in the video after 40 stations.

First of all remember I said “This ecg of “ asymptomatic “ individual !  However even then the following needed to be known!!!!! As far as managment is concerned !! So indeed very prolong PR !!! Or in other words the “ the famous first degree AV block “  So technically The P to R interval is measured from the” beginning of the P complex to the beginning of the QRS complex “  The normal P to R interval in adults is 120 to 200 msecond. It is generally shorter in children and gets longer as one ages.  “ And this interval ! is actually representative of the time required for the current to flow from the atrium through the AV node, then His bundle , then BB and then system of PF until the ventricular myocardium begins to depolarise!!!!!” The biggest caveat or the biggest challenge !  Since normally almost all of the Drs & especially the Jnr Drs either don’t actually measure it & go on eye balling or if they do measure , they don’t know from where to start ...

PVC Localization on ECG: Lets start with this ECG Case: Premature ventricular contractions (PVCs) are common arrhythmias often seen on routine ECGs or Holter monitors. While isolated PVCs are frequently benign, identifying their site of origin can be clinically important—especially in patients with symptoms, frequent ectopy, or underlying structural heart disease. ECG morphology offers valuable clues to help localize the origin of these ectopic beats within the ventricles. Basic Principles: PVCs originate from a single focus in the ventricular myocardium. Because of this, the activation spreads outside the normal conduction system, creating wide and bizarre QRS complexes. The QRS morphology and axis during a PVC provide hints about where in the ventricles the beat originates. Key Clues to Localization: 1. Outflow Tract PVCs (RVOT/LVOT) Most common type in structurally normal hearts. LBBB pattern in V1 (dominant S wave). Inferior axis (positive QRS in II, III, aVF) — indicating superior...

  ECG Interpretation The electrocardiogram (ECG) is a crucial diagnostic tool for assessing the electrical activity of the heart. A thorough understanding of ECG interpretation is essential for identifying various cardiac conditions and guiding clinical decision-making. Normal ECG A normal ECG consists of several key components: - P wave: represents atrial depolarization - PR interval: time between the onset of the P wave and the QRS complex - QRS complex: represents ventricular depolarization - QT interval: time between the onset of the QRS complex and the end of the T wave - T wave: represents ventricular repolarization Heart Rate To calculate the heart rate, count the number of R-R intervals in 6 seconds and multiply by 10. A normal heart rate is between 60-100 beats per minute. Rhythm Assess the rhythm by evaluating the P-P interval and R-R interval. A regular rhythm has a consistent P-P and R-R interval. P Wave Evaluate the P wave for morphology, duration, and axis. Abnormalit...

  So the QRS !!!!!  A few have posed me this question about the true value of QRS , its morphological presentations ,especially the clues in it , for the identification of the various types of abnormalities especially the tachycardias based on these QRS features .  But To understand the abnormalities , one must be able to understand the normalities & especially the slight aberrations associated with the other wise normalities !  The QRS is usually a very well-defined electrical signal on surface ecg and is indicative of underlying ventricular depolarisation phase( since a large mass of muscle is activated almost synchronously hence the larger deflections & this time interval coincides with repolriazation of atrium, hence the latter repolriazation is masked in the QRS complex) . The QRS usually lasts about 100 msec or even less (on average May be of 60 msec to 80 msec duration) ! Generally a duration longer than 120 msec is considered longer! The even more ...

✔Bidirectional VT The tachycardia with an identity crisis. What you'll see: Beat-to-beat alternation in QRS axis (often ~180) RBBB-like morphology, most visible in lead Il or aVF Regular rhythm, but clearly not your standard VT Why it most likely happens: Triggered activity (delayed afterdepolarizations) Classically: two competing ventricular foci or alternating fascicular exits Top causes: Digoxin toxicity (check that level!) CPVT (stress-induced VT in the young) Andersen-Tawil syndrome Rare: aconite poisoning, myocarditis Key point:  BiVT is rare - but when you see it, it narrows the differential dramatically.

Junctional escape or junctional rhythm !  Let me explain these in more detail !!!! So I know lots of confusion exists in the minds of Drs especially the very Jnr regarding some commonly heard terminologies & they always fumble when they come across any such tracings ! So the commonly heard terminologies are 1. junctional beat !  2. Junctional (escape) beat ! 3. (Premature) junctional complex (PJC) /beat !!!!!! So I will try to create a difference or differentiation among them Some other terms which are used very frequently & mostly wrongly interchanged !  1. Ventricular escape beats  3. ventricular extra systoles  4. vs ventricular escape Rhythm  Ventricular escape beats may occur when there is a significant pause in the sinus and also total lack of junctional escape complexes!!!  Morphologically the complex’s will be quite variable depending on site of origin ! Usually QRS wide and bizarre, consistent with ventricular origin!!!! As described ...

 A premature ventricular contraction (PVC)/ventricular ectopy (VE) is a prematurely occurring wide QRS beat that has a very distinct shape ( shape depending upon site of origin) and is not preceded by a P wave!!! So the most important to understand is !  Generally there are two major types of ventricular ectopies  1. The most common especially in non acute settings are the idiopathic VE / the outflow origin VE . They generally are Positive in inferior leads  2. ⁠the non outflow or the structural heart ectopies !! They generally are negative in inferior leads So  Of The various Terminologies !!!! Or the observed behaviour on the ECG !  Some of the usual terminologies and which are usually very very confusing to the Jnr Drs but even some Snr colleagues !!! So The patterns or them occurring on the surface ecg may be of the following types !  1. So Two consecutive ectopics (be called couplet) 2. alternating ectopy with normal QRS complex (be called bigemin...

  Acute pericarditis is a condition characterized by inflammation of the pericardium, the sac surrounding the heart. This inflammation can lead to a range of symptoms, including chest pain, fever, and fatigue. One of the key diagnostic tools for acute pericarditis is the electrocardiogram (ECG), which can reveal a number of characteristic changes. In the early stages of acute pericarditis, the ECG may show a pattern of widespread ST-segment elevation. This is often accompanied by a slight elevation of the PR segment, and a decrease in the amplitude of the QRS complex. The ST-segment elevation is typically concave upwards, and may be seen in all leads except aVR. This pattern of ST-segment elevation is often referred to as a "saddle-shaped" or "dome-shaped" appearance. As the condition progresses, the ECG may show a number of additional changes. One of the most characteristic features of acute pericarditis is the development of PR-segment depression. This is often se...

One of the probably most commonly seen pattern on ecg is the above!  “A regular & high-frequency "caterpillar" pattern, making it almost difficult to interpret the true underlying electrical activity of the heart!!!” This is also known as 60 hz or 60 cycle interference on ecg!  This is Common to areas where the source of electricity is “AC”With frequency of 60 hz !!! There electrical current can leak into other circuits and can results in this pattern on ecg . To help minimize 60 cycle interference one can set the mode of the 12-lead ECG monitor to 0.05 – 40 Hz!!!!! Electromagnetic interference (EMI) is defined as unwanted noise / artifacts/ interference in an electrical path or circuit caused by an outside of heart source.  Most Drs especially the jnr Drs do not have an understanding of the issue or how to resolve the problem and unfortunately accept ECG interference as something like normal !!!! Fatal arrhythmias may therefore go unnoticed! , and one can be confus...

Wandering Baseline Artifact Baseline Wander (BW) Artifact on ECG  One of the other major/common noise type on surface ecg is the baseline wander (BW). BW recorded on ECG is mainly caused by the movement and respiration of the patient hence they appears as low-frequency artifacts!!!! Generally these fluctuations on ECG are not of cardiac origin. And are typically in range below 0.5 Hz  Issues with Baseline wander  1. They can distort the ECG shape esp whenever there is body movement inc even deep rapid breathing !!! ( Some data even suggest that BW can even be caused by loose or dry electrodes)  (To mitigate this issue remember Some techs may be used to ask patients to hold their breath during a 12-lead ECG. Be aware of this as this can also alter the patient’s heart rate)  2. BW is especially important when subtle changes in the “low-frequency” ST–T segment are analyzed for the diagnosis of ischemia, for which ETT is performed .  Though The frequency conte...

ECG artefacts!!! a relatively common happening in every day clinical life can have a wide range of presentations and can create varying clinical relevance !!!!!!  ECG artifacts are distortions/ changes in the ECG that are not caused by the heart electrically activity by itself !!!!!   Commonly used terms in this regard are  1. Motion artifacts! irregular ECG baseline changes caused by movement or shaking of body.  2. ECG artefacts! on the other hand “signals that are not related to cardiac electrical activity” A. Artefacts due to technical problems with recording sys  (nuisance artefact’s)  1. malfunctioning equipment  inc loose or fractured leads 2. accumulation of static energy 3. electromagnetic interference(EMI). caused by power lines and electrical equipment.  “It can be recognized as high frequency sharp signals at 60 Hz” 4. patient-related artifact such as body movement,  5. poor electrode contact because of hairy skin or w...

A 50 years old female with normal angiography and normal Echo ,with recurrent tachycardia, came to emergency in cardiac Hospital,patient reverted to sinus rhythm with sedation, lignocaine and magnesium sulphate,normal troponin and electrolytes ,Cardiac MR dome last year was also normal ,what should be best management plan for this ? What is the location of this tachycardia or VT? Is ablation possible for this patient as she doesn't tolerate this rhythm well? Few things seems to be eye catching but keeping in mind that surface ecg being only 12 leads has lots & lots of shortfalls for exact identification of endocardial source of arrhythmia ! Hence as you know , as the EP catheters are multipolars so much much more helpful in pin pointing the exact endocardial source of arrhythmias   1. The arrhythmias seem to be Ventricular driven  2. ⁠morphologically , it’s seems mono morphic rather than polymorphic , hence supporting a single focus  3. ⁠the shortest way to furt...

  ECG Case: A 71 year old man presented with recurrent episodes of syncope, What are the findings in this EKG, How will you manage? Click the button below to view answer: Show Answer

  Can you diagnose what's going on in this ECG strip? So before I go into a diagnosis can I ask what's the atrial rate and what is the ventricular rate? Summary: This is just artifact, as you can see V rate doesnt change ,there is no Apc to trigger a reentrant rhythm like flutter,V rate is not a mutiple of 300 which u would expect if atrial rate was truly 300,termination is without any pause or any suggestion of sinus node overdrive Of All the atrial arrhythmias,  To differentiate between Atrial fibrillation (AF) and  Atrial flutter (AFL) (typical & atypical) are sometimes technically very challenging esp for the non EP , but it’s very important to be able to identify correctly as each of these has a different management strategy, however sometimes even for EP it is not that easy unless EPS is done!  Reason of such complexity especially in case of flutters is because of the so many types of atypical flutters, with so many ecg morphologies !! Any general physician...

ECG Showing Intermittent Delta Wave Above ECG is showing delta wave in some of the QRS complexes, others being normal. To decide further management we take into account various factors. When to Ablate for Pre-excitation / Delta Wave or WPW ECG Pattern or Syndrome: 1. Symptomatic AVRT 2. Pre excited AF 3. Asymptomatic with LV Dysfunction due to electrical dyssnchrony  4. Asymptomatic with High Risk Profession i.e Pilot, Professional Athlete 5. Asymptomatic with High Risk features i.e SPERRI <250 msec (Shortest Pre-excitated RR Interbal) AP ERP <250 msec Multiple APs AP mediated Tachycardia  Low Risk Features: Intermittent Pre-excitation  Delta Wave that disappears on ETT Sudden loss of Delta wave on holter monitoring Ablation is the standard first line treatment for WPW Syndrome in above enlisted scenarios but sometimes it may be delayed or not feasible then following medications can be considered: Structurally Normal Heart: Flecainide, and propafenone  Abnormal...

In pa­tients with con­gen­i­tal com­plete or high de­gree AVB, pac­ing is rec­om­mend­ed if one of the fol­low­ing risk fac­tors is pre­sent: a) Symp­toms b) Paus­es >3x the cy­cle length of the ven­tric­u­lar es­cape rhythm c) Broad QRS es­cape rhythm d) Pro­longed QT in­ter­val e) Com­plex ven­tric­u­lar ec­topy f) Mean day­time heart rate <50 b.p.m. Reference: ESC Guidelines for Pacing 2021 Thanks 

 The Q or the q wave on the surface ecg can sometimes proves very dodgy!!!   So let’s look at the normality or how & why q  is recorded on the surface ecg !!!! Here some of my comments consolidated on this aspect of ecg Normally q is The first or the initial deflection of QRS and results from the rapid depolarisation of the thin walled septum which is occurring from the left to the Right ventricle and this is inscribed in most of the surface ecg leads!!!! B. Normality Small Q are defined as less than 0.03 seconds in duration, or two small squares or less in amplitude & Generally should be no larger than 25% of the associated R. 1. Normality in all leads except V1 through V3, where they are always pathological 2. A Q of any size is generally normal in limb lead III (is varying with respiration) 3. laterally in the chest leads, reflecting left-to-right septal depolarization. 4. A large Q May be seen in lead aVR (as it looks at the endocardial of the heart, it regist...