Learning Cardiology

Case History:  A 46-year old female presents with history of palpitations.  At the time of palpitations, she also had rapid neck pulsations.  She presented to emergency and an ECG was done.  What are the findings?  What is the diagnosis?   Click here to reveal the answer The ECG shows a regular narrow complex tachycardia (ventricular rate of approximately 250/min). The P waves are not clearly visible, but there is a small deflection at the end of QRS in various leads. In lead I, this is pseudo r' and in leads this is pseudo s wave. The patient was found to have AVNRT on EPS and slow pathway was ablated successfully.  

 Cardiology MCQ Q. Which of the following leads is not an inferior lead in ECG? A. Lead II B. Lead III C. Lead aVF D. Lead aVR Click the button below to view answer Show answer Correct answer is option D. Lead aVR

What is the cause of ST changes and T wave inversions in this ECG? Should the patient be taken to Cath lab for coronary angiography? Show Answer These ST segment and T wave changes are secondary to left ventricular hypertrophy. There are classical features of left ventricular hypertrophy in this ECG which should not be missed. Hence, if the patient doesn't have any other features which suggest ischemia, then he should undergo evaluation for cause of left ventricular hypertrophy. The most common cause for left ventricular hypertrophy is hypertension.

Educational post Please have a look at the ECG shown below. Is this atrial tachycardia or atrial flutter? Show answer ECG definition of atrial flutter is atrial rate more than 240 bpm and no isoelectric line between p waves. Atrial tachycardia will have rate between 120 to 240 bpm with clear isoelectric line between p waves. However, these two ECG criteria are not specific for any of them. Atrial tachycardia with higher heart rate is possible and atrial flutter with lower heart rate is possible. Atrial flutter may have an isoelectric line between p waves because of atriotomy scars causing conduction block. More important is to identify mechanism of atrial tachycardia during electrophysiological study. Electrophysiological study gives us a better idea regarding mechanism of atrial tachycardia. Atrial tachycardia can be focal or macroreentrant. Focal can be because of automaticity, triggered activity or microreentrant cause. Coming to this case, Here, atrial...

What is the diagnosis? Click the button below to view answer: Show Answer

The patient contacts the doctor over phone with this report.   Obviously anxious because of his high heart rate (199 beats per minute) as detected by ECG machine.  Should he be worried about this and come to emergency department as soon as possible? Correct answer-  ECG machine has calculated his heart rate incorrectly.  Heart rate is around 100 beats per minute.  Other findings in this ECG include ST segment elevation in anterior chest leads along with presence of Q waves, denoting old MI changes with possibly development of LV aneurysm. In such cases, ST segment elevation can persist for long periods.    Now, should he come to emergency department? Not because of detection of high heart rate.  But, if he is having symptoms such as shortness of breath or chest pain, he should visit emergency department. Otherwise, if he is asymptomatic, he can schedule a regular visit with his cardiologist. 

  Basic principles of the ECG Voltage and timing intervals 1mV is represented by a deflection of 10 mm Each small square represents 40 milliseconds (ms) 5 small squares, thus representing 200 ms. Heart rate estimation HR = 300/ Number of large boxes between two RR waves If the number of large boxes: 5 - the HR is 60 beats per minute. 3 - the HR is 100 per minute. 2 - the HR is 150 per minute. Normal heart rate = between 60 to 100 beats per minute Electrical axis The overall direction of travel of the electrical depolarization wave through the heart is known as the electrical axis. Limb leads record ECG in the coronal plane, hence used to determine the electrical axis. The limb leads are I, II, III, AVR, AVL and AVF. The cardiac electrical axis is normally downward and to the left. The electrical axis is expressed in degrees and is normally in the range from -30 to + 90 degrees. Normal ECG P wave Depolarization of atria during sinus rhythm generates P wave  PR interval  Sh...

Q. Acute pericarditis can be differentiated from early repolarization by? A. Progressive changes in ECG over days B. PR segment depression C. ST segment/T wave height ratio> 0.25 D. All of the above Answer: D. All of the above

Q 1.  What does arrow indicate? Q 2. What is the diagnosis of the patient? Answer 1: Epsilon wave Answer 2: Arrhythmogenic right ventricular cardiomyopathy (ARVC)

Q. Which of the following is true about Brugada syndrome? A. AR inheritance B. Exertional syncope C. Functional phase 2 re-entry D. Female preponderance Answer: C. Functional phase 2 re-entry Explanation: Brugada syndrome: Cause of ventricular arrhythmia in structurally normal heart. Autosomal dominant genetic disorder. Loss of function genetic mutation in cardiac sodium channels (SCN5A and SCN10A). Functional phase 2 re-entry leads to ventricular arrhythmias in Brugada. ECG: Right bundle branch pattern with ST elevation in V1 to V3 leads. Types of Brugada syndrome (Image 1): Type 1: Coved type ST elevation (>/=2 mm) with inverted T waves Type 2:  Saddle-back ST-T wave configuration with an upright or biphasic T wave                                     Image 1: Types of Brugada syndrome  Brugada pattern ECG is more common in...

Q. A 50 year old man presents with severe crushing chest pain radiating to left arm. His ECG showed dominant R waves in V1 and V2 leads. The T waves were upright and tall along with ST segment depressions.  Which artery is most likely to be occluded? A.  Right coronary artery B.  Septal branch of left anterior descending  artery C.  Circumflex artery D. Left main coronary artery Answer: C. Circumflex artery Explanation: The ECG changes are suggestive of posterior wall MI. Posterior myocardial infarction usually results from occlusion of the left circumflex coronary artery but the anatomy can vary a little. Occlusion of the right coronary artery may also result in a posterior MI. The changes of posterior myocardial infarction are seen indirectly in the anterior precordial leads. Leads V1 to V3 face the endocardial   surface of the posterior wall of the left ventricle. As these leads record from the opposite side of the h...

Q. A 25-year old woman has presented to the clinic for assessment. She has a past medical history of palpitations and is suspected to have congenital long QT syndrome from evidence of her ECG findings. Which one of these drugs should be avoided? A. Amoxycillin B. Thyroxine C. Sertraline D. Paracetamol Answer: C - Sertraline Explanation: Common drugs which cause long QT syndrome are: Tricyclic antidepressants  ( e.g.sertraline) Antiarrhythmics: Quinidine Disopyramide Procainamide Amiodarone Sotalol Antipsychotics: Haloperidol and thioridazine Cisapride Antimalarials: Halofantrine Terfinadine

Q . Which of the following is true about NSTEMI? A. Normal ECG (electrocardiogram) does not rule out ACS. B. Patients with normal or abnormal ECG have same prognosis C. >0.2 mV ST depression should be present for diagnosis D. All are correct Ans : A. Normal ECG (electrocardiogram) does not rule out ACS. Explanation Normal ECG (electrocardiogram) carries a favorable prognosis but does not rule out ACS. Nearly 50 % of patients presenting with UA (unstable angina)/NSTEMI (non ST-elevation myocardial infarction) have a normal or unchanged ECG. UA/NSTEMI : New T wave inversions >0.2 mV and ≥ 0.05 mV ST depressions are suggestive.

Q. Total electrical alternans is seen in ? A. Large pericardial effusion B. Pulmonary embolism C. Congestive heart failure D. Myocardial infarction Answer: A  Explanation: Electric alternans is seen in cardiac tamponade or massive pericardial effusion. It occurs due to swinging motion of heart in a large sac of fluid (Pericardial fluid).  Electrical alternans must be distinguished from mechanical alternans (eg, pulsus alternans), although both may coexist. Pulsus altenans is most commonly seen in severe left ventricular systolic impairment and is suggestive of grim prognosis for the patient.

Q. Prominent U wave in ECG are seen in? A. Hyperthermia B. Hyperkalemia C. Hypokalemia D. Hypercalcemia Answer: Option C Explanation: Prominent U waves are most commonly seen in hypokalemia and hypothermia. The mechanism of appearance of these waves is not known. The two theories state that U waves occur due to: 1) Delayed repolarization of Purkinje fibres 2) Prolonged repolarization of mid myocardial M cells.

Q. El-Sherif sign is? A. rSR complex in lateral chest leads B. Persistent ST elevation in anterior leads in myocardial infarction C. PR prolongation in acute rheumatic fever D. Delta wave in WPW syndrome Answer: A Explanation: A characteristic rsR′ pattern or its variants (rSr′ or rSR′) with normal or prolonged QRS duration in left surface leads including the apex lead and the orthogonal scalar X lead may be seen in patients with coronary heart disease and left ventricular aneurysm. This was first described by El-Sherif in 1970 hence known as El-Sherif sign. Reference: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC487350/

Q. El-Sherif sign in ECG is seen in presence of ? A. Left ventricular aneurysm B. Acute myocarditis C. Acute pericarditis D. Acute rheumatic fever Answer: Option A Explanation: El-Sherif sign