…depolarization (activation). The PR interval is the distance between the onset of the P wave to the onset of the QRS complex. The PR interval…

…ventricular complex, premature ventricular beats): ECG and clinical implications Premature ventricular complexes are also referred to as premature ventricular beats , premature ventricular contractions or just…

…Study Figure 7 carefully, as it illustrates how the P wave and QRS complex are generated by the electrical vectors. Note that the first vector…

…and conduction system have repolarized. This appears as a P wave and QRS complex occurring earlier than expected ( Figure 1 ). The interval from the premature…

…QRS complex. The PR interval determines whether impulse transmission from atria to ventricles is normal. The isoelectric (flat) line between the end of the P…

…a ventricular rate slower than 50 beats per minute. P waves with constant morphology preceding every QRS complex. P wave is positive in limb lead…

…1) heart rate 50–100 beats per minute; (2) P wave precedes every QRS complex; (3) the P wave is positive in lead II and…

…Wide complex tachycardia where ventricular tachycardia must be distinguished from supraventricular tachycardia with bundle branch block or aberrancy. Narrow complex tachycardia where the P waves…

…shorter than 120 msec or longer than 220 msec. The PR segment is the flat line between the end of the P wave and the…

…the ventricles. An escape rhythm arises (which may have narrow or wide QRS complexes). There is no relationship between P waves and QRS complexes. The…

…All P waves are followed by QRS complexes. First degree AV block with wide QRS complex First degree AV block with normal QRS complex (QRS…

…rate 40–60 beats per minute. Retrograde P wave before or after the QRS, or no visible P wave. The QRS complex is generally normal…

…sick sinus syndrome) P wave No effect. AV system (AV node, His bundle, Purkinje system) Preexisting AV block, bundle branch block or fascicular block may…

…abnormal automaticity or re entry mechanisms; triggered activity is a less frequent cause. The atrial rate typically ranges from 120 to 250 beats per minute…

…direction, which results in negative (retrograde) P waves in lead II. QRS Complex QRS morphology also depends on where the pacing stimulus is delivered. Typically…

…as a gradual prolongation of the PR interval with each successive beat until a P wave fails to conduct, resulting in a dropped QRS complex…

…cells is 60 beats per minute. The resulting P wave is morphologically different from the sinus P wave, but the QRS complex is normal (provided…

…and absence of a palpable pulse. Ventricular contraction has ceased or unable to generate perfusion. SCD (sudden cardiac death) : Death resulting from sudden cardiac arrest…

…shows irregular waves with varying morphology and amplitude. No P wave, QRS complex or T wave can be seen. This is pathognomonic (unique) to ventricular…

…low molecular weight heparin and an antiplatelet agent without an indication. Interactions: strong P gp or CYP3A4 inhibitors and inducers (azole antifungals, HIV protease inhibitors…

…rhythm with ventricular rate 100 beats per minute. P wave with constant morphology preceding every QRS complex. The P wave is positive in lead II…

…1) heart rate 50–100 beats per minute; (2) P wave precedes every QRS complex; (3) the P wave is positive in lead II and…

…40 to 48 beats per minute, occasionally accompanied by junctional escape beats, which may present with P waves at the onset of the QRS complex…

…lead ECG or a single lead ECG tracing lasting ≥30 seconds, characterized by irregularly irregular R R intervals and the absence of distinct P waves…

…waveforms presented here. Activation of the atria is reflected as the P wave and activation of the ventricles results in the QRS complex. The T…

…each QRS complex then it is 2:1 block. In typical cases of atrial flutter, the atrial rate is around 300 beats per minute with…

…150 and 250 beats per minute. The P wave is not visible in most cases, because it is hidden within the QRS complex (the atria…

…becomes very discrete, or invisible. Figure 4. Stimulation artifact is seen as a spike preceding the QRS complex. This ECG displays a normal P w

…also be prolonged. This prolongation may also be due to myocardial fibrosis which is typical in hypertrophy. Finally, the QRS complex may be notched. P

…the ventricles. To sense correctly, the pacemaker must detect near field depolarization currents (P or QRS), and ignore near field repolarization currents (T waves), as…

…in chronological order: Heart rate Rhythm P wave PR interval QRS complex ST segment T wave U wave QT (QTc) interval Pediatric and neonatal electrocardiograms…

…Method of interpretation Heart rate Heart rhythm The P wave The PR interval The QRS complex The ST segment The T wave The U wave…

…50 and 100 beats/min. P wave with constant morphology preceding every QRS complex. The P wave is positive in lead II. Figure 1 (below…

…Lateral ventricular infarction. Pre excitation. Switched arm electrodes (negative P and QRS T in lead I). Situs inversus. Left posterior fascicular block is diagnosed when…

…Lateral ventricular infarction. Pre excitation. Switched arm electrodes (negative P and QRS T in lead I). Situs inversus. Left posterior fascicular block is diagnosed when…

…the left ventricle is many times larger than the right ventricles, which is why the QRS complex is dominated completely by left ventricular vectors. Hence…

ECG Video lecture: The QRS complex: Q wave, R wave & S wave

…all arrhythmias, the first task is to determine whether the arrhythmia is a wide complex tachycardia (WCT) or a narrow complex tachycardia (NCT). This is…

…low in healthy subjects; the 99 th percentile is less than a few nanograms per liter of blood (typically <5 ng/L). This is explained…

…3] . By Duration: Non sustained VT (NSVT): Defined as three or more consecutive ventricular beats at a rate exceeding 100 beats per minute (bpm), which…

[calc_syntax] SYNTAX Score: A Tool for Revascularization Strategy in Complex Coronary Artery Disease The SYNTAX Score is a semi quantitative scoring system designed to…

…failure (HF) is a complex clinical syndrome characterized by symptoms and signs resulting from structural or functional impairment of ventricular filling or ejection of blood…

…progressive, and highly complex lipid driven inflammatory disease of the arterial intima that serves as the fundamental pathophysiological substrate for acute coronary syndromes (ACS), including…

Arrhythmias and arrhythmology Pharmacology & dosing Pharmacokinetic Considerations Relevant to Dosing Amiodarone exhibits highly variable and complex pharmacokinetics that profoundly influence its dosing strategies. The drug…

…Definition and pathophysiology Obesity is a chronic, relapsing and biologically complex disease characterized by excessive accumulation of adipose tissue. It is an important cause of…

…Definition and terminology Heart failure with preserved ejection fraction (HFpEF) is a complex clinical syndrome characterized by the cardinal symptoms and signs of heart failure …

…R or Rs complex suggests VT. If the QRS complex in V1–V2 resembles a left bundle branch block (i.e negative QRS) V1 : The…

Cardiology Clinical medicine Introduction Cardiovascular disease becomes increasingly prevalent with advancing age, while its clinical expression and management become progressively more complex. Older adults, often…

…mean nothing. Capture is verified only when every pacing spike is followed by a wide QRS complex and a pulse that can be felt. The…

…recovery patterns within the left ventricle, resulting in a widened QRS complex and secondary ST T wave abnormalities [7]. Diagnostic Criteria The diagnostic requirements for…

…for depolarization and repolarization. It is measured from the beginning of the QRS complex to the end of the T wave. Prolonged QT duration predisposes…

…during ventricular tachycardia can precipitate ventricular fibrillation, whereas a synchronized shock (timed to the QRS complex) avoids this risk. Synchronized cardioversion is used for organized…

…is considered safe for patients with narrow complex tachycardia (NCT). Adenosine typically causes a short lasting second or third degree AV block which may be…

…valvular function, and ventricular function. A large body of science has demonstrated that these parameters are highly interdependent and rather complex. Indeed, myocardial mechanics constitute…

…to prolonged QT interval The QT interval is the time interval from the beginning of the QRS complex to the end of the T wave…

…risk. Clinical Applications Personalized Decision Making : SYNTAX Score II helps determine whether a patient should undergo PCI or CABG based on their risk profile. Predicting…

…exclusively at the infarct related artery (IRA), or it may extend to additional non infarct related lesions. Culprit only revascularization treats the artery responsible for…

…stenoses. Higher scores indicate more diffuse or technically complex disease and are associated with a greater relative advantage for CABG over PCI in multivessel disease…

…0.5% per year beyond the first year, although the available material does not establish a significant increase in late morbidity or mortality attributable to…

…is generally concordant with the QRS complex (which is negative in lead V1). Isolated T wave inversions also occur in leads V2, III or aVL…