Chapters Archive – Page 16 of 22

Sinoatrial block (SA block): ECG criteria, causes and clinical features

Sinoatrial block (SA block): from ECG to clinical management Sinoatrial (SA) block implies that the impulses discharged in the sinoatrial node are either not conducted to the atria…

Figure 10. ECGs presenting Brugada syndrome type 1, type 2 and type 3, respectively.

Brugada syndrome: ECG, clinical features and management

Brugada syndrome: A life-threatening arrhythmia with unknown prevalence Pedro Brugada and his two brothers, Josep and Ramon, described this syndrome in 1992. The syndrome is characterized by…

Figure 1. ECG changes seen in hyperkalaemia.

ECG changes due to electrolyte imbalance (disorder)

ECG changes due to electrolyte imbalance (electrolyte disorder) The normal cardiac action potential may be altered by electrolyte imbalance, owing to changes in intra- and extracellular electrolyte…

Figure 2. Two ECGs showing left and right ventricular hypertrophy.

Right ventricular hypertrophy (RVH): ECG criteria & clinical characteristics

ECG and clinical characteristics in right ventricular hypertrophy (RVH) Right ventricular hypertrophy (RVH) During normal circumstances, the left ventricle is many times larger than the right ventricles,…

Figure 1. Left anterior fascicular block (hemiblock) and left posterior fascicular block (hemiblock). Inspired by GS Wagner (Marriott's Practical Electrocardiography, Elsevier 2007) and AL Goldberg (Clinical Electrocardiography: A Simplified Approach, Elsevier Mosby 2006).

Fascicular block (hemiblock): Left anterior & left posterior fascicular block

Fascicular block (hemiblock): left anterior fascicular block & left posterior fascicular block Fascicular blocks were previously referred to as hemiblocks, but the latter term has been deprecated. The…

Figure 1. Characteristics of ischemic ST segment depressions on ECG.

ST segment depression in myocardial ischemia and differential diagnoses

ST segment depression due to acute myocardial ischemia ST segment depressions caused by ischemia are characterized by a horizontal or downsloping ST segment. Indeed, North…

Figure 1. ST segment depression due to digoxin treatment.

Digoxin – ECG changes, arrhythmias, conduction defects & treatment

Digoxin ECG changes: arrhythmias, conduction defects and waveform changes Digoxin may be used in patients with heart failure, atrial fibrillation, atrial flutter, and in selected cases…

Figure 2. Right bundle branch block (RBBB) and left bundle branch block (LBBB). Note that the paper speed is 50 mm/s (1 large box equals 100 ms). The hallmark of both RBBB and LBBB is the QRS duration which is by definitions 120 ms or longer. The distinction between RBBB and LBBB is simple, as illustrated in this figure.

Right bundle branch block (RBBB): ECG, criteria, definitions, causes & treatment

Right bundle branch block (RBBB) Right bundle branch block (RBBB) is due to an anatomical or functional dysfunction in the right bundle branch, such that…

Figure 1. ECG criteria (Sgarbossa criteria) for acute STEMI in the setting of LBBB. Each criteria gives 2 to 5 points. Studies show that a cut-off of ≥3 points yields a sensitivity of 20–36% and specificity of 90–98% for acute STEMI in the setting of LBBB.

Left bundle branch block (LBBB) in acute myocardial infarction: the Sgarbossa criteria

Left bundle branch block (LBBB) in acute myocardial infarction (AMI): clinical implications & Sgarbossa criteria Contrary to right bundle branch block, left bundle branch block is…

Figure 19. The Cabrera format and inverted aVR.

The Cabrera format of the 12-lead ECG and inverted lead aVR

2016