ARRHYTHMIAS

ARRHYTHMIAS

1:Bradyarrhythmias

Bradyarrhythmias occurs when there are unusual rhythms that arise when the heart rates are low.

AV Junctional Rhythm occurs when the AV junction acts as the pacemaker. Stimulation of the atria occurs in a retrograde manner leading to inversion of the P wave. At lead aV_R, the P wave is positive while at lead II, it is negative. If depolarization of the atria occurs first, the PR interval is shorter, and the P wave occurs before the QRS complex (Whyte, & Sharma, 2010). The heart rate is also slow and ranges from 30 to 60 beats per min (bpm). Some of the common causes of AV Junctional Rhythm are the use of drugs, hyperkalemia, and hypoxemia. In the EKG given, there is no abnormality of AV Junctional Rhythm since the P wave is positive at lead II.

Left Axis Deviation (LAD) occurs when the QRS axis ranges between -30^o and -90^o. Normally, a QRS complex should range from -30^o and +90⁰. In LAD, a taller R wave is observed in leads I and aV_l while lead III has a deeper S wave. LAD is caused by left anterior block, left bundle branch block, and left ventricular hypertrophy. The EKG graph shows an abnormality of LAD since the S wave is deeper at lead III.

First-Degree AV Block occurs when the PR interval takes a duration of more than 0.2 s. Normally, the PR interval occurs within a range of 0.12 to 0.2 seconds. In normal circumstances, First-Degree AV block occurs in athletes who are highly trained (Barold et al., 2006). Acute rheumatic fever, ischemic heart disease, and drugs such as quinidine can lead to First-Degree AV block. In the 12 EKG graph provided, there is no abnormality of 1 degree AV Block since the duration of the PR interval is normal.

Mobitz type I AV block occurs when the PR interval is increasing progressively up to when the QRS complex is lost since there is no more action potential. When the AV junction recovers, the pattern of PR taking a longer period is repeated (Akinseye et al., 2015).  This condition mostly occurs in athletes who are highly trained. Moreover, drugs such as calcium channel blockers and ischemic heart disease lead to Mobitz type I AV block. In the 12 lead EKG given, there is no abnormality of Mobitz type I AV block since the PR interval is taking a normal pattern.

In LBBB, there is right to left depolarization of the septum. In V₁, the R wave is lost while in V₆, Q wave is lost (Pizzo et al., 2005). The QRS complex also takes longer than 0.1 seconds. The QS wave has a notch that corresponds to W at V₁. LBBB results from coronary artery disease, valvular lesions, and heart diseases. From the EKG graph, there is no abnormality of LBBB since the QRS complex is taking less than 0.1 seconds, and the R wave is not lost at V₆.

1. Tachyarrhythmias

In Tachyarrhythmias, the heart rates have an elevated rhythm that goes beyond 100 bpm.

Premature Atrial Contraction (PAC) occurs when beats originate from the left or right atrium. Before a sinus rhythm occurs, there is a pause and a premature beat. The PR interval takes a different shape, and the T wave is invisible (Hashimoto, Yamauchi, & Inoue, 2015). PAC is linked to emotional stress, heart disease, and drugs such as theophylline and isoproterenol. In the 12 EKG graph, PAC can be ruled in due to the appearance of the P wave with a different shape and the invisibility of the T wave.

Atrial Fibrillation (AF) occurs when the heartbeat falls between 400 to 600 bpm (Hashimoto, Yamauchi, & Inoue, 2015). AF leads to an irregular pattern of F waves in the EKG diagram. Since the AV junction is stimulated randomly, the ventricles are depolarized irregularly. Excessive alcohol intake, hypertension, and ischemic heart disease are all attributed to AF. In the EKG diagram given, the F waves have a regular pattern indicating a normal heartbeat; hence there is no AF abnormality.

Premature Ventricular Contractions (PVCs) occurs prior to the expected time of the next heartbeat. The QRS appear larger and takes more than 0.12 seconds. The occurrence of PVCs varies with the frequency of the heartbeats. Heart diseases and anxiety are common causes of PVCs. In the EKG graph, there is no abnormality of PVCs since the heart beats have a regular pattern.

Ventricular Tachycardia (VT) occurs when Ventricular Ectopic (VEs) occurs consecutively more than three times. The QRS complex takes more than 0.12 seconds. The heart rate also falls within 100 to 200 bpm. Heart diseases, excessive use of caffeine, and drugs cause VT. In the EKG graph, VT is ruled out since there is no irregular pattern. The QRS wave is also normal and takes a duration of less than 0.11s.

Ventricular Fibrillation (VF) happens when the ventricles move in a disorganized pattern. VF is a risky condition that leads to loss of blood pressure and cardiac output (Rea et al., 2006). The QRS complex is prolonged, P waves take a different shape, and there is an irregular pattern in the heart beats. In the EKG graph, there is no VF abnormality since the heart beats take a normal pattern.

1. Atrial/Ventricular Enlargement

Right Ventricular Hypertrophy (RVH) occurs when there is a deviation of the axis to the right. There is also an alteration of the electrical activities in the left ventricle (Puchalski et al., 2006). Between V₁ and V₃, there is an inversion of the T-wave, and a taller R wave at lead V₁. Some of the causes of RVH are mitral stenosis and heart diseases such as septal defect. In the 12 lead EKG, there is no abnormality of ventricular enlargement since the R wave have a normal height at V1. The QRS complex also takes a normal shape and a duration of less than 0.11s.

Left Ventricular Hypertrophy (LVH) occurs when there is a deviation of the axis to the left and an increase in the electrical activity of the left ventricle. The QRS complex widens, the R waves becomes taller and there is an inversion of the T wave. Some of the causes of LVH are cardiomyopathy, valvular heart disease and hypertension (Mitsnefes et al., 2010). In the EKG graph, there is no abnormality of LVH since the QRS takes a normal duration and the R wave’s height are also normal.

1. Coronary-related/Ischemia, MI

Impaired blood flow resulting from cardiovascular disease leads to myocardial ischemia that evolves to myocardial infarction (MI). A demand of oxygen that exceeds its supply causes myocardial ischemia.

Subendocardial Ischemia leads to depression of ST segment which is elevated at aV_R. Stress and exercises are linked to the high oxygen demands leading to subendocardial ischemia (Whyte, & Sharma, 2010). This condition leads to signs such as shortness of breath and neck and chest pains. In the EKG graph, subendocardial ischemia can be ruled out since the ST segment is not depressed.

Acute Anterior MI occurs when there is no blood supply to the anterior myocardial tissues. The ST segment at leads II, III and aV_f is depressed. Additionally, there is an elevation of ST segment at V₃ and V₄. In the EKG graph, acute anterior MI can be ruled out since ST segments are not elevated.

Hypertrophic Cardiomyopathy (HCM) is an inherited abnormality in the protein’s code that leads to the heart’s contraction. T waves have an inversion appearance at V₄ to V₆ (Maron, & Maron, 2013). In the EKG, the HCM abnormality can be ruled out since the T waves at V₄ to V₆ is not inversed.

Hypokalemia results from changes in the concentration of calcium and potassium in the serum. The ST-segment is depressed and the QT interval takes a longer duration (Whyte, & Sharma, 2010). Additionally, hypokalemia leads to a narrow and peaking T wave and the QRS is prolonged. In the EKG graph, hypokalemia can be ruled out since the QRS complex takes a normal shape and the T waves are not peaking.

Long QT Syndrome results from changes in ion channelopathies which affects the concentration of calcium and potassium (Whyte, & Sharma, 2010). This affects the electrical activities that occur in the myocardial cells. Long QT syndrome is a risky condition that can lead to death. The R waves are taller and the QRS complex takes less duration. In the EKG graph, long QT syndrome can be ruled out since the QRS has a normal duration of less than 0.11s.

5.

The mean QRS axis falls within Quadrant 1 hence has normal heart beats.

References

Akinseye, O. A., Alfishawy, M., Radparvar, F., & Bakshi, S. (2015). Trazodone and omeprazole interaction causing frequent second-degree mobitz type 1 atrioventricular (AV) block (Wenckebach Phenomenon) and syncope: a case report and literature review. The American journal of case reports, 16, 319.

Barold, S. S., Ilercil, A., Leonelli, F., & Herweg, B. (2006). First-degree atrioventricular block. Journal of Interventional Cardiac Electrophysiology, 17(2), 139-152.

Hashimoto, M., Yamauchi, A., & Inoue, S. (2015). Premature atrial contraction as a predictor of postoperative atrial fibrillation. Asian Cardiovascular and Thoracic Annals, 23(2), 153-156.

Maron, B. J., & Maron, M. S. (2013). Hypertrophic cardiomyopathy. The Lancet, 381(9862), 242-255.

Mitsnefes, M., Flynn, J., Cohn, S., Samuels, J., Blydt-Hansen, T., Saland, J., & CKiD Study Group. (2010). Masked hypertension associates with left ventricular hypertrophy in children with CKD. Journal of the American Society of Nephrology, 21(1), 137-144.

Pizzo, V. R. P., Beer, I., De Cleva, R., & Zilberstein, B. (2005). Intermittent left bundle branch block (LBBB) as a clinical manifestation of myocardial contusion after blunt chest trauma. Emergency medicine journal, 22(4), 300-301.

Puchalski, M. D., Lozier, J. S., Bradley, D. J., Minich, L. L., & Tani, L. Y. (2006). Electrocardiography in the diagnosis of right ventricular hypertrophy in children. Pediatrics, 118(3), 1052-1055.

Rea, T. D., Helbock, M., Perry, S., Garcia, M., Cloyd, D., Becker, L., & Eisenberg, M. (2006). Increasing use of cardiopulmonary resuscitation during out-of-hospital ventricular fibrillation arrest. Circulation, 114(25), 2760-2765.

Whyte, G., & Sharma, S. (2010). Practical ECG for Exercise Science and Sports Medicine. Human Kinetics.