Edward Pullen, MD

This article originally appeared online at 

Paroxysmal Supraventricular Ventricular Tachycardia, or PSVT, is a common medical condition in which sudden paroxysms or attacks of very rapid heart rate seem to arise out of nowhere. They can be brief, just a few seconds or a minute or two, or can last hours and lead to circulatory compromise. PSVT is also one of the cardiac conditions where over the last few decades researchers have made tremendous progress in diagnosis, treatment, and even cure of the condition.

When everything is working normally in our heart, each heartbeat is triggered by the sinoatrial node in the right atrium. This node starts causing heart muscle fibers in the heart to depolarize, an amazing electrical/chemical reaction that rapidly spreads to all adjacent heart muscle cells. Special heart muscle cells called Purkinje cells, that connect to form Purkinje fibers, are able to incredible quickly transmit this depolarization from cell to cell and through the atria until they reach the atrioventricular node (AV node) where after a momentary pause, the depolarization races through bundles of Purkinje fibers in the ventricles called bundle branches out to the ventricular heart muscle. In the perfectly formed heart there is a fibrous tissue that separates the atria and the ventricles so that the depolarization of heart muscles can only pass from the atria to the ventricles through the AV node.

In most patients with PSVT there is an aberrant group of muscle cells that goes through this connective tissue separator allowing the depolarization to get from the atria to the ventricles, or backwards, other than through the AV node. When this is present sometimes a circular movement of the depolarization can occur, leading to a very rapid heart rate. This very rapid heart rate, often at rates as high as 190-200 beats/ minute, is called PSVT.

 that shows a specific abnormality where the PR interval is very short and there is a “slur” on the QRS wave. This specific type of PSVT is called Wolfe-Parkinson-White syndrome.

Treatment of PSVT can be with medications to slow the ability of the heart to beat, and make PSVT less rapid and so better tolerated. The biggest breakthroughs though in PSVT management have been the ability to use cardiac catheters along with tiny instruments to map the conducting ability of the heart and find the aberrant tissue that connects the atria to the ventricles. If this can be located the cardiologist can then destroy the aberrant fibers usually using thermal probes and so effectively cure PSVT. In patients with frequent, prolonged, or very rapid PSVT this has revolutionized therapy, and been life-changing and at times lifesaving therapy.

Experienced cardiology electophysiologists have 

rates of success with PSVT ablation of 95% or higher

. It has become a standard of therapy for many patients where PSVT is not easily controlled medically. Newer cryoablation procedures are being developed to allow treatment of the few PSVT patients who cannot have radiofrequency ablation. The cryotherapy procedures allow treatment of aberrant pathways in areas too close to key structures like the AV node to treat with radiofrequency.

Ed Pullen, MD, is a board-certified family physician practicing in Puyallup, WA. He blogs at 

DrPullen.com — A Medical Bog for the Informed Patient

Articles

Dr. Pullen discusses the clinical characteristics of PSVT, the tests used to diagnose this condition, and new treatment methods.

Breakthroughs in Understanding PSVT Lead to New Treatments

As a family physician essential hypertension is the most common chronic health problem seen in the office. Most patients with hypertension have essential hypertension, meaning they just have high blood pressure without another underlying identifiable medical problem causing the hypertension. It’s estimated that 5-10% of adults with hypertension have secondary hypertension. This means that they have a medical condition that is causing their blood pressure to be high. In catching up with my 

 reading I found a very good review article in the Dec. 15, 2010 issue by Viera and Neutze titled, “

Diagnosis of Secondary Hypertension: An Age-Based Approach

About one third of US adults have hypertension. If the above stats are correct then about 1.6-3.2% of adult Americans have secondary hypertension. The trick is to figure out who these patients are, make their diagnosis and make appropriate interventions to treat their underlying cause of hypertension. That’s no small task. The authors suggest taking an age related approach to index of suspicion and evaluation. This is nothing new, but I did learn a few things that I want to share.

In children under age 12 with hypertension it’s estimated that over half, maybe up to 85% of hypertension is from a secondary cause. Therefore all children with hypertension need a careful evaluation for underlying causes. By far the most common underlying cause in children is renal parenchymal disease, often caused by glomerulonephritis, congenital problems, and 

. In children and very young adults evaluation for these problems should consist of a BUN, creatinine, urine analysis and culture, and renal imaging with ultrasonography. The other common cause to consider is 

, usually able to be diagnosed in children if it is considered by transthoracic ultrasonography in combination with physical findings of hypertension and usually a systolic murmur. In adults a chest x-ray can show classic findings and often an MRI is used to confirm the diagnosis.

In young adults with hypertension, only about 5% of hypertension is secondary hypertension. Especially in women, 

renal artery stenosis from fibromuscular dysplasia

 is the most common cause of secondary hypertension. Sometimes a high-pitched holosystolic renal artery bruit can be heard. Diagnosis is usually made with an MRI with gadolinium contrast or with CT angiography.

In adults age 40-64 about 10% of patients have secondary hypertension. I was surprised to learn that this is the most common cause of secondary hypertension in this age group, being the cause of up to 6% of hypertension. I also was surprised to learn that only 30% of patients with hyperaldosteronism can be found by lab screening of potassium prior to treatment (low in primary hyperaldosteronism). The best initial screening test is an aldosterone/renin ratio done in the upright position at least 2 hours after waking. A ratio of above 20 (aldosterone in ng/dl and renin in ng/ml) along with an aldosterone level above 15 ng/dl is suggestive of hyperaldosteronism, and needs endocrinologic confirmation with one of the salt suppression tests.

Sleep apnea needs to be considered in all age groups with hypertension, especially refractory hypertension, as does alcoholism and illicit drug use.

The secondary cause of hypertension physicians seem to have the highest index of suspicion for, pheochromocytoma, is relatively rare, causing only about 1/200 cases of secondary hypertension, or about one in 2-4000 cases of hypertension.

When hypertension starts after age 65, the chances of secondary hypertension again go up to about 17%, most caused by renal artery stenosis from atherosclerosis. Clues to look for this are known atherosclerosis elsewhere, age over 50, rapid deterioration of renal function as measured by a rise of >0.5 in serum creatinine after starting an ACE or ARB drug, or unexplained renal insufficiency.

The other common cause of secondary hypertension in older adults is renal insufficiency from any of many causes.

So in summary things I learned or relearned from this nice review are:

		In kids who are less than 12 years old, most hypertension is secondary and from renal parenchymal disease

		In middle age adults, screen for hyperaldosteronism with a aldosterone/renin ratio

		In older adults, think about renal artery stenosis from atherosclerosis

		Always consider sleep apnea if hypertension is tough to control

Let’s all bear down and do better with hypertension. As a nation we do very poorly, with 

up to 30% of hypertensive patients undiagnosed and over 50% sub-optimally controlled

Dr. Pullen discusses the diagnosis of various forms of hypertension, the most common chronic health problem seen by many family physicians.

A Review of the Causes of Secondary Hypertension

, the pitcher traded from my local MBL team the Seattle Mariners to the Chicago Cubs last winter, who had to leave a game with what is reported to be 

. This type of very rapid heart rate comes intermittently in paroxysms, therefore the common name Paroxysmal Supraventricular Tachycardia (PSVT). In the normal heart the electrical conduction of the heart travels through the atria, pauses momentarily at the tiny bundle of tissue called the 

, and then travels through the specialized conduction system of the ventricles to cause the ventricles to contract. In the normal heart this AV node is the only place that has tissue able to conduct the electrical signal from the atria to the ventricles. In patients with PSVT there is usually an abnormal area of heart muscle fibers through the fibrous separation of the atria from the ventricles. This allows the electrical impulse of the heart to race in a circuit from the atria to the ventricle then back to the atria and to the ventricle leading to paroxysms of very rapid heart rate. The heart rate in this condition can get to over 200 beats per minute in young healthy people, and can be very uncomfortable, at times going so fast that there is not enough time for the heart to fill well with blood between heartbeats and leading to reduced circulation. The rapid heart rate in older patients with a degree of coronary artery blockage can lead to ischemia of the heart muscle, with angina and even a myocardial infarction. Non-surgical treatment for PSVT includes use of medications to slow the maximum heart rate like beta-blockers or calcium channel blockers. Procedures like carotid massage and holding oneâ€™s breath and bearing down (

, which slows heart rate have been used to interrupt paroxysms for years. More recently use of IV adenosine has been used in emergency room settings very successfully to convert PSVT to a normal rhythm

Carlos Silva had a fairly new surgical treatment for PSVT called 

 is done, the abnormal segment of conducting tissue is located by a procedure called endocardial mapping, and the ablation is done through the catheter to destroy the abnormal myocardial cells and prevent the circuit rhythm from occurring. This procedure has a high success rate and is well tolerated in most patients.

Silva may be able to return to baseball in a very short period of time if the procedure goes as well as it often does. Even if the procedure is not completely successful most patients with PSVT have fairly infrequent episodes, and full recovery from a cardiac catheterization is usually quick. I predict Silva is back on the mound before Sept 1.

DrPullen.com â€“ A Medical Bog for the Informed Patient

Chicago Cubs pitcher underwent radiofrequency ablation to treat paroxysmal supraventricular tachycardia.

Carlos Silva and Endocardial Ablation for PSVT

	As our US Military personnel face not only harm’s way in Afghanistan and Iraq, but repeated tours of duty, their families -- dependents in military jargon -- also face the difficulty of separation and anxiety and depression. Effective just hours ago, through 

TriWest, the Western US region of TriCare

, the government provided health plan for eligible military dependents, has opened secure online and telephone counseling services for dependents. This can be accessed confidentially and without cost to eligible military dependents. The new 

 offers a live-chat line by phone or instant messaging with professional counselors called the 

, with the acronym TRIAP, much like many private EAP (employee assistance programs) for confidential immediate access to help. It even offers video conferencing with professional behavioral health providers in a program called 

TriWest Tele-behavioral Health Care Network

 for those who prefer a visual aspect to their on-line counseling. For those more interested in just finding on-line resources in a library format, they have a virtual library of resources called 

	This is good news for military dependents in the TriWest region. Look for similar programs in other TriCare regions also. There is increasing concern about the suicide rates among active duty personnel in Iraq and Afghanistan. In 2009, for the first time, the suicide rate among active duty males was higher than in age-matched civilians. In 2009 through late November more active duty personnel died of suicide than were killed in either Afghanistan or Iraq (at least 234 suicides vs. 297 killed in Afghanistan and 144 killed in Iraq). Numbers are not available for civilian dependents of active duty personnel, but this has to be a concern for them also.

	If you know of any military dependents who may benefit from these services please forward this article to them, or let them know of this newly available service. Our armed forces members and their families face tremendous stresses as the deployments happen over and over again. They deserve the best we can offer, and this seems to be a step in the right direction.

Edward Pullen, MD, is a board-certified family physician practicing in Puyallup, WA. He blogs at 

TriCare, the government-provided health plan for eligible military dependents now offers secure online and telephone counseling services.